Datasets:

Task Categories: text2text-generation
Languages: en
Multilinguality: monolingual
Size Categories: 100K<n<1M
Licenses: unknown
Language Creators: found
Annotations Creators: found
Source Datasets: extended|eli5
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q_id (string)title (string)selftext (string)category (string)subreddit (string)answers (json)title_urls (json)selftext_urls (json)
5lchat
Why there was a 'leap second' added to the end of 2016?
Other
explainlikeimfive
{ "a_id": [ "dbuoyxl", "dbur7gi", "dbuotht" ], "text": [ "the rotation of the earth is not a constant. in fact the rotation of the earth is slowing down, which means that a full day is getting slightly longer. without leap seconds our clocks would slowly drift ever so slightly out of sync with the actual day. we could deal with this by redefining how how long 1 second is, making it slightly longer so that one day is still exactly 24*60*60 seconds. but in practice that is really inconvenient for a lot of our technology which relies on very precise timing. its easier to just move us ahead one second every couple of years or so.", "The Earth's rotation is not regular. It varies a bit, so sometimes we add a second. We do this to ensure that noon is always going to be sometime around mid-day. If we did not add leap seconds, over a very long period of time where the Earth's rotation slowly changed, noon could end up being at dusk. We want to keep 7am in the morning, noon at mid-day, 7pm around evening, etc. Though we have never had one, it's also possible to have a negative leap second. That is, taking away a second from the year. This has never happened, but if the Earth's rotation were to speed up, it could happen. The biggest thing to know about leap seconds is that they can cause computer problems. You might remember the Y2K bug. A leap second can cause similar problems, and they actually have caused problems in the past. The reason for this is that generally we expect a day to have 24 hours, and for time to always move forward. With a leap second this is not true. When writing software, programers try to think of all the possible exceptions that could happen withing their code. For example, the program might expect a word, but instead get a number. A good programmer will check for these exceptions and deal with them. However, a programer can easily forget about leap seconds and not have a fail-safe in their code for when a day have more than 24 hours. When such an exception happens, the program can produce errors or crash. It is an interesting topic, you can read more about it here: URL_0", "Because the Earth's rotation is slowing. If you multiply 24 hours by 60 minutes by 60 seconds, you find that there are 86400 seconds per day. The problem is that our definition of the second is based on [an average that is a century old.]( URL_0 ) In modern times, the average day is about 2 thousandths of a second longer—again, because of Earth's slowing rotation. Those thousandths of a second add up, so every few years we have to slip in an extra second to account for them. Without leap seconds, we'd eventually end up with noon at 7 o'clock, though admittedly, this would take a very long time." ], "score": [ 44, 5, 4 ], "text_urls": [ [], [ "http://adminhacks.com/leap-second-bugs.html" ], [ "https://en.wikipedia.org/wiki/Newcomb%27s_Tables_of_the_Sun" ] ] }
[ "url" ]
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5lcjq6
How do you claim undiscovered land?
If your on a boat, sailing through lets say the Pacific and you come across an island and later on you find its an undiscovered island then can you claim it as your own land if your are A. In international waters B. Belong to a country or are a citizen of a country? If you have the answer, who would you talk to to claim the land. By the way, this is just a hypothetical.
