Subset (10)

eli5 · 25k rows

Split (1)

train · 25k rows

query stringlengths 20 300	positive listlengths 1 1	negative listlengths 1 1
How they colorize old black and white footage	[ "The process of colorizing old footage is very tedious. Unless the color footage already exists the animators have to color each frame of video. A second of video contains approximately 23 frames. When the movie needs to be colored, all of the frames of the movie are extracted. Each frame of the movie is then color...	[ "They use this - _URL_1_ It records all of the major news channels and indexes the closed captioning data so that it's searchable. _URL_0_" ]
What is the evolutionary advantage of grief?	[ "While you're likely to get a wide array of convincing answers to your question I'll simply ask that you take them with a grain of salt. Evolutionary psychology is a field fraught with conjecture. Not everything that exists is adaptation (see neutral evolution). In any case, were grief an adaptation, any explana...	[ "No expert, but I would think that it keeps us from eating things that are bad for us more often than it keeps us from eating things we need." ]
How are half-lifes so mathematically consistent (universally accurate	[ "The formula was designed to fit the data obtained from testing and experimentation. THAT is the reason the formula fits." ]	[ "Custom and practice. If you build it and it falls down, you do it again differently. When it works, you keep it like that. That, and people weren't stupid or uneducated - the Greeks were fairly capable mathematicians, as were the Egyptians" ]
Adjusted to modern currency, the Dutch East India Company was worth $7.4 trillion in the 17th century. When ceasing operations in 1800, where did all the money go?	[ "I think this question is not exactly historical more economic. Imagine a similar situation, you buy a brand new car for £10,000. Eight years later you realise that it is no longer fit for use, and so try to sell it. Finding no buyers you scrap the clunker. Did £10,000 just disappear? No you got eight years of qual...	[ "The exponents are typically called \"share weights\" because they are the share of income that the consumer will spend on that good. So if u(x,y)=(x\\^a)\\*(y\\^b), the consumer will spend a/(a+b) of her income on good x and b/(a+b) of her income on good y. What that means in practice is that in a Cobb-Douglas wo...
Friday Free-for-All \| January 22, 2016	[ "I'm presenting my first paper at a legit conference this Sunday! Wish me luck!" ]	[ "Hi there, I've approved this question but you may want to reword it so the question is actually in the title. Most of our flaired users have alerts set up that search titles for keywords, that one isn't going to get you anywhere unfortunately :-)." ]
Why is it legal for big companies to evade taxes?	[ "It is illegal to evade taxes, but it is legal to avoid them. If a law says you can do X and you do it and that results in you paying less tax, that is avoiding taxation. If it says X and you don't do that, that's evading." ]	[ "It's pretty straightforward. A lot of the really bad ones, the men in charge, were able to amass personal fortunes either during the war or before. As things started to collapse for the Reich, they made preparations to flee. Fake documents, hidden stores of cash. They've been living under false names in South Am...
Why do the majority of terrorist organisations in the news seem to be Muslim?	[ "Because most of the terrorist groups operating today are Muslims. Terrorism, or, more correctly, asymmetric warfare, is really the only viable military strategy for impoverished and disenfranchised small groups, particularly when facing larger nation states. Today, most of the groups who fit that box are Musli...	[ "\"Just about everyone here\" Where is \"here\" for you? It sounds like your question's premise is based on a small sample set based on personal observation. Before your question is addressed, you should be making sure the premise is valid..." ]
Online Multiplayer Gaming. How does that work!?	[ "Depends on the way the online stuff is done. It's either server side calculations, where you pressing the button sends a message to the server along the lines of \"hey he pressed shoot, tell me what happened please\" or client side which is \"hey he pressed a button so I figure the bullet went here and hit that gu...	[ "You have a bunch of satellites in space, sending signals that say, \"My clocks says 5:00:00.123\", \"My clock says 5:00:00.124\", over and over again. Your GPS measures the differences it takes for the signals to reach it. If it receives one second a thousandth of a second sooner, it knows that satellite is about ...
In medieval chivalric romances, Christian and Muslim knights often encounter each other while wandering about on horseback. Is this a recollection of the pre-Carolingian era, when the Umayyad Caliphate extended into southern Gaul?	[ "Chivalric romances often played fast and loose with who was and wasn't Muslim. The most famous example of this is the Song of Roland, where the author claims Roland's rearguard was killed by Moors when in fact they were Basques." ]	[ "It's accidental in the SM given the field content---when you write down all allowed terms in the Lagrangian for the quark sector, you can get rid of all but one unitary matrix, the CKM matrix. You can put CKM in the mass matrix so gauge interactions are diagonal (this is the 'flavor basis') or in the gauge interac...
Why are houses in older communities so spaced out in age, compared to newer neighborhoods?(US)	[ "Most neighborhoods built after the 1950s, ie subdivisions in the suburbs, are built all at once. Meaning they will all be built within a year of each other and use 1-5 building plans. Homes built in cities or on privately owned lots outside the city limits that are not a part of a subdivision are built as the owne...	[ "Each builder is going to do what they want. Google pictures of Beijing some time, they have entire large blocks of buildings the same style and height. They also are far more regulated about how they build. I imagine in a more free market economy, each builder wants their building to be \"their building\" and not ...
If neutrons have no charge, why are they part of a nucleus at all?	[ "The atomic nucleus is held together by the strong nuclear force. The electromagnetic force is a different force." ]	[ "Inflatable beach balls are mostly empty space, too. The thing is, light bounces off the outside surface of the beach ball and back into our eyes, just like it bounces off the electrons around an atom's nucleus." ]
Did any religion consider the chicken sacred?	[ "Puranik Hinduism ( the one mostly in practice today in India ) does have a tiny bit of importance attached to chickens in an aspect of it. A goddess called “Bahuchara.” - an avatar of Shakti - is said to have a rooster as her vehicle. Edit: you are mistaken, Hinduism considers a lot of animals holy. Horse for exa...	[ "Some do, like the [Maasai](_URL_1_) who have a method of drawing blood from a cow without killing it There are also dishes made from blood, like [Black Pudding](_URL_0_)" ]
Why was Chris Kyle so special?	[ "Chris Kyle once used his beard as nest for the eggs of a mother Bald Eagle he took care of after she injured a wing during a firefight in Operation Iraqi Freedom." ]	[ "You answered your own question. Influential people often get streets named after them. There are streets named after JFK, Washington, and Lincoln to name a few in many large towns as well." ]
Why are people so upset about the 9/11 mattress sale, while Memorial Day sales are considered ok?	[ "Memorial Day is a traditional holiday that's been around for about 150 years. Many Americans do take the opportunity to remember fallen veterans, but the event usually is not tied to any specific event in history. I anticipate that most Americans are familiar with the holiday and its general meaning, but not its s...	[ "One thing to point out is the terrain. Iraq is in the populous parts of the country pretty flat, with a semi good road network across the country making it easy to move people around, and larger cities and towns to organize around. Afghanistan is some of the most inhospitable terrain on earth. With little nation...
