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2ct23y | why does iran, india, and australia have 1/2 hour time zone increments? | Looking at a world map of time zones, it seems like the half hour timezone increment isn't needed. But they exist. Why? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2ct23y/eli5_why_does_iran_india_and_australia_have_12/ | {
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"This is because they chose to do so. The main reason is to keep in a more precise sync with the mean solar time.",
"This isn't an explanation but newfoundland Canada also has a half hour time zone",
"/u/davinci9 provided a great explanation for India, but for another odd time zone example, Nepal has a time zone of UTC +5:45 (5 hours and 45 minutes ahead of UTC).",
"Because Australia is big enough to warrant three timezones, yet the population of the middle time zone isn't actually right in the middle. I live in Adelaide, which is +9:30GMT and is 1.5 hours ahead of Western Australia (which is in-line with China) and half an hour behind the eastern states. \n\nAdelaide is about a 9 hour drive from Melbourne, an eastern city, yet the distance to drive from Adelaide to Perth is three times as far. Because we are closer to the eastern states it makes sense to have us only half an hour behind rather than the full hour."
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bu042r | why is the dark side of the moon not black or shadow like as opposed to the transparent look it gives off during the day? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/bu042r/eli5_why_is_the_dark_side_of_the_moon_not_black/ | {
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"It is, but the sky is closer to you than the Moon so when the sky is blue there's blue light coming from the direction of the Moon, which is more apparent when there isn't strong light coming off the Moon itself. \n\nHere I'm assuming you're using \"dark side of the Moon\" to refer to the part of the Moon visible from Earth but not currently lit by the Sun, rather than the side of the Moon that's not visible from Earth.",
"The reason you can see the dark side of the moon is [Earthshine](_URL_0_). Sunlight hits the Earth, some of which gets reflected off, which hits the moon and then gets reflected back to the Earth.\n\nAnd just in case it's not obvious, the moon is not transparent during the day. The atmosphere is in front of the moon, so the blue light it scatters obscures anything less bright than it.",
"The side of the moon you see at day isn't the dark side of the Moon, it's the \"bright\" side.\n\nThe Moon is tidally locked with the Earth. It means that each times it does a full revolution around the Earth, it does a full revolution around itself. See it this way : turn around a tree somewhere. But carefully keep your eyes on the tree when you do it. You're body turns on itself (aka, your foot are not always pointed toward the same direction), and you'll find that you make a whole turn each time you complete a revolution around the tree. That is what the Moon does. No matter which part of the day, or night, no matter where you are on Earth, the Moon ALWAYS shows you its face. Not his back. \nThat's why the other side is the \"Dark Side\". Not because it's dark (it ain't, it's the same colour), not because it's in the dark (it ain't, it receives light from the same the same way the \"bright\" side does), but because we can't see it."
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10daps | Why do neodymium magnets slow down when they fall through a copper tube? | Example here _URL_0_
I'm assuming that the video isn't slowed down or anything.
| askscience | http://www.reddit.com/r/askscience/comments/10daps/why_do_neodymium_magnets_slow_down_when_they_fall/ | {
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"This phenomenon is not special to neodymium magnets, but occurs with any magnetis, although the stronger the magnet, the more obvious the effect.\n\nWhat's at play is Faraday's Law of Electromagnetic Induction, including Lenz's Law. As the flux of magnetic field through a cross section of the tube changes, a voltage is induced in that cross sectional loop, which in turn causes a current to go around such a loop, since copper is a conductor.\n\nA current loop, in turn, produces its own magnetic field. Thanks to Lenz's Law, we know that current will flow in such a direction as to try to oppose the change in magnetic flux that created that current in the first place.\n\nIn other words, for the part of the tube below the magnet, the electric current flowing is creating a magnetic field that pushes back up on the magnet; for the part of the tube above the magnet, the electric current flowing is creating a magnetic field that pulls back on the magnet.\n\nThus, the magnet falls more slowly than anticipated. If you had a tube of wood instead of copper, there would be no current induced (wood is not a conductor), and the magnets would just exhibit typical freefall behavior. ",
"This does the same thing with aluminum. Is it for the same reasons?"
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akekrx | How did lower castes live in the feudal Japan shogun era (12-17ct)? | [deleted] | AskHistorians | https://www.reddit.com/r/AskHistorians/comments/akekrx/how_did_lower_castes_live_in_the_feudal_japan/ | {
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"# Foreword\n\nThese are all really fascinating questions! The lives of peasants is often overshadowed when looking into the history of Japan, which is often focused on through the frame of ‘samurai history’. Despite this, it is a topic which is very complex, and is very connected with other aspects of Japanese history. Before starting, I think it is important to note the huge scope that is called upon by some of the questions you have brought up. The 12th-17th century is a vast amount of time, spanning (and not exclusively) 3 different shogunates (Kamakura 1180s-1330s, Muromachi 1330s-1570s, and Edo bakufu 1600s-1860s). The condition of peasants varie heavily throughout this time, as well as throughout different regions of Japan in any given time. As a result the answers to the different questions you ask are dependent on several changing factors. As a result, I will try to give a overview of the history and of peasants in the different periods, and along the way will touch on different questions you have proposed.Before diving into the topic directly, it will be helpful to go through some different conditions and phenomenons that had major impact on the lives of peasants throughout the different periods. I will focus on two underlying societal shifts that occurred in the periods:\n\n1.) The economical / administrative systems which were present, the shift being from the shōen system of Kamakura, which deteriorates during the Muromachi, and is replaced (in some regions) with the kandaka system implemented by many Sengoku daimyō, and finally the kokudaka system started by Hideyoshi, and used during the Edo period.\n\n2.)The way in which society was organized, the shift being from centering around the shōen estates, to that of the villages (and sōsons (village communes)).\n\nThese different systems and conditions were currents which in many ways drove the lives of peasants throughout the periods. As stated by Nagahara Keiji in *The Cambridge History of Japan Vol. 3*, “The life of the peasants was defined by the continuities and changes in the authority systems of the medieval period.” (\\[1\\] pg. 303) It is because of this, that it is important to keep in mind these various shifting conditions, and they will be touched upon throughout the response."
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1nei28 | Does wind have the same effect on light that it does sound? Why or why not? | We've all heard that wind can interfere with and even direct sound waves, but if all that's true then why wouldn't wind affect light? "Light is both a particle and a wave." Okay, well we KNOW that wind can carry particles . . . And if wind can carry a sound wave, why not a 'light wave'?
Forgive me if this a stupid question... | askscience | http://www.reddit.com/r/askscience/comments/1nei28/does_wind_have_the_same_effect_on_light_that_it/ | {
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"The main difference is that the gas particles carry sound waves, while light is a propagating electromagnetic wave that travels *through* the medium, and not *by* the medium.\n\nThe only way that there would be a visible effect by wind would be if it somehow changed the refraction of the air, like in a [mirage](_URL_0_), but my guess is that wind acts to homogenize the air, so there shouldn't be any noticeable effect.",
"so the mistake you are basically making is thinking that by 'a particle' the person means is like a ball that you can pick up and throw around. \n\nwhat they in fact mean when referencing wave/particle duality is that it doesnt follow the rules of the macroscopic world. \n\nwhen you look around yourself in the 'real' world things act in basically 1 of 2 ways, either like a particle or a wave. the best way most people can understand the difference here is when a ball or a brick, or a t shirt passes through a gap, it just keeps on going. but when a wave of water passes through a gap it makes a new [wave pattern that looks pretty cool](_URL_0_)\n\nbut when we look at things on the very small scale, electrons and photons and similar, their behaviour doesnt fit either of those 2 categories. depending on the situation they sometimes 'act' like particles, and sometimes like waves. so the shorthand way of saying that is wave-particle duality.\n\nso getting back to your question, you are expecting light to act like pollen or dust in the wind, to be knocked about, but that isnt the case, light is not a particle in the classical sense and understanding. now as /u/xenneract explained above there could possibly be some measurable interaction because lights travel is not instant, but i dont think thats really what you were getting at."
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3k9abx | how does compulsory school works in usa? (details inside) | I heard that school is compulsory in US, can you tell me how would it work in following case?
Let's say there is a 12 year old 'stubborn' kid who doesn't like to go to school. Even though his parents force him to go to school, he literally would sit in his house all day.
Will the police daily come to house, handcuff him, escort him to school daily ?
How else would they enforce compulsory school and truancy laws? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/3k9abx/eli5_how_does_compulsory_school_works_in_usa/ | {
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"Well in the case of an extremely problematic child it's a bit case-by-case, but something would be done, yes.\n\nThe legal obligation is more to force parents to force kids than to force kids. A parent refusing to provide education for their child has a big legal issue on their hands.\n\nIt's not just the USA, either.",
"Typically the parent of the child is fined for the child's truancy. Where I live it's like $200 for the first case of not going for like 10 days and the fines go up as time passes.\n\n(The average rent for an apartment is about $800, to kinda compare)\n\nIf the child has a legit reason (medical or otherwise) to not attend then the truancy is dismissed."
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86v9bk | how do big supermarket chains decide on what needs to be ordered and put on the shelf? | I work at a very small grocery store stocking shelves. 3 times a week we get a very large delivery from the supplier's warehouse, that we then break down by aisle and put it out on the shelf. We only have 9 aisles in the entire store, so the day before we get our delivery the store owner walks up and down the aisles and decides what we need to order for the next delivery. Do large stores like Target or Walmart do their ordering by hand or is there like some kind of computer program that decides what needs to be ordered? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/86v9bk/eli5_how_do_big_supermarket_chains_decide_on_what/ | {
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"Supply chain management. Their system knows how many of each item they order, what days they sell the most product, when items are running low, etc. ",
"At least the larger stores I've worked at had an IT system that showed exactly how many of an item you had in store, and when it was checked at the checkout counter it would subtract one from that number, and then people were hired to figure out how many of the items people bought per day, to figure out how low the stock could go before they had to order new stock.",
"It's both. Source: worked at a large chain petstore, and the logic is similar.\n\nBig box stores have something that will be called something along the lines of \"automatic replenishment.\" Some items will be ordered in set amounts every period - whether it's once a week, twice a week, etc. Others will get a specific amount ordered. Either way, when it comes in, you have an invoice for everything you ordered, and an invoice for what they sent you. Whatever the invoice says you got, a manager puts it into their POS (point of sale) database. When something is sold, the POS tells that to the database, so the inventory is tracked. \n\nEvery item has an \"order more of this\" amount, so that you order, say, 10 more when you have 2 left, so you never actually *run out*. Running out of items is bad for sales! After years and years of tracking sales data, the company generally knows how quickly stuff is sold, so they know that for that item, it'll take X number of days to sell the last Y number of items on the shelf. So if you put in your order two days before it will arrive, and you sell one item, on average, per day, then buy more when you have two left. Or more likely, three. That also means they *generally* know how much of that item they need to order. You don't want to order too much, or it'll sit around not selling and taking up space. Worse, if it's perishable it'll go bad.\n\nBut inventory is **never** perfect. There is always shrink, and less likely, swell. Shrink is whenever your actual inventory on the shelf is less than what your database says you should have. Swell is the opposite. Shrink happens for a lot of reasons. Theft is the obvious one, especially for big box stores like Walmart. Other causes might include getting damaged or returned and not reshelved, getting used for something in the store without that being written down, or even just rolling under a shelf when no one is looking and getting lost there. Occasionally the supplier makes a similar mistake or something gets miscounted and they send you too few items. That can also be a cause of swell, if they send too many; or if you fix inventory and then find an item hiding behind something on a different shelf.\n\nSome of that can be mitigated through careful records. Items written off for store use should be pulled out of inventory promptly by management. Perishable items after their sell-by date should be removed from inventory. All of that is handled manually, usually by management. *Most* of it can be accounted for as the person sees it happen.\n\nMost big stores, though, have days (or rather, usually nights, after closing) where parts of the store are counted, by hand. Presumably, this would happen at *least* once per quarter, but it depends on the needs and costs of the business. If it costs more to pay people to count your stuff than you lose because of missing items, maybe don't inventory your store quite as much. Since most big stores have different departments, each department head will be responsible for checking and adjusting the real inventory in the store according to the schedule. That manual adjustment changes the ordering levels. If you always order stuff when you have 2 left, and you didn't order more because the computer said you had 4, but hey, look, you really only had 2, then ordering automatically is going to get back on track.\n\nOf course, ordering sometimes has to be done manually, too. It's the department manager's job, or the relevant inventory type manager's job, to notice when stuff needs to be ordered and make sure it happens. The manager might notice, for example, that a particular item *usually* shows up every week on the truck, but last week it didn't get ordered. Better go count them, because the computer might *think* there are some on the shelf when there aren't any. If there aren't any to buy, the POS will never tell your inventory database to remove enough from inventory to trigger automatic replenishment. Or maybe the manager notices that one item is selling out rapidly for whatever reason and the automatic replenishment amount isn't enough, so it needs to be adjusted higher. Say, there was a cute gif of a bearded dragon that went viral and suddenly everyone is buying them, so maybe order 12 this week instead of 6.\n\nFinally, if the CEO of the company isn't dumb, they'll have a periodic, probably once or twice per year, third-party inventory. That means paying a separate company to come through and not just count, but scan every. single. item. in the store. No errors, no casual \"I saw six cans of this cat food but I didn't check to see if a customer left a can behind the bird seed.\" Every shelf is scoured, every item accounted for, and it's handled by another company so managers can't fudge the numbers if they're doing something shady. It's a hassle, but it resets the inventory for *everything*, so you *know* moving from that day on that if inventory says you have one more than you see on the shelf, that one went missing, it wasn't just someone putting it in the computer wrong or whatever.\n\n**TL;DR:** One or more managers will have, as part of their duty, counting stuff and making sure that enough of the necessary items are ordered to keep inventory at appropriate levels. However, at big retail stores that would take too many man-hours to do every single item by hand, so the computers keep track of what comes in and what gets sold so most of it is done automatically."
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4hmmmv | why can't newer software run on a slightly older version of the os? and vice versa? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/4hmmmv/eli5_why_cant_newer_software_run_on_a_slightly/ | {
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"Certain system level functionality is introduced with OS updates and the newer software relies on that.\n\nAlso frequently old ways of doing things are removed or changed which frequently means software designed for older OS's are no longer compatible.\n\nFor example, the file system might change the way files are stored on a given OS. This would dramatically break any compatibility between the OS's.",
"**TL;DR: because stuff it needs ain't there.**\n\nMyOS version 2.1 adds a new function called \"make_screen_wiggle(X)\" that MyOS version 2.0 didn't have. This new function makes the screen wiggle for X-100^ths of a second. This replaces the older function \"make_screen_bump(X)\".\n\nKing, the company that specializes in polluting Facebook with annoying \"I got this score in a game! Come play with me!\" messages, sees this and says \"Holy cow, we really need this for Candy Crush Mobile when you pop an explosive candy! Write that sucker in! Devs, get rid of the old stupid screen bump and make that puppy twerk like Miley Cyrus after ten cups of coffee!\" \n\nSo the new release of Candy Crush calls that function when the explosive candy is clicked and the screen wiggles.\n\nSomeone on MyOS version 2.0 downloads new-version Candy Crush, and it tries to run. They see an explosive candy and click it. It tries to call function make_screen_wiggle(50)... but the function isn't present in that older version of the OS, so Candy Crush Crashes.\n\nMeanwhile someone on MyOS version 2.1 downloads an older version of Candy Crush from a buffered website somewhere that still references the removed make_screen_bump(X) function. It tries to run. They see that explosive candy and click it... and it tries to call the obsolete function make_screen_bump(X). This crashes the app and causes their mobile phone to burst into flames. They drop it in surprise, it falls down into a sewer grate where there is a mild propane leak and the whole city block goes up in a massive explosion, taking out the convenience store's entire candy section and earning a massively high score.\n\n-- > edit: added context for \"vice versa\""
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3xr4ge | What was the relationship like between people on both sides of the American Civil War, after the war was over? | Mainly I'm curious how people, both former soldiers and civilians saw the 'other side', after the war was over and the confederate states lost. Was there a desire to 'forgive and forget'? Were the losing states and their inhabitants seen as less than the people on the winning side? What were the attitudes of people on either side towards people on the other side, both shortly after the war as well as say, 15-20 years later? | AskHistorians | https://www.reddit.com/r/AskHistorians/comments/3xr4ge/what_was_the_relationship_like_between_people_on/ | {
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"This seems as though it could be a survey question ..\"I still hate Yankees...strongly agree, somewhat agree, don't have an opinion, strongly disagree...\". Not sure how it could be answered.\n\n But there's one good example of them getting along afterwards. Virginian Alexander Boteler was very briefly Speaker of the House, making a futile \"can't we just get along\" speech just before the war broke out. He joined Lee's staff as an officer, and as a result had his farm torched, along with many others in the Shenandoah Valley, by Union General Hunter. Then there was a Confederate response in the burning of Chambersburg, PA. One of the Union soldiers from that area , who must have known people who'd lost property, was a man named George Beltzhoover, who became a lawyer. He and Boteler ended up living in Boteler's home, the same town of Shepherdstown,WV after the war, and became very good friends- even though they'd both ample reason to dislike each other in principle. But this may not be typical. Boteler was quite the Reconstructed Rebel, signing the loyalty oath soon after, and becoming a Federal bureaucrat, and Beltzhoover had moved himself to a Southern town- although one that was right on the border.",
"The book, \"Lee: The Last Years\", although IMO a bit of a hagiography, claims that Robert E Lee pushed hard for reconciliation after Appomattox, because he had looked at the Confederacy's defeat as God's judgment, and was a very devout man.\n\nHe told anyone who asked him to go home, accept that the South had lost, and rebuild their homes and communities. The book further claims that because of Lee's status among Confederate veterans, theIr defeat was accepted.\n\nNote: I am not a professional historian, nor am I promoting the Lost Cause narrative. I am an amateur who is interested in the Civil War and RE Lee in particular, despite being from Vermont. If the mods think I should take this down, please delete it.",
"This is a topic of some debate to this day, but basically there was a rough trajectory in the opinion of both major sides. Right after the war ended things were very tense, with some retaliatory actions occurring in the years that followed (e.g. I study 19th century WV and we had unionists murdering confederates and vice versa in the first couple of years). There was something of an immediate move by many in the North, especially those who were lukewarm toward the war and especially toward Black civil rights to immediately forgive and to begin reintegrating Southerners into the national polity. This changed, however, when in the late 1860s White Southerners organized campaigns of racial terrorism to resubjugate freedmen. This led the Ulysses Grant administration to send armed forces into the South and use the military to enforce civil rights law. This battle led to some serious anti-Northern opinion in the South and vice versa. It's worth saying that there were always Southerners who were more open to the North, especially those that were anti-secession to begin with. And, of course, much of the South was African-American and they were generally very pro-North. But things are complicated. Harriet Beecher Stowe herself founded a school for freedmen in Florida and by the middle of the 1880s she found herself adopting anti-Black attitudes and sympathizing with Southerners. By the middle of the 1880s a reconciliation philosophy began to emerge where Northerners and Southerners alike warmed to each other and sacrificed black Civil Rights to build sectional unity. This came to full flower in the late 1890s/early 1900s when the idea that, \"they all died honorably,\" became the dominant interregional interpretation of the Civil War. If you really want to know more, you can't go wrong reading \"Race and Reunion\" by David Blight, which is my primary source for this"
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5n06cj | Roman testudo in medieval times | Why did the roman testudo, obviously being the quality choice for it's inventors when faced with projectiles, not live to see a renaissance in the middle ages when longbows made an appearance and heavy infantry kept losing strategic value, seeing as they were nothing but slow moving targets for the armorpiercing longbows? Was is because shields could not easily be built to withstand such shots? | AskHistorians | https://www.reddit.com/r/AskHistorians/comments/5n06cj/roman_testudo_in_medieval_times/ | {
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"The testudo formation was never used in pitched battles, it was a tight formation designed for use next to enemy walls during a siege. The strength of the testudo was that the interlocking shields spread out the weight of anything dropped on the formation, such as rocks or pottery. Going into testudo didn't offer much more protection against arrows than simply raising your shield above your head in standard formation, which was always done during a pitched battle in both the ancient and medieval periods. Another thing to consider is that medieval shields weren't uniform, shaped right, or big enough for testudo to be used. \n\nIn short, the testudo couldn't be used by medieval armies, and even if it could it wouldn't serve much of a purpose in most contexts."
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1pdnz4 | how are companies valued at ipo? | Facebook was valued at something like $85bn at IPO, how exactly was this figure calculated?
Thanks to /u/tides8730 for his/her answer, I also have some follow up questions: So for an IPO does the company say "I want to issue 10,000 shares"? How is the number of shares they issue calculated?
Then, to maximize revenue, why do they not tell people to bid for the shares, then simply sell the 10,000 shares to the highest bidders? Or is this what happens? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1pdnz4/eli5_how_are_companies_valued_at_ipo/ | {
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"Former investment banking analyst here\nThere are SO MANY WAYS a company can be valued for an IPO and some of it is so incredibly complicated that I wont go into the full details here but the jist of it is this:\n\nA financial model is constructed for the company. Usually this model will try to encapsulate many aspects of the company's business and the 'uniqueness' of it. They can take account of future cashflows (DCF model), what a similar company is valued at (comps/prior transaction model/multiples method), what a company's assets are worth (liquidation model) or whatever else model that works.\n\nNow unlike most companies, tech companies are very very difficult to \"value\" as many tech companies are making losses when they go to IPO which would be unthinkable in some other companies. I didn't see how facebook was modeled but I can confidently say there was a LOT of guesswork and LOTS of optimistic projections. \n\nA more \"traditional\" company (read non-tech) is much easier to model and value using the methods I described above.\n\nThe biggest thing with a valuation is what investors are willing to pay for it. The valuation must try to contain all the little various factors including the company's future possible earnings. \n\nAlso it is worth nothing that an IPO valuation is a little more stringent than a M & A or unlisted valuation. Less guesswork. You would be surprised how much guessing and hoping-and-praying there is in a financial model.\n\nRead about company valuation on investopedia or let me know if you want to know more"
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3ff8kb | how does the body repair itself? | As in with scraps, scabs, and cuts, how does the body actually place new skin or reattach separated skin? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/3ff8kb/eli5_how_does_the_body_repair_itself/ | {
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"A scab itself is just a big mass of (dead) cells that stop the bleeding (platelets) mixed with some protein. Underneath, nearby cells can communicate the fact that you've been damaged. This stimulates the cells to grow and replace the damaged, dead, and now-gone cells. Each cell near the wound basically copies itself (DNA, proteins, everything) and pops out a replica of itself. It does this over and over until the wound is fixed. Blood vessels and other damaged tissue also fixes itself similarly along with skin.\n\nScars form because the protein in skin doesn't align the same way as undamaged skin, which is why scars look different. This process also occurs in damaged organs as well, such as damaged heart muscle after a heart attack. Scar tissue/replacement cells also usually do not function as well as undamaged cells (in humans), which can cause problems later.\n\nTo wrap it all up, new skin cells break down the connection of the scab to the body, shed scab, and reveal the newly patched skin."
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1o7ec5 | If we are creating super bugs by over using and incorrectly using antibiotics, are we doing the same by cleaning our hands and disinfecting surfaces etc? | Out damn spot. Is this an issue at all? | askscience | http://www.reddit.com/r/askscience/comments/1o7ec5/if_we_are_creating_super_bugs_by_over_using_and/ | {
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"Here is one way to look at it: it's easy to kill bacteria outside your body. Animals can't evolve perfect defences to the broad range of ways they can die out in the open. \n \nIt's incredibly difficult to find ways to narrowly target foreign organisms within our body using kill mechanisms that don't interact with our own cells. \n \nIt's the difference between an invading army and terrorists inside your country. You probably don't care so much if the army knows you're watching them. But if you tip off the terrorists they could easily change their tactics and disappear.",
"None of these answers are actual answers to your question. I'll put in what I know.\n\nIt depends on what you mean by disinfect. As far as we know, bacteria cannot become resistant to things like isopropanol or iodine. However, antibiotic soap can and has created antibiotic resistant bacteria, which is why you should never use it outside of it being required for your job (mortician, meat handling, things like that).\n\nNow obviously bacteria and viruses can't become resistant to things like bleach and extreme heat. If you heat a surface so it's glowing hot, there's *nothing* on it. \n\nSo, don't use antibiotic soap or anything with antibiotics in it besides ones prescribed by your doctor and we won't have an issue.",
"Also worth keeping in mind: the use of antibiotics doesn't _literally_ create superbugs (i.e. antibiotic-resistant bacteria). Antibiotics just kill off all the normal bugs so that the few superbugs which already exist have free access to food and space, and can make lots more of themselves. Without antibiotics, the superbugs have to compete with the normal bacteria, and since there are normally a lot more normal bacteria than superbugs, the superbugs tend to get crowded out from the resources they need to reproduce.",
"A short answer is yes and no. Using antimicrobial soaps leads to microbes that are resistant to these types of cleansers. Unless you specifically need it, its better to use just a regular hand soap. \n\nAs for surface cleaners, if you don't allow them to sit wet for an appropriate amount of time, you can lead to resistant strains regenerating from the remnants, though it is more of an issue in hospitals than in your kitchen."
