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Why is it that on most fans, the switch is ordered as off, high, medium, and low?
[ "When you turn the fan on, the motor that powers the fan is running at max speed. When you turn the fan to medium or low, the motor is slowed down. Running the fan at the maximum speed of the motor is more efficient and the fan will last longer since the motor does not have to adjust to the increased power flow as you go from low to high. There is not a lot of strain on the motor when you turn the fan on, as the current flows without any limitation, and when you turn the power off, the fan stops on it's own with no adjustment of the speed of the motor. When you turn the speed of the fan down, the loss of current slows the fan down. Again, no strain on the motor." ]
[ "Most likely you are dealing with a 3 way lamp switch. Off-low-high-off I haven't seen one in a long time, but there used to be light bulbs with 2 filaments in them, and the switch would light one for low, then both for high. If there is just a regular one filament bulb in it, you still have to click through both low and high, but the bulb won't change brightness." ]
eli5_question_answer
{ "query": "Represent the Reddit question:", "pos": "Represent the Reddit comment:", "neg": "Represent the Reddit comment about Electrical engineering:" }
Why does the Black Lives Matter movement not protest black on black violence in Chicago?
[ "Because the purpose of the movement is to bring attention to the high ratio of black victims of police brutality. Black victims of police violence are often overlooked and their stories disappear. The movement is geared toward bringing this issue to light and helping to end it. Not every organization can work on every issue." ]
[ "A few reasons. Chicago has one of the highest gun crime rates in the country, so reporting a gun crime there doesn't grab much attention on the national media. Also, The shooting in Washington happened involving military personnel on a military base. The concept of military personnel being made victims is a sensational one. Then there's the elephant in the room that no one likes to talk about, but the victims in Chicago were black. It's not a secret that the media focuses less time on stories dealing with people of color than other stories. Sad but true. Then there is the fact that no one died. Death > injury to the media, regardless or cause or circumstance." ]
eli5_question_answer
{ "query": "Represent the post:", "pos": "Represent the answer:", "neg": "Represent the answer:" }
Why do east Asian adult actresses seem as if they don't enjoy the act in adult movies?
[ "Japan specifically tends to place a lot of value, culturally, on sexually submissive women. The idea of women \"surrendering\" themselves during sex is popular. This leads to more aggressive-seeming sexual encounters, even though they're (hopefully) 100% consensual. That is of course a broad generalization, and there are plenty of exceptions." ]
[ "probably supply and demand. Lots of guys would be willing to work as porn stars, not many women. Also, most people watch porn for the women, most of the men are barely in the shot, so the woman is more important. She has to look better, act better, etc." ]
eli5_question_answer
{ "query": "Represent the Reddit question:", "pos": "Represent the Reddit document:", "neg": "Represent the Reddit document:" }
The Horseshoe Theory.
[ "It is the theory that the further you go to the left or right, the more similar the practices go. Look at Nazi Germany vs Soviet Russia. There is a lot of debate as to whether they were truly opposing forces. The Nazis began as National Socialists, the USSR was Communist, both were associated with the left wing in their founding. And in practice they had many similarities. They killed or jailed political dissidents, they took away freedoms, forced military service, killed millions of their own citizens, annexed neighbouring regions, etc. Even though we see Nazis as right wing fascists and Soviets as left wing communists, their functionality was very similar. This is the horseshoe theory, that when you reach the extremes the practices become similar." ]
[ "The Art of War in the Western World - Archer Jones" ]
eli5_question_answer
{ "query": "Represent the title:", "pos": "Represent the document:", "neg": "Represent the document about Education:" }
Why are manholes located in the middle of the road?
[ "It's best for city planning for them to run directly under the roads. After all, closer to the sidewalks, and you run into domestic gas lines, internet/phone cables, and maybe buried power lines. Sewers are very spacious, large pipes. It makes sense to put them under a wide, uninterrupted path with no other cables under it. Edit: this is all in the context that manholes are the access points to sewer lines." ]
[ "Easier to run sewage and the like under the road than it is under the sidewalk, where it could affect the shops and houses on the street." ]
eli5_question_answer
{ "query": "Represent the title:", "pos": "Represent the paragraph:", "neg": "Represent the paragraph:" }
Why didn't people see "the dress" in the original colors of the photograph?
[ "The lighting had a lot to do with it. Our perception of colors are based not only on the actual color of the object itself, but also on the object's visual environment (e.g adjacent colors and lighting). The dress in question appeared back-lit in the photo, so instead of merely perceiving the actual colors a lot of us automatically (and erroneously) color-corrected and subconsciously assumed that the colors were in deep shadow." ]
[ "Out of curiosity, was this post prompted by the \"Amazing Story\" video on the front page?" ]
eli5_question_answer
{ "query": "Represent the query:", "pos": "Represent the answer:", "neg": "Represent the answer:" }
What happens with excess electricity from a generator?
[ "If there really was excess electricity because the motor speed was too high, the voltage would rise. Voltage fluctuation is acceptable within certain limits, but past a certain point it could damage the devices attached to it. Generators you can buy have regulators to prevent this from happening - see [here] (_URL_0_) for an explanation with diagrams. Short version: a control circuit sends a DC voltage to a rotor coil, which actively slows the motor down as needed to maintain the correct voltage." ]
[ "It is powered by an RTG, a device that uses the heat from the decay of radioactive material to generate electricity for a long period of time." ]
eli5_question_answer
{ "query": "Represent the title:", "pos": "Represent the passage:", "neg": "Represent the passage:" }
What do the numbers in your blood pressure mean?
[ "There are two measurments of blood pressure. Systolic is a measure of blood pressure when your heart actually beats and pumps blood. Diastolic is the blood pressure between each individual pump. They are measured in units of mm Hg. This unit of measurement is basically saying \"if mercury in a tube were under this much pressure, how high would it go?\" Higher means more pressure. They aren't particularly correlated with each other, but as you can imagine, systolic blood pressure is always higher than diastolic. EDIT: I thought I read some reports of near-equivalent systolic and diastolic blood pressure, but I haven't been able to find them, so I'll take it that systolic blood pressure never comes especially close to diastolic levels." ]
[ "It has a few different meanings in different contexts. What setting are we talking about?" ]
eli5_question_answer
{ "query": "Represent the query:", "pos": "Represent the text:", "neg": "Represent the text about finance:" }
The difference between CAR and TCR therapies.
[ "Both CAR and TCR therapies are use T cells for treatment of cancers directed against specific targets known as antigens. The difference, from what I've seen are: CAR (chimeric antigens receptor) are usually used against antigens expressed on the surface of the cancer cell. The CAR itself is not a naturally occurring receptor, but man-made by combining parts of different naturally occurring proteins (hence it being called chimeric.) TCR (T cell receptor) therapies are generally used to treat antigens that are expressed inside the cell and not in it's surface. TCR are receptors that naturally occur on T cells, the difference being these TCR are specific to a certain antigen. The TCR binds to a structure on the surface of the cell known as the MHC which samples the inside of the cells. When the \"sample\" contains the antigen they are specific to, they react. Source: work in this field." ]
[ "We can. And we did. It's called CAR-T cell therapy." ]
eli5_question_answer
{ "query": "Represent the Reddit question:", "pos": "Represent the Reddit sentence:", "neg": "Represent the Reddit sentence:" }
Motion Sickness caused by Virtual Reality
[ "Motion sickness happens when one of your senses perceives movement but the others don't. For example, when you're in the cabin of a boat, your inner ear senses that the boat is rocking, but your vision doesn't corroborate. In your case, your vision is perceiving motion when you are wearing the VR headset, but your inner ear and sensory nerves aren't. In other words, you are getting motion sick *because* you are stationary." ]
[ "The things that are touching get tangled. ELI25 Version: Pursue a Ph.D. in Material Science...we still don't have all of the answers." ]
eli5_question_answer
{ "query": "Represent the Reddit post:", "pos": "Represent the Reddit comment:", "neg": "Represent the Reddit comment:" }
why so many banks have the name "First National Bank of ..." in the title.
[ "A national bank has a national charter, as opposed to a state charter. Hence there are lots of first national banks of ( name your state, city, county, etc.)." ]
[ "Did you mean in the USA, or in Japan?" ]
eli5_question_answer
{ "query": "Represent the Reddit query:", "pos": "Represent the Reddit answer:", "neg": "Represent the Reddit answer:" }
If California is so dry, why is so much food grown there? Why not just grow it elsewhere?
[ "Dry climates tend to have very rich soil because little rain leeches nutrients from the soil (but they need irrigation to make the soil productive). California also has a very mild climate that features a very long growing season allowing a large of variety of agricultural products to be grown (many are quite valuable because they can't be grown in other productive farm regions)." ]
[ "Keep in mind that less than 10% of the water California uses is for indoor residential use. Even under the worst-case scenario, nobody is going to go thirsty or lose the ability to shower or flush the toilet. The biggest user of water is agriculture. California produces a huge percentage of the fresh fruits and vegetables consumed in the United States. If the drought continues, some crops may never be economical again, and a lot of that farmland will probably switch to crops that can get by with a lot less water. That may make the price of some produce go up a lot because it will have to come from elsewhere in the world. Or, maybe less with be grown in California. The price of water in California will go up. But yeah, those are the likely scenarios. No doom and gloom, just change." ]
eli5_question_answer
{ "query": "Represent the Reddit question:", "pos": "Represent the Reddit passage:", "neg": "Represent the Reddit passage about Environment:" }
Reason for genital mutilation in several African nations
[ "FGM is carried out for cultural, religious and social reasons within families and communities. For example, it is often considered a necessary part of raising a girl properly, and as a way to prepare her for adulthood and marriage. FGM is often motivated by the belief that it is beneficial for the girl or woman. Many communities believe it will reduce a woman's libido and discourage sexual activity before marriage. FGM has many long-term consequences including abnormal periods, abdominal pain, infertility, psychological damage etc. FGM is mostly carried out on young girls sometime between infancy and age 15. FGM is illegal in the UK and considered a violation of the her human rights." ]
[ "Because of their interpretation of some details in their practically same religion and historical, tribal diferences. Two reasons of most wars and conflicts." ]
eli5_question_answer
{ "query": "Represent the Reddit title:", "pos": "Represent the Reddit document:", "neg": "Represent the Reddit document:" }
what would happen if man had two Y-chromosomes instead of XY?
