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1df20m | why did certain countries like the usa and china experience an immense population boom in the 21st century, while countries like the united kingdom, france and germany barely saw any population increase at all? | edit: 20th century, not the 21st! Sorry. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1df20m/eli5_why_did_certain_countries_like_the_usa_and/ | {
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"You accidentally THE MOST CRUCIAL KEYSTROKE IN THE ENTIRE TITLE.\n\nThat being said, without immigration the US' population would be slightly declining. Fun fact.",
"It's not really a population boom per se but a gradual increase. Population booms are mostly a thing of the past (outside sub-Saharan Africa). Two factors are immigrants and birth rates.\n\nThe US takes on a lot of immigrants, more than any country on earth, both legal and illegal. They take on a million legal immigrants and an unknown amount of illegal immigrants a year. Canada, it should be noted takes the highest *percentage* of immigrants. The US has citizenship by birth, so immigrants that come here and have children automatically gain citizenship for them and tend to stay. Generally the rule of thumb is, immigrants come from poorer countries and the birthrate is higher so the women tend to have more children than regular American women. This only lasts one generation as immigrants assimilate very quickly in America, but this is the reason for the increasing population. \n\nChina is not experiencing a population boom, in fact, China's population is leveling off. You can call it good or bad, but China's birth policies are working. China's birthrate is very low now and by the next decade, India will pass China as the most populated country on earth. A sad side effect is that many little girls that were to be born were aborted, abandoned, given away or killed after birth because of the cultural preference for a \"male heir\" for a family. This has really messed up the gender ratio in China and there are an estimated 50 million Chinese men who will NEVER marry. That's more men than in all of Germany who will be single for life unless they manage to find brides overseas. At current birth rates, China's population will start to shrink and some estimates have China with 300 million fewer citizens at the end of the century.\n\n[As for other countries, the birth rate rate worldwide \\(outside of sub-Saharan Africa\\) is falling dramatically.](_URL_0_) The world's population is actually leveling off and is normal. I can almost promise you that in 20 years from now the map I linked will mostly be light blue. Countries need basic and cheap unskilled manual labor and they use immigration to offset the need for this. It depends how much immigration they want to receive and that is the main reason for population increases, not births so much anymore.\n\n\n\n",
"[source](_URL_0_)\n\nhere is a source for breaking down reasons for changing populations.\n\nLong story short, US had a huge amount if immigration, while Europe had a large amount of net emigration. 2 World Wars that also devestated certain countries also had an impact, but much less important than just the immigration trends. ",
"Let me see if I can help.... \n\n > WWI and WWII probably had something to do with it. I mean about 400,000 people died at the Battle of the Somme in WWI alone. I think something like 1/4 of a generation of women would go without marrying. Not including the disfigured, disabled, and psychologically unstable who would never find a mate.\n\n_URL_0_\n\nAlthough, Russia suffered huge losses during these wars (They are the reason WWII was won by the allies. The US did not play as a big a role as people believe it did) yet still experienced a growing population through the second half of the century.\n\n > Decolonization- Newly decolonized states were kind of left of their own by their former colonizers. Many states opted to pursue welfare systems as opposed to maximizing industrialization, capital, etc. like in the West. Essentially, new states opted to make education and healthcare a right, not a privilege.\nTherefore, people in these states could (artificially?) afford more children and knew that the children and parents would receive care and education from the state. In addition to nice subsidies on oil, food, etc.\n(Some might say this came back to bite them economically, especially after oil prices spiked in the 1970s and the IMF/WB rushed to avoid loan default... but that's another story)\n\nTL;DR:\nIt may not be that these places did not have a population boom, it may just be that their \"baby booms\" were not as marked, expensive, or publicized as other places.\n",
"Actually, much of the Western world experienced a [baby boom](_URL_0_) following World War II, including most of Western Europe.",
"Let's not forget that the UK, France and Germany all had population booms in the 19th century as a result of increased food production, which provided the labor capital required for their industrial revolutions. The US and China were just late to the party."
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7htw7x | How did the Portugese empire go from once spanning the whole world to it's current state as not even being a G20 country? How did such a drop off from prominence occur? | AskHistorians | https://www.reddit.com/r/AskHistorians/comments/7htw7x/how_did_the_portugese_empire_go_from_once/ | {
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"I covered a lot of reasons of early decline in power in [this post](_URL_1_).\n\n\nYou can also read this very nice and concise [thread](_URL_0_) by /u/nathanial_jones "
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30karu | Czechs in the Austro-Hungarian Army | When researching World War One I often end up reading about the Czechoslovak Legion, and that lead me to an interest in Czechs in the Austrian Army. However I can't seem to find any information on them. Ergo, how many were there? Where did they fight? Did they have any great successes? And of course, were can I find more information on them myself? | AskHistorians | http://www.reddit.com/r/AskHistorians/comments/30karu/czechs_in_the_austrohungarian_army/ | {
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"Since no one answered I'll tell you what I know and give you a few things you can look up.\n\nSo, from a cemetery in Prague I know that they fought (and died) in Italy, places like Slovenia and Croatia, anywhere the Austrians fought.\n\nMany also didn't think it right they should be fighting their Slavic brothers under the Austrians and went over the Russian side and fought the Austrians. Many, actually did that. Also to France and England. French, Russian, but also other armies had hundreds or thousands of Czechs and Slovaks fighting for them against the Germans and Austrians.\n\nI co-host a show about Czech history called _URL_0_ and we did a few shows that touch on this:\n\nThe Czech foreign legion, they have an awesome tale of going all the way around the world after WWI because they were on the wrong side of the Red Army in Russia during the revolution... so they went the long way home. Through Russian to Japan and the US and Paris. Some circled around India. They had some tzarist gold at one point, which makes for great legends.\nThey had an armored train (pics elsewhere if you're interested)\n\nAnyway, we did a few WWI shows because it's the centennial, so go have a listen.\n\nIf you have any follow up questions, feel free. I think I answered a similar question before, so I can try and find my answer."
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2sroli | if photons are mass-less and travel forever without friction, if i point my flashlight at the sky, do they travel forever? | friction with the atmosphere, bends the light?
My flashlight in space would be like a mini sun?
why does my flashlight with weak batteries on only produce a dim beam of light that does not extend far, what is exactly happening to the photons then? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2sroli/eli5_if_photons_are_massless_and_travel_forever/ | {
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"Within the atmosphere, the photons are being absorbed by the molecules in the air. Those that are not absorbed are scattered, which is why in dusty air you can see the dust dancing in the air - it's the light bouncing off the dust particles and flying off in different directions. The flashlight also doesn't send all the photons out in the same direction, so they spread into a cone. A laser has them more focused, which is why a laser's effective range is much larger.\n\nNow, light does spread out ('diffract') a tiny bit on its own. But that's not at all the dominant effect until you're in space."
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duvpa4 | what's the difference between veteran's day and memorial day? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/duvpa4/eli5_whats_the_difference_between_veterans_day/ | {
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"My understanding is that Veteran's Day is meant to focus on the living veterans of the armed service, while Memorial Day is meant to focus on the _deceased_ members of the armed service who gave their lives in defense of the country.\n\nPractically, however, there is little difference."
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63quua | Once a European power in the age of exploration, Portugal isn't seen as a mighty or influential nation in the world today. What caused this? | I know this question covers a long period of history. They often are covered in world history in the US during the 1400s but largely disappear from the history books into the 1500s and 1600s.
What events led to their general disappearance as other European powers rose and spread across the Western Hemisphere? | AskHistorians | https://www.reddit.com/r/AskHistorians/comments/63quua/once_a_european_power_in_the_age_of_exploration/ | {
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"Not to discourage other answers, but while you're waiting, you might want to check out [The Decline of the Spanish Empire](_URL_1_) section of the wiki, which touches on both Spain and Portugal. You might find [this post](_URL_0_) with an answer by /u/Chilangosta to be pretty helpful, although it's pretty heavily skewed towards Spain.",
"Finally a question I can answer! The reasons for the decline of Portugal from its height as the first colonial power to its situation today as, at best, a middling european power are varied and extend over centuries. First, Portugal had an inherent disadvantage to other colonial powers like England, France, or neighboring Spain; it's simply a smaller country. It had a smaller population and economy, which meant it had fewer people to send overseas, fewer funds to spend on them, and a smaller army to defend them with. The second blow to Portugal’s power was its union with Spain beginning in 1580 after the death of King Sebastian, and lasting to 1640 with Portuguese Restoration War. During this time under the Spanish crown, Spain's enemies became Portugal’s enemies, those being most importantly the Dutch and British, who now having the opportunity to do so, took many of Portugal’s colonies and trading posts in the Indian Ocean, such as Hormuz and Malacca, as well as making attacks into Brazil. This along with having to devote resources to Spain’s numerous wars during this period (including contributing ships to the infamous Spanish Armada) drained Portugal greatly, and from this point forward only declined relative to the rapid growth of the other colonial powers. In 1755 Portugal experienced one of the worst earthquakes in European history off its coast, resulting in the widespread damage and the near complete destruction of its capital and largest city, Lisbon. The Peninsula war in 1808 and the loss of Brazil (its richest colony) in 1822 Portugal further hurt Portugal, though at this point they simply cemented Portugal’s poor position. Lack of large deposits of coal or other resources meant industrialization came slowly to Portugal, which as the 19th century progressed only hurt it. During the scramble for Africa Portugal, despite having colonies in Africa for over 400 years by then generally just expanded around their existing holdings. Portugal in the 20th century was marked by the Estado Novo, a dictatorship lasting from 1933-1974, a dictatorship which saw general isolation from the world, except for fruitless, costly wars trying to retain their colonies. \n\nIn conclusion, (tldr) Portugal from the start was doomed to a certain degree to not achieve the same height of successes of its competitors, and despite its early start it was further set back and mired by numerous disasters and generally unfortunate events. \n\nI hope this was sufficiently in depth, and while I'm sure I missed certain elements, I hope this gives you a good general insight on this topic.",
"With so many deleted comments I'm not sure if this answer is up to standards, but I'll try anyway:\n\nOne could argue that such a small nation could never hope to maintain its lead at the forefront of colonial empires for long. Despite being the first, Portugal suffered from having a population too small to keep up with other powers such as France, England or even Spain, much like the Dutch Empire. With a small population, one simply couldn't project the power necessary to challenge competing colonial nations for too long. The Portuguese had adopted gunpowder weapons early on and were better equipped than their contemporaries but only for the very first years of their empire; this advantage would wear on as the technology spread and Portugal was surpassed. With neither men nor superior weaponry, Portugal's sole advantage was being the first.\n\nFrom 1581 onwards, Portugal was in a personal union with the Habsburg king of Spain. Although this didn't mean that Portugal was annexed by Spain, its wealth would be used to fund Spanish wars and the country would be dragged into Spanish rivalries with other european powers, which disrupted the Portuguese trade (Up to this point Portugal had been a staunch English ally and it would resume to be so after the union with Spain ended). Their colonies, notably Brazil, where occupied by the French and Dutch during this period, taking the lucrative Sugarcane plantations there.\n\nThe Portuguese waged a lenghty Restoration War from 1640 to 1668, and a massive earthquake hit Lisbon in 1755, with deaths toll estimated as high as 100,000. Portugal already was a small country, and now it had even less men and had to completely rebuild their capital from the ground up. Later on Napoleon would invade the country and the royal family would flee to Brazil, indirectly bringing about the independence of that country, Portugal's major colony. \n \nOn the early days of their colonial empire and their sea route to India in 1498 the Portuguese enjoyed little to no competition, but by the 17th century, as you can see, it had to compete with the trade or directy emnity from the Dutch, English and French colonial empires. Its little country and army could not help but be eclipsed, as larger nations that could exert their power on a larger scale entered the age of colonialism.",
"Portugal was much too small. They were the first European country to start a naval trading empire, mainly through the sponsorship of Prince Henry the Navigator and their invention of the caravel (small, highly maneuverable sailing ship), but they could never really take full advantage of their position due to limited manpower and resources. Although in the beginning they enjoyed dominance on spice trade with India, the Spice Islands (now known as Moluccas), and China (as Muslim traders had to travel a treacherous, lengthly, and difficult journey by foot in comparison), they weren't powerful enough to compete with other European forces that soon joined the fray, such as the Spanish, Dutch, and English. They didn't have the resources or power to colonize the regions they traded with and further expand their trade empire, while later countries did.\n\nFrom p. 408 in Western Civilization by Jackson J. Spielvogel:\n\n > Within a few years, the Portuguese had managed to seize control of the spice trade from Muslim traders and had garnered substantial profits for the Portuguese monarchy. Nevertheless, the Portuguese Empire remained limited, consisting of only trading posts on the coasts of India and China. The Portuguese lacked the power, the population, an the desire to colonize the Asian regions.\n\n > [...] Portugal's efforts to dominate the trade of Southeast Asia were never totally successful. The Portuguese lacked both the numbers and the wealth to overcome local resistance and colonize the Asian regions. Portugal's empire was simply too large and Portugal too small to contain it.\n\n\nThe Spanish soon followed through their exploration of the New World, and their greater resources enabled them to establish a much bigger overseas empire than that of the Portugese.\n\nPortugal's main rivals, however, were the Dutch and the English, who were much better financed than the Portuguese, and they fought for control over the spice trade. Portugal, being a much weaker country, soon began to lose its trade empire. The shift in power first began when the Dutch seized a Portuguese fort in the Moluccas in the 17th century. From there, they gradually pushed the Portuguese out of the spice trade, and in the next fifty years, occupied most of the Portuguese coastal forts along the trade routes throughout the Indian Ocean (such as Ceylon and Malacca).\n\nFurthermore, the Dutch were able to bring inland regions under their control in order to protect their position and maximize profits, unlike the Portuguese who mainly stuck to coastal ports and made agreements. The Dutch East India Company established pepper plantations on the neighboring island of Sumatra, bringing massive profits and increasing their wealth and influence considerably. By the end of the eighteenth century, the Dutch had brought almost the entire Indonesian archipelago under their control.\n\nFurthermore, in Southeast Asia, where Portugal had previously established uncontested trade relations with mainland states such as Thailand, Burma, and Vietnam, other European nations soon began to actively compete for trade and missionary privileges as well, limiting Portugal's wealth and influence.\n\nSources: Western Civilization by Jackson J. Spielvogel, Brittanica Encylopedia",
"These answers are extremely shallow and mostly incorrect. Having said that I won't write a concise history of portugal here, instead I will link you to a book that explains this subject matter well: _URL_0_\n\nSadly this book has only been written in Portuguese and I doubt there have been any translations of decent books on the economic history of Portugal.\n\nTo summarise however, the influence of the Jesuits (for example destroying the education system or causing Uruguay to side with Spain), the French invasion, the lack of a strong enlightenment and the power of the old aristocracy and clergy meant that Portugal had a terrible 19th century overall, despite being wealthy by the end of the 18th century. Portugal went bankrupt several times and the successive governments were unable to solve this issue due to gross incompetence. \n\nOnce the republic was established, Portugal had about 3 decades of anarchy and further destitution, only for the fascist regime to take over for another 4 decades. At this point Portugal was so poor that over 25% of the population could not read or write their own name and its immigrants were creating *bidonvilles* in France. In essence 2 centuries of terrible economic activity will do that to you.\n\nPortugal's size is completely irrelevant in all of this as this is neither a necessary nor sufficient factor for economic prosperity or global influence, and Portugal was actually its wealthiest after the Restoration, not before. I suggest you read a good book on this matter if you're interested because you'll get an inaccurate summary at best from a reddit comment. "
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nyvkb | how computers turn 0's and 1's into text, video, and other programs/applications. | I'm having difficulty conceptualizing how computers "read" binary code, and translate into useful and understandable information. ELI5? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/nyvkb/eli5_how_computers_turn_0s_and_1s_into_text_video/ | {
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"Imagine you're sitting at a desk with three levers in front of you, each one can be \"on\" or \"off.\" Each lever controls something different in the room you are sitting in. The first switch turns the lights on or off, the second switch turns on or off some music, and the third turns on or off the television.\n\nNow lets say I told you to \"turn on the TV and the music, but keep the lights off.\" You would turn the first lever to off, and the other two to on. If we say that \"0\" means off and \"1\" means on, then that means in this example the first lever is 0, and the second two are 1. So you could write that very simply as the following sequence:\n\n 011\n\nWhich means that the lights are off, but the music and TV are on. If I were to tell you to turn the lights on, but turn the TV and music off the equivalent sequence would be:\n\n 100\n\nIf they were all on:\n\n 111\n\nIf they were all off:\n\n 000\n\nIn this way, you could execute a whole bunch of commands if I just sent you a string of three numbers. So if instead of telling you what to do in words, I just gave you a slip of paper with 0's and 1's on it, each of which corresponded to one of the switches, you would know what to do.\n\n Sequence Lights Music TV\n 000 Off Off Off\n 001 Off Off On\n 101 On Off On\n 110 On On Off\n 111 On On On\n\nAnd so on. Inside your computer are a lot of tiny electronic switches. When your computer \"reads\" in the binary code, it flips the switches on and off according to the code, and different combinations produce different outcomes. Some of the switches control what your monitor displays, others do math when they need to, and so on. When you combine hundreds, or thousands, or millions of these switches you can take the very simple example we used (where there were only three things to control) and expand it to something very complex (all the amazing things we can do with our computers today). \n\n**Edit:** Formatting.\n\n**Further Edit:** It's worth mentioning that sequences of binary numbers are also relatable to the very words I'm using to write this post. In any written language you have a combination of letters, which can be strung together to form words. Those words can be then strung together to form sentences, paragraphs, books, and so on. So from combinations of (in English anyway) 26 letters we can form infinitely complex messages. Binary is a language just like any other, and in effect your computer translates that written language into action by flipping the switches I described earlier. Wikipedia has a [nifty little GIF](_URL_0_) that shows how you can translate binary *the other way* (that is, understanding what the computer is doing in common language) by working backwards and converting 0's and 1's first into letters, and then into words.",
"Let's say you made an extremely basic program that lets you type in your name and then the program will reply with your name. You type in \"Mike\" and a text appears that says \"Mike\".\n\nWhen you first type in your name the program will know that you are typing a \"string\", which is basically a set of characters in order. It knows that you are not typing in a command to multiply two numbers or a command to turn off the PC. This is what the **program** knows. The actual processor in your computer knows nothing and it doesn't even care.\n\nThe program also knows that what it needs to do with your input is to display it as a string. It won't try to generate a Minecraft map from it or connect to a web server with what you typed in. This is where the chain of events starts that spans many levels of computer infrastructure.\n\n(If someone with better knowledge than mine spots any flaws or would like to elaborate on some issue please do.)\n\nThe program has your input. \"Mike\". It knows that it should display this input to you. The program asks the operating system (Windows, OSX, etc) to display this text. The operating system takes this request to the GPU driver, asking that it would update the area of the screen the text is to be displayed in.\n\nBinary is used in every part. The key thing to note is that it's not just the binary representation of your input \"Mike\" that is sent from the program to the operating system. The program adds a \"please display this text in my text output field\" message to the request. This message is also conveyed through the processor as binary.\n\nSo now the operating system receives a long number of 1's and 0's that it's meant to make sense of. First of all it figures out which program has sent the info (also included in the binary). Then it figures out the request (display on screen) and finally checks what is to be displayed (Mike). The operating system runs its own algorithm to determine what to do when faced with such a request and ends up sending a message to the graphics card.\n\nThe graphics card receives a binary message from the operating system that asks it to update an area of the screen. Specifically the area belonging to your program's text output field.\n\nSo basically even if you type in just what seems like a name to you, the program you type it into will know what other data to add to that name for results to appear. \"Mike\" [resembles](_URL_0_) \"01001101011010010110101101100101\" in binary, but the binary data stream your program sends forward is much longer than that. It not only contains what type of data it is carrying, but what it will be used for.\n\nI hope this wasn't too much off track, misinforming or hard to understand. I'm by no means an expert in this field.",
"Binary is used because it represents 'on' and 'off' on electrical switches. There are a lot of possible combinations of 0s and 1s, and they can all be understood in different ways. Majorly simplifying it, let's take a few of your examples. Text is pretty simple. Each chain of 0s and 1s represents a letter, or punctuation mark. A 0 or 1 is called a bit. Eight 0s/1s is called a *byte*. So for text, we can dedicate 1 byte to each letter. 01000001 is A, 01000011 is B etc. Then there could be another string of 0s and 1s that corresponds to the font.\n\nVideo is a series of pictures played quickly, one after the other, so perhaps it is more useful to think of a picture. A picture is understood by a computer as a grid with different colours in each square of the grid (called a pixel). Different colours can be represented by different binary strings again. This time though, we can choose how many digits of binary we assign to each pixel. The more digits, the more possible colours there are to choose from. For an image where we dedicate 1 byte (8 bits) to each pixel, there are 256 possible colours (from 00000000 to 11111111). If we dedicate 24 bits to each pixel, there are 16,777,216 possible colours! Of course, this takes up more memory.\n\nSound is different again, but the same basic principle. Sound is made by waves of compressed air. A speaker vibrates to create this compression. The vibrations are caused by different voltages across the speaker. Once again, each voltage can be spelled out using binary. This voltage, in CD quality audio, changes 44,100 times every second. If we dedicate 16 bits to each of these changes, there are 705,600 0s and 1s in every second of audio, and 65,536 possible voltage levels for each change (0000000000000000 to 1111111111111111).\n\nData can be compressed using shorthand ways of saying the same thing. For instance, if there are 5 red pixels together, an uncompressed image would essentially say 'One red pixel, one red pixel, one red pixel, one red pixel, one red pixel'. A compressed image would just say '5 red pixels'.\n\nHopefully you can see how data is stored using 0s and 1s. Programs and applications are outside of my knowledge, I'm afraid. Someone else will have to answer that.",
"01001001 01110100 00100111 01110011 00100000 01110001 01110101 01101001 01110100 01100101 00100000 01110011 01101001 01101101 01110000 01101100 01100101 00101100 00100000 01110010 01100101 01100001 01101100 01101100 01111001 00101110 00100000 01000001 00100000 01100010 01101001 01101110 01100001 01110010 01111001 00100000 01100011 01101111 01100100 01100101 00100000 01101001 01110011 00100000 01100001 00100000 01110111 01100001 01111001 00100000 01101111 01100110 00100000 01110010 01100101 01110000 01110010 01100101 01110011 01100101 01101110 01110100 01101001 01101110 01100111 00100000 01110100 01100101 01111000 01110100 00100000 01101111 01110010 00100000 01100011 01101111 01101101 01110000 01110101 01110100 01100101 01110010 00100000 01110000 01110010 01101111 01100011 01100101 01110011 01110011 01101111 01110010 00100000 01101001 01101110 01110011 01110100 01110010 01110101 01100011 01110100 01101001 01101111 01101110 01110011 00100000 01100010 01111001 00100000 01110100 01101000 01100101 00100000 01110101 01110011 01100101 00100000 01101111 01100110 00100000 01110100 01101000 01100101 00100000 01100010 01101001 01101110 01100001 01110010 01111001 00100000 01101110 01110101 01101101 01100010 01100101 01110010 00100000 01110011 01111001 01110011 01110100 01100101 01101101 00100111 01110011 00100000 01110100 01110111 01101111 00101101 01100010 01101001 01101110 01100001 01110010 01111001 00100000 01100100 01101001 01100111 01101001 01110100 01110011 00100000 00110000 00100000 01100001 01101110 01100100 00100000 00110001 00101110 00100000 01010100 01101000 01101001 01110011 00100000 01101001 01110011 00100000 01100001 01100011 01100011 01101111 01101101 01110000 01101100 01101001 01110011 01101000 01100101 01100100 00100000 01100010 01111001 00100000 01100001 01110011 01110011 01101001 01100111 01101110 01101001 01101110 01100111 00100000 01100001 00100000 01100010 01101001 01110100 00100000 01110011 01110100 01110010 01101001 01101110 01100111 00100000 01110100 01101111 00100000 01100101 01100001 01100011 01101000 00100000 01110000 01100001 01110010 01110100 01101001 01100011 01110101 01101100 01100001 01110010 00100000 01110011 01111001 01101101 01100010 01101111 01101100 00100000 01101111 01110010 00100000 01101001 01101110 01110011 01110100 01110010 01110101 01100011 01110100 01101001 01101111 01101110 00101110 00100000 01000110 01101111 01110010 00100000 01100101 01111000 01100001 01101101 01110000 01101100 01100101 00101100 00100000 01100001 00100000 01100010 01101001 01101110 01100001 01110010 01111001 00100000 01110011 01110100 01110010 01101001 01101110 01100111 00100000 01101111 01100110 00100000 01100101 01101001 01100111 01101000 01110100 00100000 01100010 01101001 01101110 01100001 01110010 01111001 00100000 01100100 01101001 01100111 01101001 01110100 01110011 00100000 00101000 01100010 01101001 01110100 01110011 00101001 00100000 01100011 01100001 01101110 00100000 01110010 01100101 01110000 01110010 01100101 01110011 01100101 01101110 01110100 00100000 01100001 01101110 01111001 00100000 01101111 01100110 00100000 00110010 00110101 00110110 00100000 01110000 01101111 01110011 01110011 01101001 01100010 01101100 01100101 00100000 01110110 01100001 01101100 01110101 01100101 01110011 00100000 01100001 01101110 01100100 00100000 01100011 01100001 01101110 00100000 01110100 01101000 01100101 01110010 01100101 01100110 01101111 01110010 01100101 00100000 01100011 01101111 01110010 01110010 01100101 01110011 01110000 01101111 01101110 01100100 00100000 01110100 01101111 00100000 01100001 00100000 01110110 01100001 01110010 01101001 01100101 01110100 01111001 00100000 01101111 01100110 00100000 01100100 01101001 01100110 01100110 01100101 01110010 01100101 01101110 01110100 00100000 01110011 01111001 01101101 01100010 01101111 01101100 01110011 00101100 00100000 01101100 01100101 01110100 01110100 01100101 01110010 01110011 00100000 01101111 01110010 00100000 01101001 01101110 01110011 01110100 01110010 01110101 01100011 01110100 01101001 01101111 01101110 01110011 00101110",
"I'm going to answer this based on how a computer knows a specific sequence of 1s and 0s translates to the lowercase letter 'a'.\n\nShort answer, it doesn't. The video card (for simplicity sake here) has been programed such that when it is told to \"move to location 0,0\" followed by \"display the contents of memory location 12345 as a string\" it will read that memory location and see that it has, for this example, an 8-bit value of 97. It looks up the 97th entry in the font table (basically a series of ones and zeroes which indicates which pixels should be on or off). If the system is following the ascii standard, the graphic should look like a lowercase 'a'.\n\nAs a programmer, you almost never have to deal with ones and zeroes. That said, it is still handy to know that the number 97 is stored in memory in binary and takes 8 bits (a bit is a single binary digit).\n\nI'd like to add that this font table is not the same thing as a font like you'd use in Word. A font table is used in DOS or Linux or in a full screen command prompt window in Windows (XP and earlier only). The font table is typically programmed into the hardware of the computer by the manufacturer.",
"A lot of these posts are on the basics of binary. I'm going to assume you also want to know the second part of your question.\n****\nFirst, encoding. *Encoding* is assigning a binary value to something. In akihiko's example, all on is encoded to 111. *Decoding* is taking this value apart, like \"the first 1 means the lights are off.\"\n****\nNow, text. The standard is *ASCII*(ask-ee). ASCII encoding assigns a ton of standard characters to an 8-bit number. [_URL_2_](_URL_1_) shows each character and its ASCII value.\n\nIn ASCII encoding: \n\n Hello World!\ntranslates to\n\n 010010000110010101101100011011000110111100100000010101110110111101110010011011000110010000100001\n\nIf you break apart each group of 8 bits and use the table, you can convert back to \"Hello World!\" Any .txt file is just a stream of binary numbers like the example above. There are also several other encoding schemes like Unicode that are beyond the scope of ELI5.\n****\nNow on to pictures. First, let's go over what a picture is to a computer. \n\nA picture is made up of a bunch of pixels, each with its own color, in a 3 dimensional array. The way a pixel color is represented is a 24 bit number. The first 8 bits represent the **R**ed value, the next 8 the **G**reen value, and the last 8 the **B**lue value. These values can be looked up in a color table, such as the one [here](_URL_0_). An additional 8 bits may be added to color value to represent an *alpha value*, which is the *transparency* value of the pixel.\n\nA bitmap stores a bunch of pixel values from left to right, top to bottom, much like a text file does with ASCII codes. Since it uses 24 or 32 bits per pixel, images with multiple megapixels can be quite large, which is why bitmaps are not commonly used anymore. GIF, PNG and JPEG are *compressed* image formats. I've seen many ELI5 posts on compression like *run-length* and *Huffman encoding*, so I won't bother explaining them here.\n****\nLastly, video. The most basic video format is taking a bunch of bitmaps and concatenating them together to make a series of pictures. However, the computer needs more information about this series of pictures, which is why most formats have a *header*. This header is a series of numbers in specified format that tell the computer how to play the video. For example, a header might contain the value 30 at bits 40-47, which could tell the computer that the video should be played at 30 frames per second.\n\nObviously using a series of bitmaps isn't the best way to store a video. 30 bitmaps played back at 30 frames per second would take up 10's of megabytes, even though the file is only a second long! Files like MPEG use compressed pictures like JPEG to store static images instead of bitmaps, which vastly reduces the size, but still, a 1 hour video would have 108,000 frames if it is 30 frames per second, or 108,000 pictures, which is still too large. \n\nMPEG uses another compression scheme, where you have a keyframe (or I-frame) every set number of frames (lets say 30). This means every 30 frames, the frame played back is stored in its entirety. However, the frames in between keyframes are *interpolated* (called P-frames). These frames only store information on *what has changed since the last frame*. Since a lot of things don't change in between frames in a series of pictures (say, a person is walking around, that persons position in the frame changes, but the person itself doesn't change, nor does the background), storing all this information repeatedly is redundant, which MPEG aimed to fix. You cannot seek to a P frame, since building that frame requires information from the frame before it, which is why you can only seek to certain parts of some videos.\n****\nWow, this explanation really got away from me; it's way above ELI5 but I hope it helps.",
"Let's start slowly, and just think about turning \"0s and 1s\" into text.\n\nReally, it's a lot like how one might read Morse code. After all, Morse code and binary are conceptually very similar. The same way that binary only has 0 and 1, Morse code only has \"short\" and \"long\" tones. \n\nNow, many people can't read Morse code, so we get a translator and make a simple rule for them to follow. We draw the [alphabet onto a nice chart diagram](_URL_0_), and we teach the translator that every time he reads \"A\" in Morse code, he should point to the \"A\" on our diagram so that we can see what he read.\n\n**Here's the trick: The translator doesn't actually need to *know* our alphabet in order to do this!** He/she just needs to know which part of the diagram to point at when they read the corresponding Morse code character. So as long as they point to the picture of \"T\" when they read \"-\", they'll never actually need to learn what \"T\" is.\n\nNow we can understand what they read in Morse code without either of us having to learn the other's language. That's exactly how computers are able to \"translate\" \"0s and 1s\" into text.\n\nFor a picture, it's very similar. We give our translator a blank piece of paper and some crayons, and teach them that whenever they read certain words in Morse code, they should draw a specific part of that paper a certain color. So if they read \"blue\", they might draw the whole piece of paper blue. \"Topleft blue\" would have them draw the top-left corner of the paper blue. Obviously, this is a harder and slower process than translating text, but it all works out in the end. \n\nA video is just like a flipbook, and a flipbook is just a series of pictures. So, we have our translator draw a bunch of pictures as described above, and then flip the pages for us. Voila, Youtube!",
"Can someone explain how to count numbers in binary?",
"I'll try to answer this a little different than the 0/1 approach.\n\nAn important part of the answer is, that a computer is not just one computer. It is many. There is a little computer that controls memory access (the memory controller), a little computer that calculates graphics (the graphics CPU) together with a little computer that outputs graphics (the RAMDAC), several little computers that make disk IO work (s/ata controller, the HD controller, the USB interface, the chip on the USB sticks etc)\n\nThose little computers all communicate using bus systems. The main CPU is what you might refer to when speaking of a computer, but only because it's the only part that doesn't have a specific, factory set program that it runs. Instead, it runs the BIOS and then the Operating System. This is the part that makes all the important decisions, but needs all these other components to do that. \"Get me memory from address to address\", \"Send part of the memory to disk\" etc.\n\nI hope this makes understanding the other answers here a little easier for you. ",
"The computer components are build by the simplest memory circuits and they can remember only two states, 0 and 1. This are called impulses. Zero means no impulse, 1 means there's an impulse. By doing this, they generate information. The computer translates the binary (base 2) to hexadecimal (base 16) into assembly language (machine code) and that way you can give commands to the CPU. I suggest you start with some basics for electronics, like flip-flops, counters, registers and then move onto architectures of the first microprocessors like Intel 8085, Motorola 6800 etc. Get in with the basics of assembly language also.\n\nPS: Poop, an five-year-old won't get this.",
"I don't know why everyone loves to type huge responses here. I was a computer science major and I can tell you exactly what it's like. \n\nThink of it like letters. With these letters, we make words. Words are sequences of letters put together to give the letters more meaning. Think of zeros and ones like a two letter alphabet and all the text, graphics, video, programs, data, etc are all just words, books, and libraries.",
"A lot of the answers on this thread talk about binary as being translated by a program... Would it be possible to also talk about where the program initially comes from? I would imagine that any program is a bunch of ones and zeroes as well, so it would need a program in order read it (the operating system?). But then the operating system is also a program. So what reads it? What's the first program, and how does it work?",
"I'm seriously glad people figured out computers. Seems damn complicated and awesome.",
"It's like morse code for computers. Y",
"Top comment kind of explained it, but I believe it didn't fully answer the question, so here's my take on this. Gonna be more like ELI15, but whatever, I think it's pretty interesting.\n\nFirst of all, information is determined by electricity. If there is a current, it's 1, if there isn't - 0. This gets processed in CPU (central processing unit, your good ol' Intel). CPU contains a lot of logical schemes, each of which is designed to perform certain tasks using only electrical current. Each logic circuit is arranged to perform certain task - add, multiply, save to memory, draw a dot of a certain color at a certain place etc.\n\nIn a sense, computer doesn't really \"know\" what to do. Instead, by generating input with, say, keyboard we create certain information sequence that is processed by CPU and generates output that we need. If you feed CPU with exact same information, it will always generate the same result. It can't have a \"change of heart\".\n\nExample: we have a CPU that outputs 1 if we type in 010 and 0 in all other cases. Logic circuit will be like a tree with a lot of branches. Only one of those branches contains 1, rest are 0. By using special switches we guide electrical signal and get output. Of course CPUs are way more complex than that.\n\nContinuing answering the question, these circuits make basic machine code possible. Essentially **this is what computer does** - calculates everything step by step, draws everything dot by dot. Programmers make this understandable by combining these basic functions: to show symbol \"a\" on a screen, we get a certain information in form of current from keyboard to CPU (say, 0001), determine symbol in a following fashion: \"if input is 0000 then space, if 0001 then \"a\", if 0002 then \"b\" etc and then print it dot by dot.",
"You should check out the book [Code](_URL_0_). It's an amazing book that starts with the simplest analogy and lowest level and builds layer upon layer on top of it to understand how computers work today."