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ebiiu0 | in the usa government, how is it decided whether issues get decided via ballot measure rather than legislative action? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/ebiiu0/eli5_in_the_usa_government_how_is_it_decided/ | {
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"Depending on the jurisdiction, ballot measures can either come from petitions or because the legislature decides to put it up for a vote. It's often done on divisive issues that the voters care about"
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696k83 | Why do fluorescent tubes contain mercury vapour? | I understand the the mercury electrons become excited, move up and energy level and then release a UV photon which then passes on energy to the electrons of a phosphorus coating, but why can't the electrons from the voltage supply pass on their charge directly to the electrons of a phosphorus atom inside the tube which would then emit the visible light photons, removing the need for the mercury vapour? | askscience | https://www.reddit.com/r/askscience/comments/696k83/why_do_fluorescent_tubes_contain_mercury_vapour/ | {
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"The choice to use mercury vapor rather than anything else most likely comes from a few sources I can think of:\n\n- Mercury is more volatile (has a higher vapor pressure) at the pressure possible the create inside a bulb, and as such it is probably easier to maintain mercury vapor in equilibrium than say phosphorus.\n\n- As you said, light is created when a low energy electron is raised to a higher energy state, falls back down, and then releases a photon. Mercury is a relatively small atom. As such, raising that low energy electron to the higher state would take less energy than other, equally volatile, elements.\n\n- Mercury, as a pure element, is very stable and inexpensive as compared to organic or organometallic compounds which would have similar volatility and electronic properties.\n\n- Mercury releases a very stable visible wavelength of light, I around 600nm. This falls into our visible light range and is a non-offensive yellow/orange color. Additionally, light released as invisible UV emissions can then cause mercury atoms in the vapor state to fluoresce, and release more light, this time in a visible wavelength.\n\nEDIT: thanks to /u/cratedane for pointing out some important details on mercury emission and fluorescence",
"Well, you need a gas to scatter or absorb the electrons travelling through the tube, which essentially rules out phosphorus. It's also worth noting the \"phosphor\" coating isn't pure phosphorus, instead it's usually some complicated halophosphate compound with various dopants to regulate its properties.",
"Importantly, it's not a phosphorus coating, it is a phosphor coating (eg. Europium and other elements in a mixture). \n\nThese are solid elements at standard room temperature and pressure, which is why they are formed into a solid coating.\n\nMercury (liquid at room pressure) in these very low pressure tubes is effectively vapor. The electric discharge in this vapor is what makes the UV etc etc\n\nOverall, these tubes are designed this way because that's the only way people could use these materials for this goal. Phosphors used as discharge gas would have to be gaseous and not disintegrate under the heat and ionisation energies.\n\n"
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2kecob | how did escalators become so popular? aren't they a very expensive means of overcoming a simple problem? | In the shopping centres around where I live we have some that elevate people as little as 5'. I would have thought that escalators are expensive to build and maintain whereas staircases achieve the same thing and are much cheaper. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2kecob/eli5_how_did_escalators_become_so_popular_arent/ | {
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"Escalators bring old people and less-abled to malls. In case you haven't noticed, old people have all of the money.",
"For areas with large volumes of people, one slow person can stop the whole flow of traffic. These avoid that issue.",
"People already brought up accessibility issues with elderly/disabled people. On top of that, the reason people go to malls is to buy things, and its easier to ride an escalator when your hands are full of bags (or children for mothers/fathers with younguns in tow). There are also probably very significant reasons relating to the flow of foot traffic and congestion. Escalators keep traffic moving and prevent human traffic jams; if an elderly person creates a long line of people stuck behind them as they slowly walk down stairs, the shopping center is losing money, and when large crowds build up and everyone has somewhere to be, there are very real safety concerns. "
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1ku0wz | why are so many bodily fluids sticky? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1ku0wz/why_are_so_many_bodily_fluids_sticky/ | {
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"What does it really mean to \"be sticky\"?"
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j2kfl | Would the size of the Observable Universe ever change with the progress of time..with "us"..as being Earth being the observer..and progress of time measured from the Observer's point of view..and the increasingly sophisticated technology we use to view it? Or is the size.. | Or is the size..of the Observable Universe depends on the age of the Universe? Or will it always remain the same, from this current point of the Observer's time, regardless of the age of the Universe?
And is there a difference in meaning between the terms, "Observable Universe" and "Visible Universe"? Thank you! | askscience | http://www.reddit.com/r/askscience/comments/j2kfl/would_the_size_of_the_observable_universe_ever/ | {
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"The observable universe is the farthest thing away we could have ever, in principle, received a signal from. If the universe is older, then signals will have a longer time to travel, so we could receive a signal from further away. So, the observable universe gets larger as time increases."
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6py7y8 | What's it called when a gas "precipitates" out of a liquid solution? | Saying that a dissolved gas precipitates out of a liquid solution doesn't seem right. Is there a specific term for gasses coming out an over-saturated solution? | askscience | https://www.reddit.com/r/askscience/comments/6py7y8/whats_it_called_when_a_gas_precipitates_out_of_a/ | {
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"If the gas is the same substance as the liquid then it's **boiling** or **evaporating** depending on if it nucleates to form its own bubbles or just comes off the surface.\n\nIf the gas is a different composition then the bulk liquid, like it was dissolved first and is now bubbling out, then it's called **effervescence**. A liquid doing that is said to be **effervescing**.\n\nIf the gas is actually *generated* by a chemical reaction (like it didn't exist before in the liquid until just now as it's coming out) then it's said to **evolve** or **evolving**\n\nA lot chemistry texts also refer to the process as **liberating**. Like you are liberating a gas from a liquid. Although this word is more broadly used for other processes as well.\n\nInformally, the gas can also be said to be **bubbling** out. Not very precise or technical but easily understood by most. I don't find this in formal scientific writing very much but chemists don't seem to be phased if it's said in lecture or in person. \n\nAnother term is **vaporizing**. This tends to be used less in chemistry and more in the physics and engineering disciplines. Like a substance is being vaporized in a chamber or while it's being hit by a laser beam. Vaporizing tends to be context dependent and is applied broadly even to solids and other forms of matter. Like electrons in a vacuum tube are said to be vaporizing off the filaments. \n\nEDIT: Special thanks to /u/ColinDavies for adding \"evolve\" to the list."
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at1xki | what is https and what data can our ips theoretically see and realistically see? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/at1xki/eli5_what_is_https_and_what_data_can_our_ips/ | {
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"It is a secure protocol that encrypts data before sending or receiving it. This means that the ISP can see which requests you make, so which sites you visit for example, but not the content of the site (unless they access the website themselves as well). If you are accessing a private website, they can see that you are on that website, but they can't see what you are doing on there, as long as the data is sent via HTTPS.",
"HTTPS is essentially TLS, which is a way of your device communicating with another device (typically a server) in a secure manner. The way they do this is complex, but boiling it down to its essentials, the device and server each exchange their own Public Keys, and each have their own Private Keys. These are clever, because you cannot use the public key to decrypt something encrypted with the public key - you have to use the matching private key. It works something like this (Key: **S**erver, **C**lient)\n\nC > Gives server its public key \\[CPUB\\], matching private key \\[CPRIV\\].\n\nS > Gives client its public key \\[SPUB\\], matching private key \\[SPRIV\\].\n\nC > Encrypts request data with \\[SPUB\\] and sends it to the server.\n\nS > Decrypts request data with \\[SPRIV\\], and processes it in order to get response data.\n\nS > Encrypts response data with \\[CPUB\\], and send it to the client.\n\nC > Decrypts response data with \\[CPRIV\\] and displays the web page.\n\nYour ISP needs to know at a minimum what the server IP address is, so they know who to send the data to, so from that they can make an educated guess as to which website you are going to (especially if you use your router's default DNS server - if you don't know what DNS is, you probably are). However, theoretically, they cannot see the raw data you are transferring - they will just see a load of seemingly random characters instead of, say, your banking details.\n\n**Protips: If you are expecting HTTPS, look for the green padlock in the address bar. Many places, especially banks, will also have their company name next to the padlock, so you know who they are.** ***And for crying out loud, DON'T IGNORE THE WARNINGS YOUR BROWSER SCREECHES AT YOU IF YOU DON'T KNOW WHAT YOU ARE DOING!***",
"The ISP will see you are visiting _URL_0_, but HTTPS will hide the fact that you are searching for hardcore midget porn.\n\nEdit: On the other hand, if you were to use HTTP (with no S) your ISP will be able to map your dirty mind.",
"As others have already stated HTTPS is just HTTP which is used to interact with servers world wide to retrieve information and webpages but instead all the data which is sent and received is either being encrypted or decrypted from your local modem/router. \n\nISP's will have access to information related to when you are sending/receiving data and to where your connection session is issued. For example.. Your ISP will know you logged into reddit at 9:00 from your local network to the reddit servers, they will not however know the user and password which you issued to login. \n\n & #x200B;\n\nFor some heavy users sometimes ISP's although this is not acknowledged they can use tools to inspect traffic and throttle the network, this is normally done in cases such as downloading/uploading torrents or heavy use of IPTV. In that case the use of a premium reliable VPN which would encrypt the data from your local network to the ISP's network would be beneficial as the ISP would not be able to inspect your traffic and throttle streaming services in your network. In the case of the above question this would remove the ISP's ability to decrypt the location where your traffic is headed and even if this was HTTP traffic they would not be able to read the data, instead all this information will be routed through the VPN network where the VPN company will be able to identify the same information as your ISP prior to using a VPN service."
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7w5hjn | Did people fold paper into paper airplanes before the invention of the airplane? | AskHistorians | https://www.reddit.com/r/AskHistorians/comments/7w5hjn/did_people_fold_paper_into_paper_airplanes_before/ | {
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"Posting links to previous answers is not intended to discourage questions or further discussion.\n\nFrom /u/Elm11's reply the last time this was asked, you might like to see\n\n* [Did paper airplanes exist before the Wright Brothers?](_URL_0_), responses by /u/cthulhushrugged and others in the tree\n* [Did people make paper airplanes before the airplane was invented?](_URL_1_), answer by \n/u/ashkenazeeyankee, and a comment below about recreational use of paper\n",
"The answer depends on how we define a paper airplane. Let's first consider the strictest possible definition of a paper airplane: **a toy glider made *only* out of folded paper**. The technology of papermaking has its origins in East Asia, so a good place to start is examine the history of Asian paper folding. However, we run quickly run into the problem that very little research has actually been done on topic of paper folding. \n\nOne of the few detailed accounts of the history of Chinese paper folding is presented in Tsien Tsuen-hsuin's *Paper and Printing*, published in 1985 as part of Joseph Needham's seminal *Science and Civilisation in China* series. According to Tsien, the practice of paper folding (*zhezhi*) emerged in the Tang dynasty at the latest. This is based on decorative folded and cut paper flowers dated to the 9th-10th centuries, which are believed to be among the oldest surviving examples of paper folding as an artform. The paper flowers were discovered by Aurel Stein at the turn of the 20th century in Dunhuang, a city in western China, and are currently held by the [British Museum](_URL_0_). However, there are no mentions made of folded paper gliders. Tsien *does* discuss other paper toys, but we'll come to that later.\n\nThen what about paper folding in Japan? While the Japanese term *origami* has come to encompass all forms of paper folding, it may come as a surprise that research into the history of Japanese paper folding is even more lacking. Most of the research into the origins of origami comes from hobbyists and amateurs. This includes Koshiro Hatori's \"History of Origami in the East and the West before Interfusion\" published in 2011 and Isao Honda's *The World of Origami* published in 1965. Hatori traces the origins of origami to 14th century ceremonial paper folding such as *noshi* or *ocho*-*mecho*. These were used as wrappers; *noshi* derived from *noshi-awabi* containers for abalone meat and the *ocho*-*mecho* paper butterflies were meant to adorn bottles of alcohol. It doesn't take a huge leap to imagine that one of these early origami designs was capable of gliding through the air, even if accidentally, but that was not their intended purpose.\n\nWe've apparently reached dead end. So let's use a looser definition for a paper airplane: **a toy or device made of paper (but not necessarily just paper) that is capable of flight**. There are several military devices that fit this description. /u/cthulhushrugged has already discussed the *[shen huo fei ya](_URL_1_)* (\"magic-fire flying crow\"), which was a bird-shaped bomb with a body made from bamboo that was covered in paper using an adhesive. Placed under the wings of the artificial bird were arrows propelled using gunpowder.\n\nOutside of warfare, there are several pre-modern flying paper toys that are worth mentioning. Flying kites made of paper were used by the Chinese in circa 549 at the latest, when there is an account of a paper kite being used for signalling during a rescue attempt. The first mention of flying a kite as a recreational activity (and not for military or measurement purposes) comes much later in the 10th century, from a passage in the *Xun chu lu* that describes a person attaching a kite to a bamboo to produce music using moving air currents. These kites were designed with the paper covering a bamboo frame. Prior to the invention of paper, materials such as silk would have likely been used instead. There were even kites made large enough to supposedly lift a person.\n\nIn China, there are also paper lanterns that fly by heating the air inside the lantern with a candle, similar to how a hot air balloon works. The history of these flying *tian deng* lanterns is murky at best, but (non-flying) paper lanterns were popular at least by the Tang dynasty. This dating is based on a book discovered in Khotan that references paper being bought for the purpose of making lanterns.\n\nBut why limit ourselves to paper? We might as well adopt an even more flexible definition: **Any toys capable of flight.** /u/AshkenazeeYankee mentioned George Cayley, whose \"rotary waft\" experiments were inspired by the \"Chinese tops\" popular in 18th century Europe. In China, these tops were made from bamboo rather than folded paper. They were \"helicopter tops\" that would fly off after spinning their axis by hand. The origins of this toy are unknown, but the connection of the helicopter top to the Mongol prayer-wheel and Chinese zoetrope has been speculated by Needham.\n\nGoing back to our strict definition of paper airplanes—toy gliders made of folded paper—we don't *really* starting seeing literary references to these types of paper airplanes until the 19th century. /u/AshkenazeeYankee has already cited Charles Matthews' memoirs from 1860. There's also a line about a \"broker [who] cannot... innocently fling a ‘paper dart’ at a neighbour without being amerced ten dollars\" from James Knowles Medbery's *Men and Mysteries of Wall Street* from 1870. These \"paper darts\" predate the invention of airplane. However, this does not necessarily imply that there were no premodern paper airplanes that are even older; that may just be a result of the lack of research done on the history of paper folding.",
"A story in [The British Essayists](_URL_0_) published in 1803:\n\n > ...he presented himself to the wondering eyes of Euphorion with a huge black bush wig stuck full of paper darts, and as thickly spiked as the back of a porcupine.\n\n\nAnd for reference, [here is a diagram of paper darts](_URL_1_) from *[Cassell's Complete Book of Sports and Pastimes: Being a Compendium of Out-Door and In-Door Amusements](_URL_2_)*, published in 1896. They are very similar, if not identical to a paper airplane. "
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16wrt0 | Victorian Insane Asylums: What did they look like compared to now? Details. | I love victorian history, and I LOVE the history of asylums. And yet, no matter how much I read about them, I can't seem to find pictures or even descriptions of what they looked like before today. I would like to know how the housing units were separated out, if the nurses stayed with them over night, etc. I just want to know real details. Anything would be helpful. Thank you! | AskHistorians | http://www.reddit.com/r/AskHistorians/comments/16wrt0/victorian_insane_asylums_what_did_they_look_like/ | {
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"The [Royal Derwent](_URL_8_) is the oldest mental hospital in Australia. It is [situated](_URL_1_) in the town of New Norfolk, about 20 miles from Hobart, the capital of the island colony of Tasmania. \n\nFounded in military barracks in 1827, it went through several role changes throughout it's 170 year history before finally being closed in 2000. \n\nAfter starting as an invalid hospital, it was decided in the early 1830s to repurpose the complex as an insane asylum. Men and women would be housed in separate parts of the complex. The rooms were extremely basic, with shared toilets located outside in the yards.\n\nA local newspaper (the Colonial Times and Tasmanian) [editorialised](_URL_9_) thus on December 10 1857:\n\n > THERE IS perhaps no establishment belonging to the British Crown so shamefully managed as is the New Norfolk Hospital.\n\n...\n\n > As regards the insane, no\nattempt is made to cure--the patient is\nmerely imprisoned there, and many, from\nmental derangement become confirmed ma-\nniacs in consequence of the imprisonment\nand the harsh treatment. The new law\nnow allows any person to be incarcerated\nin that jail upon the certificate of one medi-\ncal man, and among medical practitioners,\nas amongst other professions, are to be\nfound corrupt men, consequently when a\nman wishes to get rid of his wife, or a wife\nto dispose of her husband, he or she has\nnothing to do but to charge madness, ob-\ntain a medical man's certificate, and close\nthe doors of the Hospital for life upon the\nunfortunate object ; for whether the person\ncharged with insanity be insane or not, re-\nlease from the prison is equally out of the\nquestion ; for there is no means of redress\n--no one to whom complaint can be made.\n\n...\n\n > As to the tyranny practised within the\nwalls by the underlings, it is truly dreadful.\nOur readers may recollect that the patient\nwho shot Deadman the keeper, gave in his\naddress to the jury a terrible picture of what\ntook place within the walls, he more parti-\ncularly alluded to the punishment of the hot\nbath and the blanket. He stated, that if a\npatient fancied himself sane, and demanded\nto be released from imprisonment, if in fact\nany offence or trouble were given, the\npunishment was a very hot bath and a\nblanket wrapped round the head. \n\nIt continues on in like fashion, detailing the case of a patient/inmate who appears to have died after this 'hot bath' treatment/torture. The public was not able to go into the hospital, and employees rarely mentioned what went on inside. I cannot find records of patients being released. It's not to say it didn't happen, but as far as I can tell, once you were admitted, you died in there.\n\nThere are a lot of terrible and horrifying stories, but most of those are from later than Victorian era, starting with the use of elecroshock therapy in the 1930s, and another spate of abuses (especially against women) in the 1970s. The site of the hospital has become something of a grim tourist attraction, with paranormal investigators claiming it has one of the highest concentrations of ghost sightings in the world. I'm not into that stuff, but I do know a lot of misery was perpetuated there upon society's most vulnerable.\n\n:-\\\n\n[This](_URL_5_) is what the building looked like after about 8 years as a (more or less regular) hospital.\n\n[This](_URL_4_) is a typical floorplan of the patient wards.\n\n[This](_URL_0_) is a staff photo from 1886. \n\nFor further reading see: \n\n* Susan Piddock *A Space of Their Own: The Archaeology of Nineteenth Century Lunatic Asylums in Britain, South Australia and Tasmania*, Adelaide, 2007. You can find the book in it's entirety [here](_URL_2_). This would be your best bet for more exhaustive detail.\n* R Gowlland, *Troubled asylum*, New Norfolk, 1981; \n* B Burkett, *Royal Derwent Hospital and Millbrook Rise Hospital*, Hobart, 1980.\n* _URL_6_ [note, this site is run by member/s of the Australian Paranormal Institute of Australia. It does contain a lot of useful data though.]\n* The guy who runs the above site has a ton of photos of the hospital on his flickr feed [here](_URL_7_).\n* _URL_3_ [this is an advocacy group, acting on behalf of many former patients held in the hospital] "
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9itzro | i always thought free healthcare was unrealistic to implement here in america due to how much it would raise taxes. then, i saw canada’s tax rates. where does that money come from and how could it be implemented in the states? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/9itzro/eli5_i_always_thought_free_healthcare_was/ | {
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"Some numbers for you. (As of 2016) The U.S. spends almost $10,000 per person on health care, presumably much of that comes straight from individuals. Canada specifically spent almost $5,000 per person on health care. On the assumption that we could copy the Canadian model on a per cost basis, we would simply increase taxes to meet the $5k and let people pocket the rest that they would have spent themselves.\n\n\nIt's basically changing the source of the money from individuals and Medicare/Medicaid and moving it into a tax. So the money is easily found because it's not an added expense, it's actually a reduction in overall expenses. ",
"Dont forget we dont have \"universal\" healthcare up here.\n\nI pay a good deal each month. Which does NOT cover a crapload of stuff (which my employer picks up)\n\nI can see a doctor and be treated by a hospital. Labwork, xrays, all that is covered.\n Prescriptions, after care, etc, none of that is covered. Something most Americans aren't aware of.",
"The USA spends as much on healthcare per capita as other nations with universal healthcare, so all we would need to do is some restructuring to cut out a bunch of the inefficiencies (ie single payer healthcare)",
"It's because the issue isn't the amount of money. the US pays more per person for healthcare than any other country on earth. It's not a matter of shovelling more money onto the dumpster fire that is American healthcare",
"The biggest problem with healthcare in the USA : Individuals cannot properly negotiate for their own life saving care. If I tell you this life-saving drug costs 7 dollars a month, you're going to pay 7 dollars a month. If I tell you the same drug costs 124 dollars a month, you will find a way to pay 124 dollars a month. [John Green has a really good video about it.](_URL_0_)",
"Most universal healthcare system are cheaper in total than the US system. Meaning that overall, Canada spend less per capita on healthcare than the US. On average the US spend twice the amount of money per capita than most other developped country. In term of % of GDP the US spend about 55% more. I think that the GDP number if more pertinent because the US have an higher GDP per capita than most developed countries (with some exception) so it seem normal that they spend more in that situation.\n\nSo the question is why the US spend about 55% more than they should, while still having so much people struggling to have an insurance? There is several reasons.\n\nSome medical specialist in the US are paid 50 to 100% more than other countries. In 2016 a physicians in the US make 218k$, compare to 86k$ in Sweden and 154k$ in Germany.\n\nThe Administrative costs is about 8% in the US, compare to 1 to 3% for most other developped countries. Personnal opinion warning for the following. ''My guest is that universal system are bigger system, so you have less entity that each require their own administrative staff so you can save there.''\n\nDrugs are famously more expansive in the US. This is simply negotiation power. A universal healthcare representing millions of people have a lot more power against pharmaceutical company when it's time to negotiate price. The US spend 1443$ per capita on drugs, compare to 749$ per capita for the average of other developped countries.\n\nEach specific services also cost more in the US. 75k$ vs 15-36k$ for a coronary artery bypass. 896$ per tomography scan in the US vs 97-500$ in other developed countries.\n\nNot everything the US does in spending is bad. For example, good salaries will attract better candidate and some countries might be not paying their professionals enough. High spending in pharmaceutics give the US 57% of glogal production of new chemical product. So it can also be view as investment in an important industry for R & D.\n\nBut no matter what are the arguments, it's difficult to justify the amount of spending by the US healthcare system. There is clearly some inefficient spending there that doesn't exist as much in other system.\n\nThere is also the problem is distribution of that spending. Basically, in Universal system, everybody receive average service. In the US the rich receive excellent service and poor people don't. Neither system is perfect, it depend on what is the priority for each country.",
"Elect politicians that are willing to budget for healthcare instead of defense. \n\nThat would almost cover it.",
"We in NZ, Australia, Canada, UK etc pay LESS in % of GDP to have full healthcare. You are being raped by predatory insurance companies and lobbyists "
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3bijw5 | how does retirement work? | Who pays your for all the years worked if you work multiple jobs? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/3bijw5/eli5_how_does_retirement_work/ | {
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"Nobody. Well, they used to, but nowadays finding employment with a guaranteed pension plan (what you are referring to) is not that easy.\n\nIf you have a job with a pension plan, it will have a formula that calculates how much you'll get paid once you reach retirement age. That formula is heavily dependent on your years of service with the company, and is typically back end loaded, meaning that most of the value of your pension is gained during the last few years of service.\n\nIf you keep switching jobs, and if each job actually comes with a pension (hint: most don't), you won't accumulate a lot of pension from each job, but you'll still get several smaller amounts when you reach retirement age.\n\nOn top of all that you have your savings (many countries offer some form of retirement investment plan) and any government pension plans you may be entitled to.",
"In the USA each paycheck you receive has money for social security deducted from it. The records for all this are maintained by the Social Security Administration, not by the individual jobs. When you retire you receive monthly payments from social security, the amount being determined by how much you put in each year of employment.",
"It depends on what type of pay you're talking about. Social Security is established by the government and they keep track of that information through your tax forms every year. You can also establish a retirement savings plan through your company which creates an account at a bank that can transfer over if you switch companies. "
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1bt61e | why staying motivated/disciplined is so difficult? | It seems like ever fiber in my being is screaming at me to not work out and eat right. What gives? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1bt61e/eli5_why_staying_motivateddisciplined_is_so/ | {
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"It's simply easier and more enjoyable not to?",
"Maybe it is low levels of [**dopamine**](_URL_0_ \"Not yet the standard interpretation\")",
"Well for eating right and working out you can think back to cave man days. Back in those days, you had no idea when you would eat next. so you want to get as much as you can now. Also, since you don't know when you are going to eat next, you want to conserve your energy for hunting/gathering. Now, you don't have to work out so your body is continually saving up for something that will never happen. Same thing with food. ",
"Because both motivation and discipline are finite resources, neurologically speaking. It is actually impossible to stay motivated indefinitely. Therefore motivation is reliant on \"getting the ball rolling\" over and over again as you re-motivate yourself for new tasks. You can train yourself to make this easier with cognitive-behavior tricks but it's still not easy.\n\nIn regard to discipline around eating, that's hypothesized to be a behavioral reflex and has been observed in many mammals. Essentially, the hypothesis goes that early hunter-gatherer humans evolved to have an urge to eat as much high calorie food as possible when it was available because it was never known whether you were moving into a region of food scarcity for a few months. We simply inherited this urge. In a sort of similar way, our ancestors never had to \"work out.\" They got physical activity through the labor we needed to survive, so without that survival component we may just not have the evolutionary disposition to \"waste energy\" on tiring non-essential labor (hypothesis and speculation). ",
"I read (from /r/getmotivated IIRC) that motivation and discipline are two different things.\n\nAs an analogy, motivation is the fuel, discipline is the car. You can have tons of fuel, but if your car is broken, you can't go far. If your car is awesome, you can probably go far with little gas.\n\nI know this doesn't answer your question, but hopefully it gives you a better perspective."