Other
explainlikeimfive
{ "a_id": [ "dbuplm8", "dbuocvb", "dbux9vf" ], "text": [ "Imagine you are out walking in the woods near your house and you find a cave. You think to yourself, \"Gee that's a real nice cave, there's just enough room for my rocket car, my crime fighting computer and my superhero costume collection. It'd be perfect for me.\" Let's say that nobody already owns the cave, so you move in and bring in all your stuff. You carve a costume wardrobe into one of the stone walls, grab a shovel and flatten the floor a bit so your rocket car can drive in and out. After you've finished working on the cave and fixing it up you start to think of it as yours. But not everybody agrees. There's another guy a few miles away who also fancies himself a billionaire superhero like you. Flies around in a stupid metal suit that he made himself while a prisoner of the Taliban or something like that. Anyway, one day he walks by and sees your cave and thinks, \"That's a great cave, I should make that my lair.\" So he comes in for a chat. He starts by telling you that he's going to move into your cave because it's his. You tell him to get stuffed, and that if he tries to take it from you, you'll be forced to unwrap a bundle of BAM!, POW! and WHOOF! on him. And what's more, you've recently adopted a teenage boy who'll do the same. \"Yeah?\" says the guy, \"Well if that's how you feel, I'm friends with a cryogenically frozen soldier, a Norse god and some dude who owns a bow and arrow. They'll back me up if I ask them. Your move.\" \"So what?\" you say. \"One of my friends is a super strong refugee from a dying planet, another is a mythical Amazonian warrior and there's also a guy who was electrocuted by lightning while drowning in toxic chemicals. They'll take your friends for sure.\" \"Yeah? We'll see. How fast can your friends be here?\" \"Funny you should ask. There's something I didn't tell you about my friend who got struck by lightning.\" Suddenly a phone rings. It's the other guy's cell. On the phone is a cool, english sounding voice with immense gravitas. \"Forget the cave.\" it says. \"I've spent my life training superhero teams at my private academy, and I'm telling you, your team is outgunned. In any case, nobody else wants a fight over this cave when we should all be working together for the good of mankind. Everyone else has decided the cave is his cause he claimed it first. So walk away.\" This call makes all the difference. The other guy might not be happy, but he leaves you in peace. The cave is yours because a) you claimed it b) you were in a position to defend it and c) everyone else agreed that your claim and ability to defend were substantial enough to recognise your right of ownership.", "By force. Historically, nations have defended their territory via their military or the military of their allies. If you want to keep an undiscovered island for yourself, be prepared to fight for it.", "With a flag and an force/money to back the claim. Now you've got a claim and prevented people from conquering it. The next step is making everybody else acknowledge the claim you have is legitimate. Historically that was usually done by force and/or transporting people there. If you're interested there is discovered and unclaimed land in several places in the world (terra nullius). Antartica has the most unclaimed land. A few other places have border disputes that result in neither side accepting a small chunk of land." ], "score": [ 195, 39, 5 ], "text_urls": [ [], [], [] ] }
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[ "url" ]
5lcl43
Why do we fail to do realistic human CGI (like in SW Rouge One) yet we do it so great on non-human beings (like in Warcraft)?
Title pretty much, thanks for answers in advance!
Technology
explainlikeimfive
{ "a_id": [ "dbuns7l", "dbunw2c", "dbup34d", "dbuo2f1" ], "text": [ "It's more that we're really good at picking up subtle mistakes in humans, and fantasy beasts have no reference, so its a lot harder for them to look wrong.", "Probably because we are so adapted to human skin/tone/etc. that our brains can pick out what is real and what is fake. Since we can't actually conceptualize what alien skin would be, real or fake is no different to us. Think about it like being scared as a child by a man dressed in a costume, over time we learn and accept that it is fake and not a threat (except clowns fuck that shit).", "When was the last time you compared an Orc IRL to WoW?", "It's a phenomenon known as the uncanny valley. We are very good at noticing when something is off with our fellow human beings." ], "score": [ 34, 11, 7, 7 ], "text_urls": [ [], [], [], [] ] }
[ "url" ]
[ "url" ]
5lcr1h
Why is it that we calm down when we take a deep breath, hold it for a few seconds and exhale?
Biology
explainlikeimfive
{ "a_id": [ "dbuusst" ], "text": [ "Anxiety/stress are the result of your sympathetic nervous system being activated (fight or flight response). When we are threatened we experience a variety of physical effects, e.g. increased heart rate, GI upset, jittery muscles, *rapid shallow breathing*. This helps us fight the threat or run away from it. Helpful when facing down a sabre-toothed tiger; not so much when we can't speak to a large group. The parasympathetic nervous system works in opposition to the sympathetic nervous system. It's the \"all is well\" setting for your bod- relaxation in terms of muscle and heart rate, *slow deep abdominal breathing*. What intentional deep breathing does is activate the parasympathetic nervous system, even if there is an anxiety-provoking event. Basically you are overriding the stress response with the \"nothing to worry about\" system. Since you can't simultaneously be threatened and unthreatened, your body takes the cue from the slow breathing to reduce or eliminate entirely the stress response." ], "score": [ 8 ], "text_urls": [ [] ] }
[ "url" ]
[ "url" ]
5lcsyf
Why does 1080p on a 4k TV look better than 1080p on a 1080p TV?