]
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[
"http://upload.wikimedia.org/wikipedia/commons/7/77/Wikipedia_in_binary.gif"
],
[
"http://www.roubaixinteractive.com/PlayGround/Binary_Conversion/Binary_To_Text.asp"
],
[],
[],
[],
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"http://gucky.uni-muenster.de/cgi-bin/rgbtab-en",
"http://www.asciitable.com/",
"ASCIItable.com"
... | |
yvjy3 | If I had a stationary slinky hanging from a mile up, and let go. Would the bottom stay in place until the top falls down to it? | A really scaled up version of THIS phenomenon for instance. Would it work?
_URL_0_ | askscience | http://www.reddit.com/r/askscience/comments/yvjy3/if_i_had_a_stationary_slinky_hanging_from_a_mile/ | {
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"[Explanation](_URL_1_)\n\n[Longer slinky](_URL_0_)"
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"http://www.youtube.com/watch?v=JsytnJ_pSf8",
"http://www.youtube.com/watch?v=eCMmmEEyOO0"
]
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17ms7w | How important are genetics in sports? | askscience | http://www.reddit.com/r/askscience/comments/17ms7w/how_important_are_genetics_in_sports/ | {
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"Approximately 17% of people are born without the ability to create fast-twitch muscle fibers. They have nonsense genes in place of the gene that allows the creation of fast twitch muscles. [One study](_URL_0_) showed that elite sprinters and power athletes are much less likely to have the nonsense allele, and [another study](_URL_1_) showed that elite bodybuilders and strength athletes are much less likely to have the nonsense allele.\n\nIn other words, elite athletes are unlikely to have this worthless gene. However, approximately 7% of them do. In other-words, in a few people hard work seems to be able to compensate for poor genes, but it's easier if you have good genes. "
]
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"http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1180686/",
"http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2668151/"
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1ku23q | If you stacked an infinite line of standard dominoes .5 inches apart and pushed one end knocking them over. Would the whole line fall, or would the energy eventually run out? | I was in bed last night wondering if the whole line would fall over, but I do not not think it would. If they do eventually lose the energy and teh dominoes stop falling, how many would fall before it stopped? | askscience | http://www.reddit.com/r/askscience/comments/1ku23q/if_you_stacked_an_infinite_line_of_standard/ | {
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"Have you seen the gifs or youtube videos about smaller dominos knocking over bigger and bigger dominos until the biggest ones are so big a regular human probably wouldn't be strong enough to push it over?\n\nI think that demonstrates that the energy wouldn't ever run out.",
"With dominoes, the energy supplied by the push is negligible. The real source of energy in the sequence of falling dominoes is the potential energy from gravity that each of the dominoes is storing. When you tip one, you allow that energy to be released and the domino settles in a lower-energy state. ",
"The line would never stop falling. Each domino standing on its edge has a certain amount of [potential energy](_URL_1_). Dominoes have enough potential energy to more than knock over a thing equal to it in weight. Watch [this video](_URL_0_) to see it actually happen, with dominoes knocking over progressively larger dominoes. \n\n/u/Maximum20LettersUsed is right that the line would never be *done* falling, because we're talking about an infinitely long line, and falling over takes time. But it would also never *stop* falling. It would just keep going.",
"In the case of a falling domino you actually are converting potential energy to kinetic energy as each domino falls. So long as enough energy is converted to knock down he next domino it should never run out. \n\nAll you need is enough energy to destabilize the next domino. \n\nEdit:\n\nYou might find this interesting\n\n_URL_0_",
"So a related question: say this infinite line of dominoes is in a 1 atmosphere Earth-like environment. What is the maximum velocity this line of falling dominoes can reach?",
" > Infinite Line\n\n > Whole line fall\n\nNo. If you have an infinite anything then talking about the whole thing following a sequential process is useless, the line doesn't end, so they can't \"all\" fall over. Not in the age of the universe a billion times over. Literally never.\n\nAs for the nature of your question: the potential energy is what propels the \"domino effect\", not the force from the previous domino. The force from the previous domino just allows that potential energy to act. I would be interested to see if the acceleration of the dominos' falling would reach any sort of limit or cause anything interesting in physics, but that's way too much math for today. Barring some unexpected consequences due to domino falling-speed they wouldn't stop or \"run out\" of energy."
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"http://www.youtube.com/watch?v=5JCm5FY-dEY",
"http://en.wikipedia.org/wiki/Potential_energy"
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"http://www.youtube.com/watch?v=y97rBdSYbkg"
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29p9bj | what is it i'm actually smelling as a thunderstorm approaches? | Just today I walked outside to overcast skies, and I could smell the storm coming. What did I smell? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/29p9bj/eli5what_is_it_im_actually_smelling_as_a/ | {
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"An electrical charge—from lightning or a man-made source such as an electrical generator—splits atmospheric nitrogen and oxygen molecules into separate atoms. Some of these recombine into nitric oxide, and this in turn reacts with other atmospheric chemicals, occasionally producing a molecule made up of three oxygen atoms—ozone, or O3. (Most atmospheric oxygen is made up of two atoms—O2.) The scent of ozone heralds stormy weather because a thunderstorm's downdrafts carry O3 from higher altitudes to nose level.",
"If you're in the Southwest, you might be smelling creosote. The rain releases its pollen, which has a unique bittersweet odor. \nEdit: grammar."
]
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[],
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a1kppx | After light slows traveling through a medium, does it accelerate back to c upon reentering a vacuum or does it remain the same velocity as it was the moment it exited the medium? | askscience | https://www.reddit.com/r/askscience/comments/a1kppx/after_light_slows_traveling_through_a_medium_does/ | {
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"The idea of \"the speed of light in a medium\" is really just a helpful trick for simplifying a more complex phenomenon.\n\nWhat's really going on is that the incident wave, as it propagates through a material, causes charges in the material to oscillate and in turn radiate EM 'wavelets'. The combined effect of these 'wavelets' is a wave with the same frequency as the incident wave, but out of phase with it. It's important to understand that these waves still propagate at c, however the light we observe is the sum of these waves. In transparent materials, the resulting wave has the same frequency, but a shorter wavelength, resulting in a wave transmitting slower than the oscillations in the field propagate.\n\nIn a vacuum, there are no such interfering 'wavelets', and therefore no apparent slowing."
]
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d7oc58 | why is mitochondria called "the powerhouse of the cell" and what is its relationship with atp? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/d7oc58/eli5_why_is_mitochondria_called_the_powerhouse_of/ | {
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"Your mum makes you meal so that you can get energy from food to play; mitochondria makes ATP so that cells have the energy to do what they need to do.",
"It's literally the organelle that produces the \"energy\" that the body uses. That energy is ATP.",
"ATP (adenosine triphosphate) is the energy molecule that our cells use. When used, one of the phosphates comes off, leaving us with ADP+P . (Adenosine diphosphate + phosphate)\n\nThe mitochondria is bound in membranes that are equipped with everything (membrane proteins) they need to re-energize ADP+P. Using energy from food to stick that phosphate back on, we get more useful ATP. This doesn't occur anywhere else in the cell at this scale",
"ELI5 of u/kineth great description, but maybe too complex for very young people: All you eat and store gets turned into glucose when you need energy, then that gets turned into ATP on the mitochondria. Your body can use ATP as energy, not glucose directly."
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[]
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5nlxk1 | Did Henry Ford say this quote, and what did he mean by it? | After a few google searches, I haven't been able to locate anything that points to him actually saying this. Most of the links that appear seem to be conspiracy-esque sites.
The quote in question:
"It is well enough that people of the nation do not understand our banking and monetary system, for if they did, I believe there would be a revolution before tomorrow morning."
| AskHistorians | https://www.reddit.com/r/AskHistorians/comments/5nlxk1/did_henry_ford_say_this_quote_and_what_did_he/ | {
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"That particular quote first appeared in *The American Mercury* in 1957 in an article [How Internationalists Gain Power](_URL_2_), and it is important to remember that the entire passage is prefaced with \"It was Henry Ford, Sr. who said *in substance*\" (emphasis mine) - that is, the quote was abridged or paraphrased - the quote also appeared in [The Federal Reserve Hoax](_URL_1_) by Wickliffe B. Vennard in 1959.\n\nSo...Ford probably didn't say exactly that quote; if he did he was probably talking about \"sound money.\" In his book [My Life and Work](_URL_0_) 179:\n\n > The people are naturally conservative. They are more conservative than the financiers. Those who believe that the people are so easily led that they would permit the printing presses to run off money like milk tickets do not understand them. It is the innate conservation of the people that has kept our money good in spite of the fantastic tricks which financiers play-and which they cover up with high technical terms.\n\n > The people are on the side of sound money. They are so unalterably on the side of sound money that it is a serious question how they would regard the system under which they live, if they once knew what the initiate can do with it.\n\nIn context, this is from before the Great Depression - and in that period in American economic history after the introduction of the greenbacks but before the complete abandonment of the gold standard. There are plenty of goldbugs still on the far right in the United States."
]
} | [] | [] | [
[
"http://www.worldcat.org/title/my-life-and-work/oclc/123787342",
"http://www.worldcat.org/title/federal-reserve-hoax-formerly-the-federal-reserve-corporation-the-age-of-deception/oclc/3291128",
"http://www.unz.org/Pub/AmMercury-1957oct-00079?View=PDF"
]
] | |
fze530 | how are some munitions designed to detonate before they hit the ground/target? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/fze530/eli5_how_are_some_munitions_designed_to_detonate/ | {
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"In short, computers. Computers paired with some other instrument like an altimeter or simple radar that are programmed to detonate when a certain height/distance from the target is returned by the scanning instrument.",
"Proximity fuses work by measuring distance to the ground by sending out radar, laser, etc. and when it bounces back go boom.",
"In addition to the fancy things mentioned by other folks, like lasers/radar/altimeters, some air-burst munitions just use a simple timer. For example, part of calculating the details of an artillery mission is figuring out the round's time of flight to the target. So you just set a timer on the fuze to function a little bit before you know it will hit the ground.\n\nSource: former fire direction officer."
]
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[],
[],
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] | ||
5lttzi | Before Loving v Virginia how common were non white mixed race marriages? | Loving V Virginia was a Supreme Court case in 1967 deciding that there can be no law against mixed race marriages. The Virginia law had language specifying a person classified as "white" could not marry a person classified as "colored". Does this mean that marriages where neither party was white were legal. Were non white mixed marriages more acceptable? | AskHistorians | https://www.reddit.com/r/AskHistorians/comments/5lttzi/before_loving_v_virginia_how_common_were_non/ | {
"a_id": [
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"I know that the Siamese twins Chang and Eng Bunker had problems when they moved to North Carolina with attempts to classify their race. Eventually, they must have been considered white as they were married to white people and owned slaves. Their descendants (they managed to have about 23 children) ignored the \"one-drop\" rule that applied to African ancestry and were probably thought of as entirely white. I don't much about know about how relations with Indians were handled."
]
} | [] | [] | [
[]
] | |
pdfyt | How does this gyroscope hand exerciser work? | I have a Dynaflex Gyro Exerciser. This is a wrist and forearm exerciser that claims to be powered by gyroscopes.
Here is a link to the product on Amazon: _URL_0_
How does this thing work? Once you get it going, it does take quite a bit of effort and coordination to keep it spinning. But what is the actual mechanism or principal at work here? I have very little to no understanding of gyroscopes. | askscience | http://www.reddit.com/r/askscience/comments/pdfyt/how_does_this_gyroscope_hand_exerciser_work/ | {
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"text": [
"gyroscopes work by angular momentum, basically it creates a force that keeps the spinning disc inside it straight (or at a constant angle) and it 'forces' it's self back to this position, gyroscope are used to keep some large ship upright in heavy storms you know, as far as the exercise involved, what do you do with it?"
]
} | [] | [
"http://www.amazon.com/Dynaflex-Sports-Gyro-Wrist-Exerciser/dp/B000LPG5US/"
] | [
[]
] | |
mtrez | Could there, theoretically, be particles that don't interact with ANYTHING? If so, in what sense would they 'exist'? | askscience | http://www.reddit.com/r/askscience/comments/mtrez/could_there_theoretically_be_particles_that_dont/ | {
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" > If so, in what sense would they 'exist'?\n\nThat's the key question there. If there is something out there, the existence of which won't change _anything_ observable in the world, then it does not exist, as far as science is concerned. Science requires an assertion to be falsifiable.",
"We have speculated about these kinds of particles. Technically they'd still interact gravitationally, as that's tied into the curvature of space-time and its relationship to energy itself. Even so, we have speculated about things like \"Sterile\" neutrinos, neutrinos that the weak force can't \"touch.\" I think there is a recent proposal to search for them by looking for some missing something, but I'm not perfectly sure of the details.",
" > If so, in what sense would they 'exist'?\n\nThat's the key question there. If there is something out there, the existence of which won't change _anything_ observable in the world, then it does not exist, as far as science is concerned. Science requires an assertion to be falsifiable.",
"We have speculated about these kinds of particles. Technically they'd still interact gravitationally, as that's tied into the curvature of space-time and its relationship to energy itself. Even so, we have speculated about things like \"Sterile\" neutrinos, neutrinos that the weak force can't \"touch.\" I think there is a recent proposal to search for them by looking for some missing something, but I'm not perfectly sure of the details."
]
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c1p4e1 | Who are the indigenous people of Europe? | I know this answer must vary with geography but is there such a thing?
If I remember my history lesson correctly europes history is littered with people coming from somewhere else and the only people I can think of not coming from outside Europe is the celts (the Basque?) and the Sapmi peoples.
Is european people from outside Europe? | AskHistorians | https://www.reddit.com/r/AskHistorians/comments/c1p4e1/who_are_the_indigenous_people_of_europe/ | {
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"Who are the indigenous people of Europe? It depends how far you want to go back.\n\n & #x200B;\n\nIf you go back longer than 40,000 years ago the indigenous people of Europe were Neanderthals who had interbred with Homo Sapiens. About then the Neanderthals went extinct in Europe and were succeeded by the undifferentiated Sapiens fresh out of Africa streaming in from the direction of the Near East and Asia. The genotype of these peoples suggests that they had black or dark brown skin, stringy dark hair, and blue eyes. These people were simple hunter-gathers. These seem to be the first Homo Sapiens in numbers in Europe.\n\n & #x200B;\n\nNext, about 10,000 years ago, a second people entered Europe from Anatolia bringing farming with them. Farming spread throughout Europe but it varied how much these people mixed with the existing hunter gatherer population. It definitely was a population mixture rather than a population replacement.\n\n & #x200B;\n\nThe Anatolian genome survived virtually unchanged on the island of Sardinia. If you want to know what the Anatolian farmers looked like then google images of Sardinians.\n\n & #x200B;\n\nThe 10,000 year old Cheddar Man specimen from Somerset England is a example from this time period. Cheddar Man had pretty much the features of a hunter-gatherer: dark brown skin, dark hair and blue eyes. Remarkably, living relatives of Cheddar Man were found by DNA testing within 100 miles of the site where Chedder Man was found.\n\n & #x200B;\n\nSo if you want to tell Nigel Farage that the first Englishman had dark brown skin go ahead.\n\n & #x200B;\n\nFinally, the Proto-Indo-European people swept in from the steppes north of the Caspian Sea riding horses, hauling wagons, kicking ass and taking names (actually they were giving names because these are the PIE after all) and they conquered all before them.\n\n & #x200B;\n\nSo, the indigenous European was a mixture of the genomes from the hunter-gathers, the Anatolian farmers and the Proto-Indo-European peoples with a pinch of Neanderthal thrown in.\n\n & #x200B;\n\nWho We Are And How We Got Here, by David Reich\n\n & #x200B;\n\n[_URL_1_](_URL_1_)\n\n[_URL_0_](_URL_0_)"
]
} | [] | [] | [
[
"https://www.theguardian.com/science/2018/feb/07/first-modern-britons-dark-black-skin-cheddar-man-dna-analysis-reveals",
"https://www.ancient-origins.net/history/9000-year-old-cheddar-man-has-living-descendant-still-living-same-area-006961"
]
] | |
1kga5h | How powerful a magnet would I need to levitate a drop of water due to it's diamagnetic properties? | askscience | http://www.reddit.com/r/askscience/comments/1kga5h/how_powerful_a_magnet_would_i_need_to_levitate_a/ | {
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"According to Wikipedia,\n\"**A substance that is diamagnetic repels a magnetic field**. All materials have diamagnetic properties, but the effect is very weak, and is usually overcome by the object's paramagnetic or ferromagnetic properties, which act in the opposite manner. Any material in which the diamagnetic component is strongest will be repelled by a magnet.\n\n\nDiamagnetic levitation can be used to levitate very light pieces of pyrolytic graphite or bismuth above a moderately strong permanent magnet. **As water is predominantly diamagnetic, this technique has been used to levitate water droplets and even live animals, such as a grasshopper, frog and a mouse.[8] **However, the magnetic fields required for this are very high, typically in the range of 16 teslas**, and therefore create significant problems if ferromagnetic materials are nearby.\"\n\n\nThere are equations as well, but the gist of them is that the required power to levitate a material is based off of the magnetic susceptibility, the density of the material, the local gravitational acceleration (−9.8 m/s2 on Earth), and the [permeability of free space](_URL_0_).\n\nFor water, under ideal conditions, the magnet would have to be 1400 Tesla^2 / m.",
"According to [this](_URL_0_) approximately 10 Tesla.\n\nThey have done these kind of experiments at the National High Magnetic Field Laboratory in Tallahassee, FL (they have an 85 tesla magnet)\n\n"
]
} | [] | [] | [
[
"http://en.wikipedia.org/wiki/Permeability_of_free_space"
],
[
"http://www.youtube.com/watch?v=EByiuOdnO-A"
]
] | ||
b35yud | Why are there no tides in non ocean connected waters? | Why is it only bodies of water that are connected with the oceans/sea have tides? If it is a uniform lunar gravitational effect upon the earth that creates the tides,why is it only rivers,streams and so forth that are connected to the ocean that are effected? The great lakes are massive bodies of water, but have no observable tidal effect due to the moons gravitational effect. How is this possible? | askscience | https://www.reddit.com/r/askscience/comments/b35yud/why_are_there_no_tides_in_non_ocean_connected/ | {
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"The moon does have a tidal effect on all bodies of water, but it's only the oceans that are big enough that we can see it easily. The Great Lakes do have measurable tides, but they're fairly small and not as important of a regulator of water level as wind speed and direction. The great lakes are big, but still miniscule when compared to the oceans.",
"Within the size of a lake the gravitational attraction from the Moon doesn't change as much as within the much larger oceans. You do have tides but they are negligible.\n\nTides are not limited to water, by the way, the whole Earth has tides as well. This is important e.g. [for particle accelerators like the LHC](_URL_0_)."
]
} | [] | [] | [
[],
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"https://www.quantumdiaries.org/2012/06/07/is-the-moon-full-just-ask-the-lhc-operators/"
]
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4oc4jl | How much text do we have from different ancient languages? | [deleted] | AskHistorians | https://www.reddit.com/r/AskHistorians/comments/4oc4jl/how_much_text_do_we_have_from_different_ancient/ | {
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"This is going to be a very difficult question to answer, though I've often, as a Classicist, wondered something similar myself. The only way to really quantify in a way you are wanting would be by \"word count,\" which is itself problematic (Greek has articles and particles, for instance, which inflate its word count vs Latin in the long term). On [Perseus](_URL_0_) reports 13 million Greek words in its collection, and 10 million Latin words. This probably translates to about the same amount of \"text,\" give or take. There is also the problem of chronology and content. We have Greek texts from the 7th century BCE all the way to the late Medieval period. Which are included? We have many texts which are very fragmentary. Are they included? Still, Perseus has a pretty good coverage of the \"core\" or \"canon\" ancient texts, and we are fortunate that it has a word count. It's good enough to use as comparison, anyway. Now you would need to find a word count for, say, Sanskrit within a bounded time-frame. Good luck with that!"
]
} | [] | [] | [
[
"http://www.perseus.tufts.edu/hopper/collection?collection=perseus:collection:greco-roman"
]
] | |
zqqwf | If I were dropped into Jupiter's atmosphere with a spacesuit, would I be pulled in until I reached the core, or would I eventually come into contact with a surface that stops me? | I understand that Jupiter is a gas giant, so is there any surface to speak of within the planet? The wikipedia page says there is a substantial layer of "liquid metallic hydrogen," so would that halt my fall like splashing into the ocean? | askscience | http://www.reddit.com/r/askscience/comments/zqqwf/if_i_were_dropped_into_jupiters_atmosphere_with_a/ | {
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"Assuming that your suit is pressurized/rigid, you will eventually reach a point where you're too buoyant to sink any further through the planet since it gets denser and denser as you get closer to the center. We don't really have any materials that would survive at the ridiculous pressures where the metallic hydrogen is present (millions, or even hundreds of millions of PSI) so you'd likely not get that far down. ",
"I would think you sink until you reach a layer that is as dense as you are. Then you would bob there."
]
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[],
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] | |
a7mw5v | "Hollywood" is so synonymous with the motion picture industry that the word itself has become shorthand for it; how did this come to be the case? How were they able to establish and maintain (for nearly 100 years) such a dominant hold over the industry? | AskHistorians | https://www.reddit.com/r/AskHistorians/comments/a7mw5v/hollywood_is_so_synonymous_with_the_motion/ | {
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"text": [
"A very similar question was answered by /u/Strabbo in [this post](_URL_0_). /u/kirbyderwood also provides an answer lower in the thread explaining the Hollywood - Los Angeles dynamic."
]
} | [] | [] | [
[
"https://www.reddit.com/r/AskHistorians/comments/3ky337/how_did_the_us_film_industry_come_to_be_centered/"
]
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1qpjuw | if trans fats are truly as dangerous as people say, then why is it still legal to put them in food? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1qpjuw/eli5_if_trans_fats_are_truly_as_dangerous_as/ | {
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"not legal anymore...\n\n_URL_0_\n",
"It's quickly become more and more illegal, because trans fats literally stick to the sides of your arteries and slowly block them until you have a heart attack and require a bypass. "
]
} | [] | [] | [
[
"http://www.reuters.com/article/2013/11/11/idUS243461124420131111"
],
[]
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73i8rm | how does exercise benefit the body so greatly if it increases oxidative stress, the basis for all known disease? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/73i8rm/eli5_how_does_exercise_benefit_the_body_so/ | {
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"The oxidative negative effects are negligible compared to the PREVENTION of the negatives of not exercising. Basically, having amazing, \"non-oxidated\" heart arteries arent worth much if they are clogged with fat.",
" > oxidative stress, the basis for all known disease\n\nHere is the error in your thinking. Most diseases actually have *other* causes.",
"The important thing to keep in mind here is the body's ability to maintain homeostasis. When there is a stress placed on the body that is beyond what the body can readily compensate for, you get disease. Assuming normal physiology, the oxidative stress that exercise places on your body is well within what your body should be able to deal with. Hence, why the known benefits of exercise are not outweighed by the stress exercise places on the body."