Why did Bitcoins end up being worth so much?	[ "Bitcoins is a currency that cannot be taxed by governments. Shady people used them to transfer huge amounts of money. Since they were used, they became popular and therefore increased in value." ]	[ "This CGP Grey video does a really good job of explaining it all. _URL_3_" ]
How did the moral codes and values of the Mesopotamian, Egyptian, Assyrian peoples differ? How were they similar?	[ "This is a really broad question that covers a huge geographical area and thousands of years of history. Also, Mesopotamian is a general category that includes Assyrian (and Sumerian, Babylonian, Persian, and a bunch of others.) Maybe you could narrow it down a bit--is there a specific issue you're interested in?...	[ "The only archaeological evidence for a trade link between the Aztecs and what is now the USA is found along the \"Turquoise Trail\" in New Mexico. Products from Meso America, like bright tropical bird feathers, were preserved at a few sites in New Mexico and Arizona. This area was also the source of the bright blu...
Why does one ear stop working on every pair of headphones I get a few months after getting them?	[ "This is often caused by a wire getting frayed. You can fix this by buying headphones with a replaceable cord. That way when the cord wears out, you can simply replace it. If you know how to solder, you can easily repair the cord on your old headphones yourself." ]	[ "You could have [tinnitus](_URL_0_). You should see a doctor if you want any further information, since asking for medical advice is not allowed in this forum." ]
Why does my chest/heart hurt when I drink alcohol?	[ "Yes, I would generally advise seeing a doctor for sharp chest pain that is severe enough to interfere with your life." ]	[ "Acid reflux is my best guess .some rennies or milk of magnesium somethink to that like should help until you see a doctor. Trust me from experience u dont want to ignore it so much easier to deal with before the acid does damage . I posted a reply on a thread recently that covered my story with reflux ..." ]
Why was and, to a certain extent, is Chinese porcelain so popular?	[ "For centuries the best porcelain in the world was made in China, due to their advanced technology (at the time). Fine Chinese porcelain (or \"fine china\" for short) was lighter, thinner, more delicate and flawless than other types." ]	[ "Simply put, it is the most effective at what it does. This is sort of like how we use (potentially) deadly poison's for anesthesia. There are other potential options (botox for cosmetic surgery is basically a paralyzing agent), but none last as long and work as efficiently, so we don't use them. With anesthesia t...
What is a neuterino and how might it be used to kill someone?	[ "A neutrino is a really tiny fast moving particle that interacts with protons and neutrons. They are produced during nuclear decay, fusion in the sun, and in supernovae. I'm not sure why you want to use one to kill someone despite not knowing what they are, but you couldn't use a neutrino to kill someone because th...	[ "It's difficult to say, because neutron star cores are in a regime (high pressure, low temperature) that is difficult to produce experimentally. Cole Miller at UMD has a nice [page](_URL_0_) on neutron star interiors. I enjoyed the following description of the transition from crust to core: > As the density increa...
Why is nuclear fuel used to generate steam for electricity is it not possible to directly use nuclear energy?	[ "You can use the thermoelectric effect to directly convert heat to electricity, without the steam turbine, but it would be less efficient. Satellites/Space Probes use this method because they can't afford the mass of the turbine." ]	[ "Imagine you have a computer on your house. Now you want to connect that computer to your friend 100 miles away. How do you do it? You could lay a 100 mile cable, but do you have the permissions to dig up roads and pathways? You would use a company whose cables were already there, and just use that network of cab...
I understand how much you are supposed to tip in the USA, but how exactly do the transactions happen?	[ "At a restaurant you generally leave the money with the bill and then you can walk out, so you want exact change as often as possible. If you don't have it you can specify 'just give a $10 back' or whatever, or can get all your change then leave your tip on the table and clear out. For cabs it's generally just a ca...	[ "When you say cutscenes, do you mean like how they switch from the action of a guy chopping salad, to the same guy in a chair going \"I felt terrible when I messed up the salad\"? Those are recorded after actual show's events complete, they sit down and ask the person TONNNNNS of questions, so they have lots of res...
Why don't engines create max hp at max rpm?	[ "Horsepower is a measure of work which is force over time. Assuming that each cylinder produces the same amount of force every 4 stroke cycle, the more cycles you can pack into a given amount of time, the more work. So your gut feel is mostly correct. Because the rpm keeps increasing, but the cylinders are still pr...	[ "Brains easily perform many, many tasks hat are difficult for computer. Take that we know brains are optimized for pattern-finding. Consider intelligent life forms have to interact with a real 3-world and real time. Which means they can check their expectations. Testings a supposition is as simple as rotating an o...
Why does smoking marijuana make you hungry?	[ "Your body actually has nerve pathways dedicated to cannabinoids, and weed contains a lot of these (most famously THC). A lot is left to be discovered about these pathways, since the first cannabinoid your body produces on its own wasn't found until 1992. As researchers best understand it currently, activating on...	[ "Your field of vision is shaped like a cone, which gets wider the farther away something is. The higher you are, the bigger the area of 'ground ' you see is, so the farther it has to move to be noticeable. Close to the ground, the movement is much more dramatic, so your brain interprets it as a higher speed. It's ...
how instinctive knowledge and behaviour is passed through genes, as opposed to learnt behaviour. Eg. A kitten is put into isolation from day one, yet still scuffs at the floor when pooping.	[ "Brains develop, much like all organs, from the control of genes. During development, neurons use various methods of signalling to \"make\" certain parts of the brain essesntially \"hard-wired\" for a behavioural tendency, which in turn can ~~illicit~~ elicit (too much crime reading haha, thank you!) a physiologi...	[ "The fossil record: we can look at the bones of animals that died a long time ago, and do special tests to tell us when they died. We can put this together to tell us what an animal, or its ancestor, looked like a long time ago. So far, they have shown up in the correct order. Speciation: say birds are blow...