[ "If you mean YY, the X chromosome contains most of the genetic information, so a fetus with YY wouldn't be viable. If you mean XYY, that is a [known genetic syndrome] (_URL_0_). It mostly seems to affect growth (which is accelerated) and the chance of having learning difficulties is higher." ]
[ "Most of the baldness you see is caused by a gene on the X chromosome. If a man has the gene for baldness in his X chromosome then he will be bald. If a woman has the gene for baldness on an X chromosome, she has a second X chromosome that most likely will not have that gene so it is suppressed and she will not be bald. Edit - Remember Women have two X chromosomes and men have an X and a Y Chromosome." ]
eli5_question_answer
{ "query": "Represent the query:", "pos": "Represent the comment:", "neg": "Represent the comment:" }
How can some groups argue Nationalized Military "protects us, makes our lives, better, allows us to be "free", etc" while also arguing nationalized medicine is a disaster?
[ "Just because one good has a clear case for being provisioned by the government doesn't mean that's true of all goods. You're basically saying you have to believe that all goods and services should be privatized or believe that all have to be publicly provided. People against public healthcare believe that managing healthcare through the state is less efficient than allowing private actors to handle it while pretty much everyone everywhere agrees that the state should maintain a monopoly on the use of violence, which means that things like police and the military should be state run rather than private outfits." ]
[ "A lot of People in america don't understand how the socialized system works How having every single working person contributing a relative amount of their pay to a giant pot of money provides a service everyone can benefit from,and that by doing so we could practically eliminate the exorbitant insurance and prescription expenses we are so accustomed to Even though that's how things like roads and emergency services works. Meaning we are already doing this exact fucking thing in other areas An entire portion of our population has been conditioned to believe higher taxes automatically = bad...even though there is a net savings per person" ]
eli5_question_answer
{ "query": "Represent the post:", "pos": "Represent the text:", "neg": "Represent the text:" }
Why are minorities overrepresented in commercials?
[ "If it was only majority members being portrayed, the minorities would see what's being advertised as being mainly for majority members and would be less likely to spend money with that company. So showing minorities in the ads is to assure minorities that they are welcomed to be part of the culture being portrayed (say, buying a new Toyota or eating at Applebee's). Minorities feel underrepresented in general, and when they see themselves in a commercial, they feel represented and like they're welcomed or belong.. That's powerful. On the other hand, the majority group automatically feels welcomed no matter who is portrayed and isn't significantly put off by seeing minorities portrayed." ]
[ "They don't want to be known as the perpetrator of millions of deaths and ethnic cleansing." ]
eli5_question_answer
{ "query": "Represent the Reddit title:", "pos": "Represent the Reddit document:", "neg": "Represent the Reddit document:" }
Why are Arizona Iced Tea drinks allowed to place a price on its product?
[ "Why *wouldn't* they be allowed? There's no law forbidding the printing of a suggested price on a product. In fact, lots of companies do it, including many different brands of potato chips, [like these](_URL_0_). Generally, the company that produces the food item will only sell their product to retailer who sign a contract agreeing to sell it no higher than the printed price." ]
[ "It's a convenient way for companies to make their products look healthier than they are. Why say a 20oz cola is 280 calories when you can split it into two servings and put a big ol 140 calories on the label." ]
eli5_question_answer
{ "query": "Represent the Reddit title:", "pos": "Represent the Reddit post:", "neg": "Represent the Reddit post:" }
Why are windshield wipers sold as singles not pairs? Do people often replace them one at a time?
[ "Not every car has the same size blade for each side. For example, my Ford Focus uses a 22 inch driver and 19 inch passenger. My Nissan Versa uses a 26 inch driver and a 16 inch passenger. You should replace all wipers each season or two depending on quality. Also, buying the most expensive blade isn't the best. A properly clean windshield has more at play with water visibility than the most expensive wiper and a dirty window." ]
[ "If it has mechanical parts, it will break. Applies to anything. Shopping carts get used and abused everyday for extended periods of time and am guessing only get replaced every so often, if at all." ]
eli5_question_answer
{ "query": "Represent the query:", "pos": "Represent the document:", "neg": "Represent the document:" }
Why aren't high rise office fires more common/unsurvivable?
[ "They used to, then builders got wise to it. Now we build high rises out of concrete and glass, which don't catch on fire. We restrict how much flammable material is used on the floors of high rises and don't allow anything flammable at all in the stairwells (that's why the stairs are pretty much always barren concrete with metal railings), which makes it more difficult for the fires to spread between floors." ]
[ "They don't adjust their calories when their lifestyle becomes more sedentary." ]
eli5_question_answer
{ "query": "Represent the Reddit post:", "pos": "Represent the Reddit sentence:", "neg": "Represent the Reddit sentence:" }
In a dark room, why can I see something better when I look just to the side of it, instead of directly at it?
[ "As you probably know, your eyes have rods and cones that receive light. The cones pick up color, but the rods are highly light sensitive (and don't see color). Your cones are bunched in the middle of your eye (opposite your pupils) while the rods are lining around the cones. Long story short: you are looking at this object with your rod rather than your cones." ]
[ "They don't really exist like the ones that you see in the movies. What you do in real life to create that effect is to have two rooms with a glass window in between. Room 1 is darker than room 2, with some tinting on room 1's side of the window. Room 2 is kept very brightly lit, possibly with some slightly reflective tinting on room 2's side of the glass. If you are standing in room 1, you can very clearly see into room 2. However, if you are standing in room 2, you will have a difficult time seeing into room one unless you stand up next to the window and shield it with your hands." ]
eli5_question_answer
{ "query": "Represent the query about Physics:", "pos": "Represent the document about Physics:", "neg": "Represent the document:" }
; Why is it, that when we don't eat for a long period of time, we feel sick and repulsed by food but eating is what makes us feel better?
[ "Not sure if I can explain this properly but here goes. Not eating for a long time can cause stomach acids and digestive juices to build up . Juices like bile in excess cause some mild nausea , this maybe what you experienced when you tried not to gag. But as soon as you eat , these juices get put to work digesting and gets used up. So no more nausea or we don't feel sick.. hope this helps." ]
[ "Could be one of two reasons or both: After a while of being hungry your body just stops telling you that it's hungry. It seems to be the only urge that stops when it realizes nothing will change, unlike continuous infliction of pain. Second, when you go to sleep your metabolism changes. That's basically the way you turn food into energy. While you were sleeping you probably turned part of your reserves, back up energy (aka fat) into energy, thus when you wake up you're no longer hungry. And lastly, (I didn't say three I know) sometimestill hunger is actually being thirsty. So the question may be, why do I go to bed dehydrated but when I wake up my body is no longer telling so. That I can't answer." ]
eli5_question_answer
{ "query": "Represent the Reddit title about Health and Wellness:", "pos": "Represent the Reddit document about Health and Wellness:", "neg": "Represent the Reddit document about Sleep and its effects on the body:" }
how Ipods work and play music
[ "First off, iPods don't produce the songs out of no where and it doesn't 'remember' to play them. You put the songs on there yourself and then later on you tell it which one to play. The main part of an iPod is the hard drive which works just like your computer's does in the sense that you choose what you want to play/open and it will do it. Each individual song that you see inside of iTunes on your computer is it's own unique file located somewhere on your computer and when you sync all of that music to your iPod, it is actually moving each individual file over. Each of these files contains its own 'metadata' so that you can see the name/artist/album on your iPod and recognise and choose the right song to play. I think that should pretty much answer what you asked. If what you really meant was how do hard drives work (as in how do they store so much data on such a small device) then I'll leave that open to someone else!" ]
[ "They have been reading lips, same thing now add sound." ]
eli5_question_answer
{ "query": "Represent the title:", "pos": "Represent the argument:", "neg": "Represent the argument:" }
Why do military planes like the AC-130 have their wings attached at the top of the fuselage, whereas most other civilian planes have their wings attached near the bottom?
[ "Few key reasons: High wing aircraft are easier for ground support vehicles to maneuver around, and engine clearance over the ground is greater making their overall fuselage profile closer to the ground and hence easier to load/unload. Also, greater engine-ground clearance mean less chance of debris being ingested by engines which is of particular importance since military aircraft tend to operate out of unfinished/rough runway surfaces far more often than civilian craft" ]
[ "In old planes the wings, and main wheels, were located at the front. So the extra wheel came in the back. Now in modern planes the wings and main wheels are more to the center, a little to the back, and the extra wheel comes in front." ]
eli5_question_answer
{ "query": "Represent the Reddit post about Aerospace Engineering:", "pos": "Represent the Reddit comment about Aerospace Engineering:", "neg": "Represent the Reddit comment:" }
Why does the government tax income much more heavily than spending?
[ "Because the economy runs on spending not on earning. So we want to reward spending and encourage it. There is no reason for the government to encourage earning more money. People want to do that already." ]
[ "Fair tax is a tax policy that would get rid of the income tax on people and corporations and move the tax entirely to a consumer tax on retail sales. People consider this kind of tax back because it tends to cause Rich people to get Taxed less and Poor people to get taxed. It also gives people a incentive to hoard money which is bad for the economy." ]
eli5_question_answer
{ "query": "Represent the Reddit query:", "pos": "Represent the Reddit passage:", "neg": "Represent the Reddit passage:" }
How can wrist-scan age tests determine your age?
[ "Since the auto moderator won't allow an efficient answer here's a slightly longer one. They can't. Wrist scans are discredited everywhere. You can't tell the difference between a 17 year old and an 18 year old via a wrist scan. You can't even tell a 15 year old or a 19 year old. You can determine whether the bones have finished growing, but, perhaps unsurprisingly, being 18 or not is only loosely correlated with that actually happening. We all knew people who were done growing at 14 and people who were still doing it at 19 so this shouldn't be a huge suprise. There are doctors who will insist they can do this for money, but they are lying, as at FIFA. FIFA doesn't care though. They care about the appearance of a fair competition so false positives are fine by them." ]
[ "The machine measures heart rate, skin conductivity, breathing rate and sometimes pupil dilation - all to the effect that it's not able to tell if you're lying. The machines don't work reliably." ]
eli5_question_answer
{ "query": "Represent the Reddit query:", "pos": "Represent the Reddit sentence:", "neg": "Represent the Reddit sentence:" }
Why don't we use counties as congressional districts?