]
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6c11bk | how do companies sell away so many stocks to public, still totally owned and controlled by the same people, if stock are a form of ownership? | For example, Apple has stock. But if me and a million more people buy Apple stock, the company would still have the same owner and people in charge. So how are the rest of us owners? In most cases we don't even get a cut of the net profit.
This confuses me. What exactly is a stock? What is a share?
I buy 1 stock or share of Apple, what percentage of the company do I own?
| explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/6c11bk/eli5_how_do_companies_sell_away_so_many_stocks_to/ | {
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"Stock and shares are the same thing. One share is a fraction of ownership in the company.\n\nApple has approximately 5 billion shares out there, so if you own one share, you get one vote, but practically speaking, that vote doesn't matter much.\n\nThe shares of Apple are *not* controlled by any one person or small group of people. What that means is that if the majority of Apple shareholders decided to, they could vote to replace the CEO Tim Cook or vote to make Apple do something else, and the company wouldn't be able to say no. The shareholders ultimately control the company.\n\nHowever, in practice this is relatively rare. When a large company is successful, shareholders rarely have any influence.\n\nSome companies set up different rules. At Google, the founders made their own shares worth 10 votes each. That way they only owned 5% of the shares but they got 50% of the votes. So even if every shareholder in the world wanted to, they couldn't control Google. All they could do to send a message is dump Google stock and cause the share price to go down, causing employees and founders to lose money.\n",
"Apple has been regularly giving out dividends for 10 years. In 2017 they gave out .57 cents a share in February, and .63 cents a share in May for the first and second quarters respectively. That's your cut of the profits. Apple's market valuation is over 300 billion dollars. Even if Bill gates liquidated his 75 billion dollar net worth and used it all to purchase Apple Stock, he'd own only 20% of the company. Apple is so valuable no one person can gain majority control today."
]
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[],
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27sczr | why jupiter, saturn, uranus and neptune are considered giant planets and not small planets with big atmospheres? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/27sczr/eli5_why_jupiter_saturn_uranus_and_neptune_are/ | {
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"Even if you ignored their crushing atmospheres as \"just atmosphere\", you rapidly get down into the quasi-liquid, or maybe solid who knows? cores, which are still many times larger than any of the terrestrial planets.\n\nSeriously, they are giant.",
"Why shouldn't the atmosphere count as part of the planet? You may think that we don't count the atmosphere as part of Earth, but that's just because it's so thin. Go look at a globe. Earth's atmosphere is about as thick as the lacquer on it."
]
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1g0a2f | would google fiber's phenomenal download/upload speed be useful for people who don't torrent movies or software like your average redditor? why are cable companies wrong in saying that fiber's speed is unnecessary and overkill? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1g0a2f/eli5_would_google_fibers_phenomenal/ | {
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"More speed is desirable because, while we cannot predict exactly *what* customers will be doing with that bandwidth, we can predict that they will want and need it. We all use more data than we did 5 years ago and 5 years before that. We will surely use more 5 years from now. Keeping our internet services sufficiently robust to anticipate future need is simply common sense. And judging from the profits the ISP's make, they can certainly afford to upgrade. They just don't want to.",
"If all you do is a bit of web browsing and email, then fibre probably isn't that useful to you, but even then it can be in certain situations.\n\nOne of the main advantages of Fibre-to-the-Building (like Google Fibre, a system where the connection uses fibre optics all the way from your house to your ISP) is that it is *synchronous*, meaning that the upload speed is as fast as the download speed. I'm not too familiar with the situation in the US, but in the UK, and I believe most of Europe, the most commonly used technology is ADSL2+, which is *asynchronous*, meaning that the upload speed is much slower (around 20x slower) than the download speed.\n\nHaving a slow upload speed means that sending any large quantity of data can take a very long time: uploading a ten minute video clip to youtube can take me over an hour, if it is hi-def.\n\nSo what, most people don't upload HD videos, you might say. But consider that hi-definition (or at least, 720p) video cameras are now standard in most new phones. More and more people are taking videos and pictures, and uploading them to share with friends and family. For example, my mum takes lots of pictures of her children and her granddaughter, which she emails to my grandmothers local picture shop. They print them out, and my grandma can pick them up (she's 91, it's easier than emailing her them direct.) A high quality digital photo is often over a megabyte. Sending a whole album of them can really take a while on a copper ADSL connection.\n\nHere are some other examples of applications that lots of \"normal\" internet users use that would benefit from fibre:\n\n* Video conferencing. I know plenty of middle-aged and older people who use Skype for video calls, and who are far from power users.\n* Netflix/Lovefilm/Hulu etc. HD televisions are pretty much the norm for new purchases these days. To stream truly HD video (not compressed to hell) you need a fat pipe.\n* Online backup. Using Google Drive, MS Skydrive, Dropbox etc is a great easy way for the average home user to do offsite backup, but for even a few gigs, you'll need a good upload speed.\n\nNow in fairness, all these things can be done with a lot less than 1Gbps, but they do need more than the ~20Mpbs/1Mbps you get with pure copper infrastructure. You can get a bit faster (~40Mbps) by using Fibre-to-the-Cabinet, and VDSL the rest of the way, like British Telecom do, but really, for a smooth internet experience using HD quality video services, you need 50-100Mbps both ways, and that means fibre. 1Gbps may be overkill, but there isn't really a technology in-between fibre and copper.\n\nThere is a company in London called Hyperoptic, doing essentially what Google are doing, laying down their own fibre network. Although they offer speeds of 1Gbps, apparently their cheaper, 100Mbps package is more popular. Just because you have the capacity to offer 1Gbps doesn't mean you can't sell less of that capacity for cheaper, until the market wants the really high speeds: You *could* achieve 10Gbps with fibre, if you have the backend infrastructure to back it up.\n\nSorry if this has strayed a bit from LY5, comment if I've got too technical on any particular point.",
"Well, the majority of internet services can be provided using today's bandwidth/speed, but that's because they were built so that they could run on the current infrastructure. \n\nThink about a bike lane in a small town. Let's say the town starts out without bike lanes, so many people think \"there aren't bike lanes, so it isn't wise for me to take my bike. I'll take my car instead.\" Now what cable companies are claiming is that they don't need to add a bike lane because no one rides their bike. But once the town implements a bike lane, many people decide that using their bike is better and start using it. \n\nGiving wider bandwidth and higher speeds is essentially like adding the bike lane. It opens the availability for companies to develop new services that require faster internet speeds that previously weren't available. We might start streaming 1080p movies more often, or for the elite, 4K+ resolution streaming. \n\nAlso remember that many things in technology follow the trend. A new big service will be released and everyone will say \"OMG THIS IS SO MUCH THAT NO ONE CAN USE IT ALL.\"\nThey probably felt that way the first time a 1.44MB floppy disk was released. Back then they were used to store rudimentary programs and text. They would probably think a 2TB hard drive (not that uncommon today) is overkill, but we've found new ways to fill that capacity, namely HD movies, games, music albums, etc.\n\nEDIT: More elaboration:\nI remember when I was younger, we still had a 56K dial-up connection. The idea of watching online videos with that speed is atrocious. Also, the idea of cloud computing and storage would have been impossible without improving the speeds, so tools like dropbox wouldn't exist if we stuck with dial-up. Back then, we didn't have any idea of these services and probably felt that dial-up was sufficient as well. But once speeds improved, people filled in services that required higher speeds (Like youtube and Dropbox).",
"So I can download a car."
]
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fw509 | What does science have to say about Free will Vs Determinism? | askscience | http://www.reddit.com/r/askscience/comments/fw509/what_does_science_have_to_say_about_free_will_vs/ | {
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"It doesn't say much about free will, but determinism is pretty much out.\n\nAt least, on the quantum level, there's no such thing as determinism.",
"*disclaimer* This is all personal philosophy mind you. Your opinion may differ greatly from my own.\n\nThere are 3 basic structures of thought about time. Presentism, where only the present moment \"exists.\" Growing block, where the past is history and the future is being determined by actions in a special present moment. And block, where past present and future all exist as one big \"block\" of events with nothing special about what we perceive as the present. \n\nFrom my perspective, with special relativity, we can say that the present is, at best, an ill-defined notion. Different observers will disagree on what *exactly* constitutes the present. An observer will have some past and some future within another observer's present. So it seems to me that neither presentism, nor the growing block, are effective philosopical models of reality.\n\nThus, I am a block-universe-ist. We are traveling through our worldline through the block universe, perceiving each moment as it comes to us, and making choices as we arrive at them.\n\nSo what does this model say about free-will or determinism? First, there are different types of determinism, particularly ontological (we, or a sufficiently complex computer or something, can *know* the future) and metaphysical (the future is determined, but there is no way to know it). I believe in the metaphysically deterministic universe, but that ontological determinism is impossible. \n\nSo if we can't know the future, we make choices that are functionally equivalent to free will. (ie, since we don't know what we will choose in the future, or the consequences of that choice, it is functionally as free as having a not-preset future.)",
"So this is more of a philosophical answer, but it is related to science. In my view this problem only exists because free will is often poorly defined. Since I don't know what definition of free will you mean I can't concretely answer your question. \n\nIf you mean \"do people make choices?\", I would say yes from a descriptive definition of what we mean when we say choices. If you mean \"are the actions of people unpredictable?\", then free will does not exist. The entire \"purpose\" of the human intelligence is to predict other people's actions to gain reproductive advantage. Clearly people cannot predict each other perfectly, but if you know a person well you have better odds than guessing what they will do in a given situation.\n\nBut I consider the question of free will to be a question that does not matter. Imagine two worlds, one with free will (whatever that is), and one with the illusion of free will. There is no test that could distinguish between the two, therefore those two worlds are the same, and the question of free will is irrelevant."
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23d7rk | why did video games require memory cards when past games used to be able to save within the game itself? | **Example:** The Legend of Zelda and literally all Nintendo 64 games | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/23d7rk/eli5_why_did_video_games_require_memory_cards/ | {
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"When games where on cartridges they had a memory card built in. When they moved to CD's and later DVD's they required external memory because it'd be bad to be constantly writing and erasing data on the CD. Itd ruin the game disc fairly quickly.",
"Cartridge games had the equivalent of memory cards built into the game cartridge. You can't do that with games on a CD. Well, technically you can if you have a CD-burner and a re-writable CD, but that technology was *much* more expensive than read-only CDs at the time, and memory cards were a cheaper alternative.",
"Older games on cartridges had small memory modules inside that could be used for saved game storage. As game programs got larger, they needed more space than a cartridge could hold, so they moved to CDs, DVDs, Blu-Rays, etc. You can't save to a disc without changing the hardware of the system to a read/write drive, which would have increased the cost, and possibly degraded the longevity of the disc due to multiple write/rewrite operations. It was easier and cheaper to manufacture a gaming system with disc-based games, and external memory card storage. "
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lxkh9 | Would it be possible for a human being to actually walk on water? [Please, bear with me] | During a discussion about magicians last night, someone made the argument that they feel that if a human being can float on water whilst on their back without any aides, it might be possible for a human being to train themselves to 'float walk' on water.
Instinctively, I said this wasn't possible but the idea behind it has got me wondering about the science.
Any thoughts brave knights of knowledge? | askscience | http://www.reddit.com/r/askscience/comments/lxkh9/would_it_be_possible_for_a_human_being_to/ | {
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"This is the trick that [kick-started the conversation](_URL_0_).\n\n",
"Only if it's frozen. Otherwise, you'd have to displace your own weight in water before you started to float. You'd but in up to over your neck in fresh water. A bit less in very salty water, which has a greater density.\n",
"Every time I try to visualize some sort of stable device that would allow a human being to walk on water, it winds up resembling a boat. So yeah, you can walk on water in the most trivial sense. If you've ever been on a boat you've already done it.",
"You could walk on liquid water if: you were not on earth...\n\nIf you were on a planetary body with a minute fraction of earth's gravity, and enough pressure for liquid water to exist, I could see it happening. Of course the 'splashing' from your steps would basically turn the room into a giant mixture of churning air and water taking quite a while to settle down so you could do it again.\n\n",
"This is the trick that [kick-started the conversation](_URL_0_).\n\n",
"Only if it's frozen. Otherwise, you'd have to displace your own weight in water before you started to float. You'd but in up to over your neck in fresh water. A bit less in very salty water, which has a greater density.\n",
"Every time I try to visualize some sort of stable device that would allow a human being to walk on water, it winds up resembling a boat. So yeah, you can walk on water in the most trivial sense. If you've ever been on a boat you've already done it.",
"You could walk on liquid water if: you were not on earth...\n\nIf you were on a planetary body with a minute fraction of earth's gravity, and enough pressure for liquid water to exist, I could see it happening. Of course the 'splashing' from your steps would basically turn the room into a giant mixture of churning air and water taking quite a while to settle down so you could do it again.\n\n"
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5a9k99 | why is hayfever so massively common compared to other allergies? | If this isn't actually true and it's just confirmation bias, let me know. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/5a9k99/eli5_why_is_hayfever_so_massively_common_compared/ | {
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"Hayfever is not a specific allergy. It is a broad category applied to all allergies to airborne pollen regardless of what plant is producing it. It is so massively common because there are so many different species of plants. \n\nYou will sometimes get more specific diagnosis for being allergic to cedar, or ragweed, or yuka and the like if it is stronger or the only allergy you have but Hayfever is a catchall term. ",
"Hayfever isn't just one allergy, it's dozens, if not hundreds, of different allergies lumped into a single name. Somebody with a peanut allergy is probably just allergic to peanuts. Hayfever covers people allergic to any number of trees, grasses, flowers & weeds - each of them is a *specific* allergen. This is why people often notice a change in their seasonal suffering (for good or bad) when moving to a new part of the country.\n\nSo, yes, it is the most common but that's because it's it's dozens of different allergies lumped together as one thing."
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6amhqe | memory leaking | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/6amhqe/eli5_memory_leaking/ | {
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"\"Leaking\" is a metaphor. It actually refers to a situation where a program tells the computer \"I need to use some memory\" and then forgets to say \"I'm done using that memory.\" Over time, the computer allocates more and more of its memory to this program, making it hard for other programs to run."
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efd771 | If I drink a pint of water, how much of it is absorbed into my body becoming part of my organs and blood versus being excreted as urine or sweat? | askscience | https://www.reddit.com/r/askscience/comments/efd771/if_i_drink_a_pint_of_water_how_much_of_it_is/ | {
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"A bit hard to know how to answer this, because the body doesn't consume water - it creates it. Burning sugars to power the body results in carbon dioxide and water as waste products. And that water, along with what you drink and what you eat, ends up in your bloodstream, from where it used for sweat or excreted as urine.\n\nSo, basically, all of it, and a bit extra, will eventually be sweat or urine, although it may be used for a bunch of other things in the meantime - or broken down into hydrogen and oxygen and then combined later with other hydrogen and oxygen - so it this still the same water you drunk?",
"Well I mean it all gets absorbed by the body. It goes absorbed into the blood, which then gets passed throughout the body. It can go to cells which sweat it out, as well as any other cell that needs water.\n\nIf nothing needs the water, the blood hold onto the water until it goes through the kidneys, where excess water diffuses out of the blood. The kidneys collect all that extra water and make urine out of it.",
"In simpler terms: I pour a pint of water into a large bucket of water then drain out a pint how much of my original pint came out?\n\nThe water you drink diffuses throughout your body more or less equally. This was illustrated in the act of a disgruntled worker at a Canadian Nuclear Power Plant. As an act of revenge against his colleagues, he took a cup of the heavy water from the reactor and added it to the water cooler in the lunchroom. This was detected a couple of weeks later when routine urinalysis detected elevated tritium levels in the urine of several workers. (The deuterium in the heavy water in a CANDU reactor will occasionally absorb a neutron and become tritium).",
"All of its absorbed and all of its excreted. It's not a path going straight from your throat to your pisser. What you piss is simply what your kidney has filtered.\n\nWhat you sweat is obviously already absorbed as you can see it passing through an organ (your skin).",
"This question can't be answered. It's like answering the question, \"why do storks deliver babies?\" The assumption the question is based on (that water somehow can bypass your blood and organs before being secreted or excreted) is far from true.\n\nAll water that you pee is filtered from your blood. All sweat is secreted from an organ (skin). To put it simply, water is recycled by the body. It uses it until it doesn't need to anymore, then it's excreted. Then you drink more water and the process starts over. Moreover, when you sweat or pee, the water is still being used by your body to cool your body temperature or facilitate the transport of waste and excess fluid and materials out of your body respectively. It's not being dumped or wasted, like poop.\n\nTechnically speaking IF water went unused it would come out your anus with your poop, not as pee. But practically speaking all of the water you drink is absorbed. Whatever moisture you find in your poop is actually water secreted from your intestines...which has already been in your blood stream and a part of your organs (intestines in this case) before it was secreted. This doesn't even get into other facts that complicate this question (such as the fact that your body synthesized and breaks down water biochemically, as robbak mentioned).\n\nSo to answer the question you meant to ask, 100% of the water you drink becomes \"a part of you\". And 100% of the water that you release was \"a part of you\" at some point."
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1vf0ze | difference between 2-stroke and 4-stroke motorcycles (specifically dirt bikes) | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1vf0ze/eli5difference_between_2stroke_and_4stroke/ | {
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"[2 strokes](_URL_1_) have a power stroke every rotation. [4 strokes](_URL_0_) have a power stroke every second rotation.\n\nMost 2 strokes use ports that are covered and uncovered by the piston to inject air/gas and remove the exhaust. 4 strokes use valve for those jobs.\n\n2 strokes tend to be less efficient than 4 strokes.",
"A four-stroke uses valve gear in the head of the cylinder to introduce fuel-air mixture and allow the release of the burnt mixture... the four cycles are inlet, compression, ignition/expansion and exhaust as the cylinder goes up and down twice completely in the course of the complete sequence.\nIn a two-stroke the fuel /air ingress and exhaust is handled by ports in the cylinder wall being exposed or closed by the piston as it passes (in the classic version, modern engines modify the timing with extra kit). In order to force the mixture into the cylinder it is passed through the crankcase and is therefore compressed by the piston on the way down. The sequence is therefore inlet (already compressed), ignition/exhaust. ",
"2 strokes are simpler (thus cheaper), lighter, provide more power and usually require you to mix oil into the fuel. They also tend to wear out faster, make more noise & more pollution.",
"2 stroke: **breathe, explode**. Piston goes up and down once per cycle.\n\n4 stroke: **breathe, squeeze, explode, exhale**. Piston has to go up and down two times per cycle.\n\n2 strokes are simpler, louder, and not as efficient as 4 strokes. They also usually need oil mixed in with the gas since they do everything at once.",
"Even though everyone has done a fine job explaining the differences, I thought I would throw my two cents in. These comparisons assume the same displacement for both engines.\n\n2-Stroke\n\nPros: lighter, simpler, more powerful\n\nCons: Dirtier, must mix gas and oil, less efficient, wear out sooner\n\n\n4-Stroke\n\nPros: More efficient, no mixing, longer lasting, more efficient, cleaner\n\nCons: Heavier, less power, complicated\n"
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97pgqh | if you feed a cow with its own milk, will that cow be able to live out its life with no additional food source? | [deleted] | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/97pgqh/eli5if_you_feed_a_cow_with_its_own_milk_will_that/ | {
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"Like, feeding the cow milk taken from that same exact cow? That won't work because cows don't turn 100% of their food into milk. Some of it is lost.\n\nBut just feeding cows with cow milk - sure. Milk has all the nutrients necessary for the animal that the milk comes from. The only problem is that some individuals may not be able to process milk one they are adult. It can be fixed with some breeding.\n\nIn fact, humans can live off of human milk alone too. But again, only those who are not lactose intolerant.",
"No system is 100% efficient. When the cow feeds it doesn't just use energy it has gotten from the food to make milk, it also releases some of that energy in the form of heat and motion (walking). "
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6nqlr2 | what black light is and how it works to highlight many fluids and make certain colors glow | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/6nqlr2/eli5_what_black_light_is_and_how_it_works_to/ | {
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"Black light is ultraviolet light. Ultravolet means it is a wavelength too short for the eyes to see. However, some chemical compound can absorb certain wavelenghts, and emit light at an other, hence the glowing effect",
"They have an interesting property to them.\nUltraviolet (UV) light with shorter wavelengths has more overall energy, and a wider variety of materials will fluoresce (glow) under shorter wavelengths of UV light. The type of Ultraviolet light and the color of visible light is determined by its wavelength. The unit of measurement for light wavelengths is the nanometer (nm). Ultraviolet light is generally considered to be from 200 nm to 400 nm. It is safe, not harmful to the eyes, and will make fluorescent paints & markers light up brightly. It will also rapidly 'charge up' glow-in-the-dark materials (instead of holding them under bright white light for long periods of time). However, once you get into the short UV wavelengths (such as those under 300 nm) they have so much energy that they will burn your eyes & skin (which is exactly why they are used in tanning machines). Short wavelength of UV light is also the particular wavelength that will kill microorganisms in the UV wavelength of 264 nm.",
"Black light is very bright but most of its energy is in the ultraviolet spectrum which is higher in frequency than our eyes can see. Much like a dog whistle sounds silent to us because of it's pitch, ultraviolet light seems dark because of it's frequency. \n\nSome materials have a characteristic where they can absorb energy at one frequency, and re-radiate it outwards at a different frequency and we call them phosphors. When you take a black light poster and expose it to ultraviolet light, the pigment and ink in the posters colors absorb ultraviolet light and re-emit it as very pure oranges, reds, greens, and yellows making the poster appear to be self illuminating. \n\nPhosphors are also found in old television screens where they absorb electrons and re-emit their energy as photons, and flourescent tubes. \n\nFluorescent lighting is actually all black light because the electrical arc in the tubes is mostly in the ultraviolet range, so they coat the inside of the tubes with white phosophors which absorb the ultraviolet light and re-radiate it as white light. If you hold a fluorescent tube near a black light, it will glow. \n\nPhosphors are also in many bleaches and whitening agents and help make white clothing look whiter by absorbing natural UV light and re-emitting it as white light making them appear whiter. ",
"As others have explained, black light is UV light.\n\nBut an easier way to explain how it causes things to glow is to first identify what light actually *is*, and then distinguish it from UV light interactions.\n\nVisible light is a series of waves. These waves can be longer, or shorter, and their lengths determine the color that you see when it hits your eye. When you shine regular white light (which is *all* wavelengths of visible light) on gold, it shines back a bright yellowish color. That's because the gold absorbs all of the other color wavelengths.\n\nFor \"black\" (or UV) light, a similar principle occurs. The light waves hit the object, and a certain color wavelength bounces back for people to see. But UV is a higher energy light. Its wavelength is small enough to excite electrons inside of certain substances or materials. This excitation causes the electrons to elevate into a higher state of energy, and cause things to \"glow\". It isn't just a different light being bounced back. The material is energized from the UV light. This is called luminescence. "
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flpss | How can there be "a" human genome? [continued] | How can current genetic science distinguish what is part of "the" "baseline" human genome and what is an individual trait? Is there even such a thing as a "baseline" genome, or, does it even make sense to ask this question?
As far as current genetic science goes (I'm pretty much a noob in that field but..) I assume that genes and genetic expression of sequences that e.g. controls the phenotype of the individual might just as well be responsible for e.g. neurological traits (does the person have Asperger's? does the person have ADHD? any other kind of specific neurological trait?).
So is there even such a thing as a "human genome"? I _assume_ there is, but since I am a noob in genetics: how do you define it (not philosphically or anything, but strictly genetically)? | askscience | http://www.reddit.com/r/askscience/comments/flpss/how_can_there_be_a_human_genome_continued/ | {
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"Humans are about 99.9% genetically homogenous as determined by studies where groups of people were compared for differences individual base pairs, know as single nucleotide polymorphisms.\n\nA gene codes for a trait like hair color and each person has their own version of that gene like blonde brunette or redhead. These are known as alleles, so humans \"all\" have a hair color gene but we each have or own hair color allele (obviously there is a finite number of alleles for hair color).\n\nThe idea of a \"baseline\" genome is sort of redundant because the idea of a human genome *is* common genes in the first place. A genome is all the hereditary information an organism has. I think your going down the path of how to identify genetically what a species is. The definitions are sort of vague and seem to change. I don't think there is a genetic definition of species. \n\nedit: chem major go easy",
"Your question is really valid. You just got one term slightly off: its not called a \"baseline genome\", but rather a \"reference genome\". Think of it as the most average genome you can build of as many possible donors' genomes as technically feasible... The wiki article is quite clear and would probably answer your question: _URL_0_\n\nBuilding such a reference genome is the first and generally the hardest task, since all other future genome sequencing trials will highly depend on the ref genome. Once you have a ref. genome, you can just sequence random pieces of DNA and glue it together using the ref. genome as a \"guide\". Such reference genomes are maintained by govt. funded online databases and we can all use their services for our genome-guide-needs..\n\nFor other species though, it becomes quite easy because of the concept of a genetically-identical inbred strain: individuals are inbred over 10s of generations until their genomes are *exactly* the same and will be forever. Sequencing the genome of one such mouse strain, for example, will then be quite unambiguous. \n\nBut even there sequences from many different strains are combined to form a reference genome that can be used for the species as a whole.\n\nKindly note the distance of your question from asking for the genetic definition of a species though. When you talk about genome of a species, you've already assumed that you have marked which individuals classify under that species and you have no more taxonomical ambiguity. Making a reference genome within a fully-defined species (like that of humans, I hope we all accept that all people classify under *Homo sapiens sapiens*) is still a tricky issue as identified in the wiki page."
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2vhg8w | why do halogen headlights look white at some angles but blue at others? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2vhg8w/eli5_why_do_halogen_headlights_look_white_at_some/ | {
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"HIDs, which I think you're talking about, AKA Xenon, is an electric arc.\n\nThey're often used behind a projector lens, which gives a sharp cutoff of the beam, to prevent glare. At the edge of this cutoff, is a [varied color area](_URL_0_) \n\nWhen your eye is in the area of this blue fringe, they appear blue. "
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my5a2 | how radiation stays inside the nuclear plants but radiation can go through almost anything? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/my5a2/eli5_how_radiation_stays_inside_the_nuclear/ | {
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"Well, there are different types of radiation, and they all have different properties, but I'm going to give you a general answer.\n\nThere are specific materials that have a high tendency to interact with the radiation coming through it and slow it down. If the \"shielding\", such as a lead wall for example, is thick enough, it will block the radiation to a very small background (i.e. non-dangerous) level.\n\nSo if you are designing a nuclear reactor, you would want to use appropriate materials in building your reactor containment vessel to prevent any leakage of radiation.\n\nHere's a real example: On a 688 Class Nuclear Attack Submarine, the Diesel Oil storage tanks are just forward of the Reactor compartment. This has a beneficial effect because Diesel Oil is a pretty good nuclear shield. So what happens if you use up all the diesel fuel? Do you irradiate the crew? Nope. They put water in the oil tank which is also a pretty good shield. And every kid knows oil and water don't mix, so the oil and water stay separate in the tank. Neat, isn't it?\n\nOf course, there are some types of very, very high energy radiation that pass though stuff easily, but these are not the kinds that you are too worried about coming from Nuclear reactions. ",
"Well, there are different types of radiation, and they all have different properties, but I'm going to give you a general answer.\n\nThere are specific materials that have a high tendency to interact with the radiation coming through it and slow it down. If the \"shielding\", such as a lead wall for example, is thick enough, it will block the radiation to a very small background (i.e. non-dangerous) level.\n\nSo if you are designing a nuclear reactor, you would want to use appropriate materials in building your reactor containment vessel to prevent any leakage of radiation.\n\nHere's a real example: On a 688 Class Nuclear Attack Submarine, the Diesel Oil storage tanks are just forward of the Reactor compartment. This has a beneficial effect because Diesel Oil is a pretty good nuclear shield. So what happens if you use up all the diesel fuel? Do you irradiate the crew? Nope. They put water in the oil tank which is also a pretty good shield. And every kid knows oil and water don't mix, so the oil and water stay separate in the tank. Neat, isn't it?\n\nOf course, there are some types of very, very high energy radiation that pass though stuff easily, but these are not the kinds that you are too worried about coming from Nuclear reactions. "
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28qshq | Why does my sweat crystallize into salt when I sweat during exercise? | Whenever I run I get covered in salt crystals. I'm interested to know why this happens. | askscience | http://www.reddit.com/r/askscience/comments/28qshq/why_does_my_sweat_crystallize_into_salt_when_i/ | {
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"Your [sweat is salty](_URL_2_). The water evaporates and the salt precipitates out, depositing on you. Some people resorb more than others. This is the basis for the [sweat test](_URL_1_) for [cystic fibrosis](_URL_0_). Don't worry, just because you have more salt stains after running than someone else doesnt' mean you have cystic fibrosis."