Do birds and other animals with UV vision see the sky as violet instead of blue?	[ "Consider for a moment that ultraviolet is its own range of electromagnetic radiation. It is not violet. How an animal with cones that can detect UV waves sees it is likely not going to see it as what we would call \"violet.\" That said, we can't know what UV radiation actually looks like to these creatures because...	[ "I think to best answer this question one should first take a moment and think about the life cycle of plants, how they disperse, and what a seedling needs to survive. Fats are an excellent source of stored energy. Many seeds are very rich in fats/oils which are used as storage energy for the embryo within the seed...
How do scientists handle the statistical inaccuracies, record-keeping issues, and general problem regarding the mistmatched number of days in a leap year to a regular year?	[ "Leap time is to prevent the equinoxes from moving around in the calendar. When I worked in the space sciences, we just used seconds. Sometimes we used [Julian Days](_URL_0_)." ]	[ "Go to a new area of Australia (or wherever). Comb one acre very carefully, cataloging every species. Figure out how many new species there are. Do this in a few different places, figure out about how many new species there are in general, and extrapolate." ]
What does "camera exposure" mean? What do people mean when they say that a picture of a star/planet is "19 hours exposure"?	[ "It is referring to how long it took to take the photo Leaving the shutters open longer lets in more light for detailed pictures of such objects" ]	[ "Two things happen when you move from a bright space into a really dark space 1. Your pupil opens up which allows more light to enter your eye. If you enter a really dark space your pupil will open to full diameter 2. Rhodopsin starts to return to normal in the rods in your eyes. Rhodopsin is what actually detects ...
If gravity warps space, how flexible is space?	[ "The elasticity of space can be understood in terms of gravitational radiation: when two massive bodies are orbiting close to each other, there are little elastic ripples in the geometry of space. How little? If there were two solar mass objects orbiting each other and almost touching, where the sun is right now, t...	[ "Galaxies don't have them because they are not point sources; that is, they are large enough to be resolved by the telescope on the sky, while stars are too small for the telescope to resolve. As a result, the stars have the shape of the [point spread function](_URL_0_) of the instrument. The galaxies are also conv...
How do you meditate?	[ "Well, there's a lot of different types of mediation, but the form most people think of is mindfulness. Basically, you just think about one thing. Normally it's just focusing on breathing and posture, and refocusing on the breath/balance whenever you get distracted. You also can meditate upon a single word, a sylla...	[ "This video from Sagan will help. I couldn't explain it in a better way. _URL_0_" ]
Why don't teeth grow and/or repair themselves?	[ "Some work has been done in this field, and here is some more information regarding that work. _URL_2_ _URL_0_ _URL_1_" ]	[ "Every time you make a copy of a cell, there is a chance for errors. For example when you photocopy a first print, it is pretty crisp and close to the original, but there are a few minor discrepencies. Now if you photocopy the copy, it gets more distorted, and so on until some letters get hard to read, it gets diff...
Did Kings' courts really have a court jesters? Did they dress and act they way popular culture perceives them to have?	[ "A lot of courts during the royal English history had \"Professional entertainers\" called fools. Clowns and jesters were often referenced in Shakespeare's plays. They often were respected highly. They could not say anything to the king, Archibald Armstrong was thrown out of employment after insulting to many major...	[ "I don't have a lot to add to my already linked answers in the faq, but the two key questions here are: 1. What counts as \"hard evidence\"? Is hard evidence better than other kinds of evidence? Should we only formulate beliefs based on hard evidence? This is a set of epistemological and methodological questions no...
The Nuremberg Trials and how "Following Orders" isn't a valid defense.	[ "To start with Nuremberg only dealt with the highest ranking Nazi Party officials & military leaders - people in positions of great power. People like Hans would have been picked up in one of the smaller post-war trials, if at all. In the vast majority of cases, it was only people in leadership positions that were ...	[ "People care less about obeying rules when they are about to die. At this point what do they have to lose? Did Jerry over in cell D12 make a rude comment about your mother? Maybe Jerry should get stabbed 12 times with a sharpened tooth brush. What are the guards going to do about it? Kill you? lol!" ]
Where does Google maps get its traffic data from? How is it always up-to-date?	[ "They crowdsource it. They are using data from any Android user who has not opted out of giving traffic data. Here's their explanation: _URL_0_" ]	[ "Money. They just pay into the local economy and get to shoot there. The city area will get notified in advance. City workers help close off the area needed while filming as everyone flocks to watch the filming happen. Win win for all." ]
How are we able to isolate individual sounds and filter out the rest?	[ "What you're talking about is attention; I haven't done much research on auditory attention, but in visual attention, when you focus on one aspect of an image like this (a colour or feature), you're altering neurons sensitive to that aspect so that they are easier to excite, while inhibiting neurons which don't hav...	[ "I would suspect something like binaural recording would come into play. You can listen to the results here: _URL_0_" ]
What is the common reason that ancient Rome and Greece's 'democracy' failed?	[ "Could you define more narrowly what you mean by 'democracy' (as Rome was never actually a democracy) and in what way those democracies 'failed'? The question as written is too vague to allow for an appropriate answer." ]	[ "This question is getting a lot of traffic after being [tweeted by @reddit](_URL_5_), so I thought I'd welcome those of you that haven't visited /r/AskHistorians before to the subreddit. Please do bear in mind that in order to keep the quality of answers here high we have [strict rules on comments](/r/AskHistorians...
Why is wearing American flag clothing on the Cinco de Mayo wrong/controversial?	[ "You are thinking about one high school in California. It has not been banned publicly anywhere else. It was banned at this high school because there was a history of racist violent outbursts at the school between whites and Mexicans." ]	[ "Horse meat isn't rare at all. You can get it in many parts of europe. Tastes ok too. Anyway, that's culture. The same reason we think that bacon and eggs is a breakfast food, and don't eat grasshoppers." ]
Why does sleeping 8 hours at night feel much shorter than being awake for 8 hours?	[ "Most of the time you are asleep, your brain is in a sort of shutdown mode -- you are not even dreaming. So it is as if this time never happened; you aren't aware of anything during this time." ]	[ "The body can get energy from two sources (well 3, but since you are a kid I'll ignore alcohol. Also, I don't think that's stored in the body for any length of time anyway) fat and sugar. When you eat the body immediately starts using all that delicious sugar it got. After a while it starts running out of sugar an...