[ "Because many states have a lot more counties than congressional districts, especially in the East. Illinois has about 100 counties, and 18 congressional districts." ]
[ "One way to prevent it is to use a voting system that can't be gerrymandered, or is at least less prone to it. For example many countries use a Proportional Representation system where there are no districts. You just vote for a party and then that party is allocated seats in the Parliament based on what percentage of votes they got. Or a system with multi-member districts. It's harder to gerrymander districts when they are larger and elect 5 or so representatives (usually using a rank based voting system). Another way is to have an independent commission which draws the districts. That's how it works in the UK. Members of the commission are not affiliated with any political party and they have to remain neutral when making their decisions. The government can only give them broad criteria for drawing districts like how many there should be, about how many people should be in each, and so on." ]
eli5_question_answer
{ "query": "Represent the Reddit query:", "pos": "Represent the Reddit document:", "neg": "Represent the Reddit document:" }
Why do "forever storms" seem to exist in some planets like Jupiter (And now Stars)? How do they stay "forever" and not die?
[ "They're not forever. Jupiter's storm is losing it's energy and will die out eventually. I think it's been overdue for almost a decade, but I'll let someone else find the literature on it." ]
[ "Jupiter is a gas giant ( planet that is made of purely gas state and not liquid or solid state elements ). Thus, Jupiter obviously has an atmosphere ( Don't think Earths atmosphere here, think certain particles that are hotter/lighter than other and thus gravitation doesn't pull them to \"ground\" level ) which is what you are seeing in pictures/videos/artistic interpretations of Jupiter. So much like Earths atmosphere Jupiter's atmosphere is more dense and/or has different compositions in different places, the same as you could look at a video of Earth and see the \"cloudy\" bits moving and their color being slightly different." ]
eli5_question_answer
{ "query": "Represent the Reddit post:", "pos": "Represent the Reddit document:", "neg": "Represent the Reddit document:" }
How does rust harbor tetanus?
[ "And it's not the rust *per se* that necessarily harbors the tetanus. Tetanus is in the dirt. When you impale or puncture yourself on something dirty, you are sticking the dirt particles into your flesh into a place where air can't get to it. Tetanus is caused by *Clostridium tetani*, a spore-forming bacterium that likes to grow in wet, nutrient-rich, unoxygenated enviroments, like in closed-off flesh-wounds. The spores get shoved all up in there -- > they germinate -- > they multiply -- > then they make tetanus toxin -- > then lockjaw." ]
[ "A reation to dust, histamines, and other irritants." ]
eli5_question_answer
{ "query": "Represent the Reddit question:", "pos": "Represent the Reddit passage:", "neg": "Represent the Reddit passage:" }
How does walking long distances help raise fund?
[ "It's an organized publicity event for the charity. Each person who will be walking gets sponsors to agree to donate $X to the charity for each mile that they walk. Walking is done - is a great social event, and the donations are made by those who agreed to sponsor a walker. For walks done around town, individual amounts raised might be small - a few friends and family giving $25 or $50 dollars each. The Make A Wish walks that I have seen are a bit different. There is a minimum each walker must raise in order to participate ($5000 or more - if I remember correctly), but these are big trail hikes, and participants meals and hotel rooms for the event are covered." ]
[ "It means that the food contains chemicals that can help to reduce inflammation. It will not make you harder to set on fire." ]
eli5_question_answer
{ "query": "Represent the post:", "pos": "Represent the document:", "neg": "Represent the document:" }
what is zoroastrianism?
[ "It is an ancient religion that shared many elements with the later Jewish/Christian/Muslim religions. It has its origin and was practiced in the past in what is today Iran. Today there are few Zoroastrians or Mazdayasna as they call themselves left. Less than 200,000 by some counts." ]
[ "Related: what happened to the similar but different term Lakonia?" ]
eli5_question_answer
{ "query": "Represent the question:", "pos": "Represent the sentence:", "neg": "Represent the sentence:" }
How is it that cannabis has so many different 'strains' which change the appearance and other characteristics of a particular plant? Do other plants share similar significant genetic variations?
[ "Cannabis have been cultivated for many different uses over the years which have resulted in a lot of genetic variation. This is not unusual with cultivated plants. Take for instance the mustard plant which not only is prominent in the spices section in the grocery store but also consists of about half the vegetable isle with variants such as the cauliflower, broccoli, turnip, cabbage, canola, etc." ]
[ "THC is one of 113 different cannibinoid chemicals in cannabis. CBD is another that's widely known. Indica and Sativas have different ratios of THC and CBD, and the combination of the two can affect the type of \"high\" you get." ]
eli5_question_answer
{ "query": "Represent the post:", "pos": "Represent the document:", "neg": "Represent the document:" }
Why in Boxing/MMA, does the timer disappear in the last 10 seconds.
[ "That's because the clock on screen is not the \"official\" clock. There is a timekeeper on-site that is tracking the actual time left in a round. The one on screen is more of a close guess. By hiding the timer in the last 10 seconds, it prevents people from going \"Hey you ended the round too early!\" Or some other controversy because the officials will be the ones to call the end of the round as it should be." ]
[ "Same as a boxing match. They just don't have a gazelle wander round with a card saying Round 2" ]
eli5_question_answer
{ "query": "Represent the question:", "pos": "Represent the post:", "neg": "Represent the post:" }
Why is immigration such a hot button topic in UK politics at the moment? What effects are immigration having on the economy right now?
[ "Mostly, it's a non-issue. However, trying to remove freedom of movement is an effective way for parties to appeal to their more authoritarian supporters." ]
[ "Pros: * More control over laws - a lot of UK laws are influenced by EU directives * Can restrict immigration from Europe * Do not have to follow EU on trade treaties * No more issues over 'loss of sovereignty' * Free to pursue own diplomatic agenda Cons: * A huge amount of business is dependent on European free trade * No-one has ever left the EU, so the economic implications are unclear at best, and could be disastrous * Immigration to the UK from outside the EU is larger than from within, so leaving would not necessarily solve the immigration issue * Without EU backing it is unclear whether the UK would be able to maintain the same diplomatic influence A lot of points here are very contentious, and there are powerful and passionate voices on both sides." ]
eli5_question_answer
{ "query": "Represent the post:", "pos": "Represent the text:", "neg": "Represent the text:" }
What is the meaning of "rareness" in meat and why are "rarer" meats preferred?
[ "Ah Grasshopper. I was once like you. Raised by savages who thought all meat had to be cooked to a degree of dry grayness to be edible. Now, in my time of Enlightenment, I eat my steak medium rare. My counsel to you is to take this gradually. Move from well done to medium, then keep stepping down the scale of doneness until you reach a level of juiciness, texture and flavor that you like. Then go one step further just in case. Enjoy the journey young one." ]
[ "It clearly is literally meat. The answer though is that in culinary terms some cultures decided it's different enough to treat it as it's own category of food and the names got stupider when translated into english. Since english lacks a good name for \"mammal meat\"" ]
eli5_question_answer
{ "query": "Represent the query:", "pos": "Represent the document:", "neg": "Represent the document:" }
Why is my dog ecstatic to see me when I come home after going out for a couple of hours?
[ "Dogs do not like being alone. [In the wild wolves tend to live in packs of 5-11,](_URL_0_) so it is not normal for one of them to be alone for that long. They get lonely. Also, this trait was selected for when breading. A dog that is ecstatic to see you after a brief separation is more likely to do what you want. -hunting, tracking that kind of thing-" ]
[ "This is more anecdotal than anything. You have playful dogs. My dog *despises* me during and immediately after his bath. He runs and hides in his crate for a half hour every time." ]
eli5_question_answer
{ "query": "Represent the title:", "pos": "Represent the document:", "neg": "Represent the document:" }
Why is opening many restaurants in a short amount of time bad?
[ "Most restaurants, and businesses generally, will fail within a couple years. You need to be prepared financially for the entire investment to disappear." ]
[ "It's like a farmer who has to spend time and money growing the crops for months before getting a chance to harvest them... just on a longer scale. It takes money to make money, as they say. In this case one of the big upstart costs is time." ]
eli5_question_answer
{ "query": "Represent the query:", "pos": "Represent the document:", "neg": "Represent the document:" }
Why are teachers paid so little?
[ "For the most part, teachers are 'public servants'. They work for the local governmental department of education....rather than working for a business. A business usually gets money by selling a product or a service. If they sell a lot (or sell for a lot) then they might have lots of money to pay their employees a higher amount. But a government department gets it's money from the government's budget....and most governments are always looking for ways to cut costs and/or divert money here or there. Unfortunately, many of them don't put a very high priority on education, and thus the school boards don't have a lot of money to pay their teachers with. That being said, from what I can tell, in most places teachers are paid an average or above average salary. Especially once they have a few years experience. The problem, in most cases, is that teaching can be a very demanding and difficult job that might demand a higher salary, if it were in the private sector." ]
[ "Why does it cost money to get divorced? Because it's worth it!" ]
eli5_question_answer
{ "query": "Represent the query:", "pos": "Represent the document:", "neg": "Represent the document:" }
How Do The Mega Rich Like Bill Gates Have Free Access To Their Own Money If It's Mostly In Investments And Stocks?
[ "Having most of your money in investments and stocks is not the same as having all of your money in it. Gates is worth 91 billion dollars, so even if he had only 5% of his money as cash on hand he would still have 4.5 billion dollars available to him for purchases." ]
[ "Being Black Does Actually Have (Relatively Minor) Health Consequences, It's Just That They're Obviated By Modern Life. There's An Energy Cost To Have Extra Melanin, Even A Small One, So If You Don't Need It It Won't Be Selected For. Melanin Reduces Vitamin-D Uptake From The Sun If Sunlight Is Lower Than You're Adapted For. Vitamin-D Deficiency Was Very Common In Black Children In The Northern US And Europe Before Modern Technology Made Nutrients More Easily Accessible. Being Black Or Brown Outside Of The Tropics Would Have Been Maladaptive For Most Of Human History Because There Would Not Have Been Enough Sunlight For Proper Nutrient Uptake. Capital Letters." ]
eli5_question_answer
{ "query": "Represent the query:", "pos": "Represent the document:", "neg": "Represent the document:" }
When we are tired, does eating makes us less tired because of the energy provided in food, or the other way round because of the energy needed to digest the food?