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3oiqi4 | What was the Roman tax system like? | I tried to research this on my own but got kind of confused. My big question is did it involve any form of income tax at all? | AskHistorians | https://www.reddit.com/r/AskHistorians/comments/3oiqi4/what_was_the_roman_tax_system_like/ | {
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"usually tax rate would be between 1-3% on your wealth, but higher in wartime. sometimes there would be an income tax in Urban areas.\n\nin Rural areas where organised tax collection was either impossible or poorly executed Rome would put a levy and lump sum tax on the provincial governor, as long as he paid and supplied the soldiers needed, be basically got free reign over the region.\n\n_URL_1_\n_URL_0_",
"In addition to Batbuckleyourpants answer (the link he provided is great, read it! It goes more into detail): \n\nTaxation in the provinces was hard for 2 main reasons. First there was almost no reliable census data. This is also what Barbuckleyourpants' link mentions. But mainly, the problem was that there just was no formalised administration like we know it today. There was no IRS of the roman republic. Everything was taken care of by the ruling officials and a small circle of personal friends and employees. There were no bureaucrats in the modern sense. The roman republic was just not capable of taxing their provinces! That is also the reason they had to rely on Publicani, private entrepeneurs who bought the right collect taxes in a certain area from the state and did so with help of the local governor (of course enriching themselves by charging extremely high tolls and tariffs and such). \n\nAlso, the taxes you had to pay greatly depended on if you were a citizen or not. Roman citizens did not have to pay most of the direct taxes (for example the \"tributum capitis\", basically a wealth tax), they did not have to pay taxes on property (\"tributum soli\") as long as it was on the territory of roman cities, and many more exemptions. They did however have to pay a 5% inheritance tax. Taxes that everybody had to pay equally were tolls and tariffs, a 1% sales tax (3% if slaves were sold), and taxes on liberation of your slaves (5% of the value you bought him for).",
"Some of the other answers here have mentioned the tax rates (although there was no fixed rate at all, and it depended on the province--in Spain and Africa the *tributum soli* was paid at a fixed rate, regardless of the actual population or wealth of the province, and Asia paid a sort of bizarre early form of the *tributum* as laid out by the *Lex Sempronia*) and the various kinds of provincial *tributa*, but no one has mentioned the vectigals or the method of tax collection, which is what is so unique about Roman tax collection. By the late Republic the vast majority of Roman state revenue came from provincial tribute, and citizens were exempt from the *tributum* from 167 on. Most citizens wouldn't have to pay taxes at all, and colonies were also generally exempt as they had some form of Italian or Latin status. Any taxes that citizens had to pay would be some form of the *vectigalia*, the vectigals. By Cicero's day this had become a catch-all phrase for the state's revenue in general, but it appears to have originated as a term describing import/export taxes, as it's derived from \"veho,\" \"to convey\" (from which we get the word \"vehicle\"). The vectigals were duties imposed on particular goods and privileges, particularly the *portoria*, an import/export tax, and the various rents paid on the *ager publicus* and the public pastures. They were not, like the *tributum*, levied per head, and therefore citizens who weren't participating in any of the various activities included as vectigals (again, a difficult word, as tribute was often simply lumped in under the term after it came to mean \"state revenue\") didn't pay any taxes at all. This was perfectly satisfactory--the income earned from the provinces was more than enough to sustain the state, and since magistrates generally relied at least in part on their private funds there was no shortage of cash\n\nHowever, no discussion of the Roman tax system is complete without mention of the publicans, whom all the other answers have inexcusably left out. The Roman state did not collect taxes itself. That's extremely important, because it's the fundamental principle of the Roman tax system. Originally, back when Roman citizens still paid *tributa*, the state itself collected that revenue, but it appears that the vectigal was always collected by the publicans. The *publicani* were private individuals to whom the rights to collect taxes were sold. By the late Republic the publicans collected pretty much all taxes, including the vectigals in Italy. A few taxes, such as the Spanish and African *stipendium*, collected by the quaestors, and the Asian tithe (that bizarre tax provided by the *Lex Sempronia* I mentioned earlier), which was actually *sold* by the censors, were collected by magistrates, but these laws generally applied to provinces which, like Spain and Africa, had existed before the Romans really had many provinces. By Caesar's day provincial management had swelled to a size that the state, particularly the senate and the censors (no doubt made worse by the fact that the censorship basically ceased to exist in the 1st Century, B.C.), simply could not keep up with affairs, and the publicans basically take over. The publicans collected taxes on the mines, the ports, the *ager publicus* (these three in Italy as well as elsewhere), and in some provinces the various forms of *tributum*--the precise details of publican affairs is pretty complicated, and with some provinces we don't know precisely how taxes worked. It was an extremely lucrative business, more or less monopolized by the equites, who were often used synonymously with the publicans. Publican companies were large and well-organized, and in general the state sold contracts to the publicans based on how much they expected to earn--the publicans would promise a certain amount (usually by bids, with the highest bidder being the recipient of the contracts), and then whatever they earned beyond that was theirs to keep. Publicans were therefore notoriously extortionist, and their bands of thugs were often so exploitative and menacing that many promagisterial governors found it easier and safer to simply go along with it, rather than try to protect the provincials. Many governors held shares in the companies--although magistrates, senators, and promagistrates were legally barred from holding publican contracts and from holding a share in the company, by the late Republic a market for *partes*, the unregistered shares of a publican company, had developed, and thus both Caesar and Crassus held large stakes in various publican companies. From an early date they were absurdly wealthy--after Cannae the state's funds were artificially re-created by donations from the publicans from out of their private fortunes. It was also a relatively risky job--an overly-optimistic bid could cost you everything. Famously during Caesar's consulship in 59 he reorganized the contracts that particular companies of publicans, who were almost certainly connected to Crassus, held, since they had bid in excess of what they had discovered they could actually produce--if such a thing occurred the publican would have to pay the difference himself, and it could destroy him if his bid had been unwise. But Cicero described them as the foundation of the state's revenues, and therefore of the state's power itself. The civil wars cost the publicans dearly, as the opposing generals collected revenue themselves. Augustus reformed the provincial taxes, restricting publicans to the collection of the vectigal proper--henceforth *tributum* would be collected by the quaestors and procurators (who could be just as exploitative as the publicans, and as the OCD notes the exploitation of promagistrates and their staff--who could collect their own duties, particularly grain taxes to feed their troops, which were often embezzled--was generally much in excess of what the publicans could do)"
]
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"http://www.unrv.com/economy/roman-taxes.php",
"http://www.jstor.org/stable/299558"
],
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dnavrr | what does a "reset signal" to a cpu do? (computer science) | [deleted] | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/dnavrr/eli5_what_does_a_reset_signal_to_a_cpu_do/ | {
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"Well that's depends on what it's designed to do and what architecture. There's a really good book (_URL_0_) that goes through what happens when a computer boots up, this article explains in brief depth.\n\n_URL_1_\n\nThe ELI5 version is that there is an address your CPU is programmed to jump to when a reset hardware interrupt is triggered. \n\nThis is just a signal that can be wired up to some button i.e what's on your laptop. It physically tells your computer to freeze, sometimes do some stuff (clean up routines) and jump to some area in memory.\n\nThis address \"reset vector\" is just some memory that may or may not be mapped \"have something put there\". On Intel CPUs it's normally located at 0xffffffffffffffff 64bit.\n\nSo if I'm writing a bootloader (software that prepares your machine for booting up) I just map some code to that location. This allows me to hook into the boot process.\n\nAfter this it's hugely dependant on what the software has been programmed to do. But generally you need to get the processor into some state that it can initialise RAM (switching modes/turn on paging etc.), load drivers, boot a kernel and finally read the files system."
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"https://github.com/cfenollosa/os-tutorial",
"https://0xax.gitbooks.io/linux-insides/Booting/linux-bootstrap-1.html"
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51wuuw | what causes sponges to be as absorbent as they are compared to others? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/51wuuw/eli5_what_causes_sponges_to_be_as_absorbent_as/ | {
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"Assuming by 'others' you mean other materials, it's because they are full of tiny holes and chambers. Liquid is drawn into the chambers by capillary action.",
"Water sticks to materials that are hydrophilic. You'll notice that if you let some water drop onto a stone: It'll spread out into a very thin layer, and it will stick to it even if you lift the stone and turn it upside down. \n\nA sponge is like a stone, it is also hydrophilic. But unlike the stone, it has many little connected holes in it, with a huge surface area. The water sticks to the surface of these holes, spreading out through the entire sponge until it is completely filled with water, and it won't run off unless you squeeze it.\n\nSponge like materials which are made from hydrophobic material meanwhile won't let water creep into the little holes unless you force it, since the water minimizes contact area with the material. \n"
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2l0doc | Is it possible for a falling object's terminal velocity in a given atmosphere to exceed the speed of sound within that atmosphere? | It's my understanding that, as the fluid the object is falling through increases in density, the terminal velocity of the object will decrease while the speed of sound through that fluid increases, and vice versa as the fluid decreases in density. Is there a set of conditions under which the object's terminal velocity exceeds the speed of sound under those same conditions? Is it feasible that conditions like these could be met here, on earth? What kinds of extreme terminal velocities could be reached on earth, feasibly?
I'm interested in better understanding the factors at play in determining terminal velocity, and in the extremes able to be achieved. | askscience | http://www.reddit.com/r/askscience/comments/2l0doc/is_it_possible_for_a_falling_objects_terminal/ | {
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"Sure. [This guy](_URL_1_) broke the speed of sound in freefall about a week ago. All you need is a large, non-lifting, not too draggy body.\n\nFYI, speed of sound for air at the conditions found anywhere in the atmosphere is a mostly a function of just composition (as in how much water vapor, etc.) and temperature. It is only a very weak function of density.\n\nSpeed of sound for dry air is \n\nc = sqrt(gamma_air\\*R_air\\*T)\n\nwhere \n\ngamma_air is the ratio of specific heats for air, roughly 1.4\n\nR_air is the specific gas constant for air, roughly 287J/kg/K\n\nand T is the temperature, in K. \n\nFor example, the speed of sound at 20°C (293K) is [343m/s](_URL_4_).\n\nTerminal velocity of an object is the speed at which the force of drag exactly counteracts the force of gravity so that the object no longer accelerates. The force of gravity for an object of mass m is \n\nm\\*g\n\nwhere g is the acceleration of gravity (9.8m/s on earth).\n\nand the force of drag at terminal velocity is \n\n(1/2)\\*C_D\\*density_air\\*v_terminal^2 \\*A\n\nwhere A is the object's cross-sectional area and\n\nC_D is the drag coefficient, which can vary a lot with velocity and geometry, but you can set it to 0.5 for an okay approximation for non-streamlined objects.\n\nEquating those two expressions and solving for terminal velocity gives \n\nv_terminal = sqrt(2\\*m\\*g/density_air\\*C_D\\*A). \n\nFor example, an iron ball with radius 1 meter has a mass of [33500kg](_URL_0_) and a cross-sectional area of [3.14 m^2](_URL_3_). With a C_D of about .5 and air density at sea level of about 1kg/m^3, that gives a terminal velocity of [2030m/s](_URL_2_). You can play around with the formulas I gave to see what exactly it takes for terminal velocity to break the speed of sound.",
"In the atmosphere (and any gas in general), it would seem that the speed of sound is strongly dependent upon temperature as opposed to any other variable (pressure, density, water vapor). In the atmosphere, a speed of sound profile would roughly correlate with a temperature profile in terms of its shape. Wikipedia article (sorry): _URL_0_"
]
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236k29 | Has there ever been a movement to 'unite' the various Caribbean countries like Antigua and Barbuda, or Trinidad and Tobago? | Seems like a logical course of action | AskHistorians | http://www.reddit.com/r/AskHistorians/comments/236k29/has_there_ever_been_a_movement_to_unite_the/ | {
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"Are you asking why Islands of the Lesser Antilles haven't all banded together in a political union? Because I have no idea about that, sorry :/\n\nBut the way I read it, it looks like you're asking if pairs of small, neighboring islands are politically united, and they are! \n\n[Antigua & Barbuda] (_URL_0_)\n\n[Republic of Trinidad and Tobago] (_URL_1_)\n\n",
"To some extent there is a cultural union between the various Anglophone Caribbean nations, as they all compete together as the the West Indies in cricket. However, this doesn't really extend to economies or politics. ",
"Define \"unite\".\n\nThe [West Indies Federation](_URL_0_) was a thing in the 60's and was followed by [The Caribbean Free Trade Association](_URL_3_) which was then followed by the [Caribbean Community (CARICOM)](_URL_2_). The [Caribbean Single Market and Economy](_URL_1_) is the latest movement along similar lines.",
"Yes; at least twice. First, as the over-ambitious and short-lived [West Indies Federation](_URL_0_), and then as the limited-scope [CARICOM,](_URL_1_) which evolved out of the free trade agreement CARIFTA (essentially adding foreign policy understandings, a common passport, a customs union and easier movement). It resembles the gradual evolution of EU out of the EC, with blocks such as the Eastern Caribbean States having integrated faster.\n\nNote that CARICOM continues to lack real agreement on foreign policy. For example, on the recent UNGA vote condemning the Crimean referendum, Guyana, St Lucia, St Vincent and Antigua abstained, whereas Barbados, The Bahamas, Trinidad and Tobago and Haiti voted for it. In the OAS vote on that guy stuck in the Ecuadorean embassy in London, there was a similar split; it appears to follow an influence tug-of-war between Venezuela's Petrocaribe and the US' Caribbean Basin Initiative."
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"http://en.wikipedia.org/wiki/CARICOM_Single_Market_and_Economy",
"http://en.wikipedia.org/wiki/Caribbean_Community",... | |
2r001m | Why does the U.S. have so many aircraft carriers in comparison to the world? | AskHistorians | http://www.reddit.com/r/AskHistorians/comments/2r001m/why_does_the_us_have_so_many_aircraft_carriers_in/ | {
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"Hello, as you've stated the question, it essentially is violating our 20 Year Rule. You would have better luck with /r/CredibleDefense. But if you are looking for a more general answer about the development of US carrier policy through the Cold War, please feel free to resubmit the question here with some tweaking in the title!"
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i8te1 | Does mold automatically indicate spoilage? | i have a block of cheddar cheese in my fridge with the stereotypical green spots of mold on it. theoretically can't i just cut off the surface and still have a perfectly good block of cheese? same with bread. can't i just tear off the molded bits and have otherwise perfectly 'sanitary' bread to eat? if so where does this end? i don't suppose meat that's been able to grow mold would only be bad on the parts affected. | askscience | http://www.reddit.com/r/askscience/comments/i8te1/does_mold_automatically_indicate_spoilage/ | {
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"Mold *is* (one form of) spoilage. Visible mold in one place usually indicates non-visible trace amounts threaded through the food nearby. Cutting out only the visible bits will leaves these traces, and you don't know how much else to cut off.",
"Cheese is very dense, and mold hyphae (the vegetative growth of mold, almost always directly invisible) can't penetrate them more than a few millimeters*. Solid muscles of meat, or dense sausages (salamis) can be cured much like cheeses. The molds that form on them are unappetizing, but non-toxic and usually cut away before slicing. Most bread mold will be a blue form of penicillum, which may affect the flavor, but won't hurt you any.\n\nYour answer depends entirely on what molds you're encountering. Aspergillus oryzae is a mold I use to develop sugar and flavor in rice to make miso and sake. Penicillium nalgiovense is a good friend I use to protect long-cured salamis and other sausages. I try not to be afraid of anything unless it's been growing anaerobically in low acidity (inviting Clostridium botulinum, responsible for botulism) or if it's possibly been in contact with fecal coliforms, but to be safe, you should identify an organism or not eat it.\n\n*EDIT: unless, of course they are invited, like in a blue cheese, where channels are formed."
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fdgmlj | what causes tornadoes to form and why are they so often along the same historical paths? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/fdgmlj/eli5_what_causes_tornadoes_to_form_and_why_are/ | {
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"When warm, moist air mixes with cold air. When they meet the work around each other creating the cyclone. Most tornadoes form during thunderstorms, but that is not a requirement for there to be one. \n\nSame paths have to do with where these warm and cold fronts meet which is typically around “tornado alley.” (cold air from Canada & warm, moist air from the Gulf of Mexico)\n\nI live in the Midwest and at times you can predict that there will be a tornado watch or warning that day just based on how the air feels.",
"As to why they follow the same paths:\n\nGeography largely defines weather patterns. Since the actual geography of the Great Plains remains the same, the cold weather comes down to the same relative place and meet warm air masses in the same relative places and so the storms form in the same relative places."
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31w5c6 | Why did the Beer Hall Putsch fail despite the Nazis superior numbers? | AskHistorians | http://www.reddit.com/r/AskHistorians/comments/31w5c6/why_did_the_beer_hall_putsch_fail_despite_the/ | {
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"Hitler and the Nazis made a few key mistakes in their handling of the Putsch that led to it being easily defeated (Hitler wouldn't have succeeded in installing himself as leader of Germany even if the initial Putsch had succeeded, but more on that later).\n\nThe first mistake was made by SA leader Ernst Rohm. He ordered his storm troopers to occupy key buildings, namely the police headquarters and the army headquarters. But Rohm failed to occupy the most important building, which was the army barracks where there was an ample supply of weapons and more importantly soldiers willing to use them. \n\nThe other mistake was made by Ludendorff. The Nazis started the Putsch by going into a local beer hall in which the far right leader of Bavaria, named Kahr, was giving a speech. Hitler bullied Kahr into publicly supporting his the Nazis' putsch. Kahr had actually tolerated far right militant groups like the Nazis and his inaction can actually be seen as one of the reasons for the Nazis getting to this point. None the less he would also help put a stop to it. So with Kahr publicly supporting the Nazis, Hitler and his makeshift army went towards the war ministry office. All along the streets they were cheered on by Nazis supporters. Kahr was left with Ludendorff in the beer hall. Ludendorff for some reason decided to let Kahr go. Kahr quickly telephoned the army barracks and the government. \n\nWhat happened next was a bit of a mess. Hitler and his supporters were met by a group of armed police and soldiers. The Nazis marched at them and began to spit at them and just generally provoke the police. Then someone, its not known which side they belonged to, fired a shot which resulted in the police mowing down several Nazis and causing the rest to retreat. "
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yj2oa | Were past cultures attracted to fatter women? | I'm reading the Beauty Myth by Naomi Wolf and in it she claims that modern society has fetishized being underweight. When I read that, I thought back to classical depictions of women and realized that I did think they all looked plump. So was the "ideal" women larger in the past? Or did each culture have its own particular version of what was feminine? | AskHistorians | http://www.reddit.com/r/AskHistorians/comments/yj2oa/were_past_cultures_attracted_to_fatter_women/ | {
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"Each culture had an ideal body weight.\n\nIn Renaissance & Romantic Era paintings, you'll notice the women are average-'overweight' sized because that was what the nobility looked like; they looked like they could feed themselves, and that's what was desirable.\n\nIn the 20's, the flapper look, practically malnourished look, was the rage because they wanted to look less feminine, because they wanted Rights. If being manly was the way, then so be it.\n \nIn the 50s, you've got the Marilyn, big hips, small waist, because it was the baby boom; the government wanted babies, and the people were horny because the wars are over.\n\nAnd now, thin is seen as healthy, which is why people value it. But it's not enough to be fit,, you've got to be sexy, pretty, or jacked.\n\nIt's an everchanging model.",
"Fat was valued, but it wasn't the obese/power scooter fat that you see at wal-mart. No, it was the \"a few extra\" pounds, because that signified that they could feed themselves. The \"fat woman in China,\" who was, to the emperor and the people, considered the most beautiful woman in China (supposedly), looks to be perfectly normal in terms of weight. Hell, even her hips pinch inward.\n\nHowever, the standard of beauty changes with time. At no point was what we'd consider obesity \"attractive.\" Fitness is considered beautiful nowadays, with a decent amount of muscle. See how female athletes are considered more beautiful than runway models. Thinness isn't valued as much as being fit, whereas about a hundred years ago (1912s-1930) thinness was very much in vogue.\n\nEdit: I suppose honesty stings the obese amongst us, going \"I'm beautiful! I am!\" *rocks back and forth with a tub of ice cream on top of their thighs*",
"As others have said, the exact ideal of a society is somewhat fluid, though it would usually be a stretch to say that \"fat\" was the cultural ideal.\n\nOthers have mentioned Renaissance and Romantic artwork, so I'm going to go with some older examples. One of the more interesting things about Pompeii, in my opinion, is that it preserved a great many paintings for later reconstruction. A number of these contained nude women, and I doubt anyone would find the ones I've seen to be fat. Indeed, most would easily be considered attractive by modern standards, despite being painted close to 2000 years ago.\n\nMostly NSFW\n[example 1](_URL_3_)\n[example 2](_URL_0_)\n[example 3](_URL_2_)\n[example 4](_URL_1_)\n\n\n",
"A broad generalization, but a pretty good thumbnail nonetheless, is that whatever look is associated with poverty is unfashionable, and therefore less attractive.\n\nIf the poor are thin and malnourished, it is considered desirable to be heavier. If the poor are tanned from working outdoors, it is considered desirable to have pale skin. If the poor are fat and pale, the ideal is to be thin and tanned.",
"Read an article in an old Archaeology magazine yesterday (from 2009) that talked about the lengths the Maya went to do transform their bodies into their ideal of perfection. The focus was on physical things like skull shaping, teeth filing and decorating and such, but one point that was brought up was that several of the murals show larger women, and two of the more powerful Maya queens were large as well, indicating status, power and wealth if not beauty. \n\n[Image 1](_URL_0_) (the woman on the left is a ruler, the woman in gray a servant)\n\n[Image 2](_URL_2_)\n\n[Image 3](_URL_1_) (this is an image of the Maya maize god)\n\nNone of the images show what we would call \"fit\" people (though we can't really make any judgments about their overall health based on the murals). They also show the sloped heads that Maya considered to be beautiful. ",
"Others have spoke about other time periods, so I will talk a little about 19th century America and Europe. The corset was in fashion, so small waists, large bosoms, and hidden hips (hoop skirts were supposed to hide the fact that women had a pelvis) were considered attractive. This eventually turned into the S-corset, which created a large bottom and an even more exaggerated chest. However, people could not achieve these naturally and the corsets/padding were incredibly important in order to achieve the beauty ideal.",
"You won't see [these advertisements](_URL_0_) nowadays but they are not that old."
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"http://jssgallery.org/Other_Artists/Roman/pompei3graces.... | |
1jys7q | what are exactly elementary particles? | Rather: Can you explain everything around and about the elementary particles in not too technical terms? Wikipedia is not the best place to learn about our yet smallest found particles. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1jys7q/eli5_what_are_exactly_elementary_particles/ | {
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"Elementary particles are, simply put, particles that make up, and regulate the behaviour of, all of the matter around us. That is to say that they are discrete particles that cannot be broken down into other parts or particles. These include the various quarks, leptons and bosons. \n\nThe bosons are the \"force carrier\" particles. In very simple terms they are the particles that cause the various fundamental forces to act. These include the photon which \"carry\" the electromagnetic force (in other words, carry light), the W and Z bosons which carry/mediate the weak nuclear force (involved in beta radioactive decay) and gluons which carry the strong nuclear force (sticks all the particles in the nucleus of an atom together). \n\nQuarks are the \"matter particles\". There are six different types (up, down, top, bottom, strange, charm) that combine in different configurations to form the protons and neutrons that form the nuclei of atoms. \n\nLeptons include the familiar electron (responsible for electricity and chemical properties of elements) and the less familiar and more obscure electron neutrino and muons. \n\n"
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2gndho | How was Mark Antony's relationship with Cleopatra viewed by the roman and egyptian general public? | AskHistorians | http://www.reddit.com/r/AskHistorians/comments/2gndho/how_was_mark_antonys_relationship_with_cleopatra/ | {
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"Terribly, at least by Romans--we don't really know what the Egyptians thought (and it's also difficult to figure out what the different social elements within Egyptian society would've thought). But we know that the Romans despised Antony's relationship with Cleopatra, because there's an enormous body of work on it in our textual corpus. However, why is this? Why was Antony's marriage to Cleopatra demonized but Caesar's affair with her escaped notice, despite the fact that Caesar went so far as to actually bring her to Rome with him? The answer, as with most things Cleopatra-related, lies with Octavian. Our idea of Cleopatra is so intensely colored by what Octavian wanted people to believe about her that nearly everything that is said about Cleopatra by historians is pretty much assumed to be garbage, but unfortunately we don't have any other evidence. \n\nOctavian's civil war against Antony was the climactic event of a long series of wars that Octavian and Antony started, which devastated Italy and really messed Roman society up. While Caesar's wars had been relatively mild, in that they bypassed Italy and didn't involve any proscriptions or mass slaughters of Roman citizens, Octavian's early career was not quite so spotless. While in later years he would profess to despise the sort of bloodlust that Gaius Marius and Sulla allowed their followers to become prey to, the truth of the matter is that Octavian wasn't a very nice guy when he first appeared. Octavian wrestled control of the Caesarians from Antony basically by borrowing money to raise what was essentially a gang of armed bodyguards loyal to the name of Caesar, and then by stealing legions away from Antony, despite the fact that he had no official magistracy and could not legally control armies. He then duped the senate into awarding him an extraordinary magistracy to chase down Antony and finish off the remaining Caesarians, devastating Italy in his march north to the Alps, and ended up joining Antony instead. And while the war of Philippi was *relatively* safe for Italy (despite the fact that Antony and Octavian killed the last remaining Republicans they had still kept massive battle from Italian soil) they came back and instituted the largest wave of proscriptions in Roman history, butchering thousands of citizens (which was, apparently, Octavian's idea). And then while Antony went off to the east Octavian started up the War of Perusia, the War of Brundisium, and the war against Sextus Pompey. In all of these struggles Italy and the Italian people--Roman citizens who had been spared massive bloodshed since Sulla had left--bore the brunt of the fighting. As a result of this and the extremely controversial way in which he had gained power (more on this in a moment) the elder Augustus spent a huge amount of time trying to legitimize his rule in his later reign. In particular, he had gained power basically through military means, even more than Caesar. Caesar's opponents had declared his actions illegal and wanted to prosecute him (which was in itself probably an illegal action) but Octavian had gained power by snatching the Caesarians and their armies from Antony, forcing the senate to give him an extraordinary magistracy, stabbing the senate in the back, and massacring his opponents. Finally, the special privileges which Augustus held as emperor derived from certain privileges that Octavian had wrestled from the senate before going off to fight Antony in the war of Actium. These included tribunate sacrosanctity, as well as the office of pontifex maximus, extraordinary magisterial powers (which included, of course, imperium), and the personal oath of loyalty of every Roman citizen. Now these are all powers which the senate is not going to grant to just anyone. Extraordinary magistrates were fairly common, but to give one (and mind you, he was also consul at the time) tribunate powers basically means that Octavian could veto any legislation, tell anyone in the senate to sit down and shut up, prosecute anyone, and was exempt from all kinds of prosecution and legislation. The way he got all these powers was by convincing people he needed them--remember that after Philippi the only people left in the senate were people who Antony and Octavian had put there, so it was mainly a matter of either bullying Antony's supporters into submitting or convincing them Octavian was right--or by force. The former was how he got tribunate powers, by convincing the senate that he needed them to restore the order of Italy, which was currently in a state closely approaching anarchy. The latter was how he got every city in Italy, every Roman citizen, and the entire senate to swear loyalty not to Rome, the people, or the senate, but to *Octavian personally*--he surrounded the curia with his praetorians and ordered the senate to swear loyalty. Dude needed some good PR after all that, so he was very willing to go out of his way to legitimize himself.\n\nOk all that's fine and dandy, what does it have to do with Antony and Cleopatra? The thing about Octavian's war with Antony is that had Octavian just gone off to fight Antony just to get rid of him, that wouldn't have gone over too well. Antony was a Roman citizen--a triumvir, no less--and to provoke civil war against a guy that a lot of people still stood behind and whom Octavian had been formally allied with (as opposed to Caesar and Pompey, whose illegal deal was something more along the lines of an under-the-table-agreement) was not really something that very many people wanted, particularly when Italy was in such a shambles and the most important thing was to rebuild. So Octavian needed to justify war against Antony. He did this by demonizing him. It's very clever how this was done, actually. Octavian first spent several years building support for the idea that Cleopatra was some foreign seductress with her talons so far in Antony that he had no idea what was going on. Octavian painted an image of Cleopatra as the sinister eastern queen, using Roman citizens--one of the most distinguished Roman citizens--as tools to rebuild her family's empire and undermine Roman power. Now, whether this was true is a totally different matter--Octavian got people to *believe* it was true. But what really turned Roman opinion against Antony wasn't even something that Octavian did. Antony fucked up when he formally announced the Alexandrian donations, which granted huge swathes of Roman territory to Cleopatra and her children. This, combined with the fact that Antony had turned his wife Octavia, Octavian's sister, away (his marriage with Cleopatra would not be announced until later, although it's probable that it had already secretly occurred) was intolerable. The Roman people, egged on by Octavian, saw this as a betrayal of the Roman state and an insult to the Roman people. The announcement of Antony's wedding to Cleopatra and the (illegal) reading of his will by Octavian, in which it was revealed that he was basically leaving everything he had to Cleopatra and her children, was the last straw. At this point Octavian had the Roman people sold, and promptly declared war on the dynasts. Even now, though, Cleopatra was a much easier target than Antony, who, for all his mistakes, was still a Roman citizen. So it was *Cleopatra's* armies and fleets which Octavian told the Roman people would be swarming all over the shores of Italy, and *Cleopatra* who planned to make herself queen of the Romans, not Antony who, of course, was the one doing all the real work. Octavian used Cleopatra to manipulate Roman sensibilities, to turn what was in the end a rather squalid war fought for pretty petty reasons (Antony really wasn't bothering Octavian over in the east, Octavian just wanted it *all* and he wanted nobody to be in a position to challenge him) into a noble crusade in defense of Italy against the foreign menace. \n\nNot everyone bought this, of course. But even those who did had to be very careful when talking about Cleopatra. Sympathy for Antony appears quite often in Augustan literature, sometimes quite prominently. But sympathy for Cleopatra is almost always veiled. Take Horace I.37, for example. The first part of the poem trashes Cleopatra ruthlessly, calling her things like the \"fatale monstrum\" and other really nasty insults. But the second part flips that on its head, emphasizing Cleopatra's nobility in defeat and how she met her fate with head held high. After all those nasty things *that's* what Horace has to say about her? Whether we buy the idea that Horace had ambivalent feelings about Cleopatra or even felt suppressed support for her (Horace had, after all, been with the Republicans at Philippi, and though he always appreciated Augustus' sparing of him and Maecenas' decision to bring him to literary prominence, he had mixed feelings about the loss of liberty) it's clear that at the very least he wishes to remind people that Cleopatra was a human being, amidst all the rhetoric Octavian was spewing about how she was some sort of eastern demon. And there have been many attempts to connect Cleopatra with figures in the *Aeneid*. I don't know how much I buy the idea that she's Dido and that Aeneas' decision to abandon her is a reinforcement of Augustus' own sacrifice of personal gratification for his duty of leading the Roman people, but I find the idea interesting, considering how sympathetically Virgil presents Dido. And Camilla has been compared to Cleopatra, which I have somewhat more support for (although a lot of people say a lot of things about Camilla). Virgil has this strange grudging appreciation and respect for Camilla, even though she's a menace, and it's certainly compelling to read her as one of Virgil's many veiled jabs at Augustus (as is, I suppose, the idea that he stabbed Cleopatra in the back, if we accept Dido as Cleopatra)."