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31896p | the conflict between the usa and israel over iran? | Aren't they allies? What is America pushing that Israel fundamentally disagrees with? Does Israel want war or diplomacy, if diplomacy what terms is the USA agreeing to that Israel objects to. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/31896p/eli5_the_conflict_between_the_usa_and_israel_over/ | {
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"Israel is concerned that Iran will attack them with nuclear weapons if they ever attain them (there's much debate about the validity of this concern, but Iran is continuously declaring that this is what they'd do).\n\nLately, the US has been taking a softer approach to Iran, opening dialogue and offering deals where before the approach has been hard-line. \n\nIsrael feels that Iran is just stalling while they continue to develop nukes, and that the US's approach will ultimately end with Iran getting the bomb. ",
"People will say it is all about Iran wanting to nuke Israel, but here is my attempt at a Realist interpretation of the tensions (Realism is a theory within International Relations). \nIsrael is currently the major power in the Middle Eastern region, partially due to strong backing from the US, but also due to their monopoly on nuclear weapons. \n\nIran has also been a major power within the region. Back in the mid-20th century, Iran and Israel were actually de facto allies. This was because Iran is actually Persian (not Arab), and there was a big push by the Arab countries to unify (led by Egypt). Iran and Israel didn't want this to happen because it threatened their dominance in the region.\n\nIran experienced a revolution in the late 70's where they became extremely radicalized and instituted a theocracy. Israel emerged as the dominant power in the region and has maintained it ever since, partially thanks to the US being an unwavering supporter, but also because they (illegally*) developed their own nukes. Many other potential threats to Israel's hegemony have been weakened/hampered by the US's interference in the region (Iraq being the obvious example). \n\nNow, Iran has said some very threatening things towards Israel in the past, and they have backed it up by funding and supporting terrorist groups in the region and by advancing a nuclear *energy* program, which has the potential to \"breakout\" into a nuclear weapons program. Since the 90's, Israel has contended that Iran has either had a secret weapons program, but this has never been proven. \n\nIsrael and the US have always agreed that no one wants Iran to get a nuke, but they usually end up differing on how far to go to stop them. Israel has gone so far as to unilaterally bomb nuclear facilities in Iran, and assassinate Iranian scientists, while the US has opted for economic sanctions and attempted to make deals to get Iran to agree to oversight and inspections. \n\nCurrently, the US and the rest of of the UN Security Council are pushing for a deal with Iran which would provide more oversight and control over Iran's program in exchange for lifting the sanctions put on Iran's economy. The Obama administration is determined to make a lasting \"solution\" to this longstanding issue, and Israel opposes it for both specific and general reasons. \n\n1- Israel is not part of the negotiations. This is pretty straightforward...they want a seat at the table, but they are not part of it. Especially since Israel is (arguably) the most affected by a nuclear Iran, they have a good case for being involved.\n\n2- Israel just had major elections. PM Ben Netanyahu has led Israel for over a decade now, and his Likud party is generally considered far-right. This means that they campaign (and win) on a platform which is centered upon national security and national identity. Whether it is true or not, they consistently portray Iran as an existential threat to Israel, and one that should not be negotiated with. A big part of the tensions between Israel and the US stems from the more extreme, hard-line positions necessary for the Likud party to win the elections. This \"partisan\" contention was on full display last month when Netanyahu came to speak to the US congress a few days prior to his reelection.\n\n3- It's all about power. This goes back to the realist perspective. Lifting the sanctions on Iran will allow them to become an even more significant economic power within the region. Of course, with the economic power comes military power too, so even if this deal prevents The Bomb, it still leads to a stronger foe in Iran, something which is a bad thing for Israel.\n\n4- The deal is seen as giving Iran too much for too little. There are relatively short timelines for the limitations on Iran (10-15 years), and while some reactors and fissile material are surrendered under the deal, Iran gets to keep a lot of it. Many argue that the security council went to the table too soon, and Iran is getting the better end of the bargain. \n\nTL;DR: Israel doesn't want war, but they also don't want diplomacy (at least not THIS deal) because it threatens the current power structure of the status quo and thus threatens Israel. \n\nEDIT: Israel's development of nukes wasn't technically illegal because they are one of a handful of countries who did not sign the nuclear non-proliferation treaty. Iran is a signatory of that treaty, so their potential development of a bomb would be illegal. "
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32sbb8 | why is "white flight" considered an immoral/racist thing? | If the quality of life in your area has noticeably dropped, aren't you well within your legal and moral rights to leave for an area with a higher quality of life?
edit: I also want to add, is it wrong to leave if you feel out of place culturally speaking? This doesn't even have to be about race. I wouldn't want to live in a 90% Russian neighborhood as an American, I'd feel out of place. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/32sbb8/eli5_why_is_white_flight_considered_an/ | {
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"Unfortunately, people don't like to acknowledge the truth when it conflicts with their ideologies.",
"According to the people opposed to it, no, you're supposed to embrace the diversity, as your previous quality of life was the result of what they call \"white privilege\".",
"It's not immoral, or necessarily racist, but I'm sure that race was at least a small factor that influenced the \"flight.\" It's easy to make it look like race is the motivating factor because it paints a picture of white people who are too good to live in \"ghettos.\" However, we must keep in mind that the ghettos didn't exist *until* the white families left. Prior to their leaving, inner city neighborhoods were just fine. They didn't leave because the quality of the neighborhood dropped, they left because they could afford to live in suburban neighborhoods, which most people prefer.\n\nThe racist part is that minorities weren't able to get competitive jobs or make as much money as whites, thus they couldn't afford to move out of the inner city neighborhoods.",
"Nothing immoral or racist about it at all. Generally, individuals want to live around similar individuals, not necessarily anything to do with race, but more about socioeconomic status. People of similar socioeconomic status tend to cluster together. \n\nWhite flight wasn't white people leaving because black people were moving in, white flight was white people, generally better off due to various reasons, leaving due to declining property values and higher standards of education and living in the suburbs.",
"White flight ultimately is a racist issue which causes an economic one. For example, you live in a great suburban area that has been all white for years. One black family moves in. No big deal. Then two families move in. Two African American families of the same socioeconomic level as you trying to live in an area with less crime and better schools. Now the racists start to freak out. So they sell their home for less money so they can leave a neighborhood that they think is going down hill. People of a lesser socioeconomic level move in because the homes are more affordable now. People that aren't racist start thinking \"shit, my property value is going down. I've got to sell now\". So they sell to whoever will give them the best price. Eventually the wealthy black families move out too because the neighborhood isn't what it was when they bought it since the homes are now being purchased a lot cheaper by people that are just above the poverty line. Yes, it is basically about racism when you boil it down. If there were no racists freaking out, there would be the same socioeconomic neighborhood that is simply more diversified.",
"TIL that most people have not witnessed a white flight situation in action. It isn't about leaving an area for a quality of life. It is about leaving an area out of economic fear that your new neighbors will bring down the value of your home and your neighborhood quality. That is racism. Your life was fine until you all started to panic and flee."
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2gcgiq | particle half life | I see the term a lot in physics stuff I read, but I've never had it dumbed down or explained in a proper manner. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2gcgiq/eli5_particle_half_life/ | {
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"Radioactive decay of an element or substance is often defined in terms of \"half-life.\"\n\nIn the process of giving off radiation, or in any element that is \"unstable,\" eventually the element in question will degrade into another isotope of the same element, or possibly another element altogether.\n\nSince the exact future of any element cannot accurately be predicted, we choose to define the decay of elements in terms of \"half-life.\"\n\nThis \"Half-Life\" is the AVERAGE amount of time it takes for one-half of any given amount of an unstable or radioactive isotope to decay into its next form or isotope, under normal circumstances.",
"Particle half life refers to a probability curve of the chance of each atom in a sample of a radioactive element having decayed into a lighter element and is used in terms of samples of many atoms as the half life is not an absolute timer but a chance for each atom.\n\nIn terms of large samples after one half-life approximately 50% of the atoms will have decayed, after a second half-life approximately half of the remaining atoms will have decayed or 75% of the initial sample."
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3ndp9m | why do some toilets flush waste better than others? | Isn't the design basically the same? I have a cheap one from home depot in one bathroom and a drake II in another and the drake is ridiculously more powerful. What's going on? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/3ndp9m/eli5_why_do_some_toilets_flush_waste_better_than/ | {
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"A regular toilet uses gravity alone to get the bowl to clear. There is a mid-level model that has somewhat of a pressure assist and above that are models that use a jet of forceful water to assist the flush.",
"Also more generally, the plumbing of the building will affect its power. I live in an old Danish house so when I've had a bit too much Rugbrød that son of a bitch doesn't want to go down..."
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18bw0y | How would accelerometers/tilt sensors in smartphones work in space? | I was watching my cousin play a game on her mom's smartphone yesterday that involved tilting the smartphone to roll a marble through a maze.
I'm wondering how the game would react if for example, a person on the ISS was playing with their phone. Or maybe, if they're browsing reddit on the AlienBlue app for iphone, and they tilt to go to landscape mode.
What happens? | askscience | http://www.reddit.com/r/askscience/comments/18bw0y/how_would_accelerometerstilt_sensors_in/ | {
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"They wouldn't work. Tilt sensors in smartphones use an accelerometer, occasionally combined with a magnetometer. Accelerometers measure *proper acceleration*, or acceleration of free fall; that is, they measure the acceleration of the device with respect to an inertial frame. This is why an accelerometer set still upon an horizontal table measures the local acceleration of gravity on its z-axis, and this is how tilt-compensation works (by determining the orientation of the device relative to the local gravity vector).\n\nThe ISS, however, is actually in free fall - which is usually one of the most difficult things to explain to high-school physics students about gravity. This is why astronauts and objects in general float around inside it. It's not because \"there is no gravity in space\", as is often incorrectly heard, but rather because spacecraft in orbit are in free fall. And so, in answer to your question, the accelerometer in the smartphone would be unable to measure a gravity vector that could be used to determine tilt, and those marbles wouldn't move far off their original position."
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5off5j | why do trees grow through things such as chain-link fences? | Why do trees grow through things such as chain-link fences, and also, how do they know to retain the shape of a tree trunk instead of the segments that were "cut" growing to different sizes?
Thanks. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/5off5j/eli5_why_do_trees_grow_through_things_such_as/ | {
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"For the same reason seeds can sprout through concrete I imagine. Plants seek light, they'll grow around whatever they need to to get to it easier. "
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d7ccxq | what is a whistleblower? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/d7ccxq/eli5_what_is_a_whistleblower/ | {
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"A whistleblower is someone who reports that they've observed an illegal or unethical act within their organization. In many contexts, whistleblower may also suggest that the person reporting misconduct may have certain legal protections against retaliation or punishment for exposing the misconduct. \n\nELI5-level example: You're in school taking a test and you see that your classmates are passing around notes with answers on them. After class, you talk your teacher and tell her what you saw, allowing her to investigate whether the other students cheated. Since you did the honest thing, your teacher agrees not to tell the other students that you tattled on them."
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3kulv8 | how much cheaper would cars be if dealership business owners didn't lobby for dealership requirement laws? | What's the cut that the family who owns the dealership gets? I've met some of their kids and they have unbelievable amounts of money. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/3kulv8/eli5_how_much_cheaper_would_cars_be_if_dealership/ | {
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"The entire rationale behind the dealer system is to promote competition among the dealers so that you get the best price. You can argue if it's effective, but there's no one who's going to be able to say that it would reduce price by X% because it's not clear that eliminating dealers would even decrease prices.\n\nAlso, keep in mind that dealers lose money on the average new car sale. They make their profit on used cars and maintenance. Instead of selling you a car, a dealer frequently just passes along the car for free in the hope that you bring it to them to fix and maintain later."
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16w8jt | Do warts sweat like normal skin? | I realise this is a ridiculous question, but if anyone knows it'll be one of you guys. | askscience | http://www.reddit.com/r/askscience/comments/16w8jt/do_warts_sweat_like_normal_skin/ | {
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"Why has there recently been a fascination with warts?"
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1lky7h | How dark is space? | Say I was floating around in deep space but protected in a space suit, the victim of a terrible star trekking disaster. If I was stranded far away from any known star or solar system, Would I be able to see my hand infront of my face? Would the ambient universal light from distant stars provide me with enough light to read a book while I float around awaiting my lonely death? How bright is empty space? | askscience | http://www.reddit.com/r/askscience/comments/1lky7h/how_dark_is_space/ | {
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"As another post mentions, a good rule of thumb might be taking night-time with no light pollution, during a new moon. (I would add no planets here as well.) I poked around for some numbers... (Here: _URL_1_)\n\nWhat we're looking for is illuminance, which is how much incident light hits a surface for human perception (you mentioned wanting to see your hand). The figure it gives here is 2x10^-4 lux, which is on the border of perceptibility (you could probably make out objects, but not read.)\n\nYou can definitely see the stars themselves (this is determined by luminence). Scotopic vision (_URL_3_) can detect things down to maybe 3x10^-6 cd/m^2 (threshold of vision), vs. \"night sky\" at 10^-4 cd/m^2 on the chart.\n\nOkay, but you mentioned \"deep\" space, and we are still talking about being inside a galaxy. Most of the universe isn't galaxies, but empty space. So let's imagine that we were far away from the Milky Way. At this point, you can give up any hope of seeing your hand. But what other galaxies could we see? What other galaxies are visible from Earth, ignoring the Milky Way and its satellites? Turns out only a handful can be seen. (See \"naked-eye galaxies\" here: _URL_2_)\n\nBut the universe is far far more cruel than this: at the largest scale, the universe is actually organized mostly into immense voids, and almost all of the galaxies are clustered together (into clusters, filaments and walls) sit between the voids somewhat like a foam. If by \"deep space\" you mean that you find yourself in one of these voids (and if you picked a random spot in the universe to be in, you'll probably end up here), I doubt you would see anything at all with the naked eye.\n\n(See _URL_0_)",
"Kinda related: Why is it Dark at Night?\n_URL_0_",
"I'm not going to run numbers here, since the question is a little vague. This depends entirely on your definition of \"deep space\". If you mean, say, moving 4 or so light years away from our solar system and keeping that same distance from any other stars, then you're essentially talking about going to a dark sky site on Earth in the middle of the night, with the moon well below the horizon (new phase). In my professional experience, it is impossible to read a book in this light, but easily possible to see your hands and slowly and deliberately set up basic (read: not fiddly) equipment, such as portable telescopes, laptops, etc.\n\nIf we are talking about intergalactic space (halfway between the milky way and Andromeda, for example - on the order of a million light-years away), you wont be able to even see your own hand except as a shadow against the nearest galaxies - out there you wont be able to see any stars, only a few vague and very dim cloudy objects. Mostly you will see only blackness. Your eyes, once fully dark adapted, are remarkable instruments, but even they need more than the few scattered photons you will get from galaxies more than about 3 million light-years away. Even with a pretty decent (6 to 8 inch) amateur telescope, 15 million LY is about it.\n\nSo, any direction you look from out there where there are no galaxies within about 3 million LY (so, most directions you would care to look), you would see literally nothing. The blackest blackness it is possible to (fail to) perceive.\n\nIf you left our local group of galaxies and headed out into the space between groups, you would conceivably see absolutely nothing in any direction at all, even with a small telescope."
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"https://en.wikipedia.org/wiki/List_of_galaxies",
"https://en.wikipedia.org/wiki/Scotopic_vision"
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1v94pw | why isn't the primary winding on a transformer basically a short circuit? | So there are two wires: the active which has a sine wave going through it, oscillating between positive and negative potential difference with respect to the second wire - the neutral.
Now, a transformer has two windings around some core which helps electromagnetic coupling, and the ratio of windings determines the voltage on the secondary.
This part is all clear.
However, if you trace the wire on the primary winding, it comes in from the active, loops around the core a bunch of times, and then goes out the neutral. With the exception of some resistance due to the long wire, isn't this essentially a short circuit? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1v94pw/eli5_why_isnt_the_primary_winding_on_a/ | {
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"The rising and falling magnetic field created by the alternating current creates a form of resistance sometimes refered to as magnetic reluctance. See: _URL_0_",
"Short answer: the primary winding is an inductor (that's basically what a transformer is - two paired inductors, the primary and secondary). Inductors resist changes in current - meaning in AC circuits, they behave similarly to resistors. So a transformer has a short-circuit for DC, but not AC.\n\nLong answer: **Electric current generates a magnetic field**. This was experimentally demonstrated centuries ago; if you doubt, go get some iron filings, a sheet of paper, a battery, a resistor, and some wire. By piercing the wire directly through the sheet of paper, hooking up the battery and resistor, then sprinkling the iron filings on the paper, you can see this for yourself. Or you can look at [this picture](_URL_0_). Note how all the filings turned to point circularly around the wire - thus indicating the magnetic field there.\n\nSecond point: **changing magnetic fields generate electric fields**. You can, again, either accept this as an experimental result, or you can study special relativity and see why.\n\nSo when you change the current in a wire, it changes the magnetic field generated by that wire. If it is a coil of wire, electric field created by this changing magnetic field pushes on the electrons in the wire minimizing the change in current. So currents increase more slowly and decrease more slowly; the coil of wire has a resistance to AC voltage but not DC voltage. That's an inductor."
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12lc28 | Why is/was Communism considered to be an "evil" economic system? Why didn't the NATO want Communism to spread into Europe and parts of Asia? | Just decided to ask this question because I can't find any good sources on it.
More detailed question:
Why is Communism, in Western countries, considered to be so bad and a terrible economic policy? Was it really as terrible so it is said to be or was it just the how the Soviet Union used Communism? | AskHistorians | http://www.reddit.com/r/AskHistorians/comments/12lc28/why_iswas_communism_considered_to_be_an_evil/ | {
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"There has never been a communist government in the modern era, aside from those of certain less developed cultures. What we in the West have heralded as the failure of communism is really the failure of 'comunism' modeled in the vein of statist plutocratic totalitarianism . Marx never thought that a communist system would arise in the way the revolutionaries who engendered 'communist' governments worldwide envisioned and developed it. That said, actual widespread and effectively maintainable communism has yet to see it's day. In my opinion, it will be a inevitable development of human society, but one we won't see until we enter a post scarcity economy. In the meantime effectively managed capitalism seems to be the best thing we have, and that is entirely keeping with a Marxist dialectal view of modern history. What we decry as communism just simply was not, and I maintain that my claim is not a instance of a 'No true Scotsman' fallacy.",
"Because the way a number of states implemented \"communism\" caused a lot of famines, suffering, purges and deaths. Stalin and Mao are obviously the most notable examples. The Communist Parties were totalitarian regimes and had to protect themselves with totalitarian methods.\n\nIf you want a more cynical answer, it's because communist states nationalised industries and threatened western business interests.\n\nSo why is it considered so bad? Why was \"communist\" or \"commie\" used widely as an insult? Why was wider society so afraid of it? The [Red Scares](_URL_0_) were perpetrated by western governments as a result of their aversion to communism, either for humanitarian or business reasons depending on how much faith you have in humanity.",
"There's too much '-ism' in these responses and not enough history.\n\nBut then again, there's also the word \"evil\" in the way the question was phrased. *sigh*",
"Well, let's define the terms here. \"Communism\" can, I suppose, refer to a utopic egalitarian economic system. But, in its most common form, it's just a title that the Marxist-Leninist's used to distinguish themselves from democratic socialists. Marxist-Leninist's, of course, believed in doing whatever was necessary in order to establish communism as soon as possible. Fairly soon, however, it became clear that they were effectively a military dictatorship with a curious sort of ideology. At it's worst, these Marxist-Leninist governments were totalitarian (with Stalin, Mao, and North Korea taking the lead here), and at their best they were authoritarian and hard to live under.\n\n\"Planned\" economies (which are generally referred to as \"command\" economies today) were a relatively new idea then, and the Marxist-Leninists were the first to try them out. After around the 60's, I think it became clear to everyone that the experiment had failed (it mostly took that long because Communist governments totally walled themselves off from the outside). The planned economies treated the economy as if it were on a permanent war time footing, they utterly ignored consumer needs to build more and more heavy industry and such, and all of them eventually stagnated in the long run. So, at its core, you had a military dictatorship with a crappy economic system that at one time seemed like it was spreading like wildfire.",
"Stalin and Mao were openly antagonistic to western countries, much as Iran and some other Muslim countries are now. However, Stalin and his successors also had a massive number of nuclear weapons and threatened to use them, so the stakes were quite high. \n\nStalin had taken over Eastern Europe after World War II and refused to relinquish that control or allow self-government. There was reason to be concerned that Mao would do the same in Asia, especially after the Korean War. And Stalin and Mao did cause the death of tens of millions of people. So there was much to criticize. \n\nBut it was the Soviet weapons that really heightened the rhetoric about \"evil empires.\" Even when Bush labeled North Korea, Iran, and Iraq an \"axis of evil,\" only North Korea had nuclear weapons and they were very small and distant compared to the threat posed by Soviet Russia.",
"I just spent the day at the Ronald Reagan Presidential Library, so I can comment on his views.\n\nHe said that famine was the product of communism, and bounty the product of capitalism. Communism starved millions of its own citizens to death in the USSR, China, Cambodia, etc. That counts as \"evil\" if anything does. \n\nAt the end of the Soviet Union, they were buying grain from the US.\n\nAlso, Reagan made the point that any country that turned its guns on its own citizens, that walled them in with concrete and barbed wire, that spied on them relentlessly and where even a small bit of protest (in even a poem or song) could get you sent away to a gulag in Siberia... yeah, that country is \"evil\".\n\nIt's not limited to the Soviet Union. China, North Vietnam, Cuba, Cambodia, etc. all became brutal dictatorships. It's not a matter of doing communism \"right\" - tyranny is the inevitable result when the state (/cough, sorry, \"the people\") control the economy. You work where they tell you to work, you make what they tell you to make, you buy what they allow you to buy. It's not an accident or a coincidence. Nor is the inevitable poverty that accompanies it.\n\nOne of the great tragedies of modern history is that we've forgotten the horrors of communism, and treat is as a joke, alongside a sort of misguided \"well, they meant well!\" apology. Instead, we talk about \"The Red Scare\" as if there was no basis for it, as if the Soviet leaders hadn't talked openly about subverting the US from within by making us all socialists. Or that the VENONA intercepts let us know how active Soviet spy rings were (though very few had access to this information).\n\nCommunism has killed more people on this planet than any other ideology, but we pretend it almost never existed. "
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4jtias | how do charities generally work? | I trying to learn more about how humanitarian efforts work. One thing I've noticed is many focus on saving lives while I feel like the focus should be more on improving quality of living. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/4jtias/eli5how_do_charities_generally_work/ | {
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"This is way too broad of a question to answer in any helpful manner. At the most basic level, a charity works by providing goods or services to those in need. There are nearly limitless goods or services a charity can provide, though, and nearly limitless ways to define populations in need.\n\nA lot of charities do work that both save lives and improve the quality of living. However, they tend to get more donations by emphasizing the saving lives part because it sounds better to say \"$10 a month can save a child's life\" than \"$10 can power this generator, which provides electricity to a child's village, for a day.\"",
"Charity have a purpose. It could be saving lives or improving quality of life. \nUsually a charity works by taking donations ( either money, food, building material or simply time ) by people who are interested in helping others. \nSometimes , those charity are so large , they need full time employees to coordinate all the effort, then part of the donations are directed to the organization itself. This explain why only a percentage of the donations actually goes to the \"end-user\".\n\nThere are many charities , some are famous like the red cross or Doctors without borders, but there a lot more local charities that have a very small exposure and are not really well known by the public. The media is kind of guilty of this wide exposure range. They prefer the sensational to the less interesting act of smaller charities. \n\nSo the big charities can have large public campaigns while the smaller one cannot really afford to advertise on TV form their lack of financial or media support.\n"
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70408a | why is a black background and white text still not a norm in websites, apps?! | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/70408a/eli5_why_is_a_black_background_and_white_text/ | {
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"It's because white background and black text has been the norm and is what everyone is used to. It was this way because digital displays replaced paper and ink and had to be similar to get people to adopt it.",
"It resembles black ink on paper, following an old tradition.\n\nWe use black ink on paper because it's fairly easy to make light colored paper (papyrus, vellum, rag paper, wood pulp paper), and\ndark ink (oak gall). Reverse printing would require an expensive quantity of ink.\n\nEarly computer displays used light characters on a dark background since it was relatively easy to add phosphers while glowed when hit by an electron beam - I remembers monocolor displays in white, green, and orange, with light characters and dark backgrounds.\n\nThe Macintosh, in 1984, was the first to reverse this, and light up the 'blank' areas instead of the characters. This was a huge hit with people who weren't already into computers, since it resembled their familiar paper and ink, and made desktop publishing look more like the printed page while it was still on the screen.\n\nSo, the main reason is 'it looks more like a printed page'\n\nI actually like light characters on a dark background.\n\n\n",
"Because you have to be concerned about accessibility. \n\nNot everyone can read dark mode well, that is why its an option. black background with white text is one step away from black background with matrix green text. It hurts the eyes of those with contacts/elderly and people with contrast issues.\n\nLook up WAVE.",
"I mean.. how else would you have it? It's easy to read, professional and looks good ",
"Most people don't want a dark website. It's kind of like asking why doesn't everyone where black clothes.\n\nEdit: also it's harder to use some colors with a black background. Generally you can use most colors with white backgrounds and it's still readable. Put a black background on it and you start limiting what colors you can use. For example you can use both light blue and dark blue with white background and it's still pretty visible. Put light blue and dark blue on a black background and the dark blue is far less visible.",
"Everyone's saying because it's the norm but nobody is mentioning how it's painful to read after 5 minutes...",
"It's because white background and black text has been the norm and is what everyone is used to. It was this way because digital displays replaced paper and ink and had to be similar to get people to adopt it.",
"Because you have to be concerned about accessibility. \n\nNot everyone can read dark mode well, that is why its an option. black background with white text is one step away from black background with matrix green text. It hurts the eyes of those with contacts/elderly and people with contrast issues.\n\nLook up WAVE.",
"I mean.. how else would you have it? It's easy to read, professional and looks good ",
"Most people don't want a dark website. It's kind of like asking why doesn't everyone where black clothes.\n\nEdit: also it's harder to use some colors with a black background. Generally you can use most colors with white backgrounds and it's still readable. Put a black background on it and you start limiting what colors you can use. For example you can use both light blue and dark blue with white background and it's still pretty visible. Put light blue and dark blue on a black background and the dark blue is far less visible.",
"Everyone's saying because it's the norm but nobody is mentioning how it's painful to read after 5 minutes..."