[ "Eating and digesting a large meal draws a lot of blood around the stomach and intestines. This can make you sleepy because less blood is perfusing the lungs (picking up oxygen) and taking that oxygen to the brain and other tissues. Eating *in general* provides you with energy to perform required bodily functions necessary for life. Tryptophan and melatonin, which were mentioned in another post, are never consumed via food in large enough quantities (even at thanksgiving) to make you sleepy. It's digesting the large turkey dinner that makes you sleepy. A melatonin pill will make you sleepy, but that is unrelated to food digestion." ]
[ "Because it doesn't take long for your body to break down the food you eat and store it or prepare it for waste. Especially if you eat a high carb meal as carbs are the fastest to break down. Once your gut is done breaking things down and sending it to your bloodstream and organs, your stomach tells your brain its empty. Also on the psychological side, many people eat when they aren't actually hungry. They just think they are because of bad eating habits or because they mistake the body needing water for hunger." ]
eli5_question_answer
{ "query": "Represent the Reddit question about Health and Wellness:", "pos": "Represent the Reddit answer about Health and Wellness:", "neg": "Represent the Reddit answer about Health and Wellness:" }
How did they measure the height of Mt. Everest?
[ "It was fires measured in the [Great Trigonometrical Survey](_URL_1_) of India between 1802-1871. Yo measured it by triangulations. If you measure the angle between all three points in a triangle by observation where the corners are towers/mountaintops where you do the observations. You will only need to measure one side of a single trinagle to be able to calculate the distance between all points. That line was 12.1 km long You can measure the hight of a mountain by calculating the distance bu measure the angle from two points. If you then measure the angle above the horisont the peek is you can calculate the elevation. It was measured in 1865 as Peak XV at 29002 feet(the caclulate value was 29000 but it looked fake so is was changes) The accepted value today is 8848m is 29029 feet so they were not far off." ]
[ "How do you even take a picture of the center of a tornado?" ]
eli5_question_answer
{ "query": "Represent the post:", "pos": "Represent the document:", "neg": "Represent the document:" }
In MLB baseball they have technology to show if the ball was inside or outside the strike zone, so why do they still have home plate umpires making subjective calls?
[ "Tradition, and what people like. A ref's judgment is part of the game. Consulting a replay or computer to see if a ball was in or out of the strike zone every time there's a dispute changes the flow of the game." ]
[ "It would slow games down to the point of being unwatchable if every single play were reviewed via cameras. Also, not every play has a camera shot with a great angle. Finally, it would do very little to make the public believe that games were being judged more fairly. Even with replays, people seem to have extremely different opinions on a catch vs not a catch, fumbles, possession, penalties, etc etc etc." ]
eli5_question_answer
{ "query": "Represent the post:", "pos": "Represent the document:", "neg": "Represent the document:" }
Why are most small cars front-wheel drive in favor of rear-wheel?
[ "Additionally, building a rear-wheel drive vehicle is actually far more complex that building a front-wheel drive vehicle. This is for a number of reasons that would take a while to explain, but essentially involve torque, driveshafts, and space to accommodate the driveshaft" ]
[ "With AWD (All-Wheel-Drive), the transmission has the ability to spin some of any of your four tires. With FWD (Front-Wheel-Drive), the transmission can only spin one or both of the front wheels. With RWD (Rear-Wheel-Drive), the transmission can only spin one or both of the rear wheels. With 4WD (Four-Wheel-Drive), the transmission will always spin all four wheels. (There are some caveats and expansions on this scenario, but this is my shot at an ELI5 of 4WD.)" ]
eli5_question_answer
{ "query": "Represent the Reddit question:", "pos": "Represent the Reddit sentence:", "neg": "Represent the Reddit sentence:" }
How is the Gitmo force feeding procedure done on Mos Def different from the feeding tube procedure done in hospitals?
[ "Presumably the people being force-fed in hospitals WANT to be force-fed." ]
[ "Because Guantanamo Bay is in Cuba, and not in the US? Or do you mean, how come the US has a military prison where they conduct torture at Guantanamo Bay and not the US? Remember, torture is technically illegal in the US. So is detaining inmates without due process. There's your answer." ]
eli5_question_answer
{ "query": "Represent the Reddit question:", "pos": "Represent the Reddit passage:", "neg": "Represent the Reddit passage:" }
Why are some morbidly obese people given mobility scooters to get around? Doesn't it make the problem worse?
[ "Because with obesity you can reach a point of no return very quickly. For instance, peripheral edema and diabetes can severely impair circulation, causing neuropathy and skin problems, damage that may never be healed no matter how much weight is lost. Joints wear down very quickly, impairing a person's ability. A severely obese person is going to likely have sclerotic arteries, and be chronically short of breath. A person big and \"crippled\" enough to use a mobility scooter will need to diet and exercise with the help and supervision of a medical professional. It's much more expensive and has many more issues involved that the average Joe wanting to lose that extra twenty. A morbidly obese person cannot simply go on a jog (as another poster said), they may actually die attempting it. I'm not saying that a person in that situation cannot improve themselves, but it is much more difficult, involved, and costly than the average weight loss scenario." ]
[ "Because they can help you function while you take them. And sometimes that means you will be on them the rest of your life. Sometimes they are a way to support you while you incorporate other techniques that can help you deal with your depression / get away from elements in your life causing that depression. Your question is basically like asking 'what use is it to give someone without legs a wheelchair if their legs won't regrow when they don't use it'." ]
eli5_question_answer
{ "query": "Represent the Reddit query:", "pos": "Represent the Reddit comment:", "neg": "Represent the Reddit comment:" }
What is the difference between regular ice cream and soft serve ice cream?
[ "The amount of air in it. To make it \"soft serve\" there is more air injected by the machine. It's also mixed continuously, to keep the air from separating. Yummy." ]
[ "Frozen yogurt needs to be stirred as it freezes, so that air bubbles get trapped inside. That's how you get the light texture. If you have a home ice cream maker, you can make your own frozen yogurt with nothing other than store-bought yogurt." ]
eli5_question_answer
{ "query": "Represent the Reddit title:", "pos": "Represent the Reddit post:", "neg": "Represent the Reddit post:" }
what is the best way to go to sleep earlier?
[ "The keys to reduce stimuli that has the potential to keep you awake an hour or two before bedtime. This includes electronic devices or anything that emits any kind of blue light. Once you pick a bedtime and a wake-up time, make yourself stick to it. It will take a couple weeks to get your body adjusted but it's very doable." ]
[ "whats the point of hospitals if we are all going to die anyway" ]
eli5_question_answer
{ "query": "Represent the Reddit query:", "pos": "Represent the Reddit document:", "neg": "Represent the Reddit document:" }
Why do we get cold chills when we're sick?
[ "Your body is pushing its limits (from cold to hot, repeat) because it's even more annoying for the virus in your body than it is for you as a person. You merely feel cold or hot, while the virus can't stand the changes in temperature and dies." ]
[ "I still rub my eyes when I'm tired." ]
eli5_question_answer
{ "query": "Represent the question:", "pos": "Represent the document:", "neg": "Represent the document:" }
Why don't people questioned by ISIS pretend to be Sunni?
[ "Sometimes they can determine likely sect-membership by names and/or addresses/neighborhoods/towns and/or even jobs. But, with more certainty, they ask detailed and possibly obscure questions about religious practices that vary between the sects. Most people raised as Shiites won't know some details about Sunni religious practices." ]
[ "Are you asking if you go to Iraq or Syria and shoot one? Or are you asking if you know this guy is an ISIS member in your own country?" ]
eli5_question_answer
{ "query": "Represent the Reddit question:", "pos": "Represent the Reddit sentence:", "neg": "Represent the Reddit sentence:" }
Why can't car tires be solid rubber?
[ "The \"springiness\" of an air filled tire helps delivery a smoother ride, and the ability to deal with minor imperfections in a road surface. A solid (using readily available rubber technology) wouldn't have the same ability to deform itself, so every little bump or object on the road would be transmitted to the body of the vehicle. Not only would this make for an uncomfortable ride, it would also affect steering, road contact therefor safety, and put extra stress on the remainder of the vehicle (through shock damage) There are, and have been, airless tires developed. But, they are not quite ready for everyday use, either due to price or perfromance" ]
[ "Well, the material itself is somewhat stiffer, while still retaining a certain flexibility. The holes are there to offer room for the material to flex, avoiding the uncomfortable hardness you'd experience if the tires were solid- it fulfills the same purpose as the pressurized air inside a regular tire, as well as lowering weight. The classical, inflatable tires fulfill the requirements to enjoy a smooth ride, while remaining simple to produce, but early on, bike tires were, in fact, solid rubber." ]
eli5_question_answer
{ "query": "Represent the Reddit question about Automotive technology:", "pos": "Represent the Reddit passage about Automotive technology:", "neg": "Represent the Reddit passage:" }
What is the reason for the movie clapper, i understand it might help with editing but why the clap?
[ "It has already been answered, but I will add some more detail. A camera records the visuals, an microphone records the audio, obviously. The problem is, that unlike with consumer cameras, the audio isn't recorded to the same file as the video. So, you are left with a very high quality audio track, and a separate video track. The board, which also has information about each scene, is what joins together the two tracks. On set, the camera man will film the board, and the audio people will record the sound of the board. Now, when the two tracks are brought into the editing suite, they can sync the audio by going frame by frame and finding the point in which the board closes. Then, on that frame they will line it up with the peak in the sound waves. This is a lot easier than someone figuring out how to sync voices up." ]
[ "I believe they add whatever is on the screen during post production, which eliminates the bands" ]
eli5_question_answer
{ "query": "Represent the Reddit title:", "pos": "Represent the Reddit document:", "neg": "Represent the Reddit document:" }
At what point is bad grammar considered a new language?