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1oj2hn | what do the letter classifications (kroq, wfan, kmox etc.) for radio stations mean and/or how are they assigned? | It is something I have always wondered about. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1oj2hn/eli5_what_do_the_letter_classifications_kroq_wfan/ | {
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2b79ew | why does everyone in the us seem to have an ac system? | Even in areas with very mild climates? I know, weird question but I'm not from the US. I travel a lot and I've been to the US a few times. It seems to be the only country where at least 9 out of 10 people have an AC system, even in small cheap apartments in mild climate states. Most places only have them in like big supermarkets and buildings, if any at all.
Whenever I tell a friend from the US I deal with 35C+ (95F+) temperatures without an AC they're usually baffled that I don't have an AC. Meanwhile I'm baffled they do, lol.
How come? Pretty much every hot country I've been to people just deal with 40C+ (104F+) temperatures without an AC system. Yet every single person I know with no exceptions from the US has an AC.
Also, doesn't this have some bad side effects for mother nature when every single house and apartment in tightly packed areas has an AC? And doesn't it make people more weak and sensitive to hot temperatures? Especially when they walk from a cooled house into a really hot outside? That sudden change would make my circulatory go all wonky lol.
EDIT: Thanks for the answers. I get the whole: "Because it's hot and humid!" reasoning, but there's many countries where it's a lot more hot and humid that don't plonk ACs everywhere. There has to be some event or trigger that caused ACs to popularize so much in the US other than: "Everyone outside 'Murrica is dumb for not having ACs!" lol. I'm not looking for the reason why people have an AC, that one is pretty obvious. I'm trying to figure out why almost everyone in the US does, but other places don't.
By the way, I wasn't negatively judging the US for having ACs everywhere, I find it rather good and wish more places were like that since I've experienced large scale heatwave deaths in 45C+/90%+ humidity countries, mostly elderly people. So no idea why I'm getting so many racist comments.
EDIT 2: Seems like nobody understood my question whatsoever besides one person. _URL_0_ | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2b79ew/eli5_why_does_everyone_in_the_us_seem_to_have_an/ | {
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"It's hot, and they're affordable. ",
"I'm from Texas, which is definitely not a mild climate. People without AC have died from heatstroke in the summer. AC here is, I dare say, a necessity.\n\nI'm not sure where you come from, but I'd wager that those 35c days are rare. If you had to go through months in which the high temperature was over 100F every single day, you'd probably break down and get one too. \n\nAs for getting weak in hot temperatures, no. We're just used to it, I guess. I was encouraged to spend time outside as a kid, come in for a cool down and a glass of water, and go outside for a few more hours. I was very rarely sick as a child and my bodily temperature control is great. I usually feel warmer than most people in the winter, and I can handle hot summer temperatures better than most people I know. \n\nPlus, why on earth would you want to be sitting in ball soup if you had an alternative? I can't imagine sleeping at night without AC in the middle of a Texan summer. I'd probably go crazy.",
"Most people in the bay area (in California) don't. People in areas where the temperature is less temperate are more likely to make use of air conditioning units. ",
"Why does everyone outside the US not?\n\nI'm in Berlin right now and have to change multiple times a day. No one has AC in their homes. My sheltered body isn't used to having to deal with weather.\n\nEdit: To answer a few questions, as I've alluded to, yes, at the very least it makes me more sensitive to heat. Not being able to escape even 28+ degrees leaves me very uncomfortable.\n\nAnd AC doesn't really give off environmental waste so there's not an affect on the environment. But our electric bills to skyrocket during warm months. In general, though, AC units are bought and run fairly cheaply and many people have central air which is a bit more expensive. \n\nI think at the core though it's also a cultural thing. We like our comfort machines. Living in Germany I've found no one has clothes dryers; some people even don't have dishwashers. I've yet to also see a microwave here. Refrigerators and ovens and washing machines are also smaller. I think it's largely just different, accepted style of living.",
"AC is cheap, easy, and pleasant. And all that AC does is move heat from one place to another. Walk around the outer vent of the AC unit and it’s hot. As long as the system works correctly there is really almost no downside to the system. It doesn't make people more sensitive to temperature, known as acclimation, unless they spend at least a few days without going outside. The change from hot to cool is not so great that there is any damage to your body. If there was then workers who walk out of the summer heat into a freezer room would be really screwed. Plus having AC reduces the chance of dehydration, heat stroke, and other heat injuries, which are more common than you would think. Speaking from experience, that kind of injury has obvious symptoms, but it’s hard to tell it happening because one of the first symptoms is mental confusion. \n\nThat said, if the system doesn't work right the refrigerants released aren’t great for the environment, but that is usually a relatively small amount of Fluorocarbons, or their newer safer replacements, so the damage is minimal. There is also an increased risk in respiratory infections and things like mold if the filter is not cleaned or maintained regularly.",
"Practically nobody in Seattle does.",
"because a/c is pretty much the greatest invention ever(or close to it)\n\nI go to a hotel-or anyplace where I don't pay the electric bill and that a/c gets cranked as low as she'll go",
"Because we like it to be 72 degrees all the time",
"On the East coast, it's the humidity more than the heat. On the West coast, it's just the heat. In the North, well, what the hell... it's cheap enough to have it anyway.",
"I don't have one. I don't sleep much these days. ",
"In older homes in California they have 'swamp coolers' which are a water based cooling system. They don't work for shit when it's humid though.\n\nThey're everywhere mostly because they're cheap and as long as you don't have an old Freon based unit with a leak it doesn't have any environmental effects other than increased electricity use.\n\nI currently live in 'The South' and the humidity pretty much requires AC.",
"I live on Cape Cod. While our frigid, god awful, winters are what we're known for, the summer gets pretty damn hot sometimes. But that's not the issue. Everything molds in the summer. Its kind of a running joke. But yeah, I've lived plenty of places that didn't have AC on Cape, but the humidity causes such bad mold/mildew that a lot of people get them just to keep it at bay. ",
"Because it's hot.",
"A major part of this is the standardization of architecture. Homes in Arizona where it can be over 30 degrees consistently from June to September with peaks in the 40s are fundamentally the same as the homes in Minnesota where persistent temperatures under -10 define the winter. To accommodate, huge HVAC systems are installed.\n\nThe idea of energy cost is a relatively new one in an obstinate society. I live in Texas where a car parked outside can easily reach an interior temperature of 70 during the peak of summer, and no one comprehends the the idea of building for climate.",
"I own portable air conditioners but only use them if they're needed. ",
"Well, this only applies to families, but hotter temperatures increase the risk of SIDS (sudden infant death syndrome) \nEdit: sp",
"Anyone living in Virginia or below needs an AC unit. They're cheap, affordable, convenient and easy to use. I live in a state that it's pretty much illegal not to have air conditioning because it would be too hot inside.",
"because people in the U. S. won't tolerate heatwave deaths like people in europe will:\n\n_URL_0_",
"I live in texas, so if I didn't have one I would never be able to sleep in my house. As for the rest when I was in Seattle the hostel I stayed in didn't have one. I have some friends that live there as well and they don't have one either. \n\nFor the most part tho its becaus they are affordable, why not?",
"I'm just back from a 12 day work trip to Silicon Valley: I WISH the house I stayed in had AC!",
"I don't know. But I'm surprised more people here in the UK don't have them. Right now it's peaking at 32°C and all we can do is open some windows. Everything has been designed for cold, not for heat.",
"Isn't it weirder that we in Europe don't use AC systems more? \n\nWhere I live in Northern Europe we don't really need it since it's only about 1-2 months a year that it would be necessary to use it. But in the southern part of the continent I think it's strange that more people don't have one. To be honest I actually thought it was really common in Spain, France, Italy, Croatia etc because every time I've stayed at hotels in those countries you have an AC system.\n\nI've also been in Florida, USA and I understand why everyone there use AC systems.",
"For me, personally, I like having an AC just because it makes me more productive. If I am sweating and uncomfortable, I am less likely to be productive, just because I am somewhat miserable in high heat.\n\nThat isn't to say I *can't* deal with high heat, though. It just makes more sense to use an AC if it's affordable, which can help make me more comfortable and productive.",
"You miss the point, it's the cost of A/C that's changed the paradigm. I'm 51 and recall living in very hot, NJ, NC, CA and even NV with no air. I suspect it's similar to anything else in the tech world... Cost driven down by more efficient products combined with mass production. And lastly, I don't know where the OP lives, and no judgements here either, but it's also likely a socio-economic component is involved.\n\nAlso, as children, we were encouraged to be outside more than they are now. So many diversions inside versus outside. No judgements intended here.\n\nI've got to admit, given the choice of with or w/o A/C.... No competition. Btw, live in TX.",
"I live in Seattle and not many homes are equipped with AC",
"I live in the southeast US. For me, the relief of the AC is more from reduced humidity than lower temperatures. 95F is hot, but it's the 80% humidity that makes it miserable. ",
"I live in DC which is notoriously humid. If it weren't for that, I'd probably be OK with a large box fan. ",
"Canadian here. I don't see a reason to not have one.",
"It's cheap and we have access to a stable electrical grid. I pay a bit extra for renewable energy and my electric bill last month, here in Texas where it has been 90º F+ every day, was $130. And that is with us keeping our 1100 sf apartment at 70º F inside whenever we are at the apartment.",
"109$ gets you an AC from Walmart that easily lasts 3 years or so and only puts a few extra bills onto your electricity cost. Thats why",
"Because you can buy one for a hundred dollars at Wal-Mart. ",
"Well, around 75% of our geographical area has summer temperatures over 100F (do the math yourself you SI using socialists!) and where I live Kansas, it can get over 90F around 6 months out of the year, and extremely humid too. Having your house at around 70-75F with dry air just feels so amazing, that I'd change my eating habits, what clothes I wear, what car I drive, etc, before I even think about shutting off the A/C. Life is too short to live in a hot humid box ",
"I lived in the NE and I bought a window AC from Walmart for around $100usd. It was cheap enough and made my summers a lot more comfortable. There are some very hot and muggy days I'm the NE and the AC makes for a much better sleep. If it wasn't humid, I had the windows opened with a nice window fan to circulate, but once the humidity got bad in July/august it was really hard to sleep with. So the AC allowed me to sleep better and wake up not feeling like the grouch. ",
"Has to do with humidity and dew points. Moisture from the Gulf of Mexico sweeps through the eastern half of the USA, making for high humidity levels and uncomfortable conditions.\n\nI couldn't find it on google, but recall reading once that in pre-colonial times, some European explorer reported back that America was uninhabitable due to excessive humidity.",
"As an American, to me this is like asking, \"Why does everyone eat with forks and knives when you could just bury your face in the food and still get the same nutrients?\"\n\nBecause it's much better, that's why.",
"I'm from Canada and we have an A/C even though its only hot for 2 months here and we only use it when its unbearable it's a nice luxury to have.",
"Louisiana native here. I can testify 85f and near 90% humidity is fucking hot. I would gladly take a 100f+ dry heat any day. AC is required to survive down here. \n\nTl; dr Swamp ass in less than 5 min does not make for a good day. ",
"Well, at least in the South, it's because the alternative is swamp ass. \n\n",
"I live in Michigan. It was a high of 74 degrees Fahrenheit yesterday. I had the A/C on, set for 72. Why? Because that temperature feels really nice to me and I can afford nice things because I'm an American. A better question is why would you willingly live in conditions that make you worse-off when you have the means to live in more preferable conditions?",
"It gets hot as tits. ",
"I'm from australia and most if not all homes I go in to have them. I dont because I live in a shitty little unit with wooden floors that is surrounded almost completely. ",
"Why does everyone in Europe have central heating?",
"Because (A)merican (C)an",
"I live it Florida. It's always as hot as the sun here plus the humidity is killer. Before AC I'm not sure how people managed here.. ",
"It's interesting that you feel some health problems resulting from quick temperature changes. I once visited an ice sculpture display in Malaysia that had a brief waiting period at a mid range temperature before entering the refridgerated warehouse that held the display. They had signs up saying that it was for health purposes as well. \n\nI had to laugh. Where I live it's not uncommon for it to get to -40C in the winter. Nobody thinks twice about walking out the front door. We don't have special acclimatization rooms to gradually adjust. I've never heard of anyone having health problems from it either. Is it a common belief where you live that there is some health risk in rapidly changing temperatures? ",
"Midwest USA here. Besides the heat in the summer, it gets really muggy sometimes, with high dew points. AC is a great dehumidifier. Some days, I'll run the AC for awhile just to get the humidity down, without lowering the temperature much. It makes a big difference.",
"I semi-recently moved to the US from a very mild climate where the hottest summer would be about 26℃. I now live in Texas and that temperature sounds pretty Damn nice right now...",
"Architecture student chiming in:\n\nIn the parts of Europe and Northern Africa where the temperature often hits 30+ °C, cities and houses are built to accomodate the hot climate. High thermal mass to delay temperature changes, narrow streets to provide shade, etc.\n\nIn the U.S., buildings are much younger – most residential houses are not more than 30-40 years old. Energy has historically been laughably cheap, so AC has made sense from an economic perspective. Which allows you to build timber frame houses in hot, arid climates without thinking of thermal mass, positioning in relation to the sun, etc.",
"I live in Oklahoma, my grandmother talks often about growing up here without AC. It's obviously doable, however she also grew up without dishwashers, washing machines, cell phones, and the Internet...all things she has now. \n\nIt's about convenience...and nothing is as convenient during our 6+ months of hot, humid weather as a personal cooling machine in our house and cars. ",
"Where did you go in the US? Most people in the US live either places that get very hot(lower US) or places that are very humid(East Cost). Or both at the same time. Here in New York it can be 20C(70F) outside but you still need the AC on to filter out the humidity, otherwise you will sweat like a pig. In Europe a lot of people(say Germany) live inside the continent where the air is dry. So humidity is the main culprit. \n\n\n Another thing, US gets like 3 times as many sunny days as most of Europe. _URL_0_ Northern parts of the US get as much sun as Spain. Sun can heat up houses and cars up a lot. UK and Germany maybe get 1 or 2 sunny days a week, when in the US it is sunny 5-6 days each week.",
"Because 95 Fahrenheit in high humidity is unbearable. The U.S. is a huge place with a variety of climates.",
"Check out the most populated cities in the US in 1900 and again today. In a little over a hundred years, that list goes from East Coast cities to West Coast cities, made possible by the modern air-conditioner (among other reasons). ",
"Why does everyone in the US seem to wear shoes? I live in a favela in Rio de Janeiro and most of us get by with no shoes.\n\nWhy does everyone in the US seem to eat multiple times a day? I live in sub-Saharan Africa and I only eat once a week.",
"Because this is 2014?",
"I might have missed it he comments, but the US uses forced air for heating and cooling. We have gas fired furnace that heats a chamber and then air blows across it into a system of ducts throughout the house. In europe they primarily use radiant heating with hot water. Since the us system already has the duct running through the house adding a cooling system is easy and cheap. ",
"Because in most parts of the us it is both hot and cold, and ac units typically double as heating units.",
"I'm from Minnesota and as most people know it gets really cold in the winter months. However, in the summer it's necessary to have one because its humid and it's uncomfortable without it. If you were exercising outside you don't want to come into your house when it's the same temperature or even higher. Also you don't always have to have it running when it isn't hot.",
"I live in Florida, its really fucking hot.\n",
"I mean, I can go outside without my circulatory system getting wonky, so whose really weak? But yes, because most AC units are electrically powered and relatively cheap, most people have one. We don't like being uncomfortable in our own houses or workplaces. If you're comfortable, then you can relax, destress, not feel gross from sweat, and as a result be more willing to work harder with fewer breaks. I'm in China atm, I swear to god they *love* being uncomfortable. ",
"Hey why do you have indoor plumbing? Could just go outside and water the garden and give it some good fertilizer. Doesn't putting stuff down the drain have some bad side effects for mother nature when every single house and apartment in tightly packed areas has a flushing toilet? And doesn't it make people weak and sensitive to toilet paper? Especially when they walk from a 3-ply house into a 1-ply house? That sudden change would chafe my gentle under regions. ",
"I'll summarize it: electricity here is much cheaper than elsewhere in the world. ",
"Part of it is probably because most of the construction in the US is new. We aren't retrofitting old buildings, for the most part the new buildings are just built with AC. It has become a standard.\n\nI'm not sure where in Europe you're from but our climate isn't really mild. I live in Chicago and it is both Freezing in the winter and hot in the summer. Especially in the midwest, we don't have an ocean to keep us cool/warm. \n\nLike everyone else said, it's nice to have.",
"Electricity has been cheap for a long time here",
"For Europe specifically, one contributing factor is its position on the globe. The southernmost point in Europe (34 degrees 48 min) is still north of several US states.\n\nLouisiana and Florida are completely south of the southernmost point in Europe.\n\nThe majority of Arizona, New Mexico, Texas, Mississippi, Alabama and Georgia are farther south. In some the cities in these states, people either do not have heat, or never turn in on year round. Something that would be unlivable for much of Europe.\n\nThat explains the climate reasons, now for the economic. Much of the world between the hottest longitude lines are not considered wealthy. Most of Africa, Central and Eastern Asia and Central America are poverty stricken. These countries are less economically able to afford luxury items like central air conditioning. In the pockets of wealth in this region you see AC in common use where it is affordable.",
"In a lot of countries having an AC unit is either a status symbol or a luxury item. In the US it is just expected.",
"\"They should just put air conditioners on the highway\"",
" > Also, doesn't this have some bad side effects for mother nature when every single house and apartment in tightly packed areas has an AC?\n\nIn a Heat pump system, we are essentially transferring heat from one location to another using a refrigerant that boils at low temperatures. It's a closed system, which really only requires electricity. There is no \"waste\" per se.\n\nIn a standard AC system, the process works the same, but only goes one way. We use a furnace (either fossil fuel or electric) to provide heat in the winter.",
"I live in Louisiana. I can't even comprehend how someone would ask this question. \n\nI lived for 2 weeks without electricity after katrina and couldn't sleep for more than 30 minutes at the time. Opening a window doesn't work here... 90+ degree temperatures with 95%+ humidity is something that can't be explained. You have to experience it. ",
"Every state in the union is allowed to have two statues of historically significant people who were from that state in the US Capital. The man who invented ac is one of Florida's, it is a need not a want here.",
"Way late to the party, but I'll throw this in here.\n\nI'm from a country where it gets really hot in the summer. Really hot. as in we hit 40C on occasions and stretches of 35+C are normal. \n\nBut when you go inside a building, AC or not, it drops by 5 degrees. And in your actual apartment or flat it drops even more. So it might be 35 outside, but it's 25 inside. 25+fans is manageable. I never had an AC growing up (though they were becoming more and more common).\n\nThen I moved to Minnesota, where it gets to -40C on occasion. We have stretches of a month or *more* where it's below freezing. In the winter, anyway. \n\nIn the summer, it is insanely humid and gets to 35C or more. Not uncommon to have stretches of days on end where it's well over 30 *even at night*. In fact, a few years back when the heat-index was included, Minnesota was the *hottest place on Earth* (heat-indexed to **65C**). \n\nNow here's the thing. Because of the crazy winters, our houses are designed to suck heat in. If it's 20C outside, it's 25+ inside. If it's 30 outside, it can easily get to 40 inside. And *humid*. \n\nMy house didn't have AC when I moved into it. We kinda lived with it, but then we got a puppy and seeing that dog suffer was just too much. So I got a window unit which made part of the living-room bearable. Eventually I got central air instead, so now I can use the entire house. \n\nA few years ago it went out during a heat wave. The only part of the house we could be in for more than 10 minutes was the basement. \n",
"HVAC units have become standard and are often just automatically built into residential units. It's not even a choice for many people; it's a fact. A lovely and comfortable fact.",
"Humidity is a large factor. 35c at 50% humidity is VERY different from 35c at 100% humidity. \n\nAlso, wooden homes don't stay cool like brick homes. Heating and cooling is forced air, which doesn't work well in brick homes.",
"I live in Minnesota where summers are basically 80F with a handful of 90s and a couple days where we hit 100F. \n\nEveryone has AC. It's standard to put in central air for all homes being built. It uses the heating system so for very little added cost you have the option to keep your house cool.\n\nMaintenance is easy, every couple years have someone come take a look at your furnace/ac for a couple hundred bucks.\n\nCost of running it is a couple hundred dollars a summer. It is worth that to me, I get lazy in the heat and I can't sleep. Humidity sucks! We only run our AC if it's upper 80s and really humid or 90s for a couple days in a row.\n\nOf all the things humans do I don't think AC usage had much of an impact on mother nature except for the energy use.\n\nI don't have any problems going from AC to outside temp \n",
"Because it gets fucking hot",
"To add to this, as an European American, what you'll notice is that America is all about comfort. You will see a lot of people in public wearing not the latest fashion, but what's comfortable. Cars - large and comfortable, even if they handle worse or get bad gas mileage. Food - larger portions, less fancy. Of course these are generalizations but it's nice to not have to dress in extremely expensive clothes you can't even afford just to go buy some milk.",
"I'm visiting Germany for 2 weeks and it's the one time of the year it's hot and NO ONE has AC. it's silly to me, though I understand if it's only hot one month out of the year there isn't a real push for AC. But god damn, just have it in store for that one month, it isn't hard. ",
"Movie theaters were the early adopters of air conditioning in the US. They used it as a gimmick to sell tickets on hot summer days in the Great Depression and World War II era. After the war, the US enjoyed several decades of prosperity, dirt-cheap energy prices, the Baby Boom and plenty of affordable new housing. Appliances like air conditioners and televisions were now affordable to the masses. Meanwhile, as Europe rebuilt after the war (along with higher energy prices), maybe air conditioners were viewed more as a luxury than a necessity and thus never caught on. Just a theory :)",
"I live in Canada.. and almost everyone i know has an AC... i pity the people who dont in the summer... It could be because were so use of it being cold that the heat feels brutal even if its only +25-30C",
"Because it gets hot, and AC fixes that. There are probably some places AC is less standard, but I live in California, where it commonly gets over 100 degrees in the summer, and not having AC in those temps is just dangerous. I don't think it's even legal to build houses without ACs here.",
"Because in Texas during the summer, you have two options to cool off. \n\n1. AC\n\n2. Take a trip down to hell, because its colder there.",
"'Merica, that's why..",
"Because it gets hot outside, and AC keeps it nice on the inside.",
"I feel like a damn alien coming on Reddit sometimes. \"Why do you do these things!\" I like being comfortable man, jeeze.",
"Because we can afford AC/heating. Other countries where it is really hot (for example, Africa, India, some South American countries) the people are poor and cannot afford an ac/heating unit. If they could afford it they would have them. also some people are better adapted to heat then others. ",
"I come from New England. Most of the people who've lived here forever can deal with the winters, but get our 85-100 degree, 80-100% humidity summers going and we just don't do so well. Couple that with A/C and electricity being cheap, and almost everybody will have / use it.\n\nI like to say: In the winter I can just add more layers. But in the summer I can only remove so many before it's inappropriate.",
"If you go to Asia, you'll find that many people have aircon. So the hypothesis \"There's many countries where it's a lot more hot and humid that don't plonk ACs everywhere\" is....bullshit. In Southeast Asia, many, many, many homes have air conditioning. Their cars have air conditioning. The stores are air conditioned. When it's really hot, everyone congregates at malls where the air conditioning is cranked up. ",
"why not ?",
"One of the things to keep in mind is that climates in the U.S. tend to be considerably less mild than in Europe. The Gulf Stream has a warming effect in winter and a cooling effect in Summer. So if you look at two cities of aproximately the same lattitude [Chicago](_URL_0_) (41.87 N) and [Porto](_URL_1_) (41.15 N) the American city has hotter summers *and* colder winters. In August the average daily high for Chicago is 84.2 F (29 C) vs Porto's 78.3 F (25.7 C). In the winter we see the same pattern Chicago average low in January is 18.2F (-7.7 C) vs. Porto's 41.4F (5.2 C).\n\nIn fact, Chicago's *average* low in January is lower than Porto's record, while still having hotter average summers.",
"Because most Americans are wealthy enough to afford it and it vastly improves quality of life.",
"Even here in northern US, Minnesota, on the border w Canada, it's currently 92f w humidity. Everything is sticky without ac",
"Because we're the richest nation in the world and get what we want. ",
"In the Chicago area, we'll have wild, wild temperature swings, particularly in spring and fall. You can have a day start at 90F (32c) then drop to 60F (15c) in a single afternoon. Or the other way around, start at 60F and rise rapidly by noon. There's always a week or two every summer where we're hitting close to 100F (37c), usually with significant humidity since these rises/plunges are pushed in by various storm fronts, and some time in winter where we're hitting 0F (-17c).\n\nMost places will have heating and A/C systems to offset those changes.",
"Cause its hot and we're fat. ",
" > 35C+ (95F+) temperatures without an AC\n\nYou what?\n\nEveryone in the US has it because we can afford it and it's freakin' hot. It's become sort of a standard, because it's a largely richer country. I'd bet that the countries that DON'T have it are poor. ",
"Guess you've never been to the north.",
"We don't like sweating or taking multiple showers a day to keep the stench down. I think it's kind of funny people will live without something like an AC in hot temperatures even though how affordable they are now days. ",
"Next answer: we all have clean, running water because we like drinking it. ",
"Because I don't like to come home from my job at a 90f+ factory to a house that's 90f inside.",
"It costs $2-3 per day to keep my house at 72F when it's 100F outside. That is one of the biggest bang for your buck expenses I can think of in terms of general quality of life. Name one other thing you can acquire for that cheap that will provide that much comfort.",
" > Even in areas with very mild climates?\n\nThe US is very wealthy, and we tend to live in houses that have very low thermal mass. We've sort of adopted a societal expectation that you'll insulate the house and use mechanical A/C units to control the temperature instead of using the building's thermal mass and natural airflow to control temperature.\n\n > Also, doesn't this have some bad side effects for mother nature when every single house and apartment in tightly packed areas has an AC?\n\nOther than the energy draw, not really. On the other hand, this can use a lot of power if the building is poorly insulated or the home owner installs a unit that's a poor design for their particular climate.\n\n > And doesn't it make people more weak and sensitive to hot temperatures?\n\nThey're more likely to complain about it, but it doesn't induce any additional physical vulnerability.\n\n > That sudden change would make my circulatory go all wonky lol.\n\nIt doesn't have any significant effect. Your body gets used to it however you deal with climate.\n\n > I get the whole: \"Because it's hot and humid!\" reasoning, but there's many countries where it's a lot more hot and humid that don't plonk ACs everywhere.\n\nMost of those countries are also poor countries. The US is pretty exceptionally wealthy for a country with habitually hot and humid weather. Basically, we've developed our environmental conditioning this way because we're generally wealthy enough not to have to sweat it out.\n\n > There has to be some event or trigger that caused ACs to popularize so much in the US other than: \"Everyone outside 'Murrica is dumb for not having ACs!\" lol. \n\nThere's also a cultural preoccupation with reshaping the world to suit our needs, rather than adapting our expectations to the world around us. There's probably some influence from how we industrialized too.",
"Capitalism. As a result of capitalism, our electricity is very abundant and therefore relatively affordable. ",
"A lot of you are saying that ACs are necessities, but honestly, for the majority of people, I believe that they are not. Exceptions would include the weak, elderly, sick, or anyone whose body cannot withstand intense temperatures.\n\nI live in San Diego, and I can tell you that it gets hot here. This place has a good reputation for nice weather, but honestly Orange County is better. \n\nFor all of my life living here, I never once needed a heater or AC. In the winter, when it takes my feet 30 minutes to get warm so I can sleep, a heater would be nice but not absolutely needed. Right now in summer, any amount of movement can get you sweating and uncomfortable, but it's not needed.\n\nWater is needed. Food is needed. Sleep is needed. Comfort is not."