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363nt1 | Regarding the USA. What are the reasons people emmigrated there over other possible locations? | And when did this emmigration begin? | AskHistorians | http://www.reddit.com/r/AskHistorians/comments/363nt1/regarding_the_usa_what_are_the_reasons_people/ | {
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"Just to clarify: are we asking why and when Europeans started moving to the Americas?",
"Maybe you could narrow it down to a particular century or country of origin?\n\nOne major factor in choice of immigration destination is the existence of a beachhead community. It's far easier to move someplace where there are at least a few people who speak your language or might have family ties.\n\nFor example, there is a significant Hmong population in Saint Paul Minnesota. They did not move there for the weather, nor even for the funnel cakes. Most chose that city because there was already a Hmong community there.\n"
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23xs5u | why do some law enforcement entities turn off the surveillance camera during interrogations. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/23xs5u/eli5_why_do_some_law_enforcement_entities_turn/ | {
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"They usually don't. They will, however, tell you that they do in order to get you to give up self incriminating information.\n\nSource:[link](_URL_0_)"
]
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"http://boingboing.net/2008/07/28/law-prof-and-cop-agr.html"
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||
35ytxu | why don't we sue cops personally instead of suing the department? if scientology members were able to sue irs employees why aren't we doing the same with police?? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/35ytxu/eli5_why_dont_we_sue_cops_personally_instead_of/ | {
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"Officers who act within the boundaries of policy, training, and law are immune from civil lawsuits. If the officer is found to be acting illegally then they can be sued. It's called Qualified Immunity and it applies to a lot of people, not just cops.",
"Also, Scientologists are rich nutbags. They could probably find a lawyer who could sue you for the color of your shirt."
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621b0q | why is anti-immigrant sentiment so high in countries that have practiced colonialism? | It is like wanting to go to the Moon and then after you get there, complaining about having gone to the Moon. How does this make sense from a cultural perspective? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/621b0q/eli5_why_is_antiimmigrant_sentiment_so_high_in/ | {
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"Two reasons:\n\n1. The nations you're thinking of are the type of economically successful places people want to immigrate.\n\n2. Such nations typically have open immigration policies compared to the rest of the world.\n\nSo on the one hand, you've got a lot more people wanting to immigrate. On the other hand, it's possible to have a debate over immigration because immigration is actually possible rather than being mostly forbidden."
]
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|
1gkoi0 | what happens to the average middle to lower class person who is ordered to play millions of dollars in a court settlement? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1gkoi0/eli5_what_happens_to_the_average_middle_to_lower/ | {
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"They don't pay it.\n\nSomeone in that situation will probably go bankrupt and still have to make payments on it, but will be able to keep a lot of his income for necessary expenses.\n\nHowever, because of this, people usually don't go after poor people for civil damages. The expression \"trying to get blood from a stone\" is often used. This can be unfortunate because if you are harmed by a rich person or company you will be taken care of if you win the case (although they will have better lawyers), but if you are attacked by some thug you're pretty much on your own."
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2x9m9q | Do we know about (or can we see) any examples of planets still forming? | askscience | http://www.reddit.com/r/askscience/comments/2x9m9q/do_we_know_about_or_can_we_see_any_examples_of/ | {
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"Yes! (Not in our solar system of course.) There has been some indirect evidence of planet formation in proto-planetary disks for a while, but recently a new radio telescope called ALMA high in the Atacama desert in Chile [took images of such a disk](_URL_0_) and managed to resolve the gaps in the disk where planets are forming. \n\nAs planets coalesce, they sweep out rings of material from the disk of debris around them, gathering it up. The empty rings in the disk are where the newly forming planets are orbiting. \n\nThis has been expected for quite a while because the disk around the star has a temperature that depends on how far from the star it is, and things with a temperature glow at characteristic wavelengths. (Humans glow most around a wavelength of 10 microns. The Sun glows most at a wavelength around 0.5 microns. Hotter things glow at shorter wavelengths - that's called [Wein's Law](_URL_1_).) When looking at the light coming from some of these stars with disks around them, some of them seem to have lower amounts of light at the characteristic wavelength of a given temperature, and that was interpreted to mean that the part of the planetary disk at the corresponding radius was missing. Now with ALMA's new images, we can see that that is correct! ",
"My immediate thought was that the Earth might be an example of a planet late in its development. I am thinking of the molten core and the shifting mantle causing tectonic shifts, etc. Maybe it's just semantics.\n\nAs follow-up questions:\n\nAre there other planets in our solar system with molten cores or something similar? Does the appreciably change the planet?\n\nWhat about planets with very dynamic surfaces? I'm thinking about stormy and gaseous Venus atmosphere, or Jupiter maybe?"
]
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"http://en.wikipedia.org/wiki/Wien%27s_displacement_law"
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||
7fkaal | What are the origins or predicted origins of gold and silver on planet Earth? | askscience | https://www.reddit.com/r/askscience/comments/7fkaal/what_are_the_origins_or_predicted_origins_of_gold/ | {
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"Here is a really good link that explains where all elements come from (including gold and silver in your title).\n\nThe tl;dr version - all elements, including gold, silver, uranium and mundane elements like carbon and silicon all come from supernova. You (and me) are made out of the same stuff as the stars \n\n_URL_0_",
"Among the recent string of gravitational wave events detected by LIGO, the latest was a neutron star collision that [validated the hypothesis](_URL_1_) of kilonovas as a way for elements to be released into the interstellar medium.\n\nCloser to home, [ideas are still being refined](_URL_0_) as to the exact geologic mechanism that deposits gold and other materials in the Earth's crust to be eventually mined."
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||
87div5 | How did the PRC convince the Chinese people they were honoring Sun Yat-Sen? | Based on what I've learned about the Chinese Communist Revolution, the Communist Regime did not try to distance themselves from Sun Yat-Sen. However, Sun Yat-Sen supported a Western-style representative republic. From my viewpoint, as an American, it seems as if the Communists pretty blatantly hijacked and destroyed any hopes of fulfilling Sun's revolution.
Yet, the Chinese still honor Sun and seem to view modern China as what he would have wanted. How did a one-party dictatorship convince the people of China that their government was somehow honoring Sun's goals? | AskHistorians | https://www.reddit.com/r/AskHistorians/comments/87div5/how_did_the_prc_convince_the_chinese_people_they/ | {
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"To say *'Sun Yat-Sen supported a Western-style representative republic'* oversimplifies Sun's views on revolution, republicanism, and nationalism. For one, the idea that a stable enlightened democracy would spontaneously emerge from the ashes of imperial China is naive. And furthermore it didn't. The first revolution in 1911 (the Xinhai Revolution) was hijacked by the powerful general Yuan Shikai, to whom Sun ceded the title of provisional president in exchange for forcing the last Qing emperor to abdicate. And because of his military power, Yuan was able to sideline Sun and his party (the GMD) as well as oversee the erosion of the first Republic of China and finally a reversion back to monarchism with himself as Emperor. After Yuan's death in 1916, China was plunged into a era of regional warlords. \n\nNationalism lay at the core of Sun's political philosophy and he was concerned with fundamentally reforming China and its people - not merely carrying out token democratic reforms in a backwards nation. In Sun's Three Principles of the People, the principle of Nationalism makes an appearance before the principle of Democracy (Nationalism, Democracy, Livelihood). From his *A Program for National Reconstruction* (1918) we can see as to why he thought this:\n\n > It is not to be denied that the Chinese people are deficient in knowledge. Moreover, they have been soaked in the poison of absolute monarchy for several thousand years [...] the Chinese people, being for the first time under republican rule, must have a farsighted revolutionary government for their training. This calls for the period of political tutelage, which is a necessary transitional stage from monarchy to republicanism. Without this, disorder will be unavoidable.\n\nThe key word here is \"political tutelage\", which is to be administered by a \"revolutionary government\"; in essence, the people must be prepared for democracy or they won't be ready for it. A revolutionary government isn't an elected constitutional government because that would be putting the cart before the horse. Instead, the existence of an authoritative revolutionary government arises from a military revolution to first consolidate power. This is evident from Sun's division of National Reconstruction into three phases: 1. Destruction, 2. Transition, and 3. Reconstruction. Destruction here isn't a mere metaphor, but an \"extraordinary\" and violent phase to overthrow the existing establishment and oversee the elimination of archaic customs, etc. After a period of successful destruction, the transitional phase begins:\n\n > ... the provisional constitution will be promulgated in the district, defining the rights and duties of citizens and the governing powers of the revolutionary government. [...] When the constitution is promulgated and the president and the National Assembly are elected, the revolutionary government will hand over its governing power to the president, and the period of political tutelage will come to an end. \n\nIn 1918, Sun is overly optimistic by suggesting that a period of 6 years would be sufficient for such a transition. In later writings he will avoid giving any arbitrary time-line. Naturally, the length and exact nature of this transitional phase will be open to interpretation, debate, and much controversy.\n\nThis now brings us to the statement *'the Communists pretty blatantly hijacked and destroyed any hopes of fulfilling Sun's revolution'*. Setting aside Yuan Shikai's usurpation, this statement skips over the twenty-four crucial years of modern Chinese history from Sun's death in 1925 to the 1949 establishment of the PRC. After Sun's death, his vision of a national revolutionary movement uniting China was superficially realized by his party's successor Chiang Kai-shek's successful Northern Expedition against the Warlords. Chiang's model of nationalist reform would at least in theory mirror Sun's. Having conquered China, he was now in the transitionary or tutelage phase with himself as head of Sun's former Nationalist party (GMD or KMT) and therefore the leader of a single-party Chinese state. Although frequently referred to as a fascist dictator or generalissimo, Chiang's de facto power was checked by i) warlords whom he allied with during the Northern Expedition who still retained considerable power; ii) his purge and massacre of communists within the GMD leading to the splinter of the Chinese Communist Party (CCP) from the GMD and their subsequent civil war; iii) burgeoning influence and agitation in Manchuria by Imperial Japan followed by a 1931 invasion and eventual war (Second Sino-Japanese War - > Second World War).\n\nIt was only in 1947 that a new Chinese constitution was promulgated with Chiang formally elected as President of the Republic of China in 1948. However the years after the end of the Second World War only marked a new phase in China's instability. The civil war had been renewed; the communists had fully taken advantage of the Second World War to ingratiate themselves with the Chinese peasantry and to entrench themselves as a formidable military force. Chiang's political capital as a nationalist leader had been severely drained as a result of [the Xian Incident (u/ScipioAsina)](_URL_1_). Furthermore, marred by widespread government corruption and incompetence corresponding [with hyperinflation taking root from the beginning of the Second Sino-Japanese War](_URL_0_), Chiang's government had long ceased to be the revolutionary government that Sun had idealized. Within two years of being elected as President, Chiang would escape to Taiwan.\n\nIt should now be clear why the CCP holds Sun as a nationalist hero: 1. He was first and foremost a nationalist who helped overthrow dynastic rule; 2. His conception of republicanism is not inconsistent with single-party rule; under the GMD, China was also administered as a single-party state; 3. the CCP sees itself as the legitimate successor to Sun's revolution as opposed to Chiang's led GMD. \n\n*\"Selections from A Program of National Reconstruction: \"The Three Stages of Revolution\" (1918)\" By Sun Yat-sen, from* Sources of Chinese Tradition: From 1600 Through the Twentieth Century, *compiled by Wm. Theodore de Bary and Richard Lufrano, 2d ed., vol. 2 (New York: Columbia University Press, 2000), 328-330*\n\n*\"The Inflation in China\", Andrew C Huang,* The Quarterly Journal of Economics, *Vol. 62, No. 4 (Aug., 1948), pp. 562-575*"
]
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"https://www.reddit.com/r/AskHistorians/comments/1i7hpa/how_come_china_didnt_try_to_fight_off_japan_when/cb1zsdk/"
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10636r | Is there any evidence to suggest that galaxies are just young super-massive "solar" systems? | While looking at the formation of solar systems and the current state of galactic formations I noticed that they both appear to form similarly from dust and particles eventually combining around a large gravitational object at the center. Could galaxies just be young super-massive "solar" systems so-to-speak? Obviously they wouldn't be called solar systems since the gravitational center would be based around a super massive black hole. However, are there any physical limits on the size of planets/stars? Such as the core becoming too compressed by the mass of the entire object?
tl:dr version- Given enough time, could the Milky Way or other galaxies form massive "solar systems" around a super-massive black hole at the center with revolving bodies being roughly the equivalence in size to VY-Canis Majoris?
Edit for clarity: Our galaxy still has a vast amount of cosmic dust. Given enough time (in the neighborhood of billions to trillions of years), would that clear away and form a more solar system-esque structure. In my mind it looks like our current solar system but with a super-massive blackhole where our Sun is and orbiting that would be billions of stars, some as large as VY-Canis Majoris and some just the size of a white dwarf, with trillions of moons surrounding those. I suppose a somewhat condensed, cleaner and more structured/organized galaxy is what I'm trying to represent as the image. | askscience | http://www.reddit.com/r/askscience/comments/10636r/is_there_any_evidence_to_suggest_that_galaxies/ | {
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"I don't understand what you're asking really.\n\nImagine it this way: the moon orbits the earth, the earth orbits the sun, the sun orbits the black hole at the center of the Milky Way, and the galaxy orbits the center of mass of the local galaxy cluster. That's the way things are. \n\nAre you asking if all the stars will collide together to form bigger stars? Well some will, yes. We have binary star systems. Sometimes stars spiral into each other, siphoning off each others' plasma. \n\nBut not all stars will crash into each other. They are just too far apart. Just like earth will never crash into Jupiter (within the foreseeable future), just like Jupiter's moons don't crash into each other anymore. ",
"One thing to note is that the majority of the mass of a solar system (stellar system?) is contained in the mass of the star(s).\n\nHowever, the supermassive black hole at the center of a galaxy typically comprises only an insignificant fraction of the galaxy's mass. All the stars in the galaxy rotate around the center of mass of the galaxy rather than the black hole."
]
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[],
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|
yfuuc | Why do India and Africa have similar animal species? | It seems like many animal species in India and Africa are extremely similar, such as:
African Lions and Asiatic Lions
African Elephants and Indian Elephants
African Leopards and Asiatic Leopards
African Rhinos and Indian Rhinos
...and so on. Is there a legitimate reason that many species in India and in Africa are so alike? | askscience | http://www.reddit.com/r/askscience/comments/yfuuc/why_do_india_and_africa_have_similar_animal/ | {
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"There's a land bridge connecting Africa and Asia in what is now northeastern Egypt. Ten thousand years ago the whole of Sinai would have been a land bridge, because ocean levels would have been lower because of all the water locked up in glaciers. You can see this best in the historical [range of lions](_URL_0_), and [leopards](_URL_1_). I was unable to find an historical range of the other animals you mentioned, but it would be similar.\n\n",
"Most of the mammal species endemic to India died off about 20 million years ago. The Earth, and especially that region, went through some major climate changes during that period due in part to the emergence and uplift of the Himalayas but also to volcanism and some other factors. Mammals from Africa and other parts of Asia came across by land and filled the ecological niches the extinct mammals left behind.\n\nLink: _URL_0_",
"Well, in the case of elephants, it's not as if it was always relegated to bits of India and Africa, elephants used to exist in the Middle East, but were extirpated. Same with lions and leopards. Not sure about rhinos though. (Just look at the wiki-articles on them).\n\nBetter question is why Asiatic Lions/Leopards/Elephants only remain in India. Surely the human population density in the respective areas can't be to blame - because India would win there, then? \n\nI've read that the Middle East is drier now than it was in the past, so increasing desertification in conjunction with human hunting leading to extirpation, maybe?"
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"http://en.wikipedia.org/wiki/File:Lion_distribution.png",
"http://en.wikipedia.org/wiki/File:Leopard_distribution2.gif"
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"http://www.krugerpark.com/blog/index.php/india-the-other-africa/"
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|
4rrx5a | oil weights | I know that the higher the number the thicker the oil. My transmission's 75w-90 is much thicker than my engine's 0w-20. I was told the the "W" denotes the viscosity of the oil at 0 degrees Fahrenheit. So by that logic a 5w-30 gets thicker as it gets warmer but I know that isn't true. Someone explain this to me. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/4rrx5a/eli5_oil_weights/ | {
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"Let's see:\n\nIf you have a multi-grade oil like 10W-40, it behaves at 0 degrees Fahrenheit like a SAE grade 10 oil would. At 210 degrees Fahrenheit it behaves like a SAE grade 40 oil would behave *at that temperature*. \nSo, the multi-grade oil does not get thicker (as in lower viscosity) on an absolute scale, it still has a lower viscosity at the high temperature. The difference is that the viscosity does not drop as much as it would in a single grade oil, giving you a wider temperature range with acceptable viscosity.\n\nI think a graph [like this](_URL_0_) explains it better than I could. A multi-grade oil has a flatter cruve for viscosity across the temperature range than a single grade oil, you stay between the 'too thin' and 'too thick' lines longer."
]
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"http://www.kewengineering.co.uk/Auto_oils/images/graph_3_viscosity_multigrade.jpg"
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|
2wekns | Practical Applications of Relativity? | If we did not have an understanding of relativity, would we be limited in any other way besides building GPS satellites?
Either in terms of technology we would totally not be able to develop or technology that would be particularly more expensive/inefficient/ineffective? | askscience | http://www.reddit.com/r/askscience/comments/2wekns/practical_applications_of_relativity/ | {
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"Classical electromagnetism can be shown to be a consequence of special relativity. So pretty much everything in your daily life would be an application.\n\nYou could argue that that's not an application that wouldn't be possible without relativity, but then, such fundamental theories aren't created for applications sake."
]
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[]
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|
5upi9u | why have canada & usa been more successful at integrating muslims than europe? | [deleted] | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/5upi9u/eli5_why_have_canada_usa_been_more_successful_at/ | {
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"Muslim immigrants to Europe were primarily unskilled labor, while Muslim immigrants to the U.S. were primarily professionals. So what happened is that Europe developed large, lower class Muslim communities while the U.S. tended to have scattered families of Muslims with a few middle-to-upper class Muslim communities.",
"I think the biggest reason is that we have so few Muslims to begin with. Muslims make up approximately 1% of the US (*far* less, incidentally, than most Americans think). It varies by country, naturally, but Muslims make up around 6% of Europe. It's easier to not integrate as much when you have such a large community already there.",
"You can also ask the question of why do Muslims integrate better in the US than Europe. It's not a one way street. Most successful American integration has occurred when the culture has adapted to the current styles and mannerisms. "
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43p90e | how do popular highways get backed up even though everyone is going in the same direction? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/43p90e/eli5_how_do_popular_highways_get_backed_up_even/ | {
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"Just like a water pipe, a highway has a limited flow capacity. The usual constraint is places like exits, mergers and entrances. Each of these cause slowdowns of some sort - e.g. they contain capacity and upstream cars must wait.",
"The volume of vehicles is the biggest issue. Only so many cars can travel on a given lane in a given time period before the car spacing is too close for the perceived comfort of the drivers. That gets compounded by lane merges, exits and entrances. ",
"The problem isn't the traffic on the highway, it's the traffic entering and leaving the highway. If more traffic is entering than the road can handle, everyone behind the inlet will back up as the forward traffic has to accommodate for the incoming vehicle. If you're near a large city with a major thoroughfare, then you have to consider that the surface roads probably don't have the capacity to handle the exiting traffic. The city is congested with people trying to get to their destinations, and so traffic backs up the exit ramps.\n\nThe ways we know to deal with congestion is to carpool, live closer to work to minimize your road use, use the zipper method when merging, and self driving cars are more efficient than manually piloted vehicles. But the inherent problems remain, given enough traffic."
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jluwo | why can't we have living heads in jars? | Or any other body part for that matter. Fluids go in, fluids come out; ought one not explain why not? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/jluwo/eli5_why_cant_we_have_living_heads_in_jars/ | {
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"We actually already have this technology; it's how heart transplants are done. The blood flow is rerouted through a machine that pumps blood in the same fashion as a heart, the defective organ is cut out, the new one put in, and then the blood flow returned to normal.\n\nThere's two factors stopping Futurama-style head-in-a-jar types or the more traditional brain-in-a-pan sort of artificial replacements of organs to sustain vital functions. The first is economics. The money required to build such devices is astronomical, along with the cost of maintaining and repairing them if they failed. The aforementioned blood-pumping machine is cost-effective because it can be used in multiple surgeries, while the next guy getting the Donovan's Brain Special needs a whole new set. The second part is ethics. Transhumanism, while gaining acceptance on the internet, is nowhere near mainstream. Your average Jim-Joe-Bob on the street is probably rather fond of the organs that he came with, and would probably see such technologies as science infringing on the territory of God.\n\nTL;DR: It's scientifically feasible, but uneconomical and unethical to implement.",
"For long term use, the machine would need to provide dialysis, and I think at least a piece of liver and some bone marrow would need to be included since there really isn't an artificial replacement for either.\n\nThere are [neurological problems](_URL_0_) associated with bypass machines. Without a solution, using one for long term life support is problematic.\n\nI think a machine could probably be built, but due to the above problems plus infection and other factors, I doubt it could extend anyone's life for very long, at least not with the technology available today.",
"We actually already have this technology; it's how heart transplants are done. The blood flow is rerouted through a machine that pumps blood in the same fashion as a heart, the defective organ is cut out, the new one put in, and then the blood flow returned to normal.\n\nThere's two factors stopping Futurama-style head-in-a-jar types or the more traditional brain-in-a-pan sort of artificial replacements of organs to sustain vital functions. The first is economics. The money required to build such devices is astronomical, along with the cost of maintaining and repairing them if they failed. The aforementioned blood-pumping machine is cost-effective because it can be used in multiple surgeries, while the next guy getting the Donovan's Brain Special needs a whole new set. The second part is ethics. Transhumanism, while gaining acceptance on the internet, is nowhere near mainstream. Your average Jim-Joe-Bob on the street is probably rather fond of the organs that he came with, and would probably see such technologies as science infringing on the territory of God.\n\nTL;DR: It's scientifically feasible, but uneconomical and unethical to implement.",
"For long term use, the machine would need to provide dialysis, and I think at least a piece of liver and some bone marrow would need to be included since there really isn't an artificial replacement for either.\n\nThere are [neurological problems](_URL_0_) associated with bypass machines. Without a solution, using one for long term life support is problematic.\n\nI think a machine could probably be built, but due to the above problems plus infection and other factors, I doubt it could extend anyone's life for very long, at least not with the technology available today."
]
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8jbw35 | Historians obviously have to read through huge masses of research material, both while studying and as a professional. What are your methods for getting through it all? | AskHistorians | https://www.reddit.com/r/AskHistorians/comments/8jbw35/historians_obviously_have_to_read_through_huge/ | {
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"I never learned about this until graduate school. We write what is called a précis of the book. It looks like this: \nCitation: self explanatory. \nAuthor information: quick background about where they went to school and their other works. No more than two or three sentences.\nThesis: what is the point of the material\nArgument: how did they make their point\nSummary: I typically try to write one or two sentences per chapter here. If there are a lot of chapters I might break it down to writing a few sentences about the different sections if it’s divided into part 1, part 2, etc.\nEvaluation: write what you thought about the book. Was is useful? Did you like it? Would you recommend it to someone? \n\nYour précis becomes your guide to the material you looked at. Once it’s written you don’t have to reread the material, you can use your précis to go back and find what was important about the material. \n\nAs for how to “gut” a book, speed reading becomes your best friend. I had to read two books per week for a single class my last semester and I was taking other classes. So you really have to learn how to speed read in graduate school. My technique is to read the introduction all the way through because that typically summarizes the book for you. When you’re lucky some authors tell you in the introduction “in chapter one I will argue this then in chapter two I will explain this etc.” Then I would typically read the first paragraph of a chapter, skim through the rest of the chapter, but always read the bold and look at any diagrams, graphs, or pictures because they are normally important. Then I would read the end of the chapter because they typically summarize the highlights of the chapter. Typically when going through the chapters I write a summary of each one, no more than 5 or 6 sentences that can be reduced when writing the summary portion of your précis. Finally I always read the conclusions of books. That’s typically where the authors reenforce and explain thesis. If you do this you can write a decently thorough précis. \nAlso don’t forget someone else has probably read the books you are preparing to read. There are always plenty of reviews out there on the internet you can check out. If you have access to databases like jstor you can find some pretty good reviews to help you get through your material. \nHopefully this helps. Good luck! ",
"So my experience as a grad school student who was studying straight history and has now transitioned into a more media-studies-type role(with a heavy concentration on US History) is as follows: Historian's don't really meticulously read books unless they're specifically searching for certain pieces of information. Academic history books are usually structured such that the author's thesis and main supporting arguments are stated at the beginning and the end. Most of a 600+ page book is showing one's work, citing other sources, documenting topical minutiae and research methods. That is not to say that this is unimportant(as this sub's rigorous rules for documentation indicate, historians rightly value substantiated claims), merely that in an academic context, being able to prove your pedigree is of secondary interest to a surface level reader than one's main argument. There are other factors that have to do with learning strong research skills, but in my (reasonably) informed opinion that's basically what's going on there. ",
"Without wanting to disagree with the other fine responses, I'd like to highlight the importance of dealing methodically with primary source information too. This is much more of a mixed bag - depending on your period, approach and archives you'll likely end up with a hodgepodge of digital and physical copies of things. It's vital that you store them logically (ideally preserving the archives' own system to allow for better referencing) but also allowing for searching. I was (un)lucky that several of my key archives didn't allow photos or made photocopying a pain - transcribing was hell at the time, but made ctrl-f my best friend later on. For digital images (I ended up with tens of thousands), renaming them as a series of keywords based on subject, author, contents etc also made finding material easier, and I regretted not doing this across all my collections. Lastly, get familiar with database software and don't be afraid to use it. I never realised how useful it was until I started writing a thesis chapter not covered by my main database...",
"In pulp studies, it usually depends on knowing what you're looking for and what's available. A lot of basic facts as far as publication dates of various stories are readily available online, or through databases or specialist indices, but the actual stories and issues might be much more difficult to source, given the self-destructive nature of the material—and fanzines and other contemporary periodicals tend to be scarce and expensive. There *are* published biographies and collections of letters and essays by various pulp fictioneers, editors, etc., the quality and utility of which varies. The most complete correspondence yet published is that of H. P. Lovecraft and his circle, which is at 20+ volumes and counting. For others, your best hope is that their letters and/or papers survive and have been deposited at a friendly library or archive—I myself have had to make several requests of Bowling Green's exceptional Popular Culture Library and the Wisconsin Historical Society's Derleth archive (August Derleth was co-founder and primary editor/publisher of Arkham House, and a prominent pulp writer, fictioneer, and poet in his own right).\n\nBut as far as the mass of journals, scholarly and not-so-scholarly go...you're kind of on your own, there's a few indices out there, but there's still a lot of voyage of discovery where you run across a citation to an article or letter buried in an old 'zine and have to track it down. I'm rather fortunate in that regard in that I've accumulated a fairly extensive library of reference and source materials over the years, and can cross-reference a lot of stuff on my own through carefully poring through half a dozen books over a few hours, but if I didn't have that I'd be down to making interlibrary loan requests and sending emails requesting scans of letters and old pulp 'zines and the like. Fortunately, most of the fellow travelers in pulp studies are gracious pack-rats who share some of their own materials, if you know who to ask."