[ "The general rule of thumb is that if people can understand each other, it's a dialect, and if they can't it's a language. I think bad spelling and grammar vs actual rules is just a question of if people are consistent. If you accidentally wrote \"teh\" instead of \"the\", that's bad grammar. If you consistently write \"ain't\" along with all the people in your community, it's part of your dialect." ]
[ "As far as I know, it means everything you mentioned. People commonly refer to it as both a serious relationship and as a more casual scenario. It is not a very precise word." ]
eli5_question_answer
{ "query": "Represent the question:", "pos": "Represent the document:", "neg": "Represent the document:" }
how do sports announcers know how to pronounce all the players' names? Whose job is it to tell them?
[ "They know how to pronounce all their names because they are very knowledgable about the sport and have heard/seen all players many many times. Probably for years while they are in college. They know all of them." ]
[ "American football has no minor leagues, like baseball, or soccer, college is important because the better the college, the more tough competition they faced on their way into the pros. however, it might not matter too much because if someone is great in college, they might not pan out in the pros. Just my off the cuff answer, probably more to it though" ]
eli5_question_answer
{ "query": "Represent the post:", "pos": "Represent the post:", "neg": "Represent the post:" }
Structurally, how is a GPU different from a CPU?
[ "Vast oversimplification, but you can think of a GPU like having thousands of weak cores while a CPU has a few powerful cores. When you're rasterizing graphics, each pixel is independent of each other--a GPU can calculate thousands of pixels at the same time. But not all processes are this stateless. Oftentimes you can't proceed without knowing a previous step. In fact, most tasks are like this, and that's why CPUs are still more important. Only some tasks are suited for mass parallelization." ]
[ "I assume you're talking about computing? Hardware Acceleration in this context means that instead of the CPU doing the work of rendering the graphics, you have a piece of hardware (i.e. a graphics card) specifically doing that work instead." ]
eli5_question_answer
{ "query": "Represent the question:", "pos": "Represent the document:", "neg": "Represent the document:" }
Why, as an 18 yo in California, my parents need to sign a waiver allowing me to sign myself out of school or sign anything for myself.
[ "because that's the contract between your school and your parents and you as a minor. as an 18yo, you can drop out of school, if you don't like that." ]
[ "They are not legally. When people do this it is identity theft and they are acting as though the child is 18 and filling it out on their own." ]
eli5_question_answer
{ "query": "Represent the query:", "pos": "Represent the document:", "neg": "Represent the document:" }
what’s the difference between emigrate, immigrate, and migrate?
[ "Migrate is general and just suggests moving from one region to another. Emigrate is to move your residence out of your country, and immigrate means to move your residence *into* a new country. So, if I move from Germany to France, I have emigrated from Germany, immigrated to France, and I have migrated from one country to another." ]
[ "An immigrant is someone who moves to your country. An emigrant is someone who moves away from your country. A migrant is someone who moves often (sometimes to the point of being semi nomadic) primarily in search of temporary work such as harvesting crops. They may be immigrants or they may be native born citizens. An expat is technically someone who has emigrated to a different country but have not given up citizenship to their native country. It however is often used in place of emigrant as \"emigrant\" is a cognate of \"immigrant\" and it often causes confusion when talking about things." ]
eli5_question_answer
{ "query": "Represent the post:", "pos": "Represent the passage:", "neg": "Represent the passage:" }
Time flow in singularity.
[ "It definitely isn't infinite mass. It's infinite density, which is a critical difference. The rest I'll leave to others who are more educated to comment." ]
[ "Arbitrary, likely measured from FPOC with the surface." ]
eli5_question_answer
{ "query": "Represent the title:", "pos": "Represent the answer:", "neg": "Represent the answer about Science:" }
Why do objects feel colder than the temperature of the air?
[ "Heat transfers faster through conduction (touching it) than through convection (transfer through a fluid, in this case the air). The faster heat leaves your body, the colder you register it as. That is why it is colder in a windy place than a calm place of the same temperature. When it is windy you are in contact with more air in the same time, you lose more heat in the same amount of time, your body tells you that is colder." ]
[ "The coin does heat up to room temp. The important thing to note is that room temperature is cooler than your body temperature. The difference between the coin and the air is that the coin will suck up more of your heat faster than air does." ]
eli5_question_answer
{ "query": "Represent the query about Science:", "pos": "Represent the document about Science:", "neg": "Represent the document about Science:" }
When people have 'high pain tolerance', do they feel actually feel less pain or do they just tolerate it better?
[ "Pain is in the brain. There is a part of your brain that translates stimuli from nerves into pain. If you would take this part out, you wouldn't feel any pain at all. In fact, there are people who are born without a functioning pain center in their brain. They usually don't live very long because the don't learn to stay away from hazardous situations. As with everything in the brain, how it works differs wildly between human beings and it also can be trained. When you're gradually exposed to higher doses of pain you can expand your tolerance. So that's why some people have a natural high tolerance, others have it trained. My experience as a physical therapist is that many people think they have a high tolerance for pain. But this also has to do with the fact that a majority of people think they are above average. Think about that ;)" ]
[ "When you're asked how painful something feels on a scale from 1 - 10, you are judging the pain based on your previous experiences of pain. A badly scrapped knee when you're older doesn't feel too bad if you have previously broken a bone. However, for children, a scrapped knee could be the most painful thing that has ever happened in their life! That's the \"10\" on their pain scale so they end up crying. Also as we grow older, we have some control over how we feel pain. We can dull it to some level but it comes at a cost of dulling all our other feelings. All the above refers to both physical and emotional pain." ]
eli5_question_answer
{ "query": "Represent the question:", "pos": "Represent the post:", "neg": "Represent the post:" }
Why is it such a big deal that Apple has so much cash?
[ "So, one part is because it's just a huge sum of cash....but let's go deeper A public company's responsibility is to maximize shareholder value. The best way to measure that is growth in the stock price. How does a stock price grow...stuff like ROI, ROE and profits and such. So the issue here is that that cash is doing nothing; it's just sitting in the bank and in risk free assets...meaning basically 0 return on investment (ROI). The shareholders are saying, \"Give us some of that cash through dividends so I can put it to work!\" With the dividends, investors can invest in other securities to get some ROI. If Apple was constantly using this cash to generate ROI, the shareholders wouldn't care. The problem is that the money is just sitting there and not creating returns for shareholders Personally, I am torn. High tech companies tend to hold a lot of cash but Apple is just going crazy. Tim Cook recently said there isn't a reason to have *this* much cash on hand. We'll see what happens." ]
[ "It's called Corporate Social Responsibility. Basically means that a company returns what it received from society. Just look at how many charities McDonalds have. It neutralises all the debate about how unhealthy they are. Also boosts the company's reputation, and thus becomes a good marketing source as well. Remember how Apple and Steve Jobs got bashed because They both **never** donated, compared to MS and Bill Gates giving up so much money? That's CSR in a nutshell." ]
eli5_question_answer
{ "query": "Represent the query:", "pos": "Represent the passage:", "neg": "Represent the passage:" }
How come if I wake up in the middle of the night, I often feel sweaty and gross, but if I wake up in the morning, I almost always feel normal?
[ "You're probably waking up in the middle of the night because you're sweaty and gross." ]
[ "No idea but completely useless shitty info: now that it's getting cold out where I live, I wake up cold pretty often in the morning and after hitting my first snooze alarm, I lay down on my floor and plug my space heater in and lay in front of it and take a quick nap. I'm noticing I like doing this more and more and I'm wondering if it's because it helps my back feel better." ]
eli5_question_answer
{ "query": "Represent the Reddit post about Sleep and fatigue:", "pos": "Represent the Reddit sentence about Sleep and fatigue:", "neg": "Represent the Reddit sentence:" }
the difference between Yiddish and Hebrew
[ "Hebrew is the language of Jews in the Middle East and of Jewish religious texts, it's a semitic language close to Arabic and Aramaic. It had actually died out, before it was revived as the national language for the state of Israel. Yiddish, by contrast, is an amalgam of German and Hebrew (using Hebrew script most of the time, but as I understand way more German words/grammar than Hebrew). It was the language spoken by Jews in Europe with ties to Germany and Eastern Europe, as well as England and France. Jews tended to be socially and economically isolated for much of European history, and Yiddish was effectively a \"ghetto\" language that emerged from Hebrew being surrounded by all other languages, but Hebrew's speakers not being accepted enough by the speakers of those other languages to end up committing entirely to using the newer, local tongues." ]
[ "Because the pronunciation of 5 is \" ha \" in thai its the equivolent to lol in english I assume that you saw this in online games Source : I'm Thai" ]
eli5_question_answer
{ "query": "Represent the Reddit query:", "pos": "Represent the Reddit argument:", "neg": "Represent the Reddit argument:" }
How can Paper Lanterns be safe? Why don't they start fires when they land?
[ "They do start fires. They're banned in 24 US states, according to the article below, because they're such a fire hazard. _URL_0_" ]
[ "Why do people get hurt in house fires? Can't they just walk out of the building?" ]
eli5_question_answer
{ "query": "Represent the title:", "pos": "Represent the comment:", "neg": "Represent the comment:" }
Someone commented on an askreddit thread that you can get drunk off of one shot by dipping your finger into it, and licking the alcohol off your finger over and over without actually picking it up and drinking it. How does this work, and is it legit?
[ "You could consume all of the alcohol out of the glass, yes. Would it get you drunk? Not a single shot, no. They're full of shit." ]
[ "You can drink a small amount of rubbing alcohol and it's not going to hurt you. You shouldn't get into the habit of drinking rubbing alcohol, but a small amount won't do much. Alternatively, if you were to dunk an open wound into a container of alcohol and let it absorb a bottle's worth of it, you might see some undesirable results." ]
eli5_question_answer
{ "query": "Represent the Reddit query:", "pos": "Represent the Reddit sentence:", "neg": "Represent the Reddit sentence:" }
How does reverse thrust on a jet engine work?
[ "Most jet aircraft have \"buckets\". When stowed, these don't interfere with the engines at all. But when deployed, they form a barrier behind the rear of the engine, which directs the jet exhaust forwards, creating reverse thrust. There's a very good picture of the buckets in their deployed position [here](_URL_0_). Edit: I've explained how reverse thrust is created. Just noticed that you also said about it being used to reverse on the ground. As another reply has already said, it isn't. It's used on the runway after landing, to slow down. The reason it is not used for reversing is because a) it would blow dirt, stones, etc into the front of the engine, causing damage to the engine, and b) the powerful jet blowing at an airport terminal (if you were reversing out of a nose-in parking space) would likely damage the terminal building, especially if it has glass windows." ]
[ "Do you know how a fan works? If so just turn it around" ]
eli5_question_answer
{ "query": "Represent the Reddit query:", "pos": "Represent the Reddit document:", "neg": "Represent the Reddit document:" }
Why are steel surfaces relatively inhospitable to bacteria and other germs whereas stuff like acrylic are not?