]
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2bz25c | What percent of our dinosaur fossils come from the Cretaceous–Paleogene extinction event? | I was wondering if the Cretaceous–Paleogene extinction event killed so many dinosaurs that it has led to a disproportionate amount of fossils being from that time, or if the extinction event was so severe that very few of the fossils are from that time. I understand that it isn't just a dinosaur dieing that creates a fossil, that it must be preserved due to some unique circumstance, but I'm curious if the extinction event created more or less opportunity for those circumstances, and thus more or less fossils. Wordy as heck, sorry! | askscience | http://www.reddit.com/r/askscience/comments/2bz25c/what_percent_of_our_dinosaur_fossils_come_from/ | {
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"text": [
" > What percent of our dinosaur fossils come from the Cretaceous–Paleogene extinction event?\n\nFrom the event itself? I don't think that I've ever heard of even one fossil being identified as being from the event itself. "
]
} | [] | [] | [
[]
] | |
193ixo | Question about the movie Kingdom of Heaven | I know the movie is full of historical inaccuracy, but there's one scene in particular I don't understand. After Reynald kills Saladin's sister, the messengers come to Jerusalem, and Guy kills him. After that, the various factions in the court point there spears at each other. There are Templars, Hospitallers, and the guys in blue who I assume are Tiberias's men. Why did they all turn on each other like that? Weren't they on the same side? | AskHistorians | http://www.reddit.com/r/AskHistorians/comments/193ixo/question_about_the_movie_kingdom_of_heaven/ | {
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"While these organizations may have been nominally part of the same court within the kingdom of Jerusalem they all had their own objectives and motivations, which often put these groups at odds with one another.\n\nFor example shortly before the events that take place during this film there was a period of civil disorder and instability in Egypt that left that country weakened before any foreign power who might attack it. During this period (1154-1169) the crusaders under the leadership of their king Amalric attempted to attack the weakened Egyptians in order to strengthen their own position. The campaign was considered a failure and helped to pave the road to the rise of Saladin.\n\nJohn Robinson in his book \"Dungeon, Fire and Sword\" accounts that their was similar fighting between the court factions after the Egyptian failure . He says that \"back in the kingdom of Jerusalem, Amalric had to work to calm down his barons, who were trying hard to fix the blame for the Egyptian fiasco. Many blamed Amalric's seneschal, Miles de Plancy, who always encouraged Amalric to seek gold and avoid battle. The followers of the count of Nevers were universally condemned, but the fiercest accusations were leveled at Gilbert de Assailly, the Grand Master of the Hospitallers who had urged them all to take part in the doomed invasion ... (and) some might have wanted to blame the grand master of the Knights Templar, Bernard de Blanquefort, for refusing to participate, but he had died just a few days after Amalric's return\"*.\n\nWhat we can see is that these factions had turned on each other before the vents that take place in the Kingdom of Heaven film, and this was before the rise of Saladin during which the factions would have been under even more pressure. \n\nThis pressure would have been accentuated especially because Reynald was fond of breaking truces between Jerusalem and Saladin*. Reynald's actions would have further served to polarize those within the court who believed that co-existence was possible and those who believed in war with the Muslims.\n\n*John Robinson, \"Dungeon, Fire and Sword : The Knights Templar in the Crusades,\" (M. Evans & Company, New York: 1991), pg 119\n\n*Ibid 148"
]
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3d8633 | during a commercial break, what happens to live-audience shows that are not broadcast live? | Do the hosts just jump into the next segment after a few seconds of clapping from the last segment?
Or does the audience actually wait around a little for the start of the next part?
| explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/3d8633/eli5during_a_commercial_break_what_happens_to/ | {
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"It's called an intermission. They go for a break to get drinks or food or stuff like that. "
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3w6097 | odor eliminators | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/3w6097/eli5_odor_eliminators/ | {
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"It is kind of like bubbles. You are spraying a kind of chemical which is ring shaped and it traps the odor chemicals inside that ring which stops the odor. This happens at the molecular level. \n\n_URL_0_"
]
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[
"https://en.wikipedia.org/wiki/Febreze#Ingredients"
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4229s5 | the procedures taken if mid surgery there is an emergency (active shooter, tornado, fire) | [deleted] | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/4229s5/eli5the_procedures_taken_if_mid_surgery_there_is/ | {
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"It depends, each hospital is different... it wouldn't really affect anything.\n\nActive shooter, you remain in place, stay away from windows. Based on how OR rooms are situated, it's never off a hallway... there's prep rooms, etc. Only certain people get in and out. Not a concern. If the shooter is in the room, you try to disarm them or wait for security.\n\nFire, it's stay in place behind fire doors. Again, not an issue unless it's in the OR theatre. At that point you extinguish while trying to maintain your sterile field.\n\nI don't know about tornados... we don't get those."
]
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h7jm7 | When it's stated that "In the year [XXXX], the average lifespan was only [XX] years," is this figure very skewed by infant/child mortality? | i.e., if you cut out young deaths, were many people living to what we would consider old age, or was this very unusual? | askscience | http://www.reddit.com/r/askscience/comments/h7jm7/when_its_stated_that_in_the_year_xxxx_the_average/ | {
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"Once you cut out infant and childhood mortality figures, people were living what we'd consider to be normal lives, if slightly shorter. \n\nLancaster's *Expectations of Life* took data from nobility (because it's what we have the most of). Once they got to 21, noble males could expect to live through their 60s or 70s, depending on the century (the Black Death dramatically lowered life expectancy. \n\nOn the non-noble side of things, I don't have a citation right off the bat, but my family tree has reliable birth and death years back through the 16th century, and they were living \"normal\" length lives.",
"Statistically speaking, that's why it's an average. The young deaths skew it, but so do the much-older-than-expected. Often times it's nice (or even better) to have a mean, median and even a distribution to get a sense of what the age and age-range was really like."
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7vdouf | Why does Kosovo have so many more people than Montenegro? | When you look at Kosovo and Montenegro on a map, they seem really similar in size (Montenegro is actually a bit larger, at 14,000 km2 to Kosovo's 11,000 km2). Yet Kosovo has about three times as many people (1.8 million compared to 600,000). Kosovo is almost as populous as neighbouring Macedonia, which is much larger in size.
Furthermore, while both countries are mountainous, Montenegro has access to the sea (which is advantageous) whereas Kosovo is landlocked and appears to have fewer resources and fewer reasons to settle there. So, why do such similar neighbouring countries have radically different population? | askscience | https://www.reddit.com/r/askscience/comments/7vdouf/why_does_kosovo_have_so_many_more_people_than/ | {
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"dtrk9hf"
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"text": [
"Having been to both I would say that Kosovo has larger urban centres and much more agricultural land available. Standing by themselves the geography of Kosovo is more conducive to a larger agrarian and urban population than Montenegro who's landscape is much more mountainous and dry. The mountains of Montenegro have significantly less forest coverage and tend to be more rocky. "
]
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b58x6c | Did Roman legionaries' families receive compensation if they died in battle? | I've been reading about Caesar and how he managed to keep his legions fighting even after they'd technically completed their service, where they would have got their 3,000 denarii and a piece of farmland. He did so with a promise of more gold at the end.
And it got me thinking - it would be an absolute pain, and unfair, if a legionary were to die in battle in this extended service, and his family didn't get the 3,000 denarii, all of his back pay, the land, so on and so forth. I imagine this money and land was a *really big deal* for your average family - the sort of legacy that could change their lives for generations.
More generally it would be quite unfair too if a legionary in another legion, doing his regular service was, say, six months away from completing said service, got killed by a stray arrow, and his family got nothing.
Was there some sort of mechanism for ensuring proper compensation for families, and/or recognition of partially completed service?
Also, bonus question: did the legionaries have a way of sending their salary home, or somehow "banking it", while they were on campaign? Or did they just have to keep all their gold safe? | AskHistorians | https://www.reddit.com/r/AskHistorians/comments/b58x6c/did_roman_legionaries_families_receive/ | {
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"There are a few previous question you can cobble together to answer most of this. Someone may come in and give you a comprehensive answer, but in the meantime...\n\n[How did the wives of roman soldiers learn of their husbands deaths?](_URL_0_) in which /u/Celebreth explains how Roman soldiers couldn't get married, so for the most part it wasn't an issue.\n\n[Roman legionaries enlisted for a service of 25 years in the army. Were they periodically granted leave to visit their families? If so, how did the state deal with those who deserted while on leave?](_URL_1_) in which /u/Astrogator goes into more detail about the different circumstances where a soldier could have a family, although it still doesn't touch on whether these families had any legal rights to the soldier's pay.\n\n[I have just joined the Roman Army. What is my life going to be like from now on?](_URL_2_) in which we have /u/Celebreth again explaining some of the mechanics of how soldiers were paid."
]
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[
"https://www.reddit.com/r/AskHistorians/comments/1riwc2/how_did_the_wives_of_roman_soldiers_learn_of/",
"https://www.reddit.com/r/AskHistorians/comments/3rmm9j/roman_legionaries_enlisted_for_a_service_of_25/",
"https://www.reddit.com/r/AskHistorians/comments/363rhp/i_have_just_joined_the_roman_army_wh... | |
27dbv0 | how does the brain decide what is funny and what is not? | For some people, everything is hilarious, even things that morally or ethically shouldn't be. For others, their humor is lighter.
Is it their experiences that dictate what is funny and what is not? Are the people who enjoy darker humor different in any way than those who do not?
ALSO: What exactly is laughter, anyway? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/27dbv0/eli5_how_does_the_brain_decide_what_is_funny_and/ | {
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"Humour is a tough one to nail down. Generally the funniest jokes are the ones where people end up looking like assholes or idiots. Laughter is suspected to be an aggressive reaction to things, as other primates bare their teeth in aggressive displays similar to laughter. We laugh at people when they fall down and hurt themselves. Humour is also about the unexpected, generally when it isn't business as usual things are seen as funny. ",
"Humor is literally a shift in the frame of reference. You expect one thing, you get another. (Alternately, you don't know what to expect, and what you get is still unexpected.)\n\nConsider the knock-knock joke:\n\nWhen you say \"who's there?' the expectation is the name of the knocker. Instead you get something else.\n\nWhen you attempt to clarify, you are expecting an answer that will clear your confusion. Instead, you get an answer that was unexpected, but in retrospect makes (some) sense.\n\nYou laugh.\n\nPeople speculate that humor evolves from encountering the unexpected, and then signalling to others that the unexpected is not dangerous. If Oggh heard a noise in the bush and sent Blerg to investigate, if Blerg saw that it was a tiny squirrel had scared Oggh, he would be relieved, and signal to Oggh that he had been frightened by a squirrel. They were expecting/fearing a tiger and got a squirrel instead. Hilarious, no?",
"Irony is probably the source of all laughter. People laugh when they're expecting to see or hear one thing but end up getting another and I think the firmer the expectation the harder the laugh when it's broken. For most people a bit of cleverness helps - e.g. the writing of a good comedian, but my friends and I have been known to laugh at the sheer ridiculousness of natural events, often exclaiming \"what are the odds of that happening?\"\n\nI would think that some of those who laugh at unethical things laugh at them strictly *because* the things are unethical. You'll find this is the case with many cynics, they laugh because the event that took place stands in ironic contrast to accepted moral standards. "
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kj7om | How did pouch evolve on marsupials? | Edit: And by "how" I mean "how", not "why" (yes it's for babies, everybody knows that :D). How did it evolve? What/how did it used to be before they have pouch like the one they have in present time? I tried Googling but all of the results appear to be creationism sites. Help! | askscience | http://www.reddit.com/r/askscience/comments/kj7om/how_did_pouch_evolve_on_marsupials/ | {
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"I don't know the answer, but I have been led to believe that placental mammals evolved from marsupials.\n\nMarsupials exist on Australia because it has been isolated from other continents since before placental mammals evolved. In most locations, marsupials were out competed by placental mammals and became extinct.\n\nIn some ways, a marsupial is a stepping stone between placental mammals and reptiles. Reptiles, amphibians and fish all give birth to tiny embryos (in an egg, in the case of reptiles). In marsupials, they give birth to a tiny embryo, and the embryo then makes it's way into the pouch where it latches on to a teet and continues its development.",
"I read in scientific american about a prehistoric fish that hatched it's babies inside itself because laying eggs would surely result in the babies getting eaten. ",
"It is unlikely to be known unless there is a \"living fossil\" species that retains the transitional structure; the pouch is all soft tissue that won't fossilise.\n\nSpeculation: maybe derived from a small fold/flap that made it easier for somewhat older young to hold on?\n\nEDIT: [Atomfullerene says something similar, but with some actual facts.](_URL_0_) Turns put the transitional forms survive. This post is obsolete, I guess :).",
"There are even marsupials today which don't have pouches. The babies just hang on to the fur next to the teat. If the skin is a bit loose in that area, it's probably easier to grab. A bit looser still, and you have a nice little fold. Expand the fold, and viola, a pouch!",
"I don't know the answer, but I have been led to believe that placental mammals evolved from marsupials.\n\nMarsupials exist on Australia because it has been isolated from other continents since before placental mammals evolved. In most locations, marsupials were out competed by placental mammals and became extinct.\n\nIn some ways, a marsupial is a stepping stone between placental mammals and reptiles. Reptiles, amphibians and fish all give birth to tiny embryos (in an egg, in the case of reptiles). In marsupials, they give birth to a tiny embryo, and the embryo then makes it's way into the pouch where it latches on to a teet and continues its development.",
"I read in scientific american about a prehistoric fish that hatched it's babies inside itself because laying eggs would surely result in the babies getting eaten. ",
"It is unlikely to be known unless there is a \"living fossil\" species that retains the transitional structure; the pouch is all soft tissue that won't fossilise.\n\nSpeculation: maybe derived from a small fold/flap that made it easier for somewhat older young to hold on?\n\nEDIT: [Atomfullerene says something similar, but with some actual facts.](_URL_0_) Turns put the transitional forms survive. This post is obsolete, I guess :).",
"There are even marsupials today which don't have pouches. The babies just hang on to the fur next to the teat. If the skin is a bit loose in that area, it's probably easier to grab. A bit looser still, and you have a nice little fold. Expand the fold, and viola, a pouch!"
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96iybk | what is that clicking sound that nuclear radiation detectors make? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/96iybk/eli5_what_is_that_clicking_sound_that_nuclear/ | {
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"The noise is because of how [Geiger Counters](_URL_0_) function.\n\nThe Geiger counter has a chamber filled with an inert gas, like helium, and a high voltage applied to it. If high energy radiation hits the helium gas, it gives enough energy to the Helium atoms to bump electrons off their orbitals, so the atoms become non-inert (electrically charged), and thus react to the high voltage, and there's a small discharge of the electricity.\n\nThis discharge sounds like a \"pop\" if you hook it up to a speaker, because it's like a mini-lightning (thunder).",
"When an energetic particle enters the Geiger–Müller tube, it ionizes some of the gas inside and that allows a brief current to flow. That current results in a small voltage drop from the usual 400-900 volt DC which is applied to the tube. The momentary voltage drop is passed by a capacitor which blocks DC. The voltage drops are applied to a meter and speaker. No amplifier is needed. "
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3tyev6 | Could quantum entanglement be used for communication if the two ends were synchronized? | Say both sides had synchronized atomic clocks and arrays of entangled particles that represent single use binary bits. Each side knows which arrays are for receiving vs sending and what time the other side is sending a particular array so that they don't check the message until after it's sent. They could have lots of arrays with lots of particles that they just use up over time.
Why won't this work?
PS I'm a computer scientist, not a physicist, so my understanding of quantum physics is limited. | askscience | https://www.reddit.com/r/askscience/comments/3tyev6/could_quantum_entanglement_be_used_for/ | {
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"One of the absolute truths about quantum entanglement is that it can't be used for communication. If you ever think of a scheme (using entanglement) that can communicate, faster than light or otherwise, then it must be flawed.\n\nThe reason your plan does not work, even theoretically, is there is no way to control the bits. Say Me and You have a pair of entangled particles: When I measure the spin of my particle as up (1) I know that you will therefore measure down (0). This is being misinterpreted as me transmitting you the signal (0) but this is not correct, I had an equal chance to measure down (0) and you would receive an up (1). All I \"communicated\" to you is random noise. I also can not change your spin by making more measurements. Entanglement is a one shot effect, once you have made a measurement the particles decohere, they are no longer entangled. \n\nFrom /u/ymgve who raises a central matter: *One important point here: I know that you will measure down (0), but I don't know if you have already measured it or if my measure is the first.*\n\nThe true use of quantum entanglement comes from encryption. Experiments can be set up so we can be absolutely sure that only the two of us know which of us got which result and as a result we can communicate, over unencrypted public channels, using our entangled measurements as a one-time pad.\n\nWe must do so at the speed of light or below though, just like all other forms of communication.",
"/u/Robo-Connery already covered communication (or rather lack thereof) using only entanglement (a quantum communication channel).\n\nI also want to point out that with both a classical communication channel and a quantum communication channel, it is possible to transmit more than one classical bit of information in a single qubit, essentially using the quantum channel to raise the efficiency of the classical channel. This is called [superdense coding](_URL_0_) and like regular entanglement it does not allow superluminal transmission of information.",
"What about pre-planned communication though? If we have two entangled particles, and they're on two different ships:\n\n\nShip 1 is told that if spin is 0, go to A else go to B\n\nShip 2 is told that if spin is 1, go to A else go to B\n\n\nWouldn't this be communication?",
"It won't work. It just...doesn't work. You can't use entangled states to send a message.\n\nQuantum entanglement doesn't mean that actions performed on one state will spontaneously appear in the matching entangled state. All it means is that the two states were rendered so as to have a certain collective property, and when they are next measured, they are always found to preserve that collective property no matter how far they are separated in space and time. When you measure one state, you'll know what the other one is by virtue of knowing what the collective property is. But if you change your state, that destroys the entanglement, and your state no longer bears any particular relationship with the other state.",
"2 dice are entangled. Bob has one on mars, Alice has one 2 light years away.\n\nBob rolls the dice at a spceified time, the result is 4. Bob didn't know the would be four. However Bob does know that Alice will see 4 on her next roll.\n\nAlice sees 4, but is unable to know what number Bob wanted to send.\n\n",
"My friend and I have been discussing possible vulnerabilities to quantum key exchange. We have come up with a possible issue that we'd like someone to explain why this is not an issue (if possible).\n\nUsing the classic actors, Alice, Bob, and Eve:\n\n**I understand** that Eve intercepting a qubit from Alice and then sending it on to Bob will be detectable by Bob.\n\nCase 1: What prevents Eve from intercepting a qubit from Alice, reading the state, continually creating new quantumly entangled qubits until finding one that is in the same state that Alice sent, and then forwarding the paired qubit to Bob?\n\nCase 2: What prevents Alice and Eve from having a key exchange, and Eve and Bob having a key exchange, and then Eve acting as the proxy between Alice and Bob?",
"There is A LOT of misunderstanding of quantum entanglement in this thead so take anything you read here with a grain of salt unless it comes from a physicist. \n\nJust suffice to say, \"no, it cannot be used to transmit new information at FTL speeds\". It would break all sorts of models of causality and the very nature of spacetime/the universe.\n\nWatch this series of videos if you want a decent, and entertaining, explanation of reality including causality.\n_URL_0_"
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14mg7n | When and why did nations start "declaring war"? | When did war declarations become commonplace? Do countries still declare war? Why did countries start declaring war in first place, if it gives your enemy time to prepare? Is/was it regulated somehow? | AskHistorians | http://www.reddit.com/r/AskHistorians/comments/14mg7n/when_and_why_did_nations_start_declaring_war/ | {
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"The official international protocol for declaring war was defined in the Hague Convention of 1907 on the Opening of Hostilities.",
"Prior to the above, the 1648 treaty of Westphalia brought a much a more formal nature to war (from a very European perspective at least). This represented the creation of the modern state and so dialogue, diplomacy, provocations became more formal amd recognisable.",
"Rome had a type of priest knows as *fetiales* who were, among other things, in charge of formally declaring war or peace. They would be bring demands directly to the opposing territory, repeating a specific phrase to every passerby. If the demands were not met, they returned to Rome and declared war, but not before casting a spear into enemy territory and reciting a plea to both Jupiter and Juno. \n\nAdditionally, during times of peace the doors to the temple of Janus were closed and in war they were left open. The doors only closed upon a few rare occasions. "
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2ekz6j | how do tires on the landing gears of heavy airplanes withstand the speed and weight of the airplane when landing? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2ekz6j/eli5how_do_tires_on_the_landing_gears_of_heavy/ | {
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"They're big tires, so the force is spread out over a larger area, and they use quite a few tires—a Boeing 747 has 18 tires on it—further distributing the load. \n\nThey use thick rubber, so they're stronger than your average tire by a pretty wide margin.\n\nEven with these, they don't last particularly long. Any given tire will last through a few dozen landings; [this](_URL_0_) pilot states anywhere from 10-200 landings. Compared to the tens of thousands of miles that a car tire can last, that's almost nothing. ",
"They are also filled with nitrogen rather than air to prevent expansion."
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rz5ip | Healthier: high caloric intake + exercise, vs lower caloric intake | askscience | http://www.reddit.com/r/askscience/comments/rz5ip/healthier_high_caloric_intake_exercise_vs_lower/ | {
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"Caloric intake isn't specific enough. High saturated fat intake? High cholesterol intake? High carb intake?\nYou got my point. "
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1z5mhx | Do runaway stars get shot out of the Galaxy? | These things are flying through the Milky Way at up to 10 times the velocity of most stars' orbits:
[A Monster Star Plows Through the Galaxy? Shocking.](_URL_0_)
[A Corkscrew Unwinds From a Galactic Cannonball](_URL_1_)
So, do they end up cruising intergalactic space, or in parabolic trajectories into the outer halo?
| askscience | http://www.reddit.com/r/askscience/comments/1z5mhx/do_runaway_stars_get_shot_out_of_the_galaxy/ | {
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"It takes a lot of time and energy for matter to be ejected completely out of the Galaxy. Most runaway stars that are flung around thanks to close interactions with other objects remain close to the galaxy, but the probability of this actually occurring is very low. In general, stars and clusters in the Galaxy are very far apart from one another, so it \"takes a while\" for these interactions to take place. Many of the objects that populate the outer halo for this reason are older globular clusters that, when the Galaxy first formed, experienced more orbital velocity than currently observed. \n\nEven at 10x/velocity of the 220 km/s motion of most objects within, the halo occupies up to 300,000 light years of distance. For 2200 km/s, it would take an object, unperturbed, 1.4 x 10^15 seconds, or on the order of 3 x 10^8 *years*, to extend beyond what we think of as \"the Galaxy\". \n\nSo it is likely some of these stars will find their way to the halo, given they have long enough lifetimes. I would say, in general, that stars do not typically find themselves shot completely out of the Galaxy but the possibility cannot be ruled out!!"
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2isa3d | what would happen if the richest people on earth asked their banks to pay them out their fortune in cash? | Lets say the 5000 Richest People on earth all call their banks, telling them they want all their money in cash as soon as possible. Is there even enough money in cash stored at banks for them to pay out?
Or lets make the scale smaller, say Bill Gates calls his bank and tells them he wants 20 billion in cash as soon as possible. How would a bank handle this kind of request? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2isa3d/eli5_what_would_happen_if_the_richest_people_on/ | {
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"Bill Gate's bank would tell him to shove off, since he doesn't have $20 billion in cash. He probably has tens of millions in cash, so the bank would probably just ask him to wait a couple weeks so they could assemble the cash and give it to him.\n\n & nbsp;\n\nSimilar logic with other rich people.",
"Most *wealthy* people don't have 100% of their assets as liquid. part of their wealth may be stock or other possessions like their house or cars or other non liquid assets. \n\n\nWhile I'm sure they do maintain a good amount of liquid money in banks or even in cash you should expect that to be the smaller percent of their wealth. \n\nA better question would be what would happen if all the wealthiest people liquidated all their assets at once. ",
"Well, this question has a false assumption built in. You're assuming that most of a rich persons money is just sitting in a bank. It isn't, so when bill gates asks his bank for 20 billion they would likely inform him he doesn't have that much in his account."
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2uzwby | why do couples that are having trouble getting pregnant want a biological child so much when there are many children in need of adoption? | I have watched a few people spend years dealing with In Vitro fertilization and going through emotional turmoil when the process doesn't work and they have to start over again.
My question is: If they really just want to have a child and family, why do they not adopt? Is there some other driving factor making them want a child besides those things? I don't feel like I have the whole picture and it's definitely not something you can just go up to someone going through In Vitro/infertility problems and ask them about without being an asshole | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2uzwby/eli5_why_do_couples_that_are_having_trouble/ | {
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"Not a parent are you? The feeling you get from the birth of a child that YOU helped make is beyond words.",
"It is the innate human drive to carry on the individuals own genetic heritage. If you adopt, you and your partners DNA is not passed to future generations. This also plays into an individuals want/need to be genetically immortal via its offspring. ",
"This is a complex issue, but the short answer is biology, sentimentality, and socialization.\n\nPeople are biologically driven to reproduce, which at it's basic level means ensuring your genetics live on for another generation. Thus, people are biologically driven to have children that have their genes.\n\nMany couples also have a desire to share in the creative experience in producing a baby. Thus it's important for them to have a biological child because it can be considered a physical expression of the love they share together. A baby is literally both of them combined into one. \n\nFinally, our society reinforces the above notion subtly and overtly, plus generally stigmatizes children available for adoption as emotionally scarred, damaged, disabled in some way, potentially psychotic, and all sorts of other stereotypes that make many people disinclined to adopt. ",
"In the adoption market, one child is not the same as another.\n\nHealthy newborn babies are snapped up almost immediately. However, the older a children becomes (amongst other factors), the more baggage they carry with them.\n\nNext time you're walking down the street, take a gander at the homeless guys you see. Now, you could take them home, shower them with love, and maybe turn their lives around. How likely are you to actually do it?\n\nThat's pretty much the choice facing parents who adopt older children. Older children have either been taken from their parents (ie: they're damaged) or they've been bouncing around the system (ie: they're damaged). Fixing them is not a task for the faint-hearted. It's a lot easier to just start fresh."