Why does pouring hot water (~80C) in a cup, sound so differently compared to cold water (~20C)?	[ "[Here](_URL_0_)'s a great video by Steve Mould on Tom Scott's channel which explains it. Essentialy it's because the viscosity (thickness) of water changes at different temperatures, changing how it splashes as it's poured." ]	[ "0 degrees Celsius is the temperature at which the solid and liquid phases of water are at equilibrium (at standard pressure). In other words, at exactly 0 degrees C, the solid and liquid phases coexist at equilibrium. If you increase the energy of the system, you shift the equilibrium towards the liquid phase, and...
Why do some sites require you to enter your age to confirm if you're an adult if it's so easily circumventable?	[ "It's a requirement by law that the website must attempt to discourage underage viewers but the site can't be held responsible for a viewer lying to the site about their age." ]	[ "Imma answer your question, but first let me tell you about this time I watered the lawn on a warm july afternoon, there were clouds in the sky and childrens laughter.... ok seriously, who knows, maybe they just like to hear themselves type, or create an emotional connection to the recipe, perhaps they are just kil...
Why is it now that parents blame teachers for their child's poor grades instead of the child?	[ "Self-serving bias. People attribute their successes to internal factors \"I did well on this test because I am smart\", but attribute their failures to external factors \"I failed because the creator included trick questions\". Adults do the same with their kids, because their kids are an extension of themselves. ...	[ "Your employer takes money out of your paycheck throughout the year to pay your local, state, and federal taxes. The amount they take out, however, is just an estimate how much tax you will probably owe at the end of the year. There's no way for the state, local, and federal governments to know what you actually do...
Why doesn't Greece want Europe to bail them out? Also, what made them be in so much debt in the first place?	[ "I think [John Green](_URL_0_) from vlogbrothers does a pretty good job of explaining it." ]	[ "Let’s say you and Billy were talking about a classmate named Eric who sometimes doesn’t do his homework. > Billy says, “I bet you Eric will miss a homework assignment this year.” > You say, “That’s not true!” > Billy says, “Oh yeah? Let’s bet on it. I’ll give you $1 for each day Eric does his homework. Bu...
Why do businesses in the US contest ex-employees unemployment? Are they liable for some of the payment? And if so, what proportion and for how long?	[ "There's a couple things at play. Why the employee left. 1) Voluntary separation (quit) = No unemployment benefits (many states). 2) Termination for cause (fired for violation of policy) = No unemployment payments (many states) 3) At-Will Termination / End of Contract Termination (lay-off) = Standard Unemployment B...	[ "I'm a journalist. I can tell you straight up : it's for audience. These videos create shock, which is the best hook television news has over the viewer. The whole ethics speech they'll give you about people having the right to see it is BS. Television is a business, news or not, sadly. This is even more true in th...
When are you legally allowed to hit someone in self-defense? Only after their first swing?	[ "It depends on a lot of things. You need to talk to a criminal defense lawyer or prosecutor in whatever jurisdiction you're in if you want the right answer." ]	[ "[Bleeding Kansas](_URL_3_) comes to mind. Essentially, while the 'free' states were just as numerous as the 'slave' states, meaning they had equal representation in the US Senate, the 'free' states had nearly double the population. So to ensure that neither side gained an advantage in the Senate, a number of measu...
Why don't energy drink companies use any other legal and safe stimulants apart from caffeine?	[ "Because caffeine is more addictive cheaper and safer in larger quantaties" ]	[ "It's way, way, WAY, too expensive. The power plant alone would probably be more expensive than the entire lifetime cost of an average bulk carrier. Not to mention the insane mess of regulation that is involved with running a nuclear reactor. Basically, big ships run on bunker fuel, and bunker fuel is ludicrously...
Why don't free TV live stream their channel with the advertisements?	[ "It's partly due to licensing issues and partly due to the cost of setting up the infrastructure. With regard to the latter issue, streaming a live event to many people simultaneously can be extremely costly. Unlike broadcast TV where one transmission is received by many people, with online streams you have to gen...	[ "[This video explains quite well how it works online, specifically Youtube](_URL_0_) TL;DW: Youtube only sends information about changes between frames of a video. Since there is usually very little difference between 2 frames the server can just say \"ehhh take what you had last time, shift this part a tiny bit th...
why are YouTube videos not available to My country (u.s)	[ "Copyright issues. One company might have copyright laws registered in the US, but not in, say, Russia. So Youtube might block that video in the US because the company can sue them for hosting the video in the US, but won't in other countries." ]	[ "Horse meat isn't rare at all. You can get it in many parts of europe. Tastes ok too. Anyway, that's culture. The same reason we think that bacon and eggs is a breakfast food, and don't eat grasshoppers." ]
When a star goes supernova, do any of their planets survive, and if yes, where do they go?	[ "Since no one has answered this in 13 hours, the answer is generally no. A supernova gives off a lot of energy and would likely breakup any planets in relatively close orbit. The further away from the star the more likely that it would survive in some way without being vaporized." ]	[ "The thing is, our understanding of NS natal kicks is very limited. By looking at the Halo, we model the velocity distribution of these kicks as a bimodal Maxwellian with means at ~80 km/s and ~120 km/s (iirc). However, when we look at the NS retention rate in globulars we see that it is way too high than what we w...
How do manufacturers make artificial flavors taste almost exactly like the real thing!?	[ "A chemical is a chemical. The source of it doesn't make it \"real\" or \"not real\". If there was a good tasting plant that derived its flavor from a complex of Fluorine, Uranium, Carbon, and Potassium, it would be no different than making that same complex in a chemical factory." ]	[ "They play the music at the same % as how fast they plan to sped up/slow down the video and have the singers lip-sync to that version." ]
Why did most politicians study law? Is it an implicit requirement?	[ "There are really three reasons generally given for this: 1.) Most of what a politician does is either helping to write laws or helping to enforce laws. Understanding how laws actually work and their history and theory is helpful in that endeavour. 2.) Because lawyers deal with the law all the time, they are more ...	[ "They have civil clubs and/or professional minor league systems that serve the role of fostering play and training talent. In the US colleges fill that role." ]
Search warrants and probable cause in the United States	[ "American citizens have legal protection from unwarranted or undue search and seizure. If the government doesn't have good reason to believe that you are doing something illegal, they have no right to invade your privacy. It's a protection afforded by the Constitution. A search warrant is a legal document signed by...	[ "I was told this was the case during WW1. Was it both wars?" ]
how it is economically viable for meat suppliers to the UK to use horse meat instead of beef?	[ "Horse bred for meat costs more than beef bred for meat, certainly. Nobody knows what horse has been put into the food chain though. The meat could well be from old animals that were bred for farmwork, for the police, or simply to trot around town centres giving rides to tourists. Indeed the fact that the meat's be...	[ "So, I don't know if you know this, but Blackstone did just what you are suggesting. After the housing crash of 2009, they went out and bought up homes in different cities. They put them all under the umbrella of a REIT (real estate investment trust) called \"Invitation Homes\" and then spun it out in an IPO a few...