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||
ibhmf | Older theories of planetary formation? | I just finished reading the 1979 SciFi book *Macroscope* (Piers Anthony). It's a good read, if a bit convoluted.
Anyway, covered within the book was a theory of planetary formation wherein the gas giants were formed from what sounded more or less like "black dwarfs" -- burned out stellar remains, which were captured by our protosun.
While this is certainly not the current model (Wikipedia seems to indicate the [nebular hypothesis](_URL_0_) as the most accepted model right now), was it ever seriously considered?
My core question is, was this guy just making up stuff for his novel, or was this a serious model of solar system formation prior to our current understanding of stellar evolution (with the three endpoints being a white dwarf, neutron star, or black hole, if I've read correctly)? | askscience | http://www.reddit.com/r/askscience/comments/ibhmf/older_theories_of_planetary_formation/ | {
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"I know that prior to the discovery of fusion, it was thought that the mechanism of the sun's heat was Kelvin-Helmholtz contraction, which gave it about an 8 million year lifespan. (while this is the established mechanism of formation, it ends when fusion starts and there is a new hydrostatic equilibrium)",
"I don't think this idea was ever seriously considered. The closest thing to it is the theory that the gas giants formed by [disk instability leading to localized gas collapse](_URL_0_), as opposed to starting with massive cores and capturing gases (as described in this [pdf](_URL_1_)).",
"I remember an old theory of planetary formation I was taught in undergrad. Basically it went that planets form when two stars pass close enough to one another that a significant amount of mass is pulled between them and meets in the middle where it condenses into a planet which begins to orbit one of them."
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1c14ve | vinegar; who, what, where, when, how!.... do they make it? | I can build a gaming computer from components, understand global diplomacy and sovereignty, bake a mean Cheesy-bubble loaf from scratch, well educated in musical theory and development.
But, Can Not Fathom how this excellent elixir is made.
...please help me. ELI5!
But Vinegar.....
Whaaaaaaaaaaaaaaaaaaaat?
how? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1c14ve/vinegar_who_what_where_when_how_do_they_make_it/ | {
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"Vinegar is made when bacteria convert alcohol to acetic acid. This is usually done after using yeast to ferment sugar into alcohol. One common form is apple juice - > apple cider - > apple cider vinegar. \n\nThere are [many different kinds.] (_URL_0_) ",
"Vinegar is basically fermented drinking alcohol; a special type of bacteria converts the ethanol into acetic acid, i.e. vinegar.",
"Normally when you ferment something, like wine or sake, you don't want to have any air in the barrel so the yeast eat the sugar in a way that makes alcohol. The thing about alcohol is that it doesn't squeeze all of the energy out of the sugar. If you take the wine and add air and a special type of bacteria, they will then eat the alcohol (squeezing some more energy out of it) and turn it into acetic acid. This is now vinegar. The vinegar is sour because of the acetic acid."
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80t6lv | how does wicking and preassure help a cut stop bleeding? | So, I get a small cut, I take a clean tissue and press into it for a few minutes. At first it's bleeding fast, but it slows down until it stops bleeding.
I would think that pulling blood out of a wound would increase the bleeding, since putting a towel around a cut hose will do nothing to get it to stop leaking.
How does pulling blood out of a cut help it stop bleeding, and how does preassure help as well. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/80t6lv/eli5_how_does_wicking_and_preassure_help_a_cut/ | {
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"You're compressing vessels and capillaries allowing platelets to begin blocking damaged areas, stopping blood from escaping vascular walls. \n\nEdit: ELI5 You are pinching the tubes that carry blood. This causes blood to patch the damaged areas so blood cannot escape.\n\nEdit: ELI2 boo boo ouch",
"Pressure: You're squeezing the blood vessels so that less blood flows out of the wound.\n\nWicking / tissue: The fibers in the tissue have A LOT of surface area, this gets the blood to spread out into the tissue and increases the blood's surface area. Blood has \"clotting factors\" (organic chemicals) in it that cause it to coagulate (harden) in contact with oxygen in the air, and larger surface area makes it coagulate faster.\n\nThe basic idea is to slow down the flow of blood out of the wound so that you have a film of blood covering the wound and staying in place for long enough to harden and, basically, form a plug."
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3sd1um | how do rovers on mars transmit information, such as pictures and video, back to earth? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/3sd1um/eli5_how_do_rovers_on_mars_transmit_information/ | {
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"They send it to an orbiting relay satellite. Today it's the [Mars Reconnaissance Orbiter](_URL_0_).",
"NASA operates a array of high gain satellites called The Deep Space Network. The Mars Rovers will communicate to an orbiter satellite, which will then re-transmit that information to Earth to be received by the Deep Space Network. This allows them to achieve a relatively high throughput considering the distance. NASA can communicate directly to the rovers through a lower frequency, but the throughput using this is very small, like around the 300 bits per second range, which is enough for emergency recovery."
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5vf9fg | what is the difference between the observer effect and the uncertainty principal? is it possible to measure the position of electrons in a double slit experiment without forcing them to interact with a measurement particle? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/5vf9fg/eli5_what_is_the_difference_between_the_observer/ | {
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"The uncertainty principle is far more fundamental. In fact, the observer effect is not even unique to quantum mechanics. It's technically true in classical mechanics as well. \n\nThe observer effect just says that in practice, introducing some measurement device to your system generally changes things inside the system. There is nothing about that that is unique to quantum mechanics.\n\nThe uncertainty principle says that certain physical observables in quantum mechanics (and *only* in quantum mechanics) are fundamentally incompatible with each other."
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||
4zzdd5 | Why didn't British textile manufacturers' use US slave labor to produce their goods? | In the late 18th and early 19th century British textile mills bought their cotton from the US South, which used slave labor. It seems it would have been cheaper to use slave labor then ship the goods to Europe rather than buy cotton and produce the goods in England.
Why didn't British textile owners set up factories in the US South and utilize slave labor to produce their goods? Would it be because of tariffs? Lack of energy sources in the US South? Were slaves somehow not cheaper than workers in England?
Thanks | AskHistorians | https://www.reddit.com/r/AskHistorians/comments/4zzdd5/why_didnt_british_textile_manufacturers_use_us/ | {
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"British 18th & 19th century industry used alot of cheap labour to begin with. Yes we had Indian labour but we also had prison labour, child labour and also cheap poverty. Irish workers would come from poverty stricken Ireland and would be cheaper to hire than English. Poor children were illiterate as they never went to school and we're put to work in factories for long hours a day. Child labour was very cheap. Most factories would also hire orphans and pay the orphanage the child's wages.\n\nWe had alot of ways to get cheap labour that didn't require slaves since slavery was abolished - we improvised alright if you ask me.\n"
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1v44s5 | why is there a focus to raise min wage instead of creating more working class jobs? | The complaint seems to be that no one can live on min wage, isn't the root cause the lack of middle class living wage jobs?
How does raising min wage not hurt everyone else that is currently making more than min wage due to inflation? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1v44s5/eli5why_is_there_a_focus_to_raise_min_wage/ | {
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"It's much easier to pass a law that states that the minimum wage is now higher. Companies can pay more to their employees and be in compliance with the law.\n\nIt's much more difficult to pass a law that will create new middle class jobs. You can't just have a law like, \"Every company with more than 100 employees must hire 1% more people who each make at least $X per year.\"\n\nIdeally, you'd make more jobs, but it's very difficult to legislate it.",
"Inflation is related to how much people are getting paid, but it has more to do with the actual volume of dollars in existence. Imagine I have 100 dollars, and five employees, and I pay them each 10 bucks. I am left with 50 and they each have ten. Now imagine I double the number of employees I have. I still have to pay them each 10 bucks, but I still want my 50 from the profits. Instead of paying them all less, or something, I can just create more money. I now pay each of them 10 bucks, I still keep my 50, but because there is more physical money out there, everyone's money is worth a little less. That's an extremely simplified version of how inflation works. \n\nThere absolutely is a way to pay people more without increasing the rate of inflation, and that is for business folk at the upper levels to get paid less, so as to funnel more money to their employees.",
"Because minimum wages are determined by the government and most jobs are provided by private companies. While the government does have a lot of employees (6% of all employed Americans, in fact), they cannot force companies to hire more people.",
"Because creating or cutting jobs is the biggest steaming pile in politics. It's used to leverage huge amounts of wasted money and votes. \nThe fact of the matter is that the economy makes jobs. If you focus legislation on prosperity and opportunity (preventing monopolies and hegemonies, encouraging small business and innovation, etc.) and keeping the economy healthy, jobs will come naturally. If more people have more buying power (as opposed to fewer wealthy individuals saving, offshoring and investing) the economy will grow. So it's a much more effective boost to the economy to increase the opportunity and buying power of the people by large (who will spend more money and effectively create more jobs) then to employ a limited number of individuals doing something that the market doesn't necessarily demand. ",
" > How does raising min wage not hurt everyone else that is currently making more than min wage due to inflation?\n\nNo, not at all. At the moment, greedy CEOs are making obscene salaries. The USA has the highest CEO to worker wage ratio in the world (it's 415 to one). While in countries like Japan and Germany, it's only 14 to one.\n\nIn the meantime, the USA minimum wage is at its lowest level since 1950. The USA minimum wage is basically a starvation wage, one cannot live off it. \n\nIf we raise the minimum wage to a livable wage, this will mean that millions of people will not need food stamps anymore. This will help the economy since more and more people can afford to buy things. \n\nWhen economic wealth is too concentrated in the hands of the rich, the economy cannot work. Proof of this is in very poor countries, where the 1 percent of the rich control 98 percent of the wealth. The result is economic poverty and stagnation for the people. ",
"Well the government can and should be directly creating jobs - basically hire people to repair infrastructure that is long past due for upgrades. But that would require more government spending, (which would be good) but guess who objects to that? Republicans, and anyone who is confused as to the actual economic situation. \n\nAnd even then, it doesn't really make sense for the government to be hiring people to do a lot of things. Yes, sure, the government could and probably should hire more teachers, more construction workers, more bank regulators and some things like that. But the government probably shouldn't decide it wants to build a semiconductor foundry or an operating system company or an aircraft maker. Other countries have done that, and done so successfully, but they've usually done so when the private sector wasn't getting its act together, not in competition with their own businesses. \n\nWith middle class unemployment you really need to ask why there aren't jobs? Well, largely it's because there aren't jobs. Wait, what? It's a feedback loop. Without demand for services no one is hiring, and since no one is hiring there's no one with the money to demand services. Seems problematic. Eventually (and the US is starting to enter this now) enough stuff gets old/damaged/ etc that people who have money need to spend it, and the economy slowly recovers. \n\nMinimum wage is more of a coping strategy for everything else, and it doesn't come off the US government balance sheet so it's something people think they can get political traction on. \n\n\n > How does raising min wage not hurt everyone else that is currently making more than min wage due to inflation?\n\nThe US minimum wage is what, 7.25 an hour or something. A bottom tier delivery driver makes about 20k a year (which is basically no skill other than being able to drive). So as long as the minimum wage doesn't exceed 20k a year there need not be upward pressure on any other wages. Basically pushing up the minimum wage squishes jobs together. If you make the minimum wage 12 or 15 dollars an hour well then fast food, delivery driver, construction work etc would all end up at roughly the same price band. But the guy making 40 or 50 dollars an hour isn't going to care. \n\nRaising the minimum wage can actually create employment because the people who make that money have more to spend, and will spend it, thereby employing more people. As much as people complain about 'everything' being made in china, the vast majority of ones expenses end up being local, House, car, food, point of sale costs on all the other stuff, most spending is actually within ones own country (at least if you're in the US or Europe or Japan). \n\n > The complaint seems to be that no one can live on min wage, isn't the root cause the lack of middle class living wage jobs?\n\nRelated but separate issues. If you think people working minimum wage jobs should be independent (which for a long time was not the case, minimum wage was more aimed at students and part time workers) then the minimum wage needs to support that. \n\nThe lack of middle class jobs, yes, it's pushing some people who should be independent down into the minimum wage bracket, but there are also now, particularly in the US, a large collection of people who have essentially no skills and have 'finished' all of their education who need to live on whatever minimum wage will pay, likely for their entire lives. \n\n"
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1dpvqq | Could WWII have been won without America being involved eventually? | AskHistorians | http://www.reddit.com/r/AskHistorians/comments/1dpvqq/could_wwii_have_been_won_without_america_being/ | {
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"Of course it could have. All you'd need is for the Axis nations to screw up and lose, which is of course always possible. \n\nYou'd probably get a better answer for this question in r/HistoricalWhatIf where people are more free to answer such questions. ",
"The U.S. was involved though, and therefore any answer to the question as phrased would be speculation, which [we don't do here](_URL_0_)."
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gujap | After listening to RadioLab's recent episode about symmetry, a question about matter/antimatter has been brewing | They mentioned that for every billion "pieces" of antimatter, there are like a billion and one pieces of matter. And that extra matter eventually accumulates and interacts and forms stars and planets and heavy elements and eventually life. But, if there had been a bias toward antimatter, would/could life still exist as we know it? Would we just be made up of antimatter instead of matter? And we would search the universe trying to understand this mysterious concept of matter? Or would a bias toward antimatter result in a wildly different universe? | askscience | http://www.reddit.com/r/askscience/comments/gujap/after_listening_to_radiolabs_recent_episode_about/ | {
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"Yes, antimatter has exactly the same properties, chemistry, etc. as regular matter; the only reason that one has primary status is because it's what we're made of. We could just as well call what we're made of \"antimatter\" and call positrons, etc. \"matter\"."
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4pza4f | why can the sqrt of 1/-1 not be rewritten as the sqrt of 1/sqrt of -1? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/4pza4f/eli5why_can_the_sqrt_of_11_not_be_rewritten_as/ | {
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"You might want to use some parentheses to make in clear what two expressions you're trying to compare?",
"If sqrt(1/(-1)) = sqrt(1)/sqrt(-1) then since 1/(-1) = -1 and sqrt(1) = 1 therefore the sqrt(-1) = 1/ sqrt(-1) \n\nSo (sqrt(-1))^2 =1 therfore -1=1. Which cant be right...so one of our assumptions is incorrect. The first is the only one that is suspect. "
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19f62s | Have there been any instances in US history where militias abused their power? | Militias played a large role in the history of the United States, and are usually shown to be a group of honorable citizens donating their times and lives to defend their state/territory. But did they ever abuse their power and terrorize Americans? | AskHistorians | http://www.reddit.com/r/AskHistorians/comments/19f62s/have_there_been_any_instances_in_us_history_where/ | {
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"The \"Militia\" as originally termed is all adult males who are neither boys nor very old, the men who would be expected to defend the nation whether they are a part of a federal or state organization or not. \n\nSo yes, adult males did abuse their power during the reconstruction to terrorize and to assassinate black voters and black politicians and to prevent the political empowerment of African-Americans."
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4tw0kr | How does modern science help historians? | In the past few decades, the advancement in computing, genetics and other areas of science and technology has provided new tools that historians can take advantage of. Are there good examples of recent historical discoveries and research that have been possible thanks to new science and technologies? | AskHistorians | https://www.reddit.com/r/AskHistorians/comments/4tw0kr/how_does_modern_science_help_historians/ | {
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"We can distinguish between a number of ways in which modern technology can help historians:\n\n1) **information technology** helps historians analyse millions of documents with much greater ease. This reduces the amount of bias in which documents we find important, because it is easier to step outside of the known and well-studied documents which previous historians have highlighted. The most obvious application of IT are digital databases and digitized records, preferably with the possibility of computationally searching through them for keywords.\n\nSome people do something more complicated, using computer algorithms to analyse thousands of records to find patterns and relationships that are nearly impossible to find manually.\n\n2) **forensics and archaeology** make it possible to analyse DNA to determine migration, heritage and family relationships. It also helps with determining how people lived and why they died. It happens quite often that people excavate some historical figure to run some tests on them, in the hope that modern science will answer some century old questions: did Tycho Brahe get poisoned? Where did Richard III get buried? How did Tutankhamun die?\n\n3) **Physics and Chemistry** There are several techniques to measure the age of documents, artefacts or biological material. Also, we can accurately determine the composition of materials which can help us understand where they came from and how they were produced. We are also able to put stuff in scanners to look inside them and understand their structure without breaking things, and we even have ground scanners to see what's buried somewhere without having to dig. Furthermore, there are very nice methods to analyse damaged documents to figure out what was written on it, using special multi-spectrum lights and cameras that reveal otherwise invisible markings on the documents. This is also used to study pieces of art, to look underneath the paint and see what was drawn beneath it.\n\nPerhaps as a questionable fourth category, we can add **computational simulations** and real-life experiments. These are used to test the validity of historical claims, as it allows you to see what some person hundreds of years ago might have seen. It's not always possible to replicate an experiment in real life (costs, impossible to reproduce situations, etc.), so computers can help a lot. For example, we can simulate how bright a supernova would have been for observers in 1572, or the position of Jupiter's moons at the time of Galileo's observations."
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2otipz | Why didn't the conditions subjected to Germany after its defeat in WWII cause extremism like at the end of WWI? | With Germany losing even more territory, infact being split in 4, being made to pay more reparations, and having to reorient its economy, how come no party exploited those restrictions to their benefit like after the Treaty of Versailles? | AskHistorians | http://www.reddit.com/r/AskHistorians/comments/2otipz/why_didnt_the_conditions_subjected_to_germany/ | {
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"Following World War I, Germany was forced to take the blame and basically left on their own to survive, or not. Following World War II, Germany was split into four zones, occupied by the victorious Allied powers: The United States, Britain, France, and the Soviet Union. The first three essentially merged their zones into what became West Germany, allowing industry to recovery without as many reparations as the first war. With the onset of the Cold War and the grip the Soviet Union had over Eastern Europe, there was little any dictator who wasn't \"friendly\" toward the Soviets could do. Plus, you have the international backing of the United States, Britain, and many others with the creation of the United Nations. All of this was done to make sure Germans did not resort to extremism as they had after World War I. Hope I helped!"
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6fg8e6 | why do we peel potatoes before turning them into mashed potatoes? | [deleted] | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/6fg8e6/eli5_why_do_we_peel_potatoes_before_turning_them/ | {
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"The potato skins don't mash well, leading to them interfering with the creamy texture that most people expect out of mashed potatoes. Of course, it is perfectly possible to mash in the skins as well and some people even prefer it this way (I like a chunkier mashed potato)",
"That's not always done. It's usually done by people who don't like the skin, but there are many recipes, especially at higher-end restaurants that uses the skin. All in all, its just what you prefer ",
"Mashed potatoes are usually intended to be a consistent, creamy white mush. The skins don't mash so if you leave the skins on, there's a bunch of skin chunks in the mash which most people consider less beautiful or a poor texture. However, there are many who disagree and leave the skins on because they like the texture or the look, or are just lazy. ",
"Mashed potatoes made with the skin is often referred to as country style mashed potatoes, and is fairly popular down south. I'm not a fan, but my SO loves them that way. \n\nThe major difference is just texture. The skin stays together through the mashing process, so you get little flakes of skin in the dish.",
"1) Not everyone peels potatoes before mashing. I've had them both ways.\n\n2) The potato skin will produce an uneven texture in mashed potatoes. Some people are ok with this, some don't like it.",
"While texture is definitely a factor, remember there are many varieties of potatoes. Some have skins which are bitter and would not taste pleasent in mashed potatoes.",
"Most of the nutrients in the potato are just below the skin and lost when peeled. Irish person here, you can eat them every which way you want and they will be amazing. Your imagination is the limit! "
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2sliiw | why do computers get slower and unresponsive the longer they are left on/over general time? | My computer which I built a few years ago isn't old enough or obsolete enough yet to tell me it can't reach any options on ctrl-alt-del. So why did I just essentially get forced to restart my computer? Why do I have to deal with perpetual slowness and waiting for the computer to "catch up"?
I run a very tight ship so if it is a problem on my end it isn't because there were hot singles in my area. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2sliiw/eli5_why_do_computers_get_slower_and_unresponsive/ | {
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"There's a number of factors in play, that tend to all add together and compound the issue.\n\nThe biggest one is everything you install. Many programs like to hide their own bloated startup time by doing it all up front, when you turn on the computer. This means part of that program is always running. This makes both the startup slow, and the computer in general slower... but that program sure starts up quick.\n\nOther factors include:\n\n- hard-drive fragmentation (although significantly less of a problem on modern OS's than older stuff)\n- automatic updates going on in the background\n- Other background processes like indexers and servers.\n- Most virus checking software, since a lot of it actively checks what you do, meaning every operation needs to be checked by it. In my opinion many virus checkers are worse than the viruses they try to prevent.\n- Programs based on some technology (COM being a big one) require looking up things in a database of all components registered. More components registered means each lookup takes longer.\n- Just actively running more software simultaneously, this uses up resources, and while no one program seems like it's doing much, it adds up.\n- Hardware faults. Fans frequently wear out, and work worse, heat sinks get loose, chips degrade. If your CPU overheats, modern computers slow them down to compensate, same with GPU's.\n- Viruses... likely not a problem in your case, but it's hard to be sure. Being smart about what you download helps (a lot), but Zero Day exploits are sometimes used... so even if you're careful and vigilant with updates you're not totally immune.",
"Programs and drivers can \"leak\". This means a program asks for a little memory to use and doesn't give it all back when it's done. If there's a section in the program that's called over and over, it will slowly use up all your available memory. When your computer runs low on memory (because it's all allocated to this wacko program) it starts using disk as memory which is really really slow, making things worse. \n\nRebooting causes the computer to clear the memory and start fresh where the whole thing can happen again over time.\n\nIt's incredibly difficult to track down leaks as the OS will not report what's using the memory accurately. Newer versions of windows are better about dealing with this than versions from a few years ago and horrible design choices aside, this is the kind of stability they're working toward. \n",
"True \"LI5\" (confirmed, I know five year olds)\n\nWhen your computer is on, it keeps taking things in, just like you eat things... You might poop a little, but if you keep eating (the computer keeps running programs) it's just going to keep filling up. Little poos here and there help a little, but you're still eating more nachos and getting backed up.\n\nWhen you restart your computer, it's like taking a really, really big poo. Afterwards you're like \"Holy crap, i can run like a million miles an hour.\"\n\n",
"In addition to /u/doormouse76: the \"catch-up\" you experience is due to processes (a specific execution sequence of a program) making requests to the OS, which are kept in a queue in RAM until serviced by the OS. Eventually, the number of pending requests out strips the available space in RAM and everything must start shipping off to disk page by page (a page is a chunk of memory according to the OS). And in the worst case, a single request (kiloBITS at most) occupies an entire page (megabytes on average) as it is migrated from RAM to disk in order to make more space in RAM.",
"Memory leaks, as in doormouse76's explanation. But it isn't likely unless you're having zombie processes or memory leaks in background processes which would be easily noted from the \"task manager\" - they would consume a disproportionate amount of memory, or there would be 200 processes with the same name.\n\nThe second thing that I haven't seen anyone here mention, assuming you're using windows, is that windows is designed to use a lot of swap. Unlike, say, Linux. This means that you need to keep your system disk from becoming completely full.\n\nBut windows just seems to slow down with a lot of applications installed, even if we discount background applications such as Steam. I have no explanation for this phenomenon. The only operations that would scale linearly or logarithmically in time complexity with the number of applications configured would be operations indexing the registry or similar but it makes no sense that any such operations would be performed every time you e.g. load a program or open a folder. But windows is a rather complex beast.\n\nIn my experience, Linux doesn't get slower at all regardless of time or circumstances. You load a program from disk and then it runs, and most background programs spend their time sleep()ing when they aren't doing anything. The only problem is that the scheduler isn't very good for desktop use due to a long-standing problem with overprioritizing I/O, leading to slowdowns when doing things like copying files.\n\nFinally, frankly, you \"running a tight ship\" doesn't really matter much, you probably have a lot of malware anyway. Zero-day bugs are much more widespread than people think and most security precautions other than stack/heap smashing protection is just cargo-cult voodoo, including anti-virus programs.",
"I'm going to go with the very simple ELI5 since /u/doormouse76 has the full answer. The primary memory used on your computer is RAM (we'll ignore cache) and this is what we call volatile memory. This means it only stores its data while the power is on. If we turn the power off, this memory is wiped and gives you that, \"speed up\" you notice when you restart your PC.",
"And i'm just sitting here with my MacBook, with an uptime of 63 days.",
"Funny thing: It takes the same amount of time to start a wordprosessing application to day as 15 years ago.",
"In all honesty if you install your OS on a SSD you'll probably never experience noticeable slowdowns again. You can have the fastest cpu and memory available but if you're still running everything off of a mechanical disk that is a seriously huge limiting factor. \n\nI got a super cheap 120gb SSD and put windows and all my drivers on it (if you get a bigger one like 256+gb feel free to throw all your frequently used applications on it as well!) and my boot-fully loaded times are like under 30 seconds. By doing this you are freeing up your HDD to 100% do whatever else you're doing so it isn't fighting for read/write time with your OS.\n\n\nAnd the reason I say not to throw a bunch of applications on a smaller drive is because of updates and things that don't actually allow you to choose where they're installed to and therefore will just default to your boot drive. These things add up very quickly and a smaller SSD might not be enough for all users. ",
"One thing that no one seems to have mentioned is [feature creep](_URL_0_). Your OS and applications have had features added through updates since you installed it, and this can lead to lower performance over time.",
"**tl;dr** Programs eat memory, cpu power and other resources over time since they are not perfect.\n\nA few reasons are:\n\n1) Programs that run on your computer (including the operating system, OS) require memory to run. \n\nOn your computer there are 2 types or memory: RAM memory and your hard drive. \n\nWhen programs run, they take up a space in the RAM memory, a little at the time. They generally should not take over space they don't need, but since computer programs are not perfect they tend to claim unnecessary space effectively stealing space from other programs.\n\nWhen you open a new program, the operating system tries to make space for it in the RAM memory by writing portions of memory to disk that other programs are not using at the moment. When these portions are needed they have to be loaded back again by the operating system into RAM memory. This process in continuous and very time/computation power consuming.\n\n2) Programs share the power from your computer's processor to run, and even if you are thinking they might be doing nothing at the moment this might not be true. They might be performing to background task or \"awakening\" at regular intervals to check if they have to do anything.\n"
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3mo9sw | how does safety glass work? | How do they get it to crumble into small pieces instead of the big sharp chunks you get from breaking normal glass? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/3mo9sw/eli5_how_does_safety_glass_work/ | {
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"The glass is chilled suddenly from molten. That makes the outside freeze solid before the inside. As the inside cools it contracts, pulling the outer layer into considerable compression.\n\nThis has two advantages. Firstly it makes it harder, to scratch because the surface is so tightly compressed. Secondly, it means the inside is in tension, and has a lot of stored energy.\n\nWhen you finally manage to break it, this tension is released suddenly, spreading throughout the entire sheet, shattering it into tiny bits.\n\nThe technique was developed from a party trick called [Price Rupert's Drops](_URL_0_)"
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2skxu1 | why do people say today's education system is suited well for girls over boys? | Iv heard multiple times (no particular sources just general talk from online articles and in person) that today's educational system favors girls. What is the basis for this and is there truth behind it? I know that in my highschool there were more girls than guys on honor roll, and when I went to college there was a higher percentage of females as opposed to males. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2skxu1/eli5_why_do_people_say_todays_education_system_is/ | {
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"When women were still the underdogs, the government had huge incentive to cater the school system to them, to make sure that more went to university.\n\nBoys were always going to university, since they were always allowed to.\n\nThe trend has just not evened itself out, therefore skewing the system to them.\n\nIn my experience, girls are better at sitting still and boys are better at hands on learning. \n\n",
"Girls generally mature faster neurologically (the female brain is more or less developed by 19-21 while the male brain may be as late as late 20's), girls are generally also more compliant and follow orders better (whether that's due to biology or social conditioning or some of both is up for debate). Generally boys may tend to learn better through \"active\" learning techniques and competition than the current passive learning techniques used in institutions currently. ",
"In addition to other answers here, I think it's important to remember that people will generally bow to societal pressures and expectations of them. \n\nIf a boy is given the general impression by societal by society that he should be more interested in sports, that reading is for losers, etc., then he'll lean that way more than someone socialised to highly value learning (see the 'Asian parent/student' stereotype).\n\nLikewise, when girls are expected to behave themselves and do well in class, they'll feel pressured to meet that expectation or else not fit in properly.\n\nAs far as college goes, nowadays that going to college is often expected for both men and women of middle-class and above, you'll find that there are more women not just because of general diversity, but also because men are more frequently involved in crime, especially the sorts of crime that end up in a prison sentence. There's a gif somewhere of Manhattan/NYC by age and gender which is really interesting. Everywhere's mostly equal with some notable exceptions, such as the financial district being male-heavy after the age of 21... but between roughly 17 and 25, suddenly boom, suddenly the college is full of women, and the prison gets its new inmates. \n\ntotally opinion of mine, not actual fact: I don't think it's the schools that are wrong in how they're educating children. I think it's parents and media that are failing boys during the schooling years. The different expectations put on women mean that it fails them too, but it doesn't kick in until adulthood, because they're not seen as negative during childhood (keep quiet, do as you're told, play with your dolls, grow up and find a nice husband, be polite, etc.).",
"I'm curious if the gender disparities hold true in non-western countries like Japan, India or China. ",
"There are also studies that show teachers over discipline male students and grade them more harshly. In addition, certain teaching techniques are now catered towards girls. Add on to that the scarcity of male teachers, fact that it is uncool for boys to do well academically, and most programs being for girls only like the stem things and you begin to see the disparity. Of course, boys still seem to do better on standardized tests. It is funny that that is due to unfair objective testing but girls excelling in grades is because girls are smarter and made of sugar and spice and everything nice.\n\nThe disparity widens when it comes to minorities as well. But with common core and some of these other programs, neither girls or boys are getting a very good education."