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wu7b9 | bullet penetration | This video _URL_0_ was on the front page today. Why do the watermelons explode like that? Why doesn't the bullet just leave a clean hole behind? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/wu7b9/eli5_bullet_penetration/ | {
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"There are different kinds of bullets. Some bullets (called [full metal jacket bullets](_URL_0_)) are surrounded in a hard metal like steel and have rounded or pointed tips. They usually leave a clean hole.\n\nOther bullets, like the ones in this video, have [soft or hollow points](_URL_1_). They expand inside the target. Police and people who carry guns for their own protection prefer these bullets for two main reasons:\n\n- The bullet's expansion causes it to stop inside the target, keeping it from going through the target and possibly hurting someone else.\n\n- The bullet spreading out causes more damage to the target. If someone is trying to attack you, you are trying to stop them fast, so you want to do as much damage as fast as possible. This is what causes the watermelons to explode - all the bullet's energy is put into the watermelon.",
"Take the same gun and shoot a pumpkin. What does it do? It doesn't explode. Why does the watermelon get to explode but the pumpkin doesn't?\n\nIt all comes down to water: water does NOT like to be moved quickly, but air can be pushed away with ease. When a bullet hits the watermelon, it really, REALLY wants to go through it, but it has to push the water out of the way. Because the bullet pushes it so quickly, the watermelon essentially explodes.\n\nThe pumpkin, however, doesn't explode because there's a lot of air inside. The bullet can travel through the pumpkin quite easily because it just has to push the air inside around a bit.\n\nIt has very little to do with the shape of the bullet and a lot to do with the velocity of the bullet. The fast the bullet goes, the harder it pushed the water aside."
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1bn3ow | why do songs become popular on the radio months after they were released? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1bn3ow/eli5_why_do_songs_become_popular_on_the_radio/ | {
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"There are a few reasons:\n\n1) The song was not expected to be popular. The album comes out and after a little while the internet discovers how cool track 7 is - marketing people pick up on it and jam it on the radio to sell more albums.\n\n2) It is planned to not conflict with another song. If Kanye has a new album he'll release a single. Then a little while later they might start promoting a second song to keep sales up."
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258ty3 | proton cancer treatment | I have a family member who has cancer in multiple locations (Brain and lungs so far) - recently diagnosed.
They are suggesting Proton Therapy and I looked it up, but I don't really understand. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/258ty3/eli5_proton_cancer_treatment/ | {
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"It's very simple once you understand some basic biological concepts.\n\nCancer is the uncontrolled growth and reproduction of cells.\n\nCells require DNA to reproduce themselves and when DNA is damaged tremendously cell reproduction will usually just fail.\n\nRadiation destroys DNA as well as cells.\n\nThey're going to focus beams of radiation on the tumors to irradiate them. This will hopefully kill cancerous cells or at least destroy their genetic sequence making it impossible for the tumors to continue growing and damaging his body.\n\nI wish you and your relative the best of luck. I've had a few family members suffer from cancer as well."
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4fhdwc | why are so many countries aiming for 2% inflation? | Why is it good for things to get more expensive, why is there no parallel or greater wage growth target, and what makes 2% the gold standard?
Edit: thanks guys for covering this, much appreciated. I'd mark it explained but I'm new to this and don't know how | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/4fhdwc/eli5_why_are_so_many_countries_aiming_for_2/ | {
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"Inflation is a side effect of growth. As more people have more money, they can demand more goods/services which cause prices to rise since demand (generally) outstrips supply over the short-run.\n\n2% has historically been a smooth and stable level of inflation, not too fast... but still representing a reasonable amount of growth in the economy.\n\nTargeting wage growth would require much more intense regulation in areas of the business world that governments have not been involved in.\n",
"There's a link between inflation and economic growth (usually measured by the Gross Domestic Product, or GDP). \n\nIf your GDP is low, it's usually the case that unemployment is high. Any hiring sprees have very little effect on inflation in the short term because so many people are out of work that the increased worker spending still doesn't cause products to fly off the shelves.\n\nHowever, if your GDP is high, unemployment is usually low. When labor is further demanded, there are a lot of ways to attract workers from other businesses, but any of them inevitably cost the company money, and some of that cost will be borne by increases in prices for the product. Hence, GDP growth, in this situation, leads to some inflation.\n\nMost countries are willing to tolerate a little inflation if it means that their countries are being close to maximally productive. ",
"Economists generally agree that around 2% inflation is a rate that is desirable for an economy. Basically the reason this number is chosen is that it provides a balance between goals the government hopes to achieve .\n\nThe 2% rate of inflation is chosen as:\n\n1. at this amount , inflation is high enough to encourage consumer spending. (people spend money rather than saving it, as overtime their money loses its purchasing power.)\n2. But Inflation is low enough that it maintains consumer and business confidence in the economy, meaning that consumers keep spending and that businesses continue to invest and expand their business. \n\nGreater wage growth does not have a target as there is no real agreement on the appropriate level of wage growth due to difference in each industry.\n\n",
" > Why is it good for things to get more expensive\n\nBecause it encourages people to spend money, which in turn grows the economy. \n\n > why is there no parallel or greater wage growth target,\n\nA gov't can influence inflation directly with fiscal policy. They cannot directly control wages.\n\n > what makes 2% the gold standard?\n\n2% is a good middle ground between incentive and not eroding people's savings."
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3da95g | Treaty of Versailles--Trying to recall where I read a discussion on the severity of the treaty. Was the treaty too lenient? | Within the last six months I was reading a thread *somewhere* on reddit about historical misconceptions. There was an incredibly compelling comment about the Treaty of Versailles, talking about France's posturing post Franco-Prussian war and how much of the "reparations" were a political facade (which I've read several texts suggesting the same).
It was a breakdown of fiscal/financial strategy along with historical/political analysis. Did anyone happen to catch this?
If not, I'd like to hear what you all have to say: **Was the Treaty of Versailles justified in the form it took? Did Lloyd George tone down the punishments a bit too much? Is it largely German propaganda that we are hearing today when we hear people say "The treaty was inhumane and largely the reason Hitler came to power"? Were the more negative outcomes of the Treaty more linked to Woodrow Wilson's imprint on it with his nation states and empire-busting?**
I feel like there are a lot of critics of it but their arguments always strike me as flimsy "slippery slope" arguments. I really wish I could find the post I'm thinking of, though I feel like the person who posted it (or someone of similar mind) might see this in this subreddit.
Would love to hear your thoughts on the subject.
| AskHistorians | http://www.reddit.com/r/AskHistorians/comments/3da95g/treaty_of_versaillestrying_to_recall_where_i_read/ | {
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" > Was the Treaty of Versailles justified in the form it took?\n\nExpecting the Germans to pay reparations for the Damages they had done; reducing their military (in theory) to ensure that they could not seriously threaten the borders of their neighbours; relinquishing territories, most of which were off majority non-German populations. Yes, the Treaty was certainly justified in the form it took, especially considering the actions of the Kaiserreich in the past 4 and half years.\n\n > Did Lloyd George tone down the punishments a bit too much?\n\nAside from demanding plebiscites in Eastern Germany, I know of no other ways in which Lloyd-George affected the leniency/harshness of the Treaty.\n\n > Is it largely German propaganda that we are hearing today when we hear people say \"The treaty was inhumane and largely the reason Hitler came to power\"?\n\nNot solely German propaganda; people like J M Keynes were castigating the Treaty rightly or wrongly before the ink even dried, and it had become more or less gospel by the end of WWII. Before Hitler came to power, the Treaty was essentially a non-entity, and opposition to it was a common feature of most party platforms in the Weimar Republic.\n\n > Were the more negative outcomes of the Treaty more linked to Woodrow Wilson's imprint on it with his nation states and empire-busting?\n\nWilson supported reparations, and was willing to be pragmatic when it came to territorial confiscations. Had the United States managed to join the League of Nations and thus aid Britain an France (really France) in enforcing the Treaty properly, some if not all of the issues facing the Treaty in the 1920s could have been handled.\n\nBoth /u/elos_ and I were involved in the discussions I believe you are referring to. I believe I archived some on my profile page in the subreddit wiki. If you'd like an excellent source, I recommend *Paris 1919* by Margaret Macmillan."
]
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[]
] | |
196m5i | Are suicide fighters a modern development? If not, how long have they been around and where/what regime? | EDIT: Answered!! | AskHistorians | http://www.reddit.com/r/AskHistorians/comments/196m5i/are_suicide_fighters_a_modern_development_if_not/ | {
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"Suicide tactics are not a modern concept but it really comes down to your definition of suicide fighters. Soldiers have, at times, committed to attacks in which they would have known that their odds of coming out alive were next to non-existant. They may not have blown themselves to bits but the end result is still in essence a suicide attack. Examples of this are as old as 11th century (India, Chera era *Chaver* units). There are western examples too, many units did blow up positions when they were over-run if sufficient powder stores were available (17th century and onward), there are good examples of this from the Dutch soldiers in Taiwan in 1661, while not a suicide attack in the form we consider today, the effect would often be the same. \n\nHistorically, most suicide attacks were not religiously motivated but they do share many of the same characteristics, a strong group think, loyalty to the cause and willingness to sacrifice your life exists in almost all cases where suicide attacks are carried out. This environment is forstered in terror cells and military units alike. ",
"According to the [International Institute for Strategic Studies](_URL_2_) the modern phenomenon of suicide bombings using concealed explosives as an insurgency tactic originated in the late 1980's with the 'Black Tiger' wing of the [Tamil Tigers](_URL_1_) The 'Tamil Tigers' are a militant Tamil separatist group in Sri Lanka. \n\n_URL_0_\n\nSuicide tactics have a long and complex history, but the specific modern suicide-bomber archetype starts in Sri Lanka in the late 1980s. ",
"Roman writers describe semi-mythical warriors of the early Republic who engaged in self-sacrificial behavior that could be called suicidal. The story of [Horatius Cocles](_URL_1_) or [Gaius Mucius Scaevola](_URL_0_) both involve men who choose suicide missions for the good of Rome but are saved by outside circumstances.",
"The Chinese had the gan si dui (when literally translated means \"dare to die squad\"), which usually consisted of soldiers willing to face insurmountable odds. The family members of the gan si dui would be given gold and silver as a reward for their sons' courage, which spurned the gan si dui to even greater heights of suicidal bravery. Sometimes they even form the vanguard of an army. "
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56ug4s | how does new information still get uncovered from classified state archives after decades of research and analysis? | For example, new information that emerges from the archives of the USSR and the KGB. I have no clear example right now though.
Or, something that happens in my country, new information on Ceaușescu / the Romanian communist regime.
Former communist archives have been studied since the '90s, how come there is still new information to be published / revealed?
There's also things like the Vatican's archives, which are still protected by the Vatican, obviously. But communist regimes no longer exist to protect the secrets found in the former state archives, right?
(Let's not limit ourselves to the communist archives; these were the only examples that I could think of at the moment.) | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/56ug4s/eli5_how_does_new_information_still_get_uncovered/ | {
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"There are several reasons. \n\n1. First and most obvious, it's **a huge amount** of information to go through. The people digging through it all are usually academic researchers looking for some specific thing for their research. Nobody is just sitting down to read millions of pages of decades-old government papers just to see if something interesting pops up.\n\n2. Intentional obfuscation. Governments are paranoid, and dictatorships tend to be hyper-paranoid. It's likely sensitive information, when it was even recorded, was hidden. It's easy to lose a few incriminating files in a giant ocean of totally mundane documents.\n\n3. Even though the old governments are gone, new governments may not be interested in revealing everything. Remember that a lot of the guys who were young bureaucrats during the Commie days are still around and may be in powerful positions now. They have a strong motive to keep anything secret that might reflect poorly on them."
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5spy9s | Did Japanese-Americans have any warning that FDR was going to intern them during WWII? How did so many of them lose their savings and their houses? | I'm asking whether Japanese-Americans had any warning that internment was about to happen. Did they have time to prepare for a long internment, or was it a surprise?
I've read that many interned Japanese-Americans ended up losing their savings and their property. How did this occur?
Did the US government freeze all assets owned by Japanese-Americans? Were their assets seized? Or was it more of a situation where they didn't know how long they'd be interned, and had no choice but to sell off their assets at fire sale prices? | AskHistorians | https://www.reddit.com/r/AskHistorians/comments/5spy9s/did_japaneseamericans_have_any_warning_that_fdr/ | {
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"Expanded from [an earlier answer of mine](_URL_0_)\n\nIn terms of notice, FDR signed Executive Order 9066 in 19 February 1942 which authorized exclusion of enemy aliens in what were termed \"Military Areas\", on 2 March Lieutenant General John L. DeWitt declared the Pacific Coast \"Military Area No. 1\", and throughout the rest of March a series of edicts restricts Japanese-American movement in Military Area No. 1 and control over their assets. Additionally, War Relocation Authority (WRA) starts opening up camps like Manzanar. By late March, internment began to assume a reality and by April 1942 the process is well under way. So in terms of notice, the timeframe is very brief (February-March 1942). It is also important to realize that from the perspective on the ground, it is difficult to disentangle these various initiatives from wider wartime security regulations (e.g. blackouts, curfews, etc.) and DeWitt's proclamations were often quite confusing. Military Area No. 1 was initially only 100 miles inland, leaving Military Area No. 2 (the inland West coast) nominally free from these restrictions, leading some Japanese-Americans to make plans to move there. But DeWitt's Public Proclamation No. 4 of 27 March forbid Japanese-Americans from Area No. 1 to move to No. 2, thus trapping many in Area No. 1. \n\nThe relative suddenness of internment is one of the reasons why it was so economically devastating for the Japanese-American community. Many Japanese-Americans were involved in farming and their farms were among the most productive in the West Coast. The Congressional Commission on Wartime Relocation and Internment of Civilians (CWIC) of 1980 estimated that of 6,118 farms valued at $72 million with $6 million worth of equipment. Most of these farms had to be sold at firesale prices and the result was a net loss for the West Coast agricultural economy in 1942 as the evacuations took place at peak spring harvest. Shop owners and other business-owners had to liquidate stock and stores quickly. Assets in Japanese-owned banks were frozen and home owners likewise had to sell their houses. \n\nThe Japanese-American community as a whole did not have that much access to ready cash as the Roosevelt administration had before Pearl Harbor had restricted the activities of Japanese-owned banks in the US, which a number of Japanese-Americans had accounts in as it was easier to send money back to the Home Islands. After Pearl Harbor, the ability of \"enemy aliens\" to withdraw money from their accounts was also frozen. Bank accounts in American banks remained in service, but their holders could not access them until the middle of the war when Eleanor Roosevelt appealed to the US government to allow internees access to their holdings, albeit still on a limited basis. The Federal Reserve Bank was charged with protecting the financial interests of the internees, but its portfolio also included the task of ensuring that evacuation be accomplished as swiftly as possible. These two imperatives were incompatible and most FRB personnel prioritized the latter imperative. Despite this, the FRB often assured Japanese-Americans that their property would be safe if they could not sell it. Not only were there too few FRB personnel to make this a reality, they often underestimated the complexity of evacuation process. For example, cars were a form of movable property that could not be off-loaded easily, so a number of internees simply drove their cars to the evacuation centers and left them there in the hopes of being able to return and claim them once resettlement had settled down. Eventually, this became such a problem that the FRB demanded that the evacuees sell their automobiles to the US Army at FRB-evaluated prices. This was something that repeated itself in multiple areas where property that could not be carried off or sold was often left in place in the hope that it could be reclaimed. Theft, arson, and vandalism was the natural end result of this policy and neither local authorities nor the federal ones were inclined to investigate or discourage such actions. \n\nBut the financial losses were not just in concrete assets like homes, farms, automobiles, and shops. Wartime relocation and internment also meant that for a good three years, a large segment of the Japanese-American population was simply out of the workforce. The WRA camps paid wages to internees for jobs performed on site such as cooking, but these jobs paid below average rates and many internees were reluctant to participate in a system that had hurt them in many ways. Being locked out of the wartime economy meant the Japanese-American community did not by and large receive its collateral benefits. Not only did the war economy improve workers' wages, but wartime industries provided job training and other skillsets, as well as social networks for the postwar period. Many Japanese-Americans found their skillsets atrophy in the camps. This posed problems for the postwar period of adjusting to the end of internment. The economist Aimee Chin compared interned male Japanese-Americans interned to Hawaiian Japanese, who were not interned *en mass*, and found that by comparison internees' annual earnings were 9-13% less than those who escaped internment. Internment also encouraged many Japanese-Americans to funnel their resources into so-called human capital such as education instead of physical investments like buildings or businesses. \n\nThe above makes it very difficult to put an exact price tag on the cost and losses of internment. The actions of the US government during the war and the immediate aftermath made this much harder. The 1948 Evacuation Claims Act allowed for some compensation, but the IRS had destroyed the tax records for 1939-42, making evaluating the claims near impossible. The suddenness of internment also meant that internees found it difficult to preserve financial records when they were allowed only a finite amount of personal property (as anyone who has moved knows, paper in bulk is quite heavy). Japanese-Americans claimed $148 million in losses in 1948, but the government only paid out $37 million. The oft-quoted figure of $400 million which came from the Federal Reserve Bank of San Francisco is one that is often cited, but this is one of those numbers like the million casualties for an invasion of Japan; there is no real data or even research to back up this figure. Broom and Riemer's 1949 book *Removal and Return: The Socio-Economic Effects of the War on Japanese Americans* provided a more conservative figure of $77 (1941 dollars) million in property losses. Broom and Riemer extrapolated data from Los Angeles property records and was one of the most thorough estimates produced of losses close to the time of evacuation. But *Removal and Return*'s estimates are likely on the conservative end of things as they do not account for intangibles like loss of productivity and other aspects related to property loss. \n\nOf course dollar value cannot really quantify other losses, such as the psychological trauma of internment and dislocation. George Takei's memoirs for example recall arriving back on the West Coast and only being to live in a slum and being immediately greeted by a bum urinating, a fact that frightened his younger sister. Such stories, as well as others about losing family heirlooms or seeing the hard work of decades washed away over the space of a few months, which are quite common among internee memoirs, speak to intense psychic costs of internment and add a further blot to this gross violation of Japanese-Americans' civil rights. \n\n*Sources*\n\nChin, Aimee. \"Long‐Run Labor Market Effects of Japanese American Internment during World War II on Working‐Age Male Internees.\" *Journal of Labor Economics* 23, no. 3 (2005): 491-525.\n\nNg, Wendy L. *Japanese American Internment During World War II: A History and Reference Guide*. Westport, Conn: Greenwood Press, 2002. \n\nUnited States Commission on Wartime Relocation and Internment of Civilians. *Personal Justice Denied*. Wash., D.C.: Civil Liberties Public Education Fund, 1997."
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sujnb | Why can we NOT drink seawater to survive? | I know we can drink small amounts of seawater but why is it we cannot drink it to survive. We require trace metals, minerals, ions etc. that can be readily found in seawater and yet when we drink it we instinctively spit it out and feel a stomachache afterwards. We also cannot survive solely on DI water, since it has none of the trace metals, minerals, ions we require and instead we must eat food to obtain these micronutrients. Yes, seawater will dehydrate you but can you not simply drink more? | askscience | http://www.reddit.com/r/askscience/comments/sujnb/why_can_we_not_drink_seawater_to_survive/ | {
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"The problem with seawater is not trace minerals and metals, but rather the > 3% salt content. Your body needs to maintain a certain percentage of electrolytes, and doesn't have a good way to absorb only the water and not the salts from sea water. The result is that you'll need more and more water to offset the increasing amounts of salt in your body, resulting in dehydration.",
"It has to do with Osmosis and how our body process water.\n\nHere is a nice website explaining the matter: _URL_0_",
"No, drinking more saltwater won't eventually help because that water isn't going to make it into the cells due to osmotic pressure.\n\nImagine a fish tank, and in the middle of the fish tank is a wall that divides it. One side is filled with salt-water and the other side has freshwater. The dividing wall is \"semi-permiable\", which means only water molecules can go through, but salt won't. There will be a pressure, or a tendency for water to go toward the salty side, trying to dilute the salty side."
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hgnqz | Mass of falling objects | Two spheres of the same size are placed held in position above the moon, to remove air resistance. One sphere has 5 times the mass of the other. In all practical ways they would fall at the same rate. But would the additional mass of the one sphere increase the gravitational field it creates there by increasing is acceleration? Or is the increase so insignificant that it couldn't be measured? | askscience | http://www.reddit.com/r/askscience/comments/hgnqz/mass_of_falling_objects/ | {
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"Yes, technically speaking, the more massive ball does cause the moon to accelerate towards the ball faster, which means that it hits the moon quicker.\n\nHowever, this effect is so laughably small that's it's completely unmeasurable."
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26av3a | I recently learned that scientiists use zircon crystals to date rocks and, with them, the Earth. How do we know that the zircons weren't created elsewhere in material that then combined to form the Earth? | Here's a link to one example: _URL_0_ | askscience | http://www.reddit.com/r/askscience/comments/26av3a/i_recently_learned_that_scientiists_use_zircon/ | {
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"Well - sometimes they are, and in some instances that fact is the main story the rock can tell. All Zircon-based geochronology studies must begin with a morphological assessment of the material: how many populations are there, do they look fresh, are they corroded, fractured, is their geometry coherent with the setting they were found in?\n\nFor instance, some of the rocks I've worked on are metasediments - essentially sand cooked close to the melting point at high pressure. That material contained several populations of zircons which were inherited from the source material the initial sand was derived from - each source had its own zircon population. This gave us clues as to what that source area could have been. It also gives us a minimum age, as the sand can be at most as old as the youngest zircon it contains.\n\n\n\nIn intrusive or volcanic rocks, there are sometimes older inherited zircons mixed in with a [native zircon population](_URL_1_). These are recognizeable by their morphology (they usually have readily recogniseable corroded exteriors - at times they even are [at the core of zones crystals with growth rings](_URL_0_) - Those are great when you have them: each ring and the core can be dated.) Xenocrysts in this context are usually quite rare, but they are really usefull in getting some idea of the age of the otherwise inaccessible material underlying a given intrusion or volcanic centre.\n\nEdit: pictures"
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3bv9hu | How does the universe decide where an electron is when you observe it? | Hi!
So I remembered this Futurama scene where the professor is betting on a horse or something and there were two horses who were neck and neck. In order to see who won the race the people at the racecourse use a microscope to observe where the electrons were when they crossed the finishing line and hence find who won the race. The professor then claims that by observing the event you force the universe to decide where the electron is. IIRC I saw on reddit that what the professor said was true.
How does this work? How does the universe decide where the electron is? Does the universe select its position randomly?
Follow up question,
Is this the same if you were to shuffle a deck of cards where nobody knew both the initial and final position of the cards. Would turning the cards over be forcing the universe to decide what the card will be?
Thanks!
The scene:
_URL_0_
Thanks for answering guys! Still don't think I fully understand, but I think I get the jist of it. | askscience | http://www.reddit.com/r/askscience/comments/3bv9hu/how_does_the_universe_decide_where_an_electron_is/ | {
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"It is different for cards. The cards are predetermined, we just don't know where they are. The electrons are everywhere and nowhere until measured.\n\nThe truth is, we don't know how some electrons get measured over here and some get measured over there. We do know one thing that it's not: Predetermined. The universe isn't secretly conspiring where the electron is going to be, it is a completely probabilistic process. The universe doesn't know where the electron will be just as much as we don't know where it will be (and the electron doesn't know either!) This is a consequence of [Bell's Inequality](_URL_1_), and is explained [Here](_URL_0_).\n\nSo how does it decide? It doesn't, there isn't a deterministic process that it goes through to determine if it is a point A or point B. It is truly probabilistic."
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2g4023 | Say I had a beaker of water at room temperature and threw in one salt molecule (NaCl). The Salt would separate into Na and Cl ions. What if I was able to separate the water containing the Na ion from the water containing the Cl ion and evaporated them, what would happen to the ions? | Would they still exist in an ionic state? | askscience | http://www.reddit.com/r/askscience/comments/2g4023/say_i_had_a_beaker_of_water_at_room_temperature/ | {
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"First, salts such as NaCl are not molecules; they are not bound in discrete 1 sodium atom-1 chlorine atom units. Instead, they are ionic compounds which form distributed charge sharing lattices which involve many ions of both types. We say that the formula for that particular salt is NaCl, but this formula is an *empirical* formula rather than a *molecular* formula, meaning it represents the ratio of atoms or ions present in the substance, not that actual number present per unit.\n\nWith that in mind, we could modify your question to imagine you threw in one *crystal* of NaCl salt. How many sodium and chlorine ions would be present in this crystal? It depends on the size of the crystal, but there is a lower limit. There cannot exist a crystal of salt with only 1 sodium ion and 1 chlorine ion. There cannot exist a crystal of salt with only *2* ions of each type. What is the lower limit? I do not know, but it must be enough ions of each type in the proper 1:1 ratio to distribute the charges in a stable structure.\n\nYou are correct, though, that the Na and Cl ions will disassociate into free ions in the solution. If the water is removed, the ions will reassociate to form an ionic solid again! Depending on the conditions of the water removal, these ions may reform a single large crystal or many individual small crystals.\n\nYou can try this yourself by mixing a spoonful of salt into a shallow glass of water. Stir until it is all dissolved, then leave to evaporate (this may take up to several days, depending on the humidity where you live). When you return you will find the salt remains in the glass, probably as a film of very fine crystals along the bottom. A string hanging into the center of the salt solution can encourage growth of bigger crystals as the water evaporates.",
"If you're asking if ions can exist freely, the answer is yes. In our environment though they quickly become neutralized.",
"Are you asking what would happen if you separated the sodium and chloride ions into separate vessels?\n\nThis is kind of what happens when you electrolyze salt water, though some chemistry also happens at the electrodes to balance it out. \n\nIf you only had two oppositely charged ions in solution, I would guess that they would hang around nearby each other, otherwise you would generate an electric field across the water. So I'm guessing what would maybe happen for your case, if it was possible, is when you separate them the ions would split a water molecule (into H+ and OH-) to balance this out, and you'd get one molecule of NaOH on in one vessel and one molecule of HCl on the other.\n\nTotal guess by the way, but it's an interesting question.\n",
"Ions in this case would probably [adsorb](_URL_0_) to the surface of the container which originally had the water. The ions will stay as ions if there is something to stabilize them like the water originally did. In this case charges on the surface of the container (Si and O atoms in glass for example) can stabilize the ions.\n\nThere's a limit to this based on the number of sites for adsorption on the surface and how strongly the specific ion adsorbs to the site. You can't have moles of positive and negative charge stabilized.",
"You could not practically separate the ions without introducing new ions to balance the charges. The electrostatic forces are way too strong. There's enough ionic charge in a teaspoon of salt that separating the ions could power hundreds of lightning bolts.\n\nYou could separate the chlorine from the sodium, but you'd have to balance it, say by splitting water into OH^- and H^+ and making NaOH and HCl, both of which are electrically neutral.",
"As others have stated, assuming you could isolate the two separated ions by magically boiling the water off without carrying either of them away with a stabilising volume of water vapour, then they would typically \"find\" alternative counterions (or co-reactants) in the atmosphere or vessel through one mechanism or another.\n\nWhat you might find interesting to read about is a practical application of separating such ions, and correspondingly, the fairly extreme conditions that are required to manipulate and isolate them in this way:\n\n_URL_1_ (Explanations elsewhere are likely to be a little less intense!)\n\nAlso:\n_URL_0_ (Mostly for the image.)",
"I want to congratulate the OP for causing so many people to demonstrate their ignorance of Chemistry.\n\nFortunately someone posted the correct analysis already. The disassociated ions of the salt would pair with the ions *ALWAYS* present in the water H30+ (aka Hydronium ion) and OH- (aka Hydroxyl ion) to maintain electrical neutrality. You would have one beaker with NaOH solution and the other with HCl solution. Or if you wish NA+ & OH- (aq) in one beaker and H30+ & CL- (aq) in the second. Then as the water evaporates the residues would be as previously mentioned.\n\nFWIW, separating one molecule that way is trivial, even 10 molecules would tend to be split with all the same species on one side or the other fairly often. But in any normal (not necessarily '1.0N' {sorry}) solution the concentration of ions is going to be so close to uniform that we can ignore/discount the possibility of measuring the difference.",
"To add to your question, the NaCl may not even separate. They can exist as ion pairs (or even larger aggregates) in aqueous solution. For this reason, the *molality* of particles in solutions does not correspond to the total moles of ions. The ions do not dissociate 100%.",
"Sorry for the long rambling answer, I had a lot to say:\n\nSodium chloride, as a +1/-1 salt does not form very strong ion pairs. Because they attract each other, there would be some positive statistical mechanical correlation between the location of the sodium and chloride ions if you were to add a just one NaCl to ultrapure water due to the screened Coulomb potential. However, if the container was of macroscopic size, the entropy gained by expanding their spatial range throughout the container would outweigh their attractive energy, and the probability that the molecules would be in separate halves of the container would be almost fifty-fifty. Even MgSO_4, say, which, as a +2/-2 salt, forms stronger ion pairs, would succumb to this energy/entropy argument with a macroscopically sized container. With a higher concentration of salt, the expected electric imbalance between the two halves would be go up, actually, although the imbalance relative to the amount of salt would go down.\n\nThe electric field is very strong given macroscopic quantities of charge. If all the electrons in a milliliter of water were moved a football field's length away from the nuclei, the force between the two charges would be equivalent to roughly three billion metric tons. However, this case with a single electron is very different.\n\nOnce they were split apart, the beakers would have an undetectably small Coulombic attraction, but be otherwise normal behaving. The ions would be highly stabilized by their interaction with water and probably wouldn't undergo redox reactions with the environment very quickly because solvated Na+ is a very weak oxidizing agent, and solvated Cl- is a very weak reducing agent. Actually, spontaneous charge fluctuations are much larger than single elementary charges, and so this situation wouldn't be unusual at all. Only in crystals is the charge cancellation so perfect and orderly. In many gasses, liquids, and plasmas, much larger spontaneous fluctuations are possible. Even some solids can have locked in electric charges. Static electricity is a well known example of such a charge imbalance.\n\nTaking this to the extreme and asking whether you can have a bucket of positive charges and another of negative charges will get a different answer, though. To get a sense of what would happen, suppose the bucket was a spherical liter of water. Removing all of the electrons from the bucket suddenly would create a situation with so much repulsive electromagnetic potential energy that an explosion releasing the equivalent energy of fifteen billion Little Boy nuclear bombs would result.\n\nAdsorption onto the container walls, as /u/ramk13 says, is a possibility, but with a large enough container of water, the same energy/entropy argument will assure that the probability of the ion being in the aqueous phase will be very high. I'm not certain, but I'd be surprised if the container had to be larger than just macroscopic for this to happen. However, if there was a lot of unbalanced Na+ in solution, although not nearly as much as in the example in the previous paragraph, the electric repulsion would potentially cause them to approach the boundaries of the container, but this wouldn't occur with a single ion.\n\nIf you were to now evaporate the water, ignoring the spontaneous fluctuations, the stabilization afforded by the ion-water interactions would be lost. They still wouldn't be terribly reactive, but redox reactions with other species would now become much more likely. Most of the time, the charge imbalance will just be passed along from one atom or molecule to the next. Eventually, though, the two charge carrying atoms might find each other, or more likely, other charge carrying atoms from a different spontaneous dissociation and neutralize, but until then, the charge imbalance would just be a part of the random statistical mechanical charge fluctuations of the system.",
"You'd have a beaker with a single NaOH molecule and one with a single HCl molecule. Due to the auto-ionization of water, there's always OH- and H+ (technically H3O+) ions floating around. That's part of the reason why water can dissolve so many things."