[ "I believe it has to do with the surface and how porous it is/isn't. Bacteria need tiny holes to hang out in (which also traps stuff they feed on), otherwise they get brushed away easily and there is less available 'food' for them. Also some metals give off ions that apparently kill bacteria. I know silver does, not sure about other metals." ]
[ "Foods that spoil quickly are full of nutrients like simple carbohydrates and proteins for molds and bacteria. They're also hospitable to microorganisms i.e. damp, not too acidic or salty, and relatively porous or not too dense so a colony can grow into the food. E.g soft cheeses spoil easier than hard cheeses because molds can send their tendrils of mycelium into the cheese. Drying foods preserves them since microorganisms need water. Salting food also has the effect of making it relatively inhospitable." ]
eli5_question_answer
{ "query": "Represent the Reddit title:", "pos": "Represent the Reddit document:", "neg": "Represent the Reddit document:" }
It is estimated that some sharks lose over 30,000 teeth in a lifetime - where does a shark obtain the levels of calcium necessary for such rapid tooth replacement?
[ "Well they don't have bones to worry about. We have a whole skeleton to upkeep, and we manage. But sharks eat a lot of things that have bones, and calcium in them, and what's more many calcium compounds can be dissolved in water, there are calcium ions just floating around the ocean, about 400mg/L of water. They don't really need anything to get calcium, they're swimming in a solution of calcium among other salts." ]
[ "Because our bodies do not have the necessary stem cells to produce more enamel. Bones, on the other hand, are in a constant state of remineralization and demineralization, and thus have a plentiful source of bone-producing cells to grow and repair damage if need be." ]
eli5_question_answer
{ "query": "Represent the question:", "pos": "Represent the argument:", "neg": "Represent the argument:" }
What's the matter with phi and fibonacci in nature?
[ "With regard to plants; Vi Hart has an excellent three part video on when it occurs, how it happens, and why phi in some plants is \"inevitable.\" [part 1](_URL_2_) [part 2](_URL_1_) [part 3](_URL_0_) In all the other cases; the phenomenon doesn't exist. Or more clearly the only phenomenons are logical fallacies such as cherry picking and confirmation bias." ]
[ "I'm sorry, but what do you mean by the \"failure\" of Citizen Kane?" ]
eli5_question_answer
{ "query": "Represent the Reddit query about mathematics:", "pos": "Represent the Reddit document about mathematics:", "neg": "Represent the Reddit document:" }
How do scientists calculate the amount of calories in food?
[ "They light it on fire! No seriously, a calorie is a unit of measurement that measures the amount of energy it takes to raise the temperature of water 1 degree. In order to measure that, they burn things below a beaker of water and see how long it takes to raise a degree (I believe it is specifically one ml of water, but I could be mistaken.)" ]
[ "How much fat, protein and carbohydrates are there in water?" ]
eli5_question_answer
{ "query": "Represent the question about Science:", "pos": "Represent the document about Science:", "neg": "Represent the document:" }
Why, as a non-smoker, do I occasionally get the "man, a cigarette would be great right now" craving?
[ "You've probably seen the relief on a smokers face after not having one for a while and your brain has subconciously associated tobacco smoke with relief. But the truth is every time we light up we're only relieving our need for nicotine. The stress relief is entirely in our heads." ]
[ "Cutting down to that few just makes each individual cig more precious. You really should just quit completely. I HIGHLY recommend Allen Carr's \"Easy Way to Stop Smoking\". It kinda of teaches you why the \"willpower method\" is so hard, but how easy quitting cold-turkey can be. I stopped smoking and I didn't feel shitty or like I was giving anything up. I have no urges to smoke and can even be around people that do and not give a damn." ]
eli5_question_answer
{ "query": "Represent the question:", "pos": "Represent the sentence:", "neg": "Represent the sentence:" }
Why can schools ban peanuts but not enforce manditory immunizations?
[ "\"Do this\" is harder to enforce than \"Don't do this\"" ]
[ "1. Not everyone CAN be vaccinated 2. Vaccinations don't work 100% of the time 3. Some children are in school yet too young for certain vaccinations. 4. Putting unvaccinated children together is just asking for a major outbreak 5. Said outbreak could result in a mutation that renders our current vaccines worthless." ]
eli5_question_answer
{ "query": "Represent the Reddit title:", "pos": "Represent the Reddit document:", "neg": "Represent the Reddit document:" }
Do most North Koreans truely believe that their leader is a deity?
[ "Obviously some do, likely out in the boonies but North Korea isn't nearly as tightly controlled as the North Koreans or the media would have you believe. It's certainly quite bad but Vice is know to \"hype\" their stories up a bit to make them a bit more entertaining. The black market in North Korea is fairly large and the country is very dependent on it to function. This brings in many goods and information from outside the country which the North Korean authorities are largely forced to tolerate out of economic necessity. The average state worker is paid in the official rate and only makes in a month about enough to buy some cigarettes. Those workers make up the difference by working in the black markets buying and selling goods. That should give you some sense of the scale of those black markets. Organizations within North Korea have even begun advertising the black-market rate for goods in an attempt to attract investment." ]
[ "There are a lot of elites in North Korea who are happy with the way things are. If something were to change, these elites would lose their cushy lifestyles in a best case scenario or be tried and sentenced to death in the probable scenario. They have a very strong iterest to prevent change and would likely assassinate or overthrow Kim Jong Un if he were to show \"weakness\". Kim Jong Un is in a pretty terrible spot. Even if he were a nice guy, he's practically forced to continue his father's policies in order to maintain power. Remember that a large number if not the majority of north koreans think of him as a savior to the people due to brainwashing through tight control of information." ]
eli5_question_answer
{ "query": "Represent the post:", "pos": "Represent the document:", "neg": "Represent the document:" }
How were live television shows aired nationwide before the internet?
[ "They were broadcast over the airwaves, like radio still is now. Or they were broadcast by satellite to local stations, who broadcast it over the airwaves. We were able to do a lot without an internet. Even invent the internet." ]
[ "Speeches were to a much smaller audience back then for the very reasons you mention. Newspapers were the primary way people heard major speeches before audio/video recording." ]
eli5_question_answer
{ "query": "Represent the Reddit title:", "pos": "Represent the Reddit sentence:", "neg": "Represent the Reddit sentence:" }
Why do I get the urge to jump when looking off a cliff or any high object?
[ "> Imagine a person with high anxiety sensitivity. She leans over a ledge of the Grand Canyon. In super fast reaction to her physical sensation of anxiety, her survival instinct forces her away from the edge. Yet when she looks at the ledge, she sees it’s sturdy. There was never any danger. Her brain tries to process an answer to the question “Why did I back up if it was safe?” A logical answer is that she must have been tempted to jump. > > In other words, Hames explained, people misinterpret the instinctual safety signal, and conclude they must have felt an urge to leap. Hence the study’s title: “An Urge to Jump Affirms to Urge to Live.” _URL_0_" ]
[ "Your depth perception is compromised when it's above the ground making it harder for your brain to figure out how to put one foot in front of the other without tripping. Edit: spelling" ]
eli5_question_answer
{ "query": "Represent the title:", "pos": "Represent the sentence:", "neg": "Represent the sentence about Physics:" }
Why do couples so often experience a decrease in sex drive shortly after marriage?
[ "There isn't one good answer for that because for one, it isn't the same with each couple and two because it doesn't necessarily always happen. One common reason though is simply time. A married couple will most likely spend their days working and by the time the day is done, sleep sounds like a much better idea than sex. Another reason is that after a while, a couple's sex life tends to become a little bit boring. When you first start having sex, you're both willing to try different positions and other stuff to please yourself and your partner. After a while, you figure out what works and it becomes more relaxed and not as exciting. Third, as you get older, your libido drops simply because that's how your body works. But really, tons of married couples still have plenty of sex drive, but they often have to actively \"spice things up\" to keep their libidos up and continue to make sex exciting." ]
[ "With some exceptions sex is a healthy and integral part of any relationship. It’s kinda the whole point of seeking a mate, biologically speaking." ]
eli5_question_answer
{ "query": "Represent the post:", "pos": "Represent the answer:", "neg": "Represent the answer:" }
Why cold water tastes better?
[ "I don't think it has to do with the taste -- I think it has to do with the refreshment. Humans (and all animals) don't drink water because it tastes good, but rather because we need it to survive and cool down when we begin to overheat. Since cold water is so refreshing, it's more enjoyable to drink. When a drink is more enjoyable, one would automatically assume that it \"tastes\" better, but I don't think that's necessarily what's going on there." ]
[ "You’re drinking the wrong water. Properly filtered water with the right Ph level tastes wonderful. Tap water tastes different depending on where you live. I’ve been studying in Austria for some time and the water tastes amazing here." ]
eli5_question_answer
{ "query": "Represent the question about Science:", "pos": "Represent the comment about Science:", "neg": "Represent the comment:" }
What is a transistor, and why was it's invention so revolutionary?
[ "Transistors replaced vacuum tubes, which perform the same function: they both can take a small electrical current and use it to control a larger current. Both of them can be used as switches (in computers) to perform on- and off- operations (1's and 0's) or as amplifiers. Amplifiers are needed for radios, TV's and so on. The big difference is that vacuum tubes are large, heavy and many need high voltages to operate while transistors are small and use low voltage. This allowed large, heavy bulky electronics to be miniaturized into small lightweight items like smartphones, PCs, and so on." ]
[ "Just thought I would throw in a fun fact here: Einstein was the discoverer of using sunlight to directly generate elctricity. It is called the photoelectric effect and he got the Nobel prize for it." ]
eli5_question_answer
{ "query": "Represent the query:", "pos": "Represent the paragraph:", "neg": "Represent the paragraph:" }
If the FBI supercomputer would take centuries to crack a certain password, can't they build several replicas of it and then solve it faster with cluster processing?