Are cold symptoms from the virus or from your immune system?	[ "I wouldn't call the virus harmless, but yes, most of the symptoms are the result of your immune response against it. Generally speaking, it is thought that these immune-derived symptoms serve the purpose both of creating a favorable environment for the body to clear the infection as well as to encourage host behav...	[ "The temperature is, to put it simply (the actual definition(s) can get quite in-depth!), the average amount of energy the molecules have - in this case, it would be the air. At 37C, the air molecules have more energy than at 31C. Wind chill and humidity come in because they affect how well your body can regulate i...
Did the Dutch ever consider colonizing Australia?	[ "The Dutch efforts in establishing outposts in the region were organised by the Dutch East India Company. They controlled South Africa, Ceylon, Java, Taiwan among other places at some point. Their goal wasn't so much establishment of colonies but the establishment of trading lines. By the time, Australia was discov...	[ "Further question: how much did the Allies know about operation Valkyrie?" ]
How long will it take the world to run out of oil?	[ "Realistically, we will never truly run out of oil. As the \"easy\" sources of oil begin to run out, the price of oil goes up and new technology allows us to access more oil that was too expensive to get at before. At a certain price point it is actually feasible for us to create oil here on surface from raw mate...	[ "It depends on many factors: * Energy consumption rate * Body weight and fat * Age * Genetics * Many, many other ones" ]
Why if prostitution is illegal, hookers do not simply go through a motions of 'borrowing' money upfront and then pretending to want have sex afterwords?	[ "The legal loop hole I've seen is to hire the girl as a 'model' for nude photos. That way there is a legal excuse for a exchange of currency, and you can tell if the girl is an undercover cop if she doesn't agree to the 'photo session' before any talk of sex beings." ]	[ "So let's say I manufacture computer mouses. I need metal, plastics, lasers, and coding. We'll say I have all the other parts I need manufactured in house. So I trade computer mouses to miners for metal? And I pay my coder in mouses? Doesn't really work. Barter requires you to have the goods on hand that the person...
Why haven't we found a cure to cancer and is there any definitive explanation of how it started?	[ "Cancer is caused by a spontaneous mutation in a cell which cause it to divide uncontrollably. So every case of cancer is a new instance of the illness and may therefore have different cures. Most of the time the immune system can handle it but not always. We currently have several different cures like radiation th...	[ "When cells divide they make pretty much exact copies of themselves. Introduce radiation to the equation and the copying process goes screwy and the new cell is different. Rinse and repeat over and over and you end up with body cells which are completely different in shape size and function to what they were origin...
Why treadmills are bad for your knees? Or if this is a myth?	[ "Running is bad for your knees. The biomechanics of running on a treadmill are slightly different than running on the ground, but none of this is harder on your knees than running generally. In some cases, running on a treadmill is _better_ because it has a cushiony landing for you, reducing the impact to your join...	[ "Its the easiest way to get out of the kitchen for a 5 minute break." ]
Are dark energy and matter just factors entered to make equations work?	[ "What is an electron other than something we put in our models so that they match observations? I don't think there's really a distinction. Think about exoplanets. Some are detected because we see their host stars wobble. We know how gravity works, so we can determine that there is a planet orbiting the star. Dark ...	[ "This is a small complaint, but you don't have a theory about antimatter. You have a conjecture. I don't know enough about the topic to say if it has any possible credence or not, but a theory requires a lot more work than \"hmmm, maybe it's this!\" This is not supposed to discourage you wondering or asking, just h...
Are there new stars producing in universe and is this rate declining?	[ "According to the prevailing view of the universe's evolutionary future (which predicts that the universe will continue to expand and cool forever), the Stelliferous Era (the era during which stars will be able to form) will last at least until the universe is 1 trillion years old, and possibly until it's 100 trill...	[ "Fish researcher here: we make graphs of number of species discovered per year. The slope decreases over time. you then estimate how long until no more species will be discovered using the graph. Then add up all the data points. Its guess work, but the best we have" ]
Why didn't cavemen need money?	[ "Cavemen were gatherers and hunters and lived in very small groups. Their relationship was similar to nowadays families: you would fix your parents' computer and do chores for free and they will provide you with food and clothes for free, without thinking as it like a trade. Trade began when people already had dev...	[ "Hi OP, this is a cultural question, so it would greatly assist anyone considering answering if you could specify which culture you're asking about. For example, the name of a cultural group / country / geographic region, plus a rough time period. Otherwise, this question is simply too broad, as it encompasses almo...
Why don't we brush our teeth with warm water?	[ "Hot water brusher here - makes the bristles softer which is sometimes nice depending on your brush. Toilet paper still goes over though." ]	[ "I would like to have the vodka you are having. You dont swish vodka around in your mouth for 20 seconds." ]
How can a US citizen get dual citizenship in another country?	[ "Each country has their own rules. Some allow for dual citizenship - Ireland and Israel both do, I believe. Some don't, and they won't allow you to get theirs without giving up the old. The US is one example." ]	[ "Since my last answer was within the 20 year rule limit, there are other historical examples of triple agents that are somewhat well known, particularly within the period around the 2nd World War and early Cold War period. Eddie Chapman, [who worked simultaneously for the British and the Germans] (_URL_1_) and Kim ...