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60zqbv | why do employers ask you to resign instead of just firing you? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/60zqbv/eli5_why_do_employers_ask_you_to_resign_instead/ | {
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"Depends on the place. A lot of places do it so you can't later sue for wrongful termination. Others still do it so you can't demand severance pay or a severance package.",
"It looks much better on a resume / any document that shows employment history. It avoids a black mark on your background and, in the case of some companies, makes their calculated turnover rate lower than it would be if they flat-out fired you. In most cases, it's a favor to the employee.",
"In the U.S., in most places, at least, if you resign then it is harder to get unemployment. If they fire you, it is easier to get unemployment. \n\nAlso, for higher end jobs or jobs under contract/with union protections, there are often ways to contest being fired, which can make the process longer and more expensive. If you resign, that's avoided. It can also make it harder for you to come back later and claim that they wronged you in some way as part of lawsuit since they can say that you left voluntarily. ",
"Companies will do this to avoid paying severence. As a general rule if you have done nothing wrong you should not do it as it could mean you receive no severence pay. Only resign if it is a benefit to you.\n\nIt should be noted that at least where I live if you are told resign or be fired you are likely still entitled to severence pay even if you resign because it was not really a resignation. They fired you. They may argue that you had a choice but you didn't because you were losing your job either way. \n\nSource: an employment law radio show I hear every day in the tractor as I feed my cows.",
"In addition, in many professional fields (law and securities in my case), you have a permanent record that follow you around everywhere you work in the field - in securities this is called your U4 form. If you are straight up fired, the 'cause' goes on your U4 - this is called 'getting your [U4](_URL_0_) marked up' - its a very bad thing if you are trying to work in higher levels of finance eg more than some shitty institutional salesman or private banker. I've ditched candidates for having a marked up U4 a bunch of times.\n\nIf you resign (or are laid off) no markup on your U4, so its kinda a courtesy thing. ",
"The main reason is so you can't file a labor complaint or sue for wrongful termination. When you resign, it is your choice, and that makes it much harder to make a complaint later.\n\nIt is usually a kind of negotiated exit. Let's say you were pretty sure an employee was stealing, and you just want them gone. You don't want to fire them because without ironclad proof, it could go very bad for you in court. \n\nInstead you might give them the option of resigning before you called the cops and started a big messy investigation. If they were guilty, they might accept that deal rather than face legal charges. You get rid of them, they stay out of jail, everyone is happen.\n\nWhile it is true it is harder to get unemployment if your resign, this is rarely the reason you are asked to resign.",
"Working in HR, I can think of several reasons off the top of my head:\n\n1. Future employment. We understand the \"being fired\" can follow you in a way that leaving on your own does not. Believe it or not, we very often have this sort of thing in mind. We may not want you to work here any more, but we're not trying to screw you out of getting another job.\n\n2. Just makes everything easier. Don't get me wrong, we've straight up fired plenty of people if it is necessary and right. However, when possible, it is simply easier to negotiate a voluntary release. When this happens, there is a severance package offered as well as a release of any claims, confidentiality agreement, etc... It's just a smoother transition than a hard firing, and avoids any complications down the road from a disgruntled former employee.\n\n3. Unemployment. Certainly some employers try to get you to resign so that they aren't on the hook through their unemployment insurance. Depending on the nature of your release, some times the courts will see through this tactic, but it is certainly another obstacle. I currently work in an industry that is exempt from unemployment altogether, so it is not a concern for us. However, in previous workplaces, that has come up.\n\n4. PR, both internal and external. We try hard to maintain confidentiality on employee matters. It's easier for us to do that when an employee resigns themselves. And while there is always \"talk\" when someone leaves, this shortens that conversation considerably.\n\n5. Dignity. For many people who are on the verge of being let go, the know that this job is no longer right for them. Giving them the opportunity to leave of their own accord affords people some dignity and self-respect that being fired can often steal from you. Not completely, for sure, but often somewhat."
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ma4fs | What accounts for the French paradox? (Why are French people not as fat as we'd expect, given their diet) | The fact that they eat so many carbohydrates from baked goods like baguettes (with saturated fat from cheeses and pork) seems like it would flood their blood vessels with blood glucose and thus insulin, which facilitates fat storage as far as I've researched. By what mechanism is this fat storage reduced? | askscience | http://www.reddit.com/r/askscience/comments/ma4fs/what_accounts_for_the_french_paradox_why_are/ | {
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"As a chef I can say for two reasons. First are the portion sizes, a lot smaller than American plates. Secondly, a more natural diet. Less processed foods and fewer chemicals in their food. ",
"Michael Pollan discusses this in 'In Defence of Food' (forgive me for the popularist citation). He suggests that it's a combination of portion size, a preference for unprocessed ingredients, and a culture that advocates leisurely consumption of food in the context of social interaction, rather than scarfing down fuel. ",
"The so-called \"French paradox\" is not actually about obesity, but about the culture's much lower levels of coronary disease. The term was coined by a French scientist at Bordeaux U. \n\nThere are a number of proposed reasons why the French appear to have a significantly smaller incidence of heart disease than other cultures. One is under-reporting and misdiagnosis. The second is the alleged health benefits of drinking larger quantities of red wine. A third is generally higher alcohol consumption overall.\n\nIf you're actually speaking about obesity rates, not coronary disease, it probably has to do with overall food intake, less snacking, less reliance on processed and industrially-cooked foods, more frequent market shopping, greater integration of markets into residential areas, using fresher, locally produced ingredients, farmers/herders who emphasize quality instead of perishability or volume, and above all, *portion control*. What Americans would consider to be a typical serving size would usually be just about right for two people in Paris or Lyon. ",
"As a chef I can say for two reasons. First are the portion sizes, a lot smaller than American plates. Secondly, a more natural diet. Less processed foods and fewer chemicals in their food. ",
"Michael Pollan discusses this in 'In Defence of Food' (forgive me for the popularist citation). He suggests that it's a combination of portion size, a preference for unprocessed ingredients, and a culture that advocates leisurely consumption of food in the context of social interaction, rather than scarfing down fuel. ",
"The so-called \"French paradox\" is not actually about obesity, but about the culture's much lower levels of coronary disease. The term was coined by a French scientist at Bordeaux U. \n\nThere are a number of proposed reasons why the French appear to have a significantly smaller incidence of heart disease than other cultures. One is under-reporting and misdiagnosis. The second is the alleged health benefits of drinking larger quantities of red wine. A third is generally higher alcohol consumption overall.\n\nIf you're actually speaking about obesity rates, not coronary disease, it probably has to do with overall food intake, less snacking, less reliance on processed and industrially-cooked foods, more frequent market shopping, greater integration of markets into residential areas, using fresher, locally produced ingredients, farmers/herders who emphasize quality instead of perishability or volume, and above all, *portion control*. What Americans would consider to be a typical serving size would usually be just about right for two people in Paris or Lyon. "
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2o956z | Sword vs spear combat | What is the view on historical developments in combat when using swords vs spears? The Romans famously used swords and defeated spear- (or pike-) using Greeks, but that to me seems to be the exception rather than the norm; is that correct? Are there cultures (La Tene?) that switched from primarily using swords to spears, or vice versa, why, and what was the effect?
Finally, what would be good books to consult for history on individual soldier, rather than army level, warfare? | AskHistorians | http://www.reddit.com/r/AskHistorians/comments/2o956z/sword_vs_spear_combat/ | {
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"The spear, pike, halberd, when not used in a phalanx are typically best suited against cavalry/horse based combatants. The typical Roman foot soldier (legionnaire) would be using either gladius or spatha, in conjunction with a scutum, which was a devestating combination that not only enabled great versatility in melee combat, but also against ranged (especially when implementing formations like the Testudo).\n\nNow, the Greeks, as you mentioned, used a shield more similar to the Parma (I don't know if it has a unique name, if it does, I can't recall it), which while wide, did not offer the mobility and formative nature of the Scutum. And while they did use weapons like the Xiphos, it was secondary to the Dory, a long, thrusting spear. Great if your opponent is further away, but quite the liability in close quarters.\n\nThe point I'm trying to make is that it may be less about the sword vs. spear debate in the Romans vs. Greeks that you put forward, and more, shield vs. shield.\n\nSpears would long have a place in warfare, but you cannot have an army made up exclusively of them, same goes for sword and ranged.\n\nSome sources for historical warfare and weaponry.\n\nA good little website for quick references, I've found their stuff to be accurate and best of all, free\n_URL_0_ \n\n_URL_6_\n\nRequired reading:\n\nPeter Connolly - Greece and Rome at War (1981)\n\n_URL_5_ \n\nMost of my knowledge on Roman and Greek warfare and weaponry has come from this book. ~~I've attached an Amazon link for the book~~, and you may want to hop(lite) on it as I'm not sure if it is still in print.\n\nPeter Connolly is a great author, and has produced numerous books, across a variety of topics, but his main focus was Greco-Roman history.\n\n_URL_3_\n\nThe Cambridge History of Greek and Roman Warfare\n_URL_2_\n\nNow, the above book is expensive. Like college textbook expensive, but it really is comprehensive and is directly related to the topic at hand. I can't think of a better resource out there. Obvious Cassius Dio has a wealth of knowledge in there, but it covers far more than combat, and is more useful as a source on the politics.\n\nI tried to google a cheaper alternative and found _URL_4_ \n\nI haven't read it myself, but it has received positive response, and it sounds like there is a heavily illustrated one out there as well.\n\nEDIT: Forgot about the Amazon rule, apologies. Removed the link and changed it to an openlibrary link. To those interested though, Greece and Rome at War is available on _URL_1_ and is worth picking up.\n"
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"http://en.wikipedia.org/wiki/Peter_Connolly",
"http://www.amazon.com/Warfare-Classical-World-... | |
yzyoa | Is there any evidence about why "mood lighting" (dimmer lighting) makes people feel sexy or "in the mood"? | I am looking more for the reasons as to why it has that affect on people. Is it a learned behavior in that you learn to associate dim lights with romantic moods, such as in a nice fancy restaurant with dim lighting? If so, what started it?
The best thing I can think of is that the dimmer lights also has the effect on hiding blemishes/imperfections in people's bodies, but I doubt that is the only reason why it works. | askscience | http://www.reddit.com/r/askscience/comments/yzyoa/is_there_any_evidence_about_why_mood_lighting/ | {
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"It's all about the dilated pupils.\n\nYour pupils dilate when you are interested in something or someone. This results in us subconsciously interpreting someone else's dilated pupils to indicate interest in us.\n\nYou lower the light, the pupils dilate, and your subconscious does the rest.\n"
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1udhuv | what's the difference between the labour party and the liberal democrats in the uk? | I'm an American, and I was wondering what the difference was between the two parties. From a wikipedia standpoint, they seem similar - both being more progressive than the Conservatives. Also, in votes, do the two parties usually vote together? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1udhuv/eli5_whats_the_difference_between_the_labour/ | {
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"The Labour Party's ideological tradition is democratic socialism, i.e. the establishment of state ownership of the means of production and the abolition of capitalism by democratic means, but they have moderated that stand somewhat with \"New Labour's\" so-called \"third way,\" which was adopted to regain popularity after the fall of Communism made democratic socialism look like a bad idea. Now, they basically support a \"mixed economy\" that is essentially free-market in nature with heavy government intervention.\n\nThe Liberal Democrats' ideological heritage comes mainly from the old Liberal (or Whig) Party, which endorsed *classical liberalism* in the 1800s: free trade, laissez-faire, universal suffrage, and personal freedom. However, the Liberal Party gradually became more socialistic, and eventually merged with the Social Democrats, who split off from the Labour Party in the late 70s when it was still highly socialistic and committed to a policy of wide-ranging nationalization. Thus, they adopted a stance that was less interventionist than \"Old Labour\" but still more interventionist than the classical liberals.\n\nThe Conservatives (or Tories) have also changed radically from their pre-20th century views. Under Margaret Thatcher, they gained prominence by adopting many policies that would have been more in line with the 19th century Liberals, moving toward a (relatively) more pro-capitalist, pro-laissez-faire approach. In fact, Thatcher even claimed William Gladstone (the famous pro-laissez-faire Liberal Prime Minister of the 19th century) as a role model and claimed that he would have been a Tory had he lived in her era (whether that is true or not is beside the point).\n\nThe Liberal Democrats are currently in coalition with the Conservatives. Both parties are dominated by an economic view that basically supports a mixed economy with somewhat less government intervention than Labour wants (there are some factions in the Conservatives that want rather purer capitalism and some factions in the Lib-Dems that are more socialistic). David Cameron is certainly not as in favor of economic liberty as was Thatcher.\n\nThe main difference between the two is that the Liberal Democrats are (or are supposed to be, anyway) more in favor of individual freedoms in the personal sphere. The Conservatives still have a great deal of influence from the socially conservative wing that is more in favor of cracking down on drugs, pornography, homosexuality, etc. The Liberal Democrats are supposed to be balancing that out. Also, the Liberal Democrats are rather more pro-EU than many Conservatives, many of whom are anti-EU altogether and especially anti-immigrant.\n\nAs for whether Labour or the Liberal Democrats is more \"progressive\" than the other or than the Conservatives, that depends entirely on what you mean by that term. Labour is more in favor of government intervention in the economy, but does not have a great record on privacy and individual social autonomy. The Liberal Democrats are generally more pro-capitalist than Labour (but not to the extent that the Liberals were), but tend to be more in favor of privacy and individual social autonomy."
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6hdwev | Are poor people more susceptible to religious conversion? | AskHistorians | https://www.reddit.com/r/AskHistorians/comments/6hdwev/are_poor_people_more_susceptible_to_religious/ | {
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"Hi there - you may have more luck asking this question, as phrased, in /r/asksocialscience - the present tense in the question suggests you are interested in this in general rather than through history, and so that might be a question for sociologists and social psychologists and the like. Alternatively, if you're interested in historical examples of this, I'd encourage you to resubmit this question with a more specific focus that would get at the specific historical events you're interested in - e.g., a question like \"were conversions to Christianity in the 1st and 2nd century largely poor people?\" is more obviously a question about history."
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mmoyi | Could you kill somebody by injecting a large pocket of air into their blood stream? | askscience | http://www.reddit.com/r/askscience/comments/mmoyi/could_you_kill_somebody_by_injecting_a_large/ | {
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"Yes, though the amount of air required is somewhat questionable. When air gets into the blood stream it's known as a gas embolism, and it's not uncommon for it to happen during surgery. Most of the time it's harmless, however if it's large enough it can disrupt blood flow from the heart which can obviously lead to death. Gas emboli can cause other problems like stroke and hypoxia which could theoretically kill you if bad enough, so technically that's another method of death by gas embolism. ",
"Yes, though the amount of air required is somewhat questionable. When air gets into the blood stream it's known as a gas embolism, and it's not uncommon for it to happen during surgery. Most of the time it's harmless, however if it's large enough it can disrupt blood flow from the heart which can obviously lead to death. Gas emboli can cause other problems like stroke and hypoxia which could theoretically kill you if bad enough, so technically that's another method of death by gas embolism. "
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sosof | Why is the body unable to regulate the growth of all cancer cells? | I know that cancerous cells are fairly common throughout the body and that the body is typically able to regulate them without things getting out of hand. So why, then, are we sometimes unable to regulate cancer cells within our bodies? | askscience | http://www.reddit.com/r/askscience/comments/sosof/why_is_the_body_unable_to_regulate_the_growth_of/ | {
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"When the body is unable to regulate cancerous cells, that's when cancer occurs. There are several fail-safe cellular devices that are meant to kill/nullify cancerous cells before they go hay-wire. For example, there are a few well known devices in the cell that are meant to trigger cell death in the case of cancerous growth. But, if those devices are rendered incapable, it is up to extraneous cells, and when those are rendered incapable, you've got the beginnings of cancer.\n\nEDIT: I guess I should expand. Issues with cancerous cell behavior is instigated by a number of mechanism failures. Whether this be by DNA damage (and thus mutation, which can happen from a number of causes, a commonly known one being radiation), unregulated oncogene experession, oxidative stress, etc., the cell will be growing in a dangerous manner. What makes it dangerous is the average size and division rate. p53 proteins are known as sort of 'genome guardians'--they can signal DNA repair proteins, trigger apoptosis (cell death), or simply arrest growth. However, they are still coded by genes. When their structure (and thus function) is compromised, this removes one of the primary barriers that prevents cancerous cell growth. "
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53q0rb | how does bell's experiment disprove local hidden variable theory | I have no academic relationship with physics so this might be a really stupid question. I apologize.
As far as I understand, randomness of polarization is a vital point of Bell's experiment. But if local hidden variable theory held, then the universe would (or could?) be completely deterministic, so polarization wouldn't really be random. Isn't this a loophole?
No need for an actual ELI5. I'm fine with ELI20. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/53q0rb/eli5how_does_bells_experiment_disprove_local/ | {
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"Indeed, to deal with one particular loophole these tests you need to be able to choose which measurements you're going to do on your particles (for example, what directions you'll be measuring polarization relative to), and you need to do it such that each of your particles can't get information about your measurement choice for the other. So, for example, in [this experiment](_URL_0_) they randomly and quickly set what measurements they'll do right before measuring, and they do this independently at the two detectors that are more than a kilometer apart.\n\nSo sure, if you think that the universe is completely deterministic and what measurements you will do and their outcomes are predetermined, then your entangled particles would have their values determined in advance by definition. How you would test this idea, I'm not sure, and it doesn't really let you predict anything, so as a scientific explanation it's not super satisfying to a lot of people.\n\nWhat Bell's test shows is that, *assuming that making a random choice is possible,* you cannot explain the experimental results with a local hidden variable theory."
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1d1t4x | how do facebook "meme" pages get revenue from 'likes' and 'shares'? | I understand how businesses get revenue from their Facebook pages (since it is more or less advertising), but for pages that only post memes or are for a 'cause' (such as the recent "R.I.P. For Boston Massacre Victims" page being for sale for $1000), how do they get worth? How does thousands of people liking and sharing their half-assed picture get them any money? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1d1t4x/eli5_how_do_facebook_meme_pages_get_revenue_from/ | {
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"They don't, but if someone buys the page they can then post a status and get something in front of all of those people who liked it, and thats valuable to some people. "
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1y662t | What do we know about the Natives of South Western Pennsylvania pre European settlement? | I know the people after Europeans arrived consisted of the Lenape, Shawnee, Iroquois and that the people that were hear prior are typically referred to as the Monogahela people.
My understanding is that when settlers arrive these people were gone and no one really knows why, some speculate disease arrived before settlers there or other tribes ran them out or absorbed them.
Does anyone know if we know much else? Being from the area I've had an interest in the people that were there before me, especially since we occasionally find flint not native to the area and in some cases arrow heads and tools. | AskHistorians | http://www.reddit.com/r/AskHistorians/comments/1y662t/what_do_we_know_about_the_natives_of_south/ | {
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"text": [
"\"Circular Villages of the Monongahela Tradition\" by Bernard Means is a 2007 is a good overview of this poorly understood culture. Bernard Means also publishes extensively in specialized archaeology journals, so if you have access to J-STOR, you will find a treasure trove of information about the Monongahela Culture, written by him. \n Mary Butler wrote several articles about the WPA funded excavations of Monongahela sites, during the 1930s. Some of the sites they worked on in or near Meyersdale PA were visited again, more recently, when US 219 was being turned into four-lane highway that bypassed Meyersdale. Penn DOT published a book for grade school children that is a good introduction to the Monongahela Culture, based on what was found during the US 219 project at Meyersdale. \n_URL_0_ \n This web-site goes into great detail about the most interesting, late Monongahela site. Foley Farm has evidence of glass beads, showing that between 1600 and 1635 AD, the Monongahela Culture had indirect contact with Europeans and that French and Dutch glass beads were finding their way into Monongahela Culture sites, more than 100 years before any written sources described the region. Conrad Weiser, in 1748, was the first Englishman to write about his travels in western PA and the Monongahela Culture was long gone by then. ",
"In addition to the sources davratta suggested (thanks for that, btw. Added *Circular Villages* to my Amazon wishlist and have a library copy on the way), I thought I'd summarize some additional information. Just to keep things simple for now, I'll only be focusing on the Monongahela culture. If we wanted to we could go *way* back in time for a discussion of human history in southwestern Pennsylvania, which has one of the oldest archaeological sites on the continent.\n\nThe average Monongahela town might be home to 75-150 people, living in houses arranged (as you might have guessed from the title of Means' book) in a circular pattern. Their homes were usual circular as well and about 20 feet in diameter, occasionally with \"petal-like\" rooms adjoining the main central room. These side rooms seem to have been for storage mainly or possibly for family sweat-houses. However, in at least one Monongahela town, the houses were rectangular, ranging from 8x16 feet to 20x30 feet. At another site, a large 30-foot diameter circular building was found, possibly a council house, religious structure, or both. Their towns were almost always surrounded by a palisade wall.\n\nThe center of the town was an open plaza, around which all the homes were placed. These plazas seem to have been kept clean and were likely swept clear of debris regularly. A central fire seems to have burn in this plaza in some Monongahela towns, while others seem to have had a pole. A pole in the middle of a central plaza is a trait they shared with their Fort Ancient neighbors to the west and the Mississippian cultures with whom they were contemporaries. The Monongahela also seem to have picked up the chunkey game from the Mississippians, while the Fort Ancients didn't.\n\nThe Monongahela were heavily dependent on maize agriculture, with other crops like beans and squash being a comparatively small part of their diet. Like many other Eastern Woodland cultures, the Monongahela stored their crops in pits that were protected from the elements by a bark-and-grass lining. These were found within homes, in side rooms, or elsewhere in town. They also gathered wild plants and hunted--though some sites on the Monongahela River itself seem to have relied very little on hunting in favor of fishing. \n\nAs for their \"disappearance,\" European diseases are thought to have played a part but their not the sole cause. Their heavily reliance on maize, coupled with several years for drought conditions, has also been implicated. Weakened by disease and short on supplies, they were easy targets for the more powerful Seneca. Under pressure from the Seneca, the Monongahela dispersed and were absorbed into neighboring nations (including the Seneca).\n\nThe Monongahela are often identified as an Iroquoian-speaking nation. If so, it seems likely that their the same people as the historic Massawomecks--an Algonquian name for an Iroquoian-speaking people that frequently raided the Chesapeake Bay in the early 1600s, coming across the Appalachians and down the Potomac. The the Monongahela, the Massawomeck appear to have been an important link in the exchange of goods from Chesapeake Bay (acquiring those goods through both raiding and trading). The Massawomecks disappear from history about the same time the Monongahela do from archaeology; the last contemporary mention of the Massawomecks is from 1634. Europeans did encounter the Massawomeck, first as enemies and later as trading partners. Early Massawomeck-European (usually English) trade took place at the Great Falls of the Potomac. From there, it was a 5-10 days' journey to the Massawomeck's homeland, a trip that a few Englishmen claim to have made. Of course, it's not as clear cut as I'm perhaps making it sound here. Several colonial accounts indicate that the Massawomeck lived on the Great Lakes and within or near France's claims to Canada. This might be the results of confusion regarding exactly how far away French Canada was from English Virginia and attempts to reconcile John Smith's early account of the Massawomeck living on a saltwater sea with later information. You can see where Smith originally thought the Massaswomeck's lived on [his map of Virginia](_URL_1_), in the upper right hand corner. He put a large body of water right were the Appalachian Mountains are. He would later have this error pointed out to him by the Powhatans and correct it, but other colonial writers (notably Strachey) continued to repeat the mistake.\n\n**SOURCES**\n\n* Handbook of North American Indians, vol. 15: the Northeast\n* [The Disappearance of the Monongahela: Solved?](_URL_0_)\n* [The Massawomeck: Raiders and Traders Into the Chesapeake Bay in the Seventeenth Century](_URL_2_)"
]
} | [] | [] | [
[
"http://www.academia.edu/409895/Protohistoric_Monongahela_trade_relations_evidence_from_the_Foley_farm_phase_glass_beads"
],
[
"http://www.jstor.org/discover/10.2307/40914458?uid=3739256&uid=2&uid=4&sid=21103472793397",
"http://upload.wikimedia.org/wikipedia/commons/5/5e/Capt_John_Smit... | |
hq2kf | Why are jokes less funny when you've already heard them?
| askscience | http://www.reddit.com/r/askscience/comments/hq2kf/why_are_jokes_less_funny_when_youve_already_heard/ | {
"a_id": [
"c1xepm1",
"c1xfsbr"
],
"score": [
12,
3
],
"text": [
"Part of what makes jokes funny is the element of the unexpected, usually in the punchline. Once you've heard it, it's no longer surprising. /opinion",
"Jokes are a puzzle to be solved or an idea to be completed.\n\n\"Two guys walked into a bar, the third one ducked.\"\n\nIn order to understand the joke, your brain imagines what's going on.\n \nThree guys walking into a tavern, but that doesn't make any sense. Why did the third one duck? ahh, it's the other term for a bar. A horizontal object. 2 guys were walking along and smacked their heads, while the third one managed to duck and avoid it in the first place. \n\nThe dilemma is resolved and the story is understood. \nAs soon as you make this connection, you have solved a problem and the brains reward center hits you with a shot of dopamine for solving this mental puzzle. \n\nThe next time you hear the joke, there's nothing to solve. You just recall what they were saying. So, no joy from the reward center.\n\nThis is only part of the answer though as humor is more complex then just puzzle solving, but it is a large part of it."
]
} | [] | [] | [
[],
[]
] | ||
71sgaz | Why does the spin of a Black Hole affect how it looks? | I was reading another post on here about black holes and Interstellar, and stumbled on [this](
_URL_0_) article. There is a difference between how a non-spinning black hole looks and how a spinning black hole looks. No matter whether it's spinning, the black hole still has the same density and gravity right? If so, how come it bends the light differently in both instances? | askscience | https://www.reddit.com/r/askscience/comments/71sgaz/why_does_the_spin_of_a_black_hole_affect_how_it/ | {
"a_id": [
"dnegq9b"
],
"score": [
8
],
"text": [
"It is not really appropriate to say density since it is a singularity but yes they should both have the same mass. However I think it has to do with the fact that spinning black holes twist spacetime with it's rotation. In short it creates an area outside the event horizon called the ergosphere which can do work on passing objects. As i have understood it, the faster a black hole is spinning the closer an accreation disc can come to it. I would guess that this twisted spacetime(look up frame dragging) is what also changes the passing of light around it."
]
} | [] | [
"http://iopscience.iop.org/article/10.1088/0264-9381/32/6/065001/pdf"
] | [
[]
] |
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