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3notkz | How does heat affect the wavelength of radiation emitted? | I get that there is more energy and so on but I thought that a specific element had a specific energy level needed to make an electron leap to the next shell. Wouldn't this mean that an element can only emit one wavelength of light? If so why does iron glow red and then white as it is heated? If not how do we use wavelength of radiation to determine what elements are in distant galaxies? | askscience | https://www.reddit.com/r/askscience/comments/3notkz/how_does_heat_affect_the_wavelength_of_radiation/ | {
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"This is because there isn't just one specific transition going on. An element can have multiple electrons and they can undergo multiple transitions at a time. If the substance is heated, then the molecules and atoms vibrate. Each of them can have an available energy (say E0) that they can utilize to go to higher states. But only those possible transitions with energy difference below E0 can occur. This available energy is less in lower temperatures, so there are fewer possible transition states that can utilize this (they have lower energy difference so the light is predominantly red), as temperature increases the available energy is larger and hence there are many possible transitions, so more colors get emitted and this tends to be seen as white. Furthermore, in the case of heating an iron, the iron isn't perfectly pure and will contain traces of impurities like carbon, sulfur which will contribute to its glow with their own spectrum.\n\nHowever, the spectrum of light emitted is not continuous. You see a white light, but that doesn't mean that it contains all possible frequencies of light. In simple terms, if you pass the light coming from a hot iron bar through a prism, you will not see a a continuous rainbow. Instead you would see lots of solid bars like in the picture. _URL_0_\n\nEach of the bars represent the light that is emitted from a specific transition. Since each element has its own set of electrons with their own allotted energy levels, it will have its own unique spectra. So you can compare the spectra of galaxies with known spectra of elements like Hydrogen or Helium and you can know whether they are present in those galaxies or not."
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1kq1ko | why doesn't the mlb drug test every player monthly/weekly for steroids? | It seems to me like one way to solve the PED problem in baseball would be to just test every single player in the league on a regular basis. Is it that MLB doesn't really want to catch everyone? Do they think the game would get boring without players cranking HR's all day? Is it too expensive? I know its not too expensive in the sense they can't afford it, but too expensive in the sense that its not worth the trouble to them. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1kq1ko/eli5_why_doesnt_the_mlb_drug_test_every_player/ | {
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"My own personal theory is that they really don't want to catch players and only drug test and punish PED users to make the game more family friendly.",
"Because anything like that would need to be included in the collective bargaining agreement with the players' union. The players are, naturally, opposed to having to give a urine sample every week of every season. In order to get something like that included in the CBA, baseball would have to give up some pretty major concessions.",
"You have to realize what has happened in baseball in the last 15 years. We went from a culture where everyone ignored the problem to where the players would say that steroids did not help you to being dragged by Congress to implement a joke of a policy. But finally, things have changed. Some players are now calling out for harsher punishments. A-Rod got thrown at by another player because his relation to steroids. \n\nHR's have been down the past several years to levels in the early 90s which would make you believe that steroids have been removed from the game for the most part. \n\nIn MLB and the Olympics you are not going to catch everyone but that is not what I see as the problem since these are the only two sports that actually attempt to remove steroids from the sports.\n\nOne of the people that released the information about this current steroid scandal has said that he has names from other sports not limited to the NBA, NCAA, high schoolers and the Olympics and yet not a one of them have called him except for MLB. The NFL stated that they would start doing HGH testing but its been 2-3 years and that has not happened.\n\nBasically, MLB is never going to be 100% clean again but unlike many other sports at least they can look in the mirror and say that they are trying.",
"Player union would never stand for it. The more steroid usage the players get away with the longer their careers and the more money they're likely to make. "
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2vlqrz | when did rc toys start being called drones? | Is there an actual differentiation? I've heard the explanation that one has a camera, but then its just an RC Helicopter with a camera on it. I feel like its a media buzzword that has turning into common language. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2vlqrz/eli5_when_did_rc_toys_start_being_called_drones/ | {
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"The FAA says a drone is an unmanned air vehicle that can be flown beyond line of sight. Other uses are buzzwords.",
"Drone: \n-A radio-controlled pilotless aircraft or missile\n-Unmanned aerial vehicle, or UAV\n-Unmanned combat aerial vehicle, or UCAV, a UAV for combat\n-Quadcopter or quadrotor helicopter\n-Robot vehicle, in general\n\nPs: nowadays they (companies) decided to rename RC helicopters and related products because DRONES are a hot topic in the society right now, so, something with that name on it, will sell quite well... Of course they will claim that it is indeed a drone, with the excuse that they added a camera into the RC helicopter and therefore now you can see what the equipment \"sees\" and in a more advance level you could add for example a gun and \"fire\" something with precision - drone!",
"When it became convenient click-bait for the ignorant masses.",
"When they can fly themselves without an operator controlling them.\nI have built 5 autonomous aircraft, and dozens of RC craft. I only call them a drone when they are capable of taking off, flying a route, and landing without an operator touching the sticks.",
"When they stopped being toys and started being tools. Quad copter isn't catchy enough anyway",
"Can we stop calling them drones. It gives them a negative connotation. They're toys. Radio controlled toys.",
"The meanings of words change over time. Additionally, words mean different things in different contexts. So while \"drone\" might mean something more specific in a technical or industry context, it can mean something else in a common usage context.",
"When it became cool to be a \"Drone Operator\" rather than \"RC Toy Enthusiast.\"",
"When the media decided to leverage the negative connotations associated with 'drone' to sensationalise things.",
"My understand is that a we fly model aircraft. some airplanes gliders jets helicopters multi rotors (quad copter is a 4 motor multi rotor)\n\netc.. etc..\n\n\"technically\" all model aircraft are UAV (even paper airplanes) but in reality when we say UAV what we really mean is FPV.\n\nRemotely piloting from onboard but not inside (so with a camera typical or a GPS interface)\n\na DRONE today means anything the media wants it to be typically quad copters.\n\nbut in reality a drone would for example NOT be a phantom. that is a quad copter or fpv UAV quad copter.\n\na bebop on the other hand would be a drone.\n\nto me (and the military) a drone is a UAV that does not REQUIRE a pilot. it can and does fly itself.\n\nto explain the difference. Think of a car. you drive the car. now think of a car where you don't drive but instead give instruction to another driver. you tell him what you want and he figures out how to do it.\n\nnow replace him with a machine. a computer. that is a drone.\n\nwhen you fly a quad copter you have to command up and control how much up and left and right etc..\n\nwhen I fly my bebop I do not take off. I instruct the drone. \"take of\" and it \"does it\" with no involvement from me besides initiating the command to \"take off\"\n\nI flipped it over once because I tried to land it. it is not designed for me to land it. I get low and I press the \"land\" button and IT lands.\n\nit will hold position and altitude. I tell it I want to go \"that way\" and it goes that way figuring out how to do it adjusting to maintain altitude unless I also commanded it to change that.\n\nit could be argued that is a drone. with an update I will actually be able to give it a mission.\n\nPhantoms CAN be drones. example you can command a phantom to \"return home\" and it will try and fly back from where it took off from and land. it does this with no input from you.\n\nthat makes it a drone.\n\nso a drone would be a flying machine that can fly itself including a \"mission\" start to finish with no instructions from you except to \"do it\"\n\na really good example of this would be the IRIS+ that \"IS\" a drone.\n\nwith a drone you are \"less\" a pilot and more a coordinator/operator.\n\nwe don't have many TRUE drones more hybrids like the bebop phantom and iris+ with the iris+ being the closest to a true drone that I am aware of.\n\nhope that helps.",
"When they stopped being toys basically. RC toys were for entertaining primarily, whereas drones as used commercially as actual tools.\n\nSame reason you wouldn't call an actual digger a toy, but you would call a small plastic one a toy. Its all about purpose and what it is used for.",
"When idiots started flying them near airports.",
"If it has GPS and can be programmed to fly autonomously by giving it a set of waypoints, it can be referred to as a drone. If it needs a human operator with a remote control unit to guide it at all times, it's an RC aircraft.\n\nThat's my informal definition but I think it's a good guide. The DJI Phantoms are definitely drones as their flight path is programmable. I'm not so sure about the Parrot ARs as it seems to imply you must guide it at all times, even if it has a computer system to stabilise its flight.",
"I thought the idea of drones is that they require no control from the human e.g. you plot out a course before hand and the drone flies the route.",
"When the military started putting bombs on them.",
"RC toys become drones with the addition of one of two technologies; cameras and autopilots. ",
"As a member of the hobby, I have thought about this. \n\nIt is largely a buzzword I think, but I think it stems from the origins. These multirotors (quadcopters, octocopters, etc) have been around for a while as experimental aircraft. But they didn't become a mainstream trend until autonomous flight systems started to be developed. \n\nA lot of robotics labs adopted these quads as a platform for autonomous flying machines. Then that technology started to seep out into the public market. \n\nTake the best selling \"drone\" for instance. The DJI Phantom. It will fly *for you*. There are so many little digital nannies on it that it takes absolutely zero skill or practice to fly one. You could literally teach a monkey to fly it. Which is why it's so widely adopted. (as opposed to traditional helicopters that take quite a bit of skill and practice). \n\nThese new quads have GPS hold to keep it from moving outside of a column of airspace, altitude lock that keeps it at a certain height, bubbles around the pilot to keep the quad from hitting them, limits on how hard it can bank (so it won't stall and crash).... They even have a \"return to home\" feature where the drone will automatically fly itself back to where it took off from. \n\nPiloting one of these things has more in common with operating a computer mouse than it does with actually Piloting an aircraft. So with that said... The machine is making a lot of decisions for itself. \nThis isn't like an airplane that you take out and fly around. It's more like a machine that you direct it where to go and it flies itself. So I think the reason these call called drones and helicopters and airplanes aren't... Is because they have increasing abilities to make their own decisions. \n\nLook at the Amazon delivery drones. Really, the only difference between those and most other quads is that they are taking their orders from a computer system instead of from a human. ",
"[I think they are called like this since 1946](_URL_0_)\n\nSo, there's that\n\nEdit: although, this seems to be only for flying devices",
"More on the use of the word \"drone\" in an article I wrote last year: _URL_0_\n\n\nMost people in the hobby are cool with the term at the moment. There's drone user groups and people don't see \"drone\" as a bad thing anymore. It's time to just embrace it and move on. ",
"sUAS tech here. In the industry we despise the title \"drone\", due to its relation with systems like the Predator, which has built up a hefty kill count for the military and the CIA. \nHowever, our products are not for hobby enthusiasts either. The cheapest unit we sell with video transmission is the DJI Phantom (fully loaded its a bit over a grand). The most expensive unit we sell is $300k and is used by the military. \n\nMost of our customers are aerial photographers, who use the multi-rotor platforms for building inspections and documentary film making. Others are getting units outfitted for search and rescue and fire fighting purposes. The last group are farmers, using our fixed wing platform with specially designed cameras to map farms in several light spectrums to determine the health of the crop. \n\n",
"RC you control on the fly at all times. Drones are programmable for precision. You change their pattern via programming and not by direct control. ",
"When did eli5 become Google?",
"When I went to MakerFair this year, nearly every exhibit was 3D printers or Drones. My favorite was the RC tank called a \"***Ground Drone***.\" ",
"It's marketing flavor of the month. Just like 'cloud' being used where 'internet' or 'online' use to be.",
"Its the media associating radio control aircraft with actual miltary drones in a fear mongering campaign, as the media says \"if it bleeds it leads\". The weird part is that they have only associated the word \"drone\" to multirotor aircraft (three or more blades, tricopter, quadrocopter, pentacopter, ect) as if they are the only radio control aircraft that could be used with a camera, however I personaly fly FPV (first person view) with a plane and a helicopter because I prefer the speed and agility of these types of aircraft over multirotors, and the plane can fly a bloody lone way on a single charge. Unfrortunatley I work in a hobby shop were we sell radio control aircraft and I have to listen to people come in all day asking for \"drones\" to which i reply \"you mean multirotors right?\" leaving them looking confused. What is probably the most annoying part of all this \"drone\" buisness is the idea that being able to fly them is A. Easy. and B. That building/installing a system that would give any decent range (over 300m) is easy to do, yet laws are made up against them for the fear of people making them.",
"They are still RC toys, drone is just the latest marketing term glued to it. ",
"RC aircraft require line of sight to fly. Drones can fly remotely without having to stay in range of sight. ",
"Drones are somewhat or fully autonomous. Old school RC toys only took inputs from user. Drone \"toys\" can do programmed tricks or even have sensors to self-navigate. I don't see a problem putting a new name to such things.",
"Meanwhile, when did Dress Up become Cosplay?",
"There is a Wall Street Journal article that addressed some of the struggles companies in the industry are having with classifying machines under the word 'Drone'. It also talked about some of the historical origins of the word 'drone' which I found particularly interesting. \n\nFound it!\n\n_URL_0_\n\n\"However, it was the military that originally nicknamed the devices “drones,” said Ben Zimmer, a lexicographer who has researched the history of the term. In 1935, the U.S. Navy began using unmanned aircraft as aerial targets for shooting practice. The British Royal Navy had named its unmanned target aircraft the Queen Bee, Mr. Zimmer said, so in homage, the Navy called its targets “drones,” which means male bee.\"\n",
"About when computer programs started being called \"apps.\"",
"A drone has to have some sort of autonomous flight capability. Some of the models of quadcopter that have become popular such as the Dji Phantom do have autonomous flight capability such as following gps waypoints and return to home when signal is lost and so are actually drones. The media and people are stupid though so now anything that flies is called a drone.",
"When we started building quadcopters that fly themselves. The name fits, just unfortunately carries multiple meanings, some with negative sentiment attached. ",
"When the Government and the News Media colluded together to drive fear and disinformation about these toys, and decided to regulate them and arrest people for flying them.",
"I was listening to NPR a few days ago and they had a segment on this exact subject. I cannot remember which program it was, but I will look. \n\nFrom what I remember the term drone has been around since the 1930's and was used to describe anything that was remotely controlled. During the 50's to current Hollywood did an incredible job at demonizing the term drone. \n\nThere is a key difference between a toy RC device{car, boat, quad, plane, chopper, submarine, etc.} and a drone, and that is that the drone has a live action camera that allows the operator to see from the device in real time. ",
"I believe it is called a quadcopter in the rc world.",
"A drone used to be only termed for military UAVs (remotely piloted). These UAVs can be the size of a small passenger aircraft, armed with weapons, or just purely for scouting / reconnaissance. These UAVs are generally piloted by military drone pilots from far away to provide support toward ground troops stationed in other countries (e.g. middle east for USA) \n\nThe term \"drone\" was coined from the general public is synonymous to quadcopters. To understand where the phrase \"drone \" = \"quadcopter\", you need to understand how quadcopters became popular in the first place.\n\nBefore quadcopters, small RC based flying toys were essentially miniature scaled versions of helicopters. These toys had limitations in stability when it came to external forces such as wind, and do not stabilize nearly as well for camera feed. Plus cameras back in the day used to be seriously bulky, poor resolution, and there were no smartphones to catch remote feed/control. People only saw the use of RC copters as merely just as a fun toy for kids to play with. \n\nWith the progress of technology and ability for microcomputing, improvements in manufacturing (i.e. 3d Printing for example), understanding the algorithms (ease of access on programming modules as well), mechanical engineering, etc are making quadcopters very affordable. You can buy a quadcopter or even build your own for ~$500 to ~$1000 and there's lots of media press following behind it\n\nThe main professional application of quadchopters is with remote camera feeds, as the quadcopter can support a payload the size of a camera (i.e. GoPro and other cameras). Professional SFX, movie makers, real estate agents (not legal in most cases), photographers, etc. rely on aerial based feed and views to entertain an audience or achieve a marketing based objective that was not possible in the past. Not only that, there is also potential for quadcopters to carry higher payloads to deliver packages in dense locations (i.e. Amazon had a marketing fun day with this, quadcopters are not actually used to deliver packages on a wide scale application yet) \n\nBecause of all the buzz and usefulness of quadchopters in the professional world, the media has picked up on it. Media sources such as SFX based youtube videos like freddiew, GoPro videos, Amazon's quadcopter marketing last year?, TV media outlets, combined with the affordability and ease of access to buy one has made it popular.\n\nBecause the media generally oversimplifies things (i.e. dumbs down things, as people of all intelligence need to understand them), and the word \"quadcopter\" is too long for people to remember (3syllables). Therefore the word \"drone\" is used instead as there are technically both UAVs (unmanned aerial vehicles). Drone is just 1 syllable, and catches easier with the general public, and therefore a catchier marketing term. \n\nNow that the word drone is mixed up with quadcopter, news outlets tend to confuse military based drones with civilian based helicopters. It is very well possible to equip a modern day quadcopter with a payload large enough to handle a gun though, as seen on FPSrussia on youtube. Because the general public doesn't understand how quadcopters work, and the mysterious nature of drones, there is fear when it comes to these.\n\nNot only fear in weaponizing quadcopters, but more generally speaking invasion of privacy. Those quadcopters can be seriously loud, and draws lots of attentions. Who wants a quadcopter with a GoPro sneaking up from their privacy of their own house window, etc? With the avenues of easily uploading and permanently putting things up in the internet for the world to see, there's obviously fear of being recorded of you doing stupid things, which is a legitimate concern.\n\nTL;DR drones used to be for military applications (UAVs). Quadcopters and the progression of technology has made it affordable to anyone, and quadcopters have some possible implications that people do not like. The media has a fun day with quadcopters and calls them drones because its shorter and easier to memorize, plus has all the potential buzz of military drones. General public starts using the word \"drones\" more so than quadcopters now. \n",
"When they put cameras and microphones on them.",
"I had asked this in a local subreddit discussion and I think there are some pretty valid points for certain RC toys/quadcopters.\n\nSome quadcopters (like the one that crashed on the White House lawn) have the capability to fly beyond visual line-of-sight using on-board cameras connected to transmitters (for first-person-view (FPV) flight). I have a toy RC quadcopter that has an on-board camera, but I cannot fly it (safely) beyond visual line of sight because there is no transmitter (with an associated pilot's display) to allow that.\n\nFurthermore, some quadcopters can also be programmed for autonomous flight using pre-programmed GPS waypoints. Even without FPV capability, having it completely autonomous from launch to landing is not what you typically see in RC toys.",
"When the toys became autonomous via autopilot. ",
"When marketing teams wanted kids to feel more excited about their cheap pieces of plastic.",
"It's not a drone unless it has some form of autonomous flight. So like DJI phantoms are drones because they come back to you automatically, where as Parrots (even though they are marketed as drones) as just shitty pieces of crap that no one should buy. ",
"its not a drone... its a quadcopter. if it flies it's self it is a drone, if not its just a quadcopter",
"When the public narrative suddenly became that they were scary privacy-invading devices of evil.\n\nWhat's worse is that *people who own them* have started calling them drones themselves.\n\n",
"When those quadcopters became popular. People started calling them drones but by definition any rc toy is a drone. ",
"Drones are a more serious name for the same thing. Nobody working in the newspaper industry would print \"25 People Killed In RC Toy Attack!\" with a serious story.",
"To me an RC toy is an externally controlled craft which is intended to imitate a larger craft. It is built and used with the intention of being used recreationally. They don't have any purpose beyond that and therefore dont require innovation.\n\nA drone would be an externally controlled craft which is built and used for a job, or used as a utility. Therefore they don't have to be modelled after a larger craft, as they can be simplified or more complex depending on what it needs to do. \n\nJust as a note, when I say that an RC toy imitates a larger design, I mean that it imitates a whole model. Like an apache. Obviously drones need to use technology such as a compustion engine which is used in previous designs, but that (for the purpose of defining here) would not be considered imitating a previous design.\n\nI think this seperates it well. If there was a team continuously developing a quad rotor as a better alternative to some other design, then I would consider it a drone. However if they complete the design and someone buys one to use at home, I would consider it an RC toy.\n\nI think this separation works well. There is obviously a bit if grey area in which it becomes a but messy but that is the nature if some definitions. ",
"The use of the word drone predates the military drone program.\n\nRC flying toys have always technically been drones, we just started using drone more in our modern vocabulary due to the military ones being in the news. So now that we are used to saying the word, we use it for more things that it has always applied to."
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32rbr3 | the different kinds of military aircraft; their roles and "generations" | What's the different between 4, 4.5 and 5th generation?
What do multirole and air superiority aircraft actually do?
How does a country's military decide what it needs and what kind of aircraft they should get? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/32rbr3/eli5_the_different_kinds_of_military_aircraft/ | {
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" > How does a country's military decide what it needs and what kind of aircraft they should get?\n\nThe military decides what equipment it needs to fulfill the goals its countries leadership wants it to do. For most nations, this may mean having fighter aircraft that can defend its airspace and perhaps participate in limited engagements worldwide - in which case, a military will decide which aircraft best fits that bill.\n\n > What's the different between 4, 4.5 and 5th generation?\n\nTo explain what a fighter jet generation is, let's look back from the first:\n\n* The first generation jet fighter is that built during WW2 through the Korean War. This includes the range from the German Me 262 through to the F-86 Sabre and MiG-15. These are primarily WW2-type fighters with the first jet engines and so they use guns and fly in similar styles to that of WW2 fighter planes.\n* The second generation fighter jet incorporated much more powerful afterburning engines along with advances in aerodynamics (such as swept and delta wings) that permitted fighter jets to reach supersonic speeds. In addition, the first infrared and radar guided missiles became the primary armament of many of these 2nd gen fighters, who were also much larger and could carry more fuel and even the first radars. Analog avionics started appearing as well. These fighters were focused primarily on being fast at high altitudes because the thought was that the next war would be based on a nuclear war.\n* Third generation aircraft further refined second generation aircraft, but with more advanced avionics and a heavier reliance on missile technology that had grown to allow longer ranges than before. Radars were more powerful now and this increase in versatility allowed fighter jets to start taking on ground attack roles. \n* Fourth generation aircraft took the lessons learned from third generation aircraft and put a renewed emphasis on maneuverability. Indeed, fourth generation aircraft pushed aircraft designs to the limits of human tolerance of high-G maneuvering as well as the limits of aircraft in general. More powerful engines, and advanced avionics entered at this time. The first digital cockpits as well as digital fly-by-wire designs were introduced in this generation as well. Ironically, while the fourth generation designs renewed the idea of aircraft focused solely on single missions (e.g. F-14s were interceptors, F-15s air superiority fighters, F-16s light fighters), their designs were so flexible and digital avionics so powerful that all these aircraft started adopting multi-role capabilities again.... which leads to Gen 4.5 aircraft.\n* Gen 4.5 aircraft are primarily Gen 4 designs built with the latest advancements in avionics and digital flight controls in mind. Aircraft like the Eurofighter Typhoon and the F/A-18E/F Super Hornet fit this model: they were all designed in the 80s and 90s for the digital age. Advanced powerful radars, digital/glass cockpits, and advanced flight computers have pushed these aircraft to do aerodynamically impressive maneuvers while affording single pilots the ability to execute air-to-air and air-to-ground missions all in one trip.\n* Generation 5 aircraft are primarily considered to be aircraft designed from the ground up to be stealth fighters. They not only have the shape of stealth aircraft, but they have classified techniques to mask their compressor blades, have classified radar absorbent materials, etc. In addition, these aircraft are built from the ground-up with digital cockpits and digital flight controls in mind, so they aren't designed with very much consideration on traditional aerodynamic stability in mind. Couple this with advanced engines capable of supercruise or thrust vectoring, and the most powerful avionics in the world (including the ability to share data with other aircraft), and they are thus a step above what Gen 4/4.5 aircraft are capable of."