[ "A supercomputer is already made of thousands of processors. Sure, you could make two, and it would take half as many centuries. You can't make hundreds (to reduce the time to years), because even the FBI doesn't have the money to build and operate that." ]
[ "Depends on the type of job you're running. Different types of jobs can benefit from massively parallel processors, like you'd get by combining a bunch of smaller computers into a \"bigger\" one. Say you had a list of 100 million numbers that you had to add up. You could do it on one processor but it would take X amount of time. So you take the numbers, split them in to 100 groups, run each of those groups on a processor, then combine the 100 results. The resulting process takes that much less time. But there are also jobs that don't parallelize very easy. If your algorithm requires the result of another algorithm, you end up waiting on the first one to complete before you can start the next one. In that case, you want faster single processors more than a bunch of possibly slower processors." ]
eli5_question_answer
{ "query": "Represent the question:", "pos": "Represent the document:", "neg": "Represent the document:" }
What causes people’s voices to sound funny when they inhale helium?
[ "We are accustomed to hearing vocal cords vibrate in ***air***. Helium is lighter than air (that's why helium balloons float). When vocal cords are vibrating in helium, they can vibrate faster, resulting in a higher pitch, because they vocal cords aren't pushing against the heavy air. Similarly, if a person inhales something *heavier* than air (like sodium hexafluoride) their voice sounds *lower*." ]
[ "Our vocal cords get coated in fluid and mucus while we sleep. This results in a deeper, raspier voice when we first wake up." ]
eli5_question_answer
{ "query": "Represent the title:", "pos": "Represent the paragraph:", "neg": "Represent the paragraph about Health and Wellness:" }
Why places like fast-food chains support either Coke or Pepsi, but not both.
[ "With big chains Coke or Pepsi will try to get an exclusive contract, and they'll make an offer to sell really cheaply. IIRC Disneyworld gets theirs for free because it's such a big advertisement to have your product all over Disney." ]
[ "If they never advertised they wouldn't stay on top forever. Competitors are always trying to break into the market, so even if your product is the best now, you need to work to stay there. You see the same thing for other industries. Coca Cola pretty much dominates the soft drink industry, to the point that \"Coke\" and \"soft drink\" are almost synonymous, but they still advertise because if they don't one of their many competitors might take over more of the market." ]
eli5_question_answer
{ "query": "Represent the Reddit title:", "pos": "Represent the Reddit sentence:", "neg": "Represent the Reddit sentence about Technology:" }
Why can women have multiple orgasms while men can only have one?
[ "Wow, I think these comments are way off the mark. Do you guys think that cavemen were running trains on the cavewomen? And \"The strongest sperm\" != The strongest offspring, considering the first sperm to reach the egg don't fertilize it as they die breaking down the egg wall. Also, human females are better with a single partner, that way paternity can be verified and it's more likely the male will stay to support his own offspring. If a female can only orgasm once, they might do it before the male has finished and be done with intercourse. The female isn't getting pregnant then, so it is beneficial that females have no refractory period. If a male orgasms and keeps going, he has a good chance of scraping out his own sperm (the shape of the tip of the penis was designed to do this to other male's sperm). But once he orgasms, his seed his in there and he can pack up." ]
[ "Evolutionarily, it's to increase chances of having a baby. If a man continues to engage in intercourse after ejaculating, he risks inadvertently pushing the semen out of the way, making pregnancy more difficult. For a woman, if she orgasms first, she needs to stay interested until the man is done in order for there to be a chance of pregnancy. Because of these evolutionary needs, men have long \"refractory periods\" (lack of sexual desire after orgasm), whereas women either don't have them or have really short ones. The exact cause of the refractory periods in terms of body chemistry is still up for debate." ]
eli5_question_answer
{ "query": "Represent the question:", "pos": "Represent the paragraph:", "neg": "Represent the paragraph:" }
Soo, if we are flying around the sun flying around the solar system, flying around the galaxy...How are the stars we see at night in the same predictable places?
[ "The stars we see in the sky are pretty much all in the Milky Way, so they're moving the around the galactic center at the same time we are. It's important to note: the stars we see at night do change over the course of the year. Sirius (the dog star) is only seen during the \"dog days\" of summer (in the northern hemisphere)." ]
[ "Sorry. That star is nothing special. If it wasn't Polaris, it would have been another star. There is bound to be a star in the sky that the axis of the earth points too. And the stars are so far away 4 light years minimum, that the 16 light minutes Earth carved out around the sun just doesn't matter." ]
eli5_question_answer
{ "query": "Represent the Reddit title about science:", "pos": "Represent the Reddit argument about science:", "neg": "Represent the Reddit argument:" }
If antibacterial soaps are banned, what is ‘hand soap’ actually doing?
[ "You've got a field filled with rabbits, and they're eating your crops. Antibacterial agents and hand sanitizers are like poisoning the rabbits. The problem is that dead rabbit bodies are still strewn about, and some of the rabbits survive the poisoning, and their kids will also be good at surviving poisoning. And rabbits hold a grudge. Scrubbing your hands with soap is like flooding the rabbit holes, and physically washing them off of your field. The advantage is that rabbits don't blame you for floods, and their kids don't grow up flood-resistant. That is the strangest analogy I've ever thought of." ]
[ "Soap is not really antibacterial. But bacteria survives in the oils and dirt on your skin, which soap and water removes, along with most bacteria. This mechanism is not something that a strain of bacteria can develop resistance to, as much as it cannot become resistant to alcohol or high temperatures. There are soaps with antibacterial ingredients, but they cause much more problems than they solve (including resistance!), so should be avoided - unless you are about to engage in surgery. Yes, this means that the shelves of advertized antibacterial soap in your supermarket should be avoided. Plain soap with limited fragrances is best. Just remember that skin health depends on a natural amount of skin bacteria, and removing them can trigger problems like eczema." ]
eli5_question_answer
{ "query": "Represent the title about Science:", "pos": "Represent the argument about Science:", "neg": "Represent the argument about Science:" }
why is human excrement brown?
[ "There are a number of reason it's brown but the biggest contributor would be the presence of bilirubin. Bilirubin is a chemical that comes out of dead red blood cells. Basically, your poo includes expired blood, and that's brown." ]
[ "why do we yawn when we read about yawning?" ]
eli5_question_answer
{ "query": "Represent the Reddit title about Biology:", "pos": "Represent the Reddit argument about Biology:", "neg": "Represent the Reddit argument:" }
Why are some console versions of PC games not given the same treatment by the developers in terms of updates, patching, and DLC (i.e. Team Fortress 2 and Diablo 3)?
[ "Every update, patch and DLC has to go through certification and quality assurance on consoles. That process takes not only time, but money as well. Depending on much your particular audience is skewed towards PC, it is understandable that some developers will prioritize putting it up on that platform first, and then rolling it out on consoles after a while, if at all." ]
[ "Some games are easier to mod than others. Most have no official modding tools, unlike games like Skyrim or Valve games." ]
eli5_question_answer
{ "query": "Represent the Reddit title:", "pos": "Represent the Reddit post:", "neg": "Represent the Reddit post:" }
Why do I get so lovey-dovey when I'm tired?
[ "Depends on what you mean by tired and lovey-dovey but probably due to the happy chemicals your brain releases when you're about to fall asleep. Dopamine and such." ]
[ "Because it helps to take your mind off of the embarrassing thought. I do that a lot when I'm hung over." ]
eli5_question_answer
{ "query": "Represent the Reddit title:", "pos": "Represent the Reddit argument:", "neg": "Represent the Reddit argument:" }
Why road construction crews don't re-pave bridges?
[ "Because the bridges are likely made of concrete and the crews are re-laying asphalt. They are two different materials with different maintenance cycles." ]
[ "Concrete is durable and has a long \"life\" so they're great for holding the bridge up. Asphalt is cheaper to make and sets faster when building a road. It's also recyclable and gives better traction for the wheels during rain and snow. Asphalt is also easier to fix (the lines you can see over road cracks or filled potholes). If concrete gets a crack or pothole the whole slab has to be replaced. Source: _URL_0_" ]
eli5_question_answer
{ "query": "Represent the Reddit question:", "pos": "Represent the Reddit document:", "neg": "Represent the Reddit document:" }
When games on Steam go on sale dirt cheap, who makes the money, and how do they make profit?
[ "There are a few reasons for it. First, making a game costs X dollars. Let's say it costs $1000. They sell the game at $10 per copy when it comes out. After 100 copies are sold, every single sale after that is pure profit. If after 100 copies are sold they lower the price to $1, every single copy they sell is pure profit. (This is subject to a few things, if they sell disc copies they have to manufacture and deliver the disc, if it through Steam the developer has to pay Steam a cut for providing the service). Second, it is a way to get you to use Steam. The more you use Steam to buy cheap games, the more likely you are to use Steam to buy full price games." ]
[ "It's important to remember retails often lose either nothing or close to nothing when selling a game, they didn't have to pay for a had copy or box, they didn't have to rent space for the shop and they didn't have to pay someone to sell that copy to you, so the over head is very small. The reason all games aren't 90% off all the time has nothing to do with losing money, and everything to do with losing POTENTIAL money. Sales bring in the people who often wouldn't have bought the game at all otherwise, while it takes a while to go on sale - and a fairly long time before going on DEEP sales, to make sure that the people willing to pay full price - do." ]
eli5_question_answer
{ "query": "Represent the post:", "pos": "Represent the sentence:", "neg": "Represent the sentence:" }
Dependent and Independent variable.
[ "The dependent variable is what you are measuring (e.g. number of correct answers on a test). The independent variable is what you are manipulating (or think of it like groups you are categorising people into e.g. gender (male/female), age (teenagers, older adults)) This usually leads to a hypothesis such as \"There will be an effect of the IV on the DV\"." ]
[ "Same difference between color and colour. Continent-based spelling differences." ]
eli5_question_answer
{ "query": "Represent the question:", "pos": "Represent the post:", "neg": "Represent the post:" }
Why are cans for canned goods not square?