Is the lava from different volcanos around the world made out of the same material, or do different volcanos have diffetent lava composition?	[ "There are indeed several different types. Lava is classified in various ways, SiO2 content increases from Komatiite (ultra low), to basalt, andesite, dacite and rhyolite (high) ([example of SiO2-based classification](_URL_1_)). There are also more subtle geochemical signatures recognized by trace elements (Zr vs Y...	[ "Your cigarette lighter is burning liquid fuel that must be vaporized before it can mix with air and burn. That liquid fuel vaporizes more easily at high temperatures than at low temperatures. This is why it's harder to start a car engine when it's cold, and why engine block heaters solve the problem." ]
How did Biologists initially learn that you could live with only one kidney?	[ "It was known from 1690 that it was possible to survive on one kidney. Animal experiments in 1869 confirmed that dogs could survive deliberate removal of one kidney (nephrectomy), and the first human nephrectomy was performed shortly after. _URL_1_ Kidney disease was known to ancient Greeks (not just the course of ...	[ "We don't, we go by the most logical and most common accounts. If there is a fight with 10 people, and 6 of them all say the same thing and the evidence backs it up, then the other 4 saying it was aliens was probably wrong." ]
Will the continents eventually connect to recreate Pangea?	[ "Not Pangaea, but another supercontinent. There have been multiple supercontinents in the past and plate tectonics probably aren't stopping any time soon. Not all supercontinents consist of all 7 of today's continents, but there were still supercontinents before Pangaea that did. Pangaea is notable mostly for being...	[ "Here are a couple previous threads on the subject: * [How many years will it take until the entire human race is relatively uniform in skin colour?](_URL_0_) * [If all the races of the world continuously cross-bread with each other would we eventually get one composite race?](_URL_1_)" ]
How do objects get their "feeling"?	[ "When you drive, your wheels are always between you and the road. Does this mean that you do not move up and down with the road? (Negating the effects of your shocks) you will still feel the entire topography of the road as if you were in direct contact with it. To avoid confusion it is better not to look at the fo...	[ "Regular use of a metal knife won't cause any molecules or chunks of molecules to detach; the ionic bonds are generally strong enough to prevent this. Because there are relatively fewer molecules across at the edge of a blade, the material is more flexible and malleable, so repeated use can cause the edge to deflec...
What would happen to a helicopter that was hovering over a tall building if the building collapsed?	[ "Helicopters hovering in close proximity to the ground or other deck experience what is known as \"ground effect\", or an increased amount of lift resulting from the downdraft air cushion than would otherwise exist in free air. Pilots need to increase collective thrust in order to break out of ground effect and cli...	[ "Depends on the material and temperature. Sometimes the surface forms a reconstruction, as dreykevins explains. Other times the surface forms an oxide or some other surface layer, which can prevent recombination. Other times the pieces actually CAN be put back together, and this process is called \"cold welding\". ...
Why does the United States hate Russia so much?	[ "Russia's previous incarnation (the USSR) and the US spent ~40 years competing with each other for global influence which included: * Spying * Proxy Wars * Economic fuckery * Subverting each other's political system * lots of propaganda to their people in order to justify the above. Additionally, Russia actively pr...	[ "Greetings everyone. In the few minutes this sub has been up, it's attracting sub-standard responses. Just a reminder of a few of the rules: * no responses covering events/conditions post-1994, per this sub's \"20-year rule\" prohibiting discussion of current events * no anecdotes * no speculation OP: your question...
Why are so many people obsessed with Nicholas Cage?	[ "His face evokes a strong reaction. Part madman, part little boy lost, permanently indignant and sometimes melancholy on top of that." ]	[ "\"Just about everyone here\" Where is \"here\" for you? It sounds like your question's premise is based on a small sample set based on personal observation. Before your question is addressed, you should be making sure the premise is valid..." ]
Why is caffeine found in so many plants while other compounds like nicotine/cocaine/THC only come from a single source?	[ "Many plants fall under the Cannabaceae family and contain THC, much like many plants fall under the Nicotiana tabacum and contain Nicotine. You're probably used to just hearing the more popularized plants: Weed and Tobacco, which are very specific labels that can classify a broad spectrum of plants. The chemicals ...	[ "Humans react to human hormones, dogs react to dog hormones and cats react to cat hormones. Catnip mimics a cat pheromone." ]
In the Iliad, Bellerophon delivers a letter. Does this indicate during the period that writing was lost in ancient Greece that people still knew about writing? That is, no one knew how to write, but still knew it existed because of contacts with civilizations like Egypt?	[ "Followup question: woah, the ancient Greeks lost writing?! Anyone have detail on what we know about that, or a link to an earlier question on the same?" ]	[ "As WWI was not as heated as WWII, there would often be opporotunties for, exactly as you said, a mail truck (flying a white flag of peace of course) to cross no man's land. Sometimes, a mail ship from one nation would sail into international waters to deposit their cargo onto the opposing nation's ship, all done c...
Why would checking your credit affect your credit?	[ "It doesn't! There are 2 types of checking credit -- a hard pull, which happens when you apply for a loan or line of credit, and a soft pull, which is what happens when you check your own credit. If you go to try and buy a car or apply for a new credit card and a hard credit check is done, this impacts your score b...	[ "Kind of like data mining. Some companies will alert you if you buy something off a new website, or if the website is frequented by hackers. Let’s say you buy a bike online for $130. $130 isn’t that much money. However, people usually don’t order bikes off the internet. That’ll raise a red flag. And of course if th...
Why did speech become the universal method of communication?	[ "well, functionally, its the best. you don't need to look at someone to get a message (which can nice for when your eyes need to be focused on something else), you don't need your hands to communicate, and it can provide tone or intent more easily and more clearly than hand" ]	[ "CGP Gray has a pretty good take on this question. [This Video Will Make You Angry](_URL_0_) Time: 7:25 Subject: Transfer of ideas from person to person. It is a pretty awesome video if you feel like giving it the time to watch." ]
What exactly gets ruined when you put sugar in a gas tank, and why?	[ "The sugar leaves residue in the cylinders and exhaust and it clogs up the injectors and any other things that have fuel them. Also, it won't do much if you don't dissolve it in something like alcohol first because sugar doesn't dissolve in gasoline." ]	[ "Basic anatomy: Your mouth is connected to your esophagus, which is a muscular tube that connects your mouth to your stomach. At the junction of the esophagus and stomach is a sphincter - called the cardiac sphincter - which acts as a valve between the esophagus and stomach. The cardiac sphincter is normally closed...
Why do some of the newer Captchas only require you to click a button stating that you aren't a robot?	[ "Because there's spambots out there that are only looking for HTML forms to blindly submit spam to. They find a form, inject whatever spam text into textfields, and fire off the submit function. There's no intelligence to them, and they're not customized for a specific form. So a simple question like that will defe...	[ "Their claim hasn't been verified in any scientific way. If I gave 10000 people a sugar pill and 1000 of them lost weight I could legally claim that the pill helps with weight loss. It wouldn't make the claim true, and the results might not be repeated in a larger sample population. The disclaimer would keep people...