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3nxho8 | what is the difference between a language and a dialect? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/3nxho8/eli5_what_is_the_difference_between_a_language/ | {
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"Both refer to a particular form of communication; they're the same general sort of thing. The actual line is **incredibly** fuzzy; Chinese is considered a language, but \"dialects\" of Chinese have more differences than the various Romance languages. There's a saying that \"a language is a dialect with an army and a navy;\" having something be a *language* is often of cultural importance.",
"[/r/linguistics has had various posts about this topic.](_URL_0_)\n\nThere is no absolutely iron-clad method deciding whether two things or \"[varieties](_URL_3_)\" are dialects of the same language or two separate languages.\n\n Why people decide two varieties are the same language or not can become a political question: in Yugoslavia there was an official \"[Serbo-Croatian](_URL_5_)\" language though after the breakup of Yugoslavia involving separate years of ethnic conflict and war, [there is now a \"Serbian\" language in Serbia distinct from a \"Croatian\" language in Croatia](_URL_1_). How people speak in former Yugoslavia hasn't changed radically, but whether or not people say they speak the same language has changed due to politics.\n\nUsing [whether or not people understand each other](_URL_2_) as a criteria for where or not people speak the same language can be tricky if [understanding is asymmetric](_URL_2_) or if there is a [dialect continuum](_URL_4_), where how people speak changes gradually as you travel through a region and people on opposite sides of the region might not understand each other, but there is no obvious place to draw a \"border\" between two languages.\n"
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"https://en.wikipedia.org/wiki/Dialect_continuum",
"https://en.wikipedia.org/wiki/Serbo-Croatian#Present_sociolinguistic_situation"
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1wwpwg | What prevented the unification of Europe through inter marriage of the ruling families? | The nobility in Europe from the middle ages onward was constantly inter marrying and as time approached WWI the signs of this were extremely apparent with genetic disorders from inbreeding. My question though is aimed at isolating the reasons why kingdoms such as France and England didn't simply arrange a marriage to unify their empires, or when they did, this union didn't continue on to the next generation to bring in others such as Spain, Austria, and Denmark.
Was there a mindset that if a king had one daughter and she married into another kingdom, that the girl's father had ended his bloodline or lost in someway?
Was it the fear that other nations would take action against a union, as in the War of the Spanish Succession?
I recognize that there are many forces acting to break kingdoms down, such as inheritance dividing the holdings between sons. I would like to hear some opinions on what prevented sudden and massive unifications. | AskHistorians | http://www.reddit.com/r/AskHistorians/comments/1wwpwg/what_prevented_the_unification_of_europe_through/ | {
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"Bloodline was certainly important - a marriage of families could well end one house's power over a kingdom.\n\nAlso, consider the laws of succession differed greatly between countries. In England, a female could inherit the throne - in France, a female could not. Thus a female could become Queen of England but her male cousin might be the one who inherits the Kingdom of France. \n\nKeep in mind that the modern nation state is a much more recent idea, and that we are talking about titles being inherited more than entire empires. Charles V was Emperor of the Holy Roman Empire as well as King of Spain (and the colonial Spanish Empire) - but he voluntarily abdicated in favor of his younger brother who became Emperor of the Holy Roman Empire and his son who became King of Spain. The idea that they could become a unified superpower simply didn't exist given the disparity/difference in how the two entities were run or simply existed.\n\nUltimately though, I don't think it's all that different from why modern countries don't get together and just unite. Even within the EU, there is major dissent between the various countries about the level of integration. It could be pride, an issue of practicality, economic/social differences, etc.",
"The Habsburg family actually created an empire - mostly by means of marriages. They could have united Europe, but the foreign policy of Richelieu stopped them during the thirty year war.",
" > > My question though is aimed at isolating the reasons why kingdoms such as France and England didn't simply arrange a marriage to unify their empires, or when they did, this union didn't continue on to the next generation to bring in others such as Spain, Austria, and Denmark.\n\nThis was basically what the Hundreds Year War was about, the English house of Plantagenet had a better claim on the French throne than the French House of Valois did. The reason why there was a war was because the French nobility refuse to accept Edward III's claim to the throne and instead nominated the Valois branch of house of Capet onto the throne. One of the reasons is that there's too many regional interest groups against the an incoming foreign ruler in a large percentage of the cases. For something as powerful as a throne there were simply too many other claimants to it for one house to hold it for a long time. Even in England itself, the Plantagenets would destroy themselves fighting for the throne. \n\nThere was also the fact that even personal unions didn't have to be unifying, the Hapsburgs under Charles V for instance, theoritically ruled Portugal, Castille, Aragon, and Austria and the Netherlands at one point in time. Yet the governments of each of those places remained independent and not integrated with each other. This is especially striking of Portugal and Spain, even though they are right next to each other and had the same king, they were not integrated with each and Portugal would eventually gain independence. The means by which pre-modern monarchs could rule over vast territories was simply too limited for a pan-European monarch to be viable on the long run.",
"That is a good question, actually. An important aspect of this dynamic is the fact that each kingship or lordship is a distinct legal entity. James I of England, for example, was also James VI of Scotland but the two remained separate realms who happened to have the same sovereign. It wasn't until the 1707 Act of Union that they became a single political entity. So even where a single person had amassed a huge stretch of territory, they often were not a single cohesive unit which makes them subject to instability. It is difficult to be a king in absentia and hold on to your rule, but with a large empire it is impossible to be present everywhere, especially in an era in which travel was so difficult and lengthy.\n\nIt is also important to consider the sentiments of the leading lords within a country as well. A King can't rule effectively if he spends all of his time fighting his own lords. And the lords' aren't going to be pleased at the idea of a stranger staking a claim to the throne. Jealousies and grudges between countries are a powerful deterrent to this kind of thing.\n \nThat is part of the reason why Mary I of England, for example, forced her husband Phillip II of Spain to sign a pre-nup saying that he could not claim title to the English throne. The English leading citizens were not about to allow a foreign born Catholic of all people to come usurp the English throne just by marrying Mary.\n \nBasically long story short, administering and ruling a country was hard work. Ruling an empire was even harder. Ruling an empire that spanned the entirety of Europe - with all the cultural, religious, ethnic and linguistic diversity therein - is nigh on impossible. Other countries will see the weakness inherent in trying to control all that and use the opportunity to snap up your stuff. "
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3a0npn | why are some letters in the old latin script revsersed to the modern latin script? what happened in the evolution of the old script for some of the letters to be turned around? | I'm researching the Duenos Inscription, and one of the things I've noticed is that a lot of the Old Latin letters are very similar to Modern Latin script, just turned around.
For example _URL_0_
Letters like L, K, F, E ect are just turned. Is there a reason for this? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/3a0npn/eli5_why_are_some_letters_in_the_old_latin_script/ | {
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"Originally, it was written from right to left. The script descended from Semitic scripts like Canaanite and Hebrew, which is still written right to left to this day.\n\nThe problem is that most scribes were right-handed, and this makes writing right to left difficult: scribes would have to be careful not to drag their hand across what they had just written, smudging it (I am left-handed, and find it nearly impossible to use a fountain pen). So they switched to writing left to right, and during that process, as well as switching the direction of writing, they also reversed the letters."
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1sc9t9 | To what extent did the Native Americans really think the white Europeans were gods and how long into the abuses by Europeans did the natives really internalize that these people were not gods. | The first question is self-explanitory. What I mean by the second question is: if they truly believed that these people were gods, would they have accepted some amount abuse from them (since these gods could have been angry). Would there have been some breaking point where they finally say, "wait a minute, these are just people!"? | AskHistorians | http://www.reddit.com/r/AskHistorians/comments/1sc9t9/to_what_extent_did_the_native_americans_really/ | {
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"[A similar question](_URL_0_) came up a few weeks ago, and I gave a long answer there. To summarize, we don't know for sure if they did or didn't, but most scholars today seem to think they didn't. If there is truth to the claim that they did think the Europeans were 'gods,' it wasn't a belief that they held for very long, and the issue is still complicated by different understandings of divinity."
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3h4p0f | why does a vacuum 'suck'? | An empty space, not the machine. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/3h4p0f/eli5_why_does_a_vacuum_suck/ | {
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"It's not actually that a vacuum sucks, but that any gas will spreed out as there is nothing to contain it. It's just something of higher pressure will move towards lower pressure to even it out.",
"It's not really a \"suck,\" it's a push. But, first, some background. \n\nWe tend to think of most of the world as \"empty.\" Think of the air around you. It seems almost non-existent, right?\n\nBut, it turns out that there are trillions upon trillions upon trillions of molecules in a given volume of air. [There are only about a thousand times as many molecules in the same volume of diamond.](_URL_1_) \n\nAnd, those particles are MOVING. Here's a simple calculation putting their speed at about [1100 mph](_URL_0_). \n\nSo, when you have a vacuum---a space where there really are virtually no particles, it's no surprise that whatever is around them would try to fill the space very quickly. And that's what happens, creating the \"suck.\"\n"
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cc0a3z | Do non-Western historians, writing in their own languages and about their own cultures, use BC and AD, or some other "year zero"? If so, what is it? | AskHistorians | https://www.reddit.com/r/AskHistorians/comments/cc0a3z/do_nonwestern_historians_writing_in_their_own/ | {
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"Depending a bit on what \"non-western\" means...and with the permission of mods I'm gonna answer this about history-adjacent academia more broadly...\n\nA lot of non-western historians write in western languages (which nowadays usually, but not always, means English) frequently, so their work can be read by the widest possible pool of scholars. Additionally options for publication are much more plentiful in English. When writing in English, dating is generally BC(E)/AD/CE.\n\nHowever, Jewish academic fields sometimes also write in Hebrew. Besides the fact that a large share of Jewish-focused academic fields are Israeli, Hebrew is extremely important if not essential for a lot of Judaism-adjacent specialties (though the level needed to read a text is generally lower than being able to write an academic paper). But perhaps more importantly, there is an extremely long literary tradition of the language of Jewish scholarship being in Hebrew, even when it was not anybody's first language.\n\nThis is particularly evident in Rabbinic-adjacent fields, where the writers may be discussing the history of a subject in Rabbinic texts. They may tend to write in Hebrew and use features of Rabbinic literary Hebrew (*tons* of specific acronyms, occasional Aramaic phrases, technical jargon). In such a case, they'll tend to use the Jewish dating system, in called \"AM\" (anno mundi), which counts years from biblical creation using a particular calendar arithmetic as calculated in the *Seder Olam Rabba*, a text which works out the age of the earth from the bible. Prior to that, years from the Seleucid era was the main way to reckon years, which continued through the Middle Ages in pockets, and sometimes much later (especially in Yemenite texts). In Hebrew the millenium is usually dropped, so this year is תשע\"ט (which is the way to write 779 in Hebrew letters, but the year is 5779).\n\nBut here the border between religious text and academic text is often not really clear. There are journals that publish Jewish scholarship that might affect religious practice, and where most pieces are written by Rabbi-academics, where their bio will mention both their Rabbinic ordination and their degrees. Some publish pieces in both Hebrew and English. Both are intended for the audience of a combination of academics (who are mostly Jewish), Jewish clergy, and educated laymen. While both are written for slightly different audiences (the Hebrew being more for Israelis, the English for Americans) in reality the audience can mostly read both, it's a question of who'll have an easier time (and decide to pick it as what they'll read from a variety of articles).\n\nAnyway, in these sorts of articles you can find all sorts of stylistic oddities which arise from the mixture of styles. One of my favorites is Haym Soloveitchik's essay *Rupture and Reconstruction* about the evolution of post-enlightenment Judaism, where he has mostly academic footnotes, but one footnote where he notes that he mentioned a particular observation to his father, who agreed with him--his father was an extremely prominent Rabbi, and that sort of \"my prominent Rabbinic father/grandfather/uncle agreed with me\" is common in Rabbinic writing (both as a way to give your words additional weight, but also brag a bit about your lineage), but unusual in academic writing. You get phrases from one language in a text written in the other, which means switching both direction and language, and figuring out how to punctuate that. In referencing page numbers there are interesting interplays of using Hindu-Arabic numerals or using Hebrew letters.\n\nSometimes the genres are more distinct, but authors will write in one style or the other. R Shaul Lieberman (or should I say Professor Saul Liberman? Or perhaps call him by his Rabbinic acronym title, the Gra\"sh? In names just as in academic writing there's a lot of code switching here) was a professor *and* the dean of a major seminary. This English-language *Hellenism in Jewish Palestine* is clearly academic in style, but the identification of particular Greek concepts in the Talmud are of use to Rabbis. But his Hebrew-language commentaries to the Tosefta and Palestinian Talmud are clearly Rabbinic texts from the tradition of commentaries (with scattered English-language citations and numbers), though they may be of great use to people using those sources in academic writing, either the Rabbi-academic or the non-Jewish scholar of Jewish studies.\n\nAnyway, enough context--to answer your question. I decided to get some real data by looking at the journal *Ḥakirah*. It is an interesting journal, which definitely is somewhere in between an academic journal and traditional Rabbinic text. Its format is a peer-reviewed journal, and it has a style guide, both of which are clearly from the world of academic writing. And its own name is transliterated from Hebrew in an academic-style transcription system. It is mostly in English, with a few articles in each issue in Hebrew. But, it has several components that place it within the Jewish world. Publication is virtually only by Jews. They frequently publish pieces from laymen, or Rabbis without higher-level academic training. The pieces often assume a traditional Jewish worldview. They sometimes publish pieces by Rabbis using academic style that argue a particular position in Jewish law, or even pieces that are in English but have more in common with responsa literature (a genre which is usually, but not always, in Hebrew). It calls itself \"an Orthodox Jewish journal\". Its style guide assumes a willingness to interact with academia, but also assumes that writers may not be familiar with academic writing (which makes sense, as many have more traditional Jewish educations). They published PDFs of Ashkenazi afternoon and evening prayers as a freebie. This makes it probably the best fit with your question about academic writing for internal Jewish consumption, because in format and genre it's definitely academic, but it also is aimed at and by a traditional Jewish audience.\n\nWithout doing a detailed survey, just looking through the articles in the last few issues, the English-language work virtually always uses dates in Arabic numerals in CE. Hebrew is more mixed. There is a clear tendency to use either CE dates with Arabic numerals *or* Hebrew dates in Hebrew letters (Hebrew dates in Arabic numerals pop up sometimes too, but not here). Even within a particular piece, there's variation. Citations to English-language secular tend to use CE dates, but narratives and dates of traditional-format text tend to use Hebrew dates (but not always). Some articles have a tendency to use one in the main text and a different in the footnotes, but with little consistency between articles.\n\nThe main conclusion seems to be that in the case of academic writing by and for a traditional Jewish audience, BCE/CE dates in Arabic numerals are used in English, and a mixture of BCE/CE in Arabic numerals and Hebrew dates in Hebrew letters in Hebrew-language writing.",
"I saw this on the r/AH twitter, and I'm not sure if I need to cite sources because it would just be... most Tibetan histories that I'm not sure if anyone here would even be able to read, so I guess you'll just have to trust me? \n\nTibetan historians usually use a combination of \"rab byung,\" Buddhist Era, and more recently the \"Outsider Calendar\" (i.e. the Gregorian). \n\nThe \"rab byung\" cycle is a more complicated version that anyone who's ever been to an American Chinese Buffet would be familair with. It's a sixty year cycle with a combination of one of the five elements and twelve animals. So the year of the Fire Dragon in the Tenth Rabjung Cycle would be 1616, the year that Bhutan marks its independence from Tibet. This system was also at work in Korea (among other countries where the Kalacakra Tantra reached, This is why the Japanese invasion of Korea is called \"the Black Water Dragon War,\" because it began in 1592, the year of the Water Dragon). You can check the rab byung cycle and its associated years [here](_URL_0_). Worth noting that this is why 60 is considered an auspicious age in Buddhist cultures, because it's the age one completes a full rabjung cycle. \n\nThe Buddhist Era, or \"sangs rgyas lo,\" also called the Nirvana Era, \"mya ngan lo,\" which I suppose is also refers to the \"Era of Suffering,\" but compared to other calendars refers to the era after the Buddha's Parinirvana, the traditional date starts from 545 B.C.E. Modern scholars are debating this year, but the ball's been rolling for 2500 years and Buddhist sources, even when writing today, will reference the Buddha's Parinirvana when dating treatises though it's less common for traditional histories who will prefer the Rabjung. \n\nFinally there's \"phyi lo,\" which literally means \"the Outer Year\" but specifically always refers to the Gregorian Calendar. Tibetan histories will usually say the Rabjung first, the Buddhist second (if applicable) and then say \"which is phyi lo 1946.\" \n\nThere are other Tibetan year styles. One starts from 146 B.C.E. dating to the alleged origin of the Tibetan Royal House with Nyatri Tsenpo. Who was allegedly a contemporary of Ashoka. Who... *ahem* lived in the 200s B.C.E. It's funny, Karma Phuntsho usually says that the Bhutanese and Tibetans were actually traditionally *terrible* historians, unable to critically associate the years and ages of things in front of them, or just more willing to promote the idea without too much critical thinking that certain figures are contemporaries, or that they were living in the apocalypse 5,000 years after the start of Buddhism (in reality, we've only *just* reached the half way point to the alleged Buddhist apocalypse). \n\nThere's also a Tibetan Year 0 that starts with a successor of Nyatri Tsenpo's called Lhathothori Nyantsen who was given a book called \"The Ferocious Secret\" which no Tibetan could read (because writing hadn't been introduced to Tibet yet), and dates Year 0 from 255 C.E. Another calendar starts from the year the Rabjung was introduced to Tibet (1027 C.E.) and counts up from there. Neither of these three systems is in current use and takes a bit of context. (I.e. the Tibetan Currency issued 1912-1950 uses the 146 B.C.E. numbers, probably to draw a level of continuity from the first Tibetan sovereign to the Independent Tibetan State.) \n\nThat's probably why modern Tibetans are eager to tack on a \"phyi lo\" and four digits at the end of a sentence dating the listed events. There's so many systems native to their history, and it's easy just to use one that's commonly known and accepted around the world."
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4dck0w | why are lights yellow? | Asking for a friend. All the houses on my street look yellow on the inside at night. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/4dck0w/eli5_why_are_lights_yellow/ | {
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"Conventional Light bulbs work by running electricity through a filament made of metal (there's also fluorescent and LED bulbs, but they're not in wide home use). Different metals produce slightly different colors. In lighting, when you're talking about the tint of \"white\" lights, this is referred to as the 'color temperature'. Light bulbs are available in a wide range of color temperatures, generally ranging from yellow-orange to blue. Blue lights can feel kind of 'harsh' when inside at night because it looks a lot like noon sunlight, which is also strongly on the blue side. Yellow lights tend to make the interior feel softer and more homey, so most people opt for that color when lighting their homes.",
"The standard for streetlights for at least the last 50 years (probably longer) is *low pressure sodium lamps*. This bulb design emits light in the yellowish end of the spectrum and the human eye us very sensitive in that area. On the downside, they render colour poorly. They are/were used because they are rather efficient. \n\n\n There is a huge push to move to LED lights, which are more closely full spectrum (i.e. whiter).\n\nEdit: Low pressure, not high pressure!",
"Indoor lights are often a warmer color temperature of 3200-3400k. Streetlights are often even more red. Outdoor lights are usually daylight-tuned at 5600k. \n"
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5nubfw | why does the saturn v rocket engine's flame appear to come out "unlit"? | I've noticed in videos ([like this one](_URL_0_)) that the F-1's flame doesn't glow coming right out of the engine. It's only a few feet later that it begins to "light". What's going on here? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/5nubfw/eli5_why_does_the_saturn_v_rocket_engines_flame/ | {
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"The video explains it. The F-1 engine dumps the fuel into the cone from the walls of the nozzle, that allows the hydrogen and oxygen liquid to keep the temps of the titanium down so it doesn't melt. That is what makes the exhaust look like it isn't actually lit when it really is, but on the inside of the flame its much hotter, not near the edges."
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3dux4n | what is the job hunt, résumé, and interview process like at the ceo level like? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/3dux4n/eli5_what_is_the_job_hunt_résumé_and_interview/ | {
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"A lot of C-level execs (particularly CMOs and CIOs or their equivalents) have profiles up on linkedin you can check out to get an idea of what their resume's look like. Generally, they'll have started in some technical role in their industry and moved on to leadership roles at lower levels before being promoted/hired by another firm over time. I can't give too much insight into what the recruitment/interview process would be like, but I can say it would be way different for some small company vs. someone like GE.",
"Small companies will most likely go through the same process as other candidates (looking through resume, skill, experience, industries worked). Larger companies base it on the candidates portfolio; for instance Barclays may see that the CEO for Legal and General has done amazing things so approach the CEO with a better offer. Usually for larger companies; CEO's are headhunted with better offers.",
"At that level its also about exposure to good connections. You could be the smartest person in the world, but without somebody validating and introducing you to the right people, you will never get a high level job. Many high level executives come from other companies in the industry (even client companies), government agencies, military personal because the know the right people and can \"seal the deal\", in many cases they are using personal contacts to sign final contracts.",
"Hopefully not too late here, but I have recently left an Executive Search firm that placed a lot of Director and CEO level positions across industries. The process (if they hire) usually goes,\n1) layout all the details of the job\n2) we would then look at all relevant companies and industries and 'map' out these companies \n3) We would bring the 'best' of these companies' people to the top of the list.\n4) Then the client chooses who they want us to approach, we would approach and interview those interested.\n5) From there, a report would be generated on the candidate with our recommendation of whether the candidate is of a high calibre or not. Internal candidates are usually interviewed at this point as well (either for retention or they might be right for the role)\n6)The client then decides on who they want to interview, this could be more then one interview and this is also when the candidate might have to do competency tests. \n7) If all of this goes well then it's background checks and negotiating salaries. \n\nLast steps would be press announcements"
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3wnzjj | why the main holidays of many religions mostly focused around the end of the year(i.e. christmas on dec. 25)? | . | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/3wnzjj/eli5_why_the_main_holidays_of_many_religions/ | {
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"Because they revolve around the shortest day of the year (Dec 22). People like having something to lift their spirits up at that time if year, and they get to celebrate light/warmth coming back into the world as the days get longer. ",
"Easter is arguably a much more signicant holiday than Christmas. Ramadan takes place mid-year. And I don't think that Hannakuh is really considered a major spiritual holiday.",
"It's all based off of pagan festivals that revolved around the solstice with a little bit of Roman politics. According to evidence found in the bible, Jesus was probably born in the springtime. However, after the Romans declared their official religion to be Christianity, they probably declared that Christ's birth was to be celebrated on December 25th, much like how they had a fixed date for celebrating the emperor's birthday (it didn't matter what the emperor's actual birthday was or the fact that emperors changed, they picked one day out of the year and every year on that date, they celebrated his birthday)."
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k973h | If so many flying insects are attracted to light, why are there no species of spider that are attracted to light as well? | While watching some David Attenborough documentary, the quote "these insects have been waging an evolutionary arms race that has lasted millennia" stuck in my head. It seems for every weakness in a prey animal, there is a predator animal that's evolved to exploit that weakness.
If so many flying insects are attracted to light, I would think it would make an easy meal for a spider to set up shop near a light source. Is there any specific reason no spiders seem to have caught on to this? | askscience | http://www.reddit.com/r/askscience/comments/k973h/if_so_many_flying_insects_are_attracted_to_light/ | {
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"If there's a benefit to be had for a spider by preferring light sources (that outweighs risks created by being more visible to hungry birds, etc.), perhaps eventually they will evolve such behaviors. However, it's only been the last couple of hundred years that we've had any really permanent light sources (other than the sun and moon), so there simply hasn't been sufficient time.\n\nYet. ;)",
"Well, it's purely anecdotal, but here in Cambridge (UK) I have noticed (and not only myself) that at least a species of common spiders cluster very clearly and consistently around strong nighttime light sources (street lamps and pub's illuminated windows) - and only around them. [Like that](_URL_0_).\n",
"Spiders (mostly Araneidae) in my area are very wise to this technique. I can confirm from recent observations that the ones who do are the largest females accompanied by large egg sacs, and likely to be giving rise to more offspring: evolution in action (if the next generation also builds near lights, which some of them likely will). Based on the egg sac size and presumed higher number of offspring, it so far fits for at least differential reproductive success.\n\nI tried to get a photograph of an enormous orb-weaver next to my neighbor's lights last weekend while we were blacklighting, but the photos were not very good. There were 4 smaller females set up right near her, each with their webs built in a different plane and each with many recent catches.\n\nAlso, there are many members of the Agelenidae family which are light attracted - if the movement is fast, like with a pinpoint beam, they'll pounce on it if they are nearby (observation from pitfall trapping in grasslands).\n\nEdited for spelling.",
"If there's a benefit to be had for a spider by preferring light sources (that outweighs risks created by being more visible to hungry birds, etc.), perhaps eventually they will evolve such behaviors. However, it's only been the last couple of hundred years that we've had any really permanent light sources (other than the sun and moon), so there simply hasn't been sufficient time.\n\nYet. ;)",
"Well, it's purely anecdotal, but here in Cambridge (UK) I have noticed (and not only myself) that at least a species of common spiders cluster very clearly and consistently around strong nighttime light sources (street lamps and pub's illuminated windows) - and only around them. [Like that](_URL_0_).\n",
"Spiders (mostly Araneidae) in my area are very wise to this technique. I can confirm from recent observations that the ones who do are the largest females accompanied by large egg sacs, and likely to be giving rise to more offspring: evolution in action (if the next generation also builds near lights, which some of them likely will). Based on the egg sac size and presumed higher number of offspring, it so far fits for at least differential reproductive success.\n\nI tried to get a photograph of an enormous orb-weaver next to my neighbor's lights last weekend while we were blacklighting, but the photos were not very good. There were 4 smaller females set up right near her, each with their webs built in a different plane and each with many recent catches.\n\nAlso, there are many members of the Agelenidae family which are light attracted - if the movement is fast, like with a pinpoint beam, they'll pounce on it if they are nearby (observation from pitfall trapping in grasslands).\n\nEdited for spelling."