[ "Cans are round because it maximizes the volume per amount of metal used and because being round makes them stronger than cubes." ]
[ "Not all cans are like that. I've got cans of pet food in my cabinet that stack perfectly. I've got cans of Bumblebee tuna that stack just fine too. It's most likely just that particular brand's decision to use a different can. Maybe that type of can is cheaper or maybe they can save money on manufacturing by using a different can that just happens to topple easier." ]
eli5_question_answer
{ "query": "Represent the query:", "pos": "Represent the document:", "neg": "Represent the document:" }
Why does the north star never move but all the other stars do?
[ "The others appear to move because the earth is spinning on its axis. Directly above either of the poles of that axis, a star will appear to barely move at all, but other stars will trace circles around it through the night. You can take some cool long exposure photographs by pointing your camera at celestial north and waiting. Stars will smear out into concentric circles around celestial north." ]
[ "Because the moon is continually orbiting the earth. The moon doesn't follow the night when it orbits, so sometimes we can see the moon during the day." ]
eli5_question_answer
{ "query": "Represent the query:", "pos": "Represent the paragraph:", "neg": "Represent the paragraph:" }
How can we so distinctly remember things that never actually happened?
[ "It is possible to vividly imagine something and then simply re-categorize that mental image as a memory rather than something you imagined. The act of remembering it works just the same. You can see what it looks like, hear the sounds or voices, and so forth. You just have attached a wrong category to it." ]
[ "Anything in the past is history. For example, the Paris shootings were a historical event. It doesn't matter how recently something happened to be considered history." ]
eli5_question_answer
{ "query": "Represent the question about Psychology:", "pos": "Represent the document about Psychology:", "neg": "Represent the document:" }
Why do large explosions result in a mushroom cloud?
[ "[Wikipedia says](_URL_0_): > Mushroom clouds result from the sudden formation of a large volume of lower-density gases at any altitude, causing a Rayleigh–Taylor instability. The buoyant mass of gas rises rapidly, resulting in turbulent vortices curling downward around its edges, forming a temporary vortex ring that draws up a central column, possibly with smoke, debris, or/and condensed water vapor to form the \"mushroom stem\". So in ELI5-terms: the hot gas resulting from the explosion creates an updraft which pulls debris/dust from the ground up and forms a vortext at the top. Check this diagram, because [images are better than words](_URL_1_)" ]
[ "Lighting is very hot. When there's a lightning bolt, it rapidly heats the air around it, creating a sort of explosion. That explosion is thunder." ]
eli5_question_answer
{ "query": "Represent the question:", "pos": "Represent the document:", "neg": "Represent the document:" }
why isn't there more footage on the Internet of US soldiers in close combat (e.g. clearing buildings) situations?
[ "When you are in close combat, you are at immediate risk of being killed. You have better things to do then screw around with a camera. Now that cameras are very very small and wearable, and have longer battery life, this kind of footage will become more common. A separate issue is that many military organizations prohibit sharing pictures or video taken during combat until it is approved by senior command. There is a strong desire to keep operational details secret, and to protect the identities of the people involved in case they are captured later." ]
[ "Well, for starters Jarhead was set during the Gulf War, which was a fairly short and almost entirely mechanized campaign. We took a long time to build up our forces, then steamrolled through kuwait and kicked the iraqis out with relatively little trouble, with airpower and tanks shouldering a lot of the workload. The Iraq war was like that for the first bit, but has since settled into more of an occupation, with infantry doing most of the work in house to house fighting. This type provides a lot more work for a sniper, especially a really good one." ]
eli5_question_answer
{ "query": "Represent the query about Current events:", "pos": "Represent the argument about Current events:", "neg": "Represent the argument:" }
how come some people have long, pointy canine teeth, which are longer than their regular teeth; and some people have flat canines the same length as the rest of their teeth?
[ "How long your teeth are based on a few things. Mainly its because of the genes (traits) you inherit from your parents and their parents before them. Shapes and size of teeth are different in people from different races which is also a trait thing. Pointy-ness of your teeth depends on how much you use them. The more you use them the more they wear out despite being quite strong. This dulls the point and can make them flatter. Canines are generally (especially upper canines) large, long and pointy because of the way they have been used by all the animals that have them. Over time they have become what they are to tear and hold onto things (like lions hunting deer). Sometimes they can appear longer if the tooth opposite the canine is missing. Teeth are always moving and growing into the mouth but things that come in the way stop them. If the opposite tooth is gone then usually nothing is stopping the canine from growing longer." ]
[ "The human skull is born with all the teeth it's gonna have. If you look at an [x-ray of a child's head](_URL_0_), you can see they've got their adult teeth all crammed up in their gums above their baby teeth. So our teeth don't really \"grow back\". All the teeth you were ever gonna have are already there, from birth. Also, you have more adult teeth than baby teeth. You have 20 baby teeth (10 on top, 10 on bottom), but you have 32 permanent teeth (16 on top, 16 on bottom). This is different than many animals, like sharks, that continually shed their teeth throughout their life and will grow them back indefinitely. Humans don't do this. Our teeth don't grow back. Some animals, like rats, also have teeth that grow bigger continuously, and so must be continually blunted and shortened by gnawing on things. This again is unlike humans. Our teeth do not repair themselves, unlike bones. If your tooth chips, it will not grow back." ]
eli5_question_answer
{ "query": "Represent the Reddit query about Dentistry:", "pos": "Represent the Reddit paragraph about Dentistry:", "neg": "Represent the Reddit paragraph:" }
Why does everyone hate comcast?
[ "They stand against innovation by working in what is essentially a monopoly. They have outrageously high prices for outrageously low-quality products. Other countries have internet that is 5-6 times faster than Comcast for half the price. Why is Comcast able to do this? Because they have 0 competition. Basically, they are able to do whatever anti-consumer policies they want because there's no other company to give them competition. Customers *have* to deal with it in most cases. This ends up with them raising prices, adding fees, having terrible customer support, having a low-quality product, and overall halting the innovation and expansion that the internet provides. TL;DR Their company policy isn't: \"You'll want buy our product because it's the best available\" It's: \"You'll have to buy our product because it's the only one available." ]
[ "Why can't you? What type of internet do you have?" ]
eli5_question_answer
{ "query": "Represent the post:", "pos": "Represent the document:", "neg": "Represent the document:" }
Why do people on reality survivalist shows bring firestarters instead of a lighter? It seams that a disposable lighter would work much easier and last more than the 30 or so days that they are in the wild.
[ "Because if they wanted to do things the easy way they wouldn't be on a survivalist show in the first place." ]
[ "Stormproof matches are basically regular matches with a light coating of wax to keep them waterproof. Scratching the match on a surface removes the wax, then simply strike like normal. You can easily make your own waterproof matches by simply dipping regular matches in melted candle wax. Cover the head of the match in a thin but complete layer of wax. Simple enough. Your survival kit should always include multiple ways to start a fire, especially in bad weather. Waterproof matches are good. Cotton balls with a bit of petroleum jelly (vaseline) on them make for great tinder. Finally, a flint striker is also very easy to include in any kit. Redundancy in your fire starting capabilities (as well as your water collection capabilities) can mean a big difference if you are in a situation where you need to use the survival kit." ]
eli5_question_answer
{ "query": "Represent the post:", "pos": "Represent the document:", "neg": "Represent the document:" }
How do speakers of Japanese, Chinese and other languages with pictographic writing systems organise their dictionaries?
[ "Japanese does have a common way of ordering their sounds. It is the order they use for their hirigana (Ka, ki, ku, ke, ko.) So some dictionaries get ordered in that way. (well, Japanese - english dictionaries do, at least). Then another way to order them would be by kanji radical. Kanji are made up of several reoccurring pieces called radicals. So if you would come across an unknown kanji, you could use a kanji dictionary and start looking up things on a radical base. Radicals, as far as I know, are ordered by stroke order, from least strokes to most strokes" ]
[ "It's a feature particular to languages that use the Latin, Greek, and Cyrillic alphabets (and a couple of related alphabets). In particular, Chinese, Korean, Japanese, the Indian and Southeast Asian scripts, and Arabic (and Hebrew) do not capitalize. Having tried to learn a language (Bengali) that does not use capitals, I can attest to their use. If you're starting out, how do you tell a name from another noun? Are you talking about chandra (the moon) or Chandra (the common surname)? There are so many cases in every language where common and proper nouns overlap, and having capitalization is very helpful. I'm not too sure why sentences begin with capitals, but it certainly makes English easier to read." ]
eli5_question_answer
{ "query": "Represent the Reddit title:", "pos": "Represent the Reddit document:", "neg": "Represent the Reddit document:" }
We have vitamin A , B, C, D, E and K but not F, G, H, I and J. Why?
[ "Vitamins A through E were named alphabetically. Vitamin K was discovered later and is essential in coagulation. But when they name it they spelled it koagulation." ]
[ "Sunlight is needed to start a process in your body which makes vitamin D. So vitamin D actually isn't a vitamin." ]
eli5_question_answer
{ "query": "Represent the title:", "pos": "Represent the passage:", "neg": "Represent the passage:" }
Why does exercise such as running or cycling feel much more strenuous during the first couple of minutes?
[ "Blood is constantly pumped all around our body to supply oxygen to all our muscles. In the case of running and cycling, we predominantly use our legs, but seeing as though we still have a regular blood circulation, our muscles find it difficult to work comfortably due to the lack of oxygen for the task they are performing. So, our body makes the decision to divert more blood towards those specific working muscles through the contraction and dilation of the blood vessels. This is why people tend to do a \"warm up\" before going on a run or cycle as it helps raise the heart rate to a level where your body would be comfortable performing strenuous tasks" ]
[ "Unless you're walking over rough terrain or up steep inclines a 4 mile walk should not be tiring on the level of a strenuous workout. In general your perceived exertion is a good guide for how fast you're burning calories" ]
eli5_question_answer
{ "query": "Represent the Reddit question:", "pos": "Represent the Reddit document:", "neg": "Represent the Reddit document:" }
Why were people shown as having pure white skin in ancient asian portraits?
[ "Pale skin was in China, as in Europe at one time, a symbol of the upper class--you cannot avoid being tanned if you perform outdoor labor. It's long been represented in art, dolls and make-up fashions as a beauty ideal." ]
[ "They thought the Human body was divine and beautiful. The renaissance just copied them. There are plenty of clothed statues as well." ]
eli5_question_answer
{ "query": "Represent the Reddit question:", "pos": "Represent the Reddit document:", "neg": "Represent the Reddit document:" }