Why does lighting a match in a bathroom help when someone's caused a stench in there?	[ "When a match is struck, the first thing to burn is the head. The head of a match contains a chemical cocktail that includes a lot of sulfur. In the initial burst of combustion products there is therefore a lot of sulfur dioxide. Sulfur dioxide is an extremely pungent substance, to which the smell receptors are ext...	[ "A few reasons, first you may remember from high school chemistry the ideal gas law. PV=nRT, where P=pressure, V=volume, n= number of moles, R is a constant and T is temperature. If you spray a pressurized gas (the propellant in the can), which is typically butane or propane, as the gas comes out of the spray nozz...
If our body temperature is ~98°F, why are we most comfortable at room temperature (65-70°F), rather than our actual body temperature?	[ "Your body generates heat, so it needs to cool off. The warmer it is outside your body the harder it is to cool off. However if it is too cold then it can cause damage to your body. Basically chemical reactions happen at different rates depending on temperature so you don't want temperature to change much if you h...	[ "Honey often contains botulism spores, growth of botulism is suppressed when there is low water activity (such as in honey), and it's suppressed when the pH is low. It needs to get 125'C to kill the spores. Botulism produces one of the most toxic poisons known to man when it grows. The temperature to kill botulism ...
What is the difference between quantum uncertainty and ordinary uncertainty?	[ "The best way to get a grasp on this is simple: Heisenberg, a German speaking man, used the word \"ungenauigkeit\", which more literally translates to \"unknowability\". There is a _fundamental_ limit to what we can measure with regards to complimentary properties, such as position and momentum, and it's not a resu...	[ "> People with obsessive compulsive disorder are often aware that their obsessions are abnormal, but are compelled to perform them anyway. People with obsessive compulsive personality disorder, however, believe their need for strict order and rules is perfectly normal. There's more information here: _URL_0_ It sou...
Why did pants suddenly become more popular than pantaloons in 1903? What was happening around then that spurned this change?	[ "What is the difference between the two? A quick google searched pretty much said pantaloons are pants. Are you asking why the word changed or am I missing something?" ]	[ "Hi readers! Since questions like these often attract anecdotal answers, just a quick reminder: you are in /r/AskHistorians, so do ensure that answers are comprehensive and informative, and based on solid source material. Personal anecdotes or other casual chitchat/speculation/opinion are not accepted as answers he...
How well do batteries compare to human energy storage in fat?	[ "According to Wikipedia's entry for the energy density of Lead Acid batteries (cheap+heavy), you would need 878kg of batteries to equal that amount of energy. If you used Lithium Ion batteries instead(light+expensive), you would only need 122Kg of them. So compared to fat, batteries are crap. Here's Wikipedia's ch...	[ "Incidentally, this is the problem that _URL_0_ is trying to solve. Here is the map of the overall plan: _URL_1_ There is enough solar energy in the Sahara desert in 6 hours to power the entire world in 1 year. From the Sahara, they plan on connecting Europe with underwater high voltage direct current lines. The p...
Why does ocean surf appear static from a great distance?	[ "I don't know the observation you are directly talking about, though I think I may understand you. The major reason here is the lack of relative movement to compare the wavefront to. The waves generally move at the same rate so even if they are moving quite quickly they are all moving together so their seperation ...	[ "The same way you can see your house if you are in it. It looks different from if you were looking at it from the outside, but you can still see the walls." ]
Is it possible that after thousands of years of having humans as riders, some geographical horse groups have anatomy evolved to better suit themselves for humans to ride them?	[ "Actually this probably wouldn't have to take thousands of years, with the way we breed horses. If we were to find a type of horse that was more suitable for us to ride, we would then breed that horse with other horses trying to keep the trait that we like." ]	[ "Happens in dogs all the time. The ACL (called the CCL in a dog) can degenerate over time and rupture with minor trauma. Major cause of lameness and hindlimb arthritis. There are about 4 major surgical techniques to fix it, its a major area of work. I'm sure wild canids are fairly similar. Horses rupture assorted l...
Kinda understand the Higgs Boson/Field, but there is one open question.	[ "> what determines how much a particle is influenced by the Higgs field? We don't know. These parameters are known as the yukawa couplings, and in the standard model they are regarded as input parameters- we just measure them using experiments. Specifically we measure the particle masses and the [CKM matrix elemen...	[ "Because: > when enough energy is applied to split the quarks apart Essentially, the energy you input to tear a quark out of a hadron goes into the cost of creating new quarks and gluons to dress it." ]
A question about the Delhi Gang-Rape Case - Is Intestinal transplant possible?	[ "Intestinal transplants are real and possible, this year I saw a documentary about a woman with a rare intestinal disorder who'd been surviving on a drip for over a decade who got a full intestinal transplant, and [here's another story about someone else with it having the same thing done](_URL_0_). Eating and drin...	[ "> GMO is destroying life of farmers...in India a farmer commits a suicide every 30 minutes. This is an urban legend that has been debunked countless numbers of times. _URL_3_ _URL_4_ _URL_2_ _URL_1_ _URL_0_" ]
Why does checking your credit score hurt it?	[ "There's two types of credit checks - soft & hard. A soft check is what they do when you personally want to see your score, somebody does a background check on you or a company wants to give you a pre-approved credit card. These don't alter your score. A hard check is when you're applying for credit & trying to bor...	[ "One theory is that [we're too clean](_URL_0_). By keeping our kids clean and not letting them chew on UFOs (unidentified floor objects), we're either preventing their immune systems from building a proper \"database\" of pathogens early on, or we're preventing them from coming into contact with symbiotic species t...
What was the public's reaction to Truman's announcement of the atomic bomb?	[ "Generally pretty neutral. We remember Nagasaki and Hiroshima because today we realize the long term effects of the fallout, the radiation, and of course the fact that we've got a crapton of them around and could turn pretty much the entire habitable surface of the planet into green glass. Destroying cities wasn't ...	[ "Mostly they are far enough so that it doesn't matter. Zoom lenses are a wonderful thing. There are sometimes cases of cameras being put close enough to suffer some damage. The way they get around this is by building a bunker for the camera. [Here's a photo of a camera bunker from the Trinity test](_URL_0_) — the w...