]
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[],
[
"http://www.flickr.com/photos/yurukov/2841833302/lightbox/"
],
[],
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"http://www.flickr.com/photos/yurukov/2841833302/lightbox/"
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|
bip3gl | why do the majority of plastic containers/tubs/bottles have a small ‘ramp’ going downwards in the bottom of them. | It’s like an inlet into the plastic in a ramp/slant shape.
Praying someone knows what I’m talking about
Edit: [this is what I’m talking about](_URL_0_) | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/bip3gl/eli5_why_do_the_majority_of_plastic/ | {
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"Can you take a picture of a plastic bottle and highlight what you're referencing?",
"Pretty sure its to keep it moving along the production line and to keep it still at the appropriate time it gets filled up and the cap screwed on.",
"That's for the production line equipment to grab and twist the bottle for labeling and/or attaching the cap.",
"A search resulted in this patent [_URL_0_](_URL_0_) called \"Container having bottom lug for radial positioning and bottom mold therefor\" The pattern have FIG. 7 as a example of prior art fot a similar system where you rotate something with a spring loaded pin and then rotate the bottle to a fixed direction\n\nThe bottles are made by blow molding and you have a seam between the mold that can see along the side of the bottle. So the indexing make it possible to put in the sticker on the bottle on the orientation you what or just to put more then one label on it that have a fix position compared to the first. You could even put them all in a box with the labels in one orientation in a automatic way\n\nIt might not be the case that most companies use it but as long as the patent is to old as it would be when it is a prior art back in 2000 there is almost no extra cost to attach to the mold. I suspect that there is a lot of standard bottle shape like the one in your post where you just purchase a standard mold from the manufacturer that have the ramps on all molds."
]
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"https://imgur.com/WRh4Kq3"
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[],
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vgc8g | relativity (also difference between general and special) as well as string theory | I've heard explanations of both but they're either to simple (5 year old) our too in depth. I just finished taking high school chemistry if that gives you any idea of what level. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/vgc8g/relativity_also_difference_between_general_and/ | {
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"Special relativity: The speed of light is the same in all reference frames. You can't accelerate to the speed of light. You can't travel at the speed of light unless you're massless, in which case you must travel at the speed of light. Time passes differently in different rest frames.\n\nGeneral relativity: As above, plus gravity is the effect of curvature of spacetime around massive objects. This is why it affects massless things like light.\n\nString theory: Trying to describe reality in terms of tiny vibrating strings. If successful, would overcome existing problems in relativity and quantum mechanics where these two fields are not compatible. Would be a leap ahead in our understanding of reality. But currently makes no testable predictions.\n\nIf you want to know more, search. These things are asked all the time. If you want a more helpful response than that, ask a specific question; we have no way to know what your problem with the existing explanations is."
]
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[]
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|
o6cnp | why i can only stomach the idea of certain foods at breakfast? | I'm aware that your typical breakfast cuisine varies from culture-to-culture (I'm an Australian), but above all of that, why is it that there are certain foods I'd quite happily eat for lunch or dinner that I could not even stomach the idea of for breakfast? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/o6cnp/eli5_why_i_can_only_stomach_the_idea_of_certain/ | {
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"In the morning your body usually craves sugar and carbs/fats. You've been hungry for 7-8 hours and need immediate energy.\n\nSome people also don't like salty foods because the body is already dehydrated.\n\nPersonally, I'll eat anything from cold pizza to fish curry. Then again, I' not a picky eater at all.",
"I'm wondering how much of it is cultural conditioning. And by that, I mean that you've grown up with foods that are 'normal' breakfast foods for your culture, so eating anything else seems weird. What's acceptable for breakfast does seem to vary across different cultures.\n\n(I should add that this is speculation and not necessarily based on any facts I know of.)",
"I cant stomach anything but coffee and water in the morning, and juice."
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40441j | Why did the U.S.S.R ban homosexuality, when Lenin originally decriminalized homosexuality? What did Marx say about homosexuality? | AskHistorians | https://www.reddit.com/r/AskHistorians/comments/40441j/why_did_the_ussr_ban_homosexuality_when_lenin/ | {
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"I am hoping for someone who can answer this question with greater expertise than my own but [here](_URL_1_) is a link to a recent discussion I had about this with u/Subs-man and on a [question of my own](_URL_0_) u/The_Manchurian recommended \"Homosexual Desire in Revolutionary Russia: The Regulation of Sexual and Gender Dissent\" and \"Bolshevik Sexual Forensics: Diagnosing Sexual Disorder in Clinic and Courtroom, 1917-1939\", both by Dan Healey.\n\nAs far as I am aware Marx says very little about the subject. But as I said, I am hoping someone more knowledgeable will provide an answer here."
]
} | [] | [] | [
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"https://www.reddit.com/r/AskHistorians/comments/3zp5k2/homosexuality_and_trans_individuals_in_the_early/",
"https://www.reddit.com/r/AskHistorians/comments/3zcqpb/minorities_what_was_the_experience_of_homosexuals/"
]
] |
||
nw0m5 | Are our bodies just biological vehicles for bacteria? | Just general curiosity getting the better of me here. I recall a lecture I had listened to some time ago that had touched on the fact that our bodies are pretty much filled and covered with bacteria from top to bottom and everywhere in between. I'm wondering if we know how much of our total mass is comprised of these bacteria and I'm also curious if they could survive outside our bodies without us and us them, though I strongly suspect we'd be screwed without our micro friends. | askscience | http://www.reddit.com/r/askscience/comments/nw0m5/are_our_bodies_just_biological_vehicles_for/ | {
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"While the bacteria on and in our best comprise a large number of cells (approx. 10 times as many as our own), they are relatively light. Based on [this]( _URL_1_), they are estimated to weigh anywhere from 2-9 pounds. In many ways we do work together, primarily in the digestive system, and not having important bacteria (like after a lot of antibiotic use) can really screw it up. One somewhat bizarre remedy for this is to... *ahem*... [reintroduce the bacteria using poop]( _URL_0_). Interesting stuff to say the least.",
"While the bacteria on and in our best comprise a large number of cells (approx. 10 times as many as our own), they are relatively light. Based on [this]( _URL_1_), they are estimated to weigh anywhere from 2-9 pounds. In many ways we do work together, primarily in the digestive system, and not having important bacteria (like after a lot of antibiotic use) can really screw it up. One somewhat bizarre remedy for this is to... *ahem*... [reintroduce the bacteria using poop]( _URL_0_). Interesting stuff to say the least."
]
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"http://en.m.wikipedia.org/wiki/Fecal_bacteriotherapy",
"http://answers.google.com/answers/threadview/id/208733.html"
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"http://en.m.wikipedia.org/wiki/Fecal_bacteriotherapy",
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6c6grl | Were maces more expensive or harder to make than warhammers? And were there any historical evidence of people prefering one to the other or thinking one was better? | ^((For clarity I'm talking about the historical 1 handed warhammer, not the sort you see in most video games and media)^)
Recently I've began to think that maces were more expensive to make compared to warhammers, as well as being more of a weapon for the rich or nobles. This was based on:
* What a historical youtuber said
* Maces looking like they have more metal in them
* Maces seeming harder to make than a warhammer
* Maces and mace like looking weapons sometimes being shown by nobles or royality ^((An example being the queen of england in modern times)^)
But I haven't actually got any real sources, so that's why I'm here. I've seen some evidence to the contrary, [like this knight using a warhammer on horseback](_URL_0_), but not much else. Although this could just be the knight depicted here as prefering a warhammer to a mace, or it being better for cavelry or better in general in his eyes.
Which brings me onto my second question, are there any primary sources that state a preference or an advantage of the mace over the warhammer and/or vice versa?
| AskHistorians | https://www.reddit.com/r/AskHistorians/comments/6c6grl/were_maces_more_expensive_or_harder_to_make_than/ | {
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"Before we start talking about warhammers and maces we should define what we mean. In this answer I will be talking about single-handed, short-hafted weapons with either hammer heads or more symetrical, weighted heads (most often flanged). Most warhammers had wooden hafts, many maces had metal halfts from the 15th century on. In particular, I will be talking about them in the later middle ages and early modern period in Europe - the age of plate armour. It is important to be specific because maces of various types have been used for thousands of years, with stone, cast bronze and forged iron heads. Both of these are primarily cavalry weapons - I have not seen evidence for the use of single-handed warhammers on foot in Western Europe in the middle ages or Early Modern period. Not to say it didn't happen, but it was not the primary use of these weapons. For instance, maces and warhammers are not included in late medieval and early modern fencing manuals, and I have not seen illustrations of them used in combat (you do see illustrations of Eastern Europeans and Ottomans carrying long-hafted maces, but these may have been used in two hands; I have studied these less than Western European weapons). I think a simple thought experiment shows why this is the case - imagine dueling with framing hammers - these are not weapons designed for anything other than simple attacks. \n\nInstead, the illustration that you link from Uccello's Battle of San Romano shows the core use of both of these weapons - their use by mounted, generally armoured soldiers to attack other armoured soldiers. Both maces and warhammers would be hung from the saddle and then used once lances were broken or discarded (swords would also be used as secondary weapons). On horseback, fencing as such isn't as important (not that it is a major factor in an infantry melee, necessarily) and the extra height, supportive saddle and near-standing position of the stirrups gives mounted men at arms a good platform to maximize the power of their swing. I should also mention that wrestling, one of the most effective ways to defeat armoured opponents, isn't possible from horseback, which may have made attacking with brute force using armour-piecing weapons even more important than it was on foot (not that foot soldiers didn't use armour piercing weapons, but their typical secondary weapons were swords, not hammers or maces). Both of these are wapons for attacking men in armour. However, there is an important difference. Maces don't have a point, which means while they can smash armour they're not necessarily as good at piecing it straight through. Warhammers, by contrast, have a sharp point opposite the hammer face, and this is exactly how that Italian man at arms is using his hammer in the Uccelo painting. While I know of no details analysis of the force exerted by maces, experiments conducted against armour as well as simple mechanics demonstrate that the best way to penetrate armour is to concentrate a massive amount of force in a single point. The beak of a warhammer can do this better than any other single-handed weapon. However both weapons can hurt people in armour (albeit with difficulty).\n\nBoth of these weapons can be highly decorated, or fairly plain, depending upon the individual piece. The wallace collection in London has both this [fairly plain](_URL_4_) warhammer, and this [etched and gilt example](_URL_3_) example. Both of these could be used in warfare - the etching and gilding of the latter would not make it any less lethal. Maces [could also be plain](_URL_2_) or [more decorative](_URL_1_). However, unlike warhammers maces were used in a purely ceremonial way from a fairly early period - these [15th century maces](_URL_0_) of the Holy Roman Emperors Frederick and Maximilian look more like contemorary bishop's croziers or even cathedrals than they look like weapons. They even include game boards in their hollow handles! This ceremonial use continues with the ceremonial maces used by royalty, civic institutions and even colleges.\n\nBased on the above, I don't see evidence for a social division in the use of maces versus warhammers. Both are the weapons of cavalry and so, while they are not necessarily 'noble' weapons (most mounted soldiers in the later middle ages had no title, let alone a peerage), they are the weapons of those soldiers wealthy enough to afford a horse and some armour, or socially connected enough to be given these. As to the costs, I have not seen a comparative cost for a 'plain' mace and a 'plain' warhammer. I suspect that you are right that a wooden-hafted hammer would be less expensive than a contemporary 'gothic' mace, but both weapons had a wide variety of 'trim levels' if I can use a modern term. This illustrates an important point about the social history of weapons - the class associations of a weapon are determined not just by the cost of the weapon itself, but also by the context in which the weapon is used. To use another example lances are the weapons of mounted men at arms, and therefor their use is associated with the military aristocracy (and those in lower social orders with pretensions of -joining- the military aristocracy). Never mind that lances themselves are simple weapons - not cheap, necessarily, but not expensive or complex. But economically their use is bound up with the costs of armour, a horse (multiple horses) and the servants required to assist with these. Socially their use is associated with the warrior aristocracy - hence the high status of fighting with lances, as seen in jousting.\n\nNow, there were two-handed weapons used with hammer heads, and other used with spikes, flanges and other mace-like features. The social context and cost of these weapons varied a great deal. Many hammer-headed polearms were pollaxes of one kind or another - weapons often used by dismounted men at arms in both war and sport/judicial combats on foot. These were correspondingly well made and sometimes quite beautifully decorated. On the other hand we see references to English Archers using 'becs de faucon' at Agincourt, and these may have had hammer-heads (they certainly had beaks, hence the name). Two-handed weapons with mace-like heads are less well made and more associated with common soldiers with less money. Both of these types of weapon have wooden hafts unlike many maces and some warhammers from the later middle ages. "
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"http://wallacelive.wallacecollection.org/eMuseumPlus?service=ExternalInterface&module=collection&objectId=61475&viewType=detailView",
"http://wallacelive.wallacecollection.org/eMuseumPlus?service=ExternalInterface&module=collection&objectId=61473&viewType=detailView",
"http://wallacelive.wallacecollection.org/eMuseumPlus?service=ExternalInterface&module=collection&objectId=61472&viewType=detailView"
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1rv6us | Are there publicly-available detailed (date/localization, nationalities, etc.) lists of all the military casualties of WWI? | The records I am looking would include date and place of death/MIA, ideally nationalities too. Online search pointed to database that were more oriented toward personal details (name, DOB etc.) for genealogical purposes but I would "just" like to know how many, where and where were they from. It would be for a long-term journalism project.
Thanks a lot. | AskHistorians | http://www.reddit.com/r/AskHistorians/comments/1rv6us/are_there_publiclyavailable_detailed/ | {
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"I suggest you look at the [Commonwealth War Graves Commission](_URL_1_), which is a great resource to locate war dead from various parts of the former British empire. You might also check the German equivalent, [Volksbund Deutsche Kriegsgräberfürsorge](_URL_0_). Although both resources have their issues, this should provide a good foundation on which future inquiries build. You can always get in touch with representatives from these types of institutions or archives and I'm sure they would be happy to point you towards other resources. I'm not sure if these were the types of databases to which you are referring?",
"The In Flanders Fields museum is working on a database of all military and civilian casualties (of any nationality) in Belgium, [have a look](_URL_0_)."
]
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1zav6w | how does my game cube know exactly what time it is 7 years later? | 7 years ago I moved and during packaging I unplugged my game cube and have kept it in storage for 7 years. Just a little bit ago I plugged it in. When I started a new save file I noticed the time on the game was exactly the time of month/day/year, on the dot. 3/1/2014 2:50. I have kept it unplugged for 7 years, no power, no internet, nothing. Just kept in the dark storage for a very long time. How does that work? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1zav6w/eli5_how_does_my_game_cube_know_exactly_what_time/ | {
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"text": [
"It'll have a watch battery on its motherboard. They can last aaaaaages without forgetting the time. "
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|
2m8ugr | Does light lose energy as it escapes a gravity well? | askscience | http://www.reddit.com/r/askscience/comments/2m8ugr/does_light_lose_energy_as_it_escapes_a_gravity/ | {
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"text": [
"See [gravitational redshift](_URL_0_)."
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||
ak6al6 | why do our bodies not ache after sleeping for several hours vs. when awake in a stilled position for several hours? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/ak6al6/eli5_why_do_our_bodies_not_ache_after_sleeping/ | {
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"When you sleep, all your muscles are in their relaxed state, and not under any stress. When seated, you aren't fully relaxed. Your back muscles are tensed as well as others like your butt. So that's the difference.",
"Because when you sleep your body completely shuts down all muscles except for eye muscles and a few others needed for survival. When sitting a few muscles are perpetually tensed to keep you from falling over like a heart attack victim, leading to the ache. That and you really can't feel much when you get up, so any small aches are gone by the time you're fully awake.",
"As others have noted, your muscles are not relaxed while sitting or standing but they are (mostly) while sleeping.\n\nHowever, I don't see others mentioning that you aren't lying still all night. If you were to lay still for several hours, you would almost certainly wake up sore and may even develop a DVT blood clot.",
"You move when sleeping. That's why people who are quadriplegic or in coma have to be moved every couple of hours to avoid bed sores or pressure ulcers",
"Cuz your under 40 right? Just wait kid. ",
"Hmmm. I am never as sore as when I wake up. The first hour is the worst. So, so sore and aching. ",
"It does when you’re over 40! There are so many great things about your 40s, but this was the biggest shock. It’s a big motivator to be fit when you’re older. ",
"OP must not be over ~30 yet because that's about the age I started waking up sore most days. ",
"When you stand you have all the weight on you feet and legs. When you sleep your bed is holding you. And you are relying on anything on your body to keep you up",
"Ok ELI5 why my body DOES get sore when I wake up?",
"The opposite... I can lay awake in an awful contorted position for as long as possible. No problem. Fall asleep 20 minutes on my back? It’s like I was in a midgets coffin for 34,000 years",
"Personally, if I sleep for more than 5 hours straight I wake up aching all over, especially my back. ",
"My shoulders, ribs, hips and jaws hurt when I lay in bed on the same side for several hours. Especially if I'm sleeping on a hard mattress or pillow. This is why I got a sleep number bed. My husband's back will completely give out if he sleeps on a soft mattress. \n\nI've had this experience since childhood but my husband claims he didn't have this issue until his early 30s. Probably from all the wear and tear his body endured from the 14 years in the Army infantry. ",
"I’m horrible sleeper and I always have been. Lie awake at night unable to fall asleep, and when I do, I toss and turn a lot and wake up a lot. I was blown away when I started sleeping in the same bed as my girlfriend and found out that there are some people who just fall asleep normally and lie there all night without writhing around tossing and turning and changing position a lot.",
"Speak for yourself. I usually wake up in pain, and have to do some stretching and shaking before I feel ready to face the world.\n\nIt’s just arthritis, no big deal.",
"How do I relax muscles while awake?"
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3xzex9 | Does nuclear work in space? If so are we using it? If not why not? | I obviously don't have a huge understanding of nuclear power or using it for propulsion, etc...
I added it to Engineering, but I'm not sure that is the correct one. | askscience | https://www.reddit.com/r/askscience/comments/3xzex9/does_nuclear_work_in_space_if_so_are_we_using_it/ | {
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"Someone correct me if I'm wrong. But our sun is actually a really massive nuclear reaction. It's nuclear fission at the core which is why its core is considerably cooler than the surface. Now as far as nuclear energy, that'd be a bit different. A standard nuclear power plant uses a reaction to generate a lot of heat, and then steam which drives a turbine. Of course you need water to create steam which poses a problem in space. It all depends on what area of nuclear power you're talking about.",
"The sun uses nuclear fusion, which combines lighter elements to create heavier ones. Such as two hydrogen atoms combining to create helium. Today's nuclear power stations on earth use fission, splitting heavy atoms like uranium. They are completely different processes. \n\nBoth processes do work in space. \n\nThe main problem with using fission in space is that it is highly radioactive and what happens if/when it falls to earth. We could contaminate the entire biosphere. Which makes it a huge problem for anything in Earth's gravity well. \n\nBeyond Earth's gravity well there are many possible uses. \n\n[NASA has investigated doing just what you propose:](_URL_0_)\n\n\n\n",
"Yes, nuclear power works in space and several satellites are using it *as a source of electric power*, but it's not being used for any propulsive purposes due to regulations/political constraints.\n\nThe main challenge is cooling down the reactor. Most of the energy comes out in the form of heat, and we can only turn it into other useful forms of energy if there is a meaningful temperature difference on different parts of the machine, e.g. a [Brayton cycle](_URL_3_) or the [thermoelectric effect](_URL_4_). Since dissipating heat in space in the long term is only possible through radiation, and it is a very inefficient method, really huge radiators are needed. This is a meaningful disadvantage of nuclear reactors in space.\n\nIt's important to be very careful of what happens to the radioactive materials in case of failure. The rocket could fail to launch making the satellite end in the bottom of the ocean, or it could be placed in an unstable orbit that at a later point reenters the atmosphere. [It has happened in the past](_URL_5_) and we don't want civilians to be affected if it happens again. For those reasons, [UNOOSA](_URL_0_) has published a very comprehensive list of [principles to the safe use of nuclear power sources in space](_URL_2_).\n\nAs an alternative to nuclear reactors, [Radioisotope thermoelectric generators](_URL_6_) can be used when lower power is required. It is a much simpler design: just a chunk of a radioactive material, not reaching its critical mass, generates constant heat by spontaneous decay. Curiosity is powered this way.\n\nSo far its use for propulsion has not been accepted by UNOOSA. Their reasoning is that if there is any failure you won't be able to move your satellite into a graveyard orbit. However they are researching about this and may change their minds in the future.\n\nIn theory, it could be used for propulsion in 3 ways:\n\n* Nuclear-thermal propulsion: Instead of burning fuel to power a rocket, heat the propellant by letting it flow through a nuclear reactor. Can achieve relatively high thrust with a good specific impulse, about 600s with methane and 800-1000s with hydrogen.\n\n* Nuclear-electric propulsion: Use a nuclear reactor to generate electricity and use it to drive [Ion thrusters](_URL_1_) or other forms of electromagnetic propulsion.\n\n* Nuclear-pulse propulsion: Crazy as it sounds, push the spacecraft by detonating nuclear bombs behind it.\n\nThe latter is banned by article IV of the [Outer Space Treaty](_URL_0_pdf/publications/STSPACE11E.pdf) (no nuclear weapons in orbit).\n\nEdit: added link"
]
} | [] | [] | [
[],
[
"http://www.space.com/21519-nasa-fusion-rocket-space-exploration.html"
],
[
"http://www.unoosa.org/",
"https://en.wikipedia.org/wiki/Ion_thruster",
"http://www.un.org/documents/ga/res/47/a47r068.htm",
"https://en.wikipedia.org/wiki/Brayton_cycle",
"https://en.wikipedia.org/wiki/Thermoelectric_effect",
"https://en.wikipedia.org/wiki/Kosmos_954",
"https://en.wikipedia.org/wiki/Radioisotope_thermoelectric_generator",
"http://www.unoosa.org/pdf/publications/STSPACE11E.pdf"
]
] |
|
6dtt99 | how does wearing more clothes that cover more areas of skin keep you cooler when outside in the sun? | I work outside all day so I wear a long sleeve turtle neck Under Armor under my work clothes. Many people I work with who work in the offices inside ask we why I wear my attire but all I can tell them is it keeps the sun off my skin. Preventing skin cancer and keeping me cooler, but idk how to explain HOW its keeping me cooler. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/6dtt99/eli5how_does_wearing_more_clothes_that_cover_more/ | {
"a_id": [
"di5aobw",
"di5dffl"
],
"score": [
14,
3
],
"text": [
"Because the clothing you have on is blocking the suns rays from directly affecting you and putting a barrier up that blocks them.\n\nClothing on your skin blocks up to 95% of the UVA/UVB radiation that the sun puts off into our atmosphere. That high intensity radiation, along with the visible and infrared radiation are all forms of energy that are easily stopped by layers of clothing.\n\nWhen you wear long sleeve clothing across your body, the cloth heats up and disperses that energy before its absorbed by your skin and body, so you pick up less heat over time.",
"There were studies on middle eastern women some years ago that looked at why wearing a black robe was tolerable in some of the hottest places on Earth.\n\nThe answer was that the black robes heated the air just under them moreso than the air next to your skin creating an upward breeze inside the robe, which kept the women cool.\n\nProbably the same thing going on with your turtle neck. Or it could be that it's some super-material that lets sweat pass through and evaporate on a larger surface, cooling you down more effectivly than skin sweat. Or you may just not be particularly sensitive to heat (I'm the same way)."
]
} | [] | [] | [
[],
[]
] |
|
abt80h | why are cruise ships not registered out of the port they leave from? why are most the north american ships registered to nassau, the bahamas? | (If I flair this wrong please correct me) | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/abt80h/eli5_why_are_cruise_ships_not_registered_out_of/ | {
"a_id": [
"ed2qlz6",
"ed2qqev",
"ed2rdeu"
],
"score": [
9,
9,
5
],
"text": [
"Because when ships are at sea they follow the laws of the country of registration, so most cruise ships will register in countries with lax workers right laws to save money",
"Most ships are registered under \"Flags of Convenience\". Because they travel internationally, they are free to register in any country that will take them. They operate under the laws of that country and they usually register in one that has little regulation and low fees. They may rarely if ever visit their home port.\n\n_URL_0_",
"Most countries allow foreign ships access to their ports. For example a Norwegian ship is allowed to ferry cargo between China and the US. And this have created a market for countries to make registering ships with them cheapest. If it costs $10M to register a ship in the US and Panama offers to register the ship with them for $5M then the owners would much rather register the ship in Panama. They still have access to the same ports at the same rates no matter where they are registered."
]
} | [] | [] | [
[],
[
"https://en.m.wikipedia.org/wiki/Flag_of_convenience"
],
[]
] |
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