Why do people go at great lengths to defuse a bomb (e.g. carefully cutting the correct wires, etc.)? Can’t you break it by making it wet or throwing it to a pool of water?	[ "If you're talking about movies - theatrics. The point of a movie is to entertain; if the protagonist could defuse a bomb simply by dumping a kettle (or better yet, peeing) on it, it would be anticlimactic. If you're talking about real life, hopefully an engineer can chime in. In the interim, based on my pedestria...	[ "I like the dry ice and water idea, and then put a balloon in the water too (underwater). Then all you need is a mechanism to pop the balloon, the water will muffle the pop into a poof, and you should get a nice burst of vapor along with it." ]
What is blood pressure and how is measured? Every time my blood pressure is taken they say it’s good but I couldn’t tell from looking at the numbers	[ "It's the pressure (like water pressure) of the blood circulating through your body. The first number is at the beat (pump) and so higher, the second at the rest. 120/70 is good. Anything higher than that is going to make many doctors unhappy. Higher in terms of what is good/what requires treatment varies from time...	[ "Yer not alone in askin', and kind strangers have explained: 1. [ELI5: How do snakes move? ](_URL_0_) ^(_7 comments_) 1. [How the fuck do snakes move? ](_URL_4_) ^(_1 comment_) 1. [ELI5: How do snakes move so fast? Actually how do they move forward at all? ](_URL_5_) ^(_4 comments_) 1. [ELI5: How do snakes move for...
Pierogi is one of the delicacies of slavic cuisine. Is it true that they are an adaptation from the chinese jiaozi/dumplings? What are the earliest known records about pierogi recipes?	[ "The more exact equivalent to jiaozi/gyoza in Russian cuisine is pelmeni. _URL_0_ has some background on history." ]	[ "Could you provide an example of what you are referring to? I don't think I've ever noticed dogs in early American political cartoons, but I do know that dogs both domesticated and semi-feral, were common fixtures of both urban and rural life in the 18th century. Dogs in art could imply both servility or loyalty, ...
Is ~-40C to 40C the only temperature range for any lifeforms to exist? Or could there be lifeforms that we cannot imagine at -150C or 4000C?	[ "Any water based life form would require the temperatures and pressures to be around those required for H2O to be liquid. Other life could theoretically exist at temperatures and pressure outside that range, but would have to be based on a different solvent. For example, ammonia based life would require much colder...	[ "If you add water to a zero degree environ, it will stay water. To freeze it you have to remove the latent heat of fusion. You have to continue to remove heat energy to get it to freeze into ice at zero degrees. Similar thing happens at the saturation point when water becomes steam, to it takes 1BTU/Lb of heat ener...
As the Western Roman Empire was falling apart, what was happening in the provinces it formerly controlled?	[ "In Britain to a certain extent the emperor sent out a \"good luck, you're on your own now\" called the Rescript of Honorius, which is one of the reasons Britain is essentially the only place you can coherently talk about a distinct end of the Roman period, although there is still a pretty active debate over whet...	[ "[Bleeding Kansas](_URL_3_) comes to mind. Essentially, while the 'free' states were just as numerous as the 'slave' states, meaning they had equal representation in the US Senate, the 'free' states had nearly double the population. So to ensure that neither side gained an advantage in the Senate, a number of measu...
Why did none of the Native American peoples enter the Iron Age?	[ "Although copper working was known in North America, it was only in South America and Mesoamerica that copper smelting from ores took place. In the most of North America the source of copper was metallic nodules and nuggets rather than from ores. Iron tends not to be available in this form. (edited) One significant...	[ "It helps to have easy access to wheat, rice or corn - the basic building blocks of...or never mind :)" ]
Why do most products cost "X.99" units of currency, rather than simply round up? [Economics]	[ "Psychological pricing (also price ending, charm pricing) is a pricing/marketing strategy based on the theory that certain prices have a psychological impact. ... Thus, prices such as $1.99 are associated with spending $1 rather than $2." ]	[ "The posted comments are right, I'm sure, but I think that there's another issue. You never start counting something at zero. If you have five elephants and you're going to count them, you don't say zero elephants, one elephant, two elephants...etc. You say one elephant, two elephants, three elephants, four elephan...
How does radiation cause mutations?	[ "Simple answer: Ionizing radiation causes formation of reactive oxygen species. These are molecules and ions that can react with things in your cells - namely DNA. Usually, the changes to DNA can be repaired. Sometimes the changes to DNA are permanent, and can: - Be such a drastic change that the cell cannot surviv...	[ "Most of the people with melanoma now are the ones who were out in the sun back in the 60s to 80s, before there was so much awareness of skin cancer and when being tan was quite fashionable." ]
why do most cats hate water so much?	[ "I'm convinced it's because they look so damned undignified when they're wet. And no animal values its dignity as highly as a cat." ]	[ "1. Boxes are instinctively a safe place where they feel protected. 2. Boxes are fun for them to jump in and out of." ]
What would happen if I heated something to the temperature of combustion, but kept it in an oxygen-free environment?	[ "Lots of chemical reactions can occur at relatively high temperature and of course vary depending on the composition of the environment. For example, in the deep sea, the maximum observed temperature of hydrothemal vents is around 420C, far above what could be a combustion temperature. The exchange reactions betwee...	[ "Depends on the material and temperature. Sometimes the surface forms a reconstruction, as dreykevins explains. Other times the surface forms an oxide or some other surface layer, which can prevent recombination. Other times the pieces actually CAN be put back together, and this process is called \"cold welding\". ...
Subjective question about WWI cruisers and dreadnaughts	[ "Sailing ships definitely had a romantic quality to them (it's part of the reason why I got interested in my area of study). I'm not qualified to answer the question of how people in general thought about them, but perhaps /u/nmw or /u/thefourthmaninaboat could help? I can answer this question, at least: > Bonus ...	[ "hi all. Just a reminder that this is a history sub, so we're looking for in-depth and informed responses from people with expertise in the subject matter. Source material citation is encouraged. Conjecture, opinions, and rumours do not meet sub standards. Thanks!" ]
Did we all come from people with a black skin tone?	[ "There is no definitive way to know, as there were no cameras or even written records, of course. However, yes, the common wisdom is that ancient pro to humans in Africa had dark skin tone, as this is an evolutionary advantage for living there in the intense sunlight." ]	[ "The distinction between the Nubians (from present day Sudan) and the ancient Egyptians you're referring to (Nile River Valley, present day Egypt) is probably lost on her. American command of distant geography and/or ancient history is not usually excellent." ]
Can gravity-fed water turbines be repeated down more levels?	[ "Although water turbines aren't my field I will point out that due to mechanical waste (i.e. friction etc) you will never produce enough power from the water falling to push it back up again. In a perfect system you still would only create enough power to push the column of water back up and never 'feed the grid'. ...	[ "A village well's. There is enough water deep undeground, just not at the surface. And most beduins today have satelite dishes and internet, So i think they are managing just fine :D" ]

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