Technology
explainlikeimfive
{ "a_id": [ "dbuq0qt", "dbuqstj" ], "text": [ "In a 1080p screen each pixel is represented by four individual points of light, one for each color and two for green. However when projecting 1080p video on a 4K screen you have 16 individual points of light for each pixel. This gives you a lot more room to play with. If you just map it naively you end up with a crispier image since there now is less distance between the pixels. However you have room for some filters on top which can interpolate the additional pixels from the surrounding pixels depending on the context. So an intelligent algorithm will find out where you want a smoother gradient and where you want a crispier line.", "Besides what people are saying about upscaling interpolation. It may just be a better tv, the same way an excellent 1080p will look better than a Westinghouse UHD tv. Another option is vibrant picture settings, like added sharpness and enhanced color, which while they give you what the picture is supposed to look like, it makes it more eye catching." ], "score": [ 9, 4 ], "text_urls": [ [], [] ] }
[ "url" ]
[ "url" ]
5lcz56
How is property in outer space valued? If the earth colonized Mars what government/organisation would technically own it
ELI5: How is property in outer space valued? If the earth colonized Mars what government/organisation would technically own it
Other
explainlikeimfive
{ "a_id": [ "dbusxe1" ], "text": [ "There's a [treaty] ( URL_0 ) that forbids countries from claiming territory in outer space. That means that while theoretically a private company could simply go up there and claim it, but it wouldn't be recognised by any earthly government... they'd have to set up their own government" ], "score": [ 5 ], "text_urls": [ [ "https://en.m.wikipedia.org/wiki/Outer_Space_Treaty" ] ] }
[ "url" ]
[ "url" ]
5ld008
Why does lights make a "blinking" effect when looking at them from far away?
Other
explainlikeimfive
{ "a_id": [ "dbusvko" ], "text": [ "Because of the air in between you and the light source. The air is at slightly different temperatures so it's like a heat shimmer effect you get above a fire, also the air is full of dust and other stuff we don't normally notice, but at distances it blocks a bit of the light." ], "score": [ 5 ], "text_urls": [ [] ] }
[ "url" ]
[ "url" ]
5ld14u
Why are internet speeds in America so slow
Technology
explainlikeimfive
{ "a_id": [ "dburxe8", "dbursr8", "dbuuxnd", "dbuutes", "dbuy0vg", "dbuxrff", "dbuyci8", "dbuy3lo", "dbuxujv", "dbuxyrh", "dbuyev3", "dbuy1ya", "dbux4mj" ], "text": [ "It mainly has to do with the monopoly that ISP's hold over different areas. Most people have one choice for their internet provider. It's not like you can switch to a different company if you aren't happy with their shit service. Another thing is that the capacity for fast internet exists it's just that they have no reason to give it to you. My city recently became a prospective city for google fiber and TWC immediately upgraded our 20mb/s connection (maximum available) to 100mb/s for free and also started offering 200mb/s and 300mb/s for not much extra. They're also doing everything they can lawsuit wise to keep google fiber out of the city", "Verizon has the best coverage, but it's not the fastest, I'm visiting family in Atlanta and I get > 110Mbps on T-Mobile. Though, I'm on their Wi-Fi as [it's much faster]( URL_0 ) (he's an exec at HP so gotta have fast Internet). 90% of the answer is because they can. 10% of the answer is because money, America is huge, and dense, so having to have thousands/millions of cell towers spread across the country and having hundreds in a single city is expensive in regards to renting out the land, supplying enough data per tower, etc.", "Of all of the countries to use as an example, you use Australia? They still have a good chunk of the country on dialup since it's such a large region but has only six or so metropolitan areas. Really, America's internet speeds aren't that bad. They're not #1 but I think they were in the top 10. Meanwhile, Australia is still trying to build a fiber network but its own government keeps sabotaging it", "Several reasons: 1. there's little or no competition in most markets. 2. the cost of starting up puts it out of reach for most companies. Even Google is growing insanely slow due to the cost of laying new lines 3. we've got other problems. My Internet is reliable (like 95%+ uptime) and fast enough (50 Mb) for just about anything my family of 4 needs for $65 a month. The only way things are going to change is if we make a widespread political effort to change it and frankly, my efforts there are better spent on other issues.", "Speeds are so slow because the telecom industry in America is a monopoly. In certain areas you only have one choice for a provider, so why would they spend money to improve their services if you don't have any other choice? The telecom industry has been vigorously lobbying and filing lawsuits to prevent competition. Things like poles, switches, and boxes (the kind you find outside) are owned and rented out. Lawsuits have been thrown around to prevent other companies from using those utilities which makes it hard to compete. Telecom companies also sign deals with the cities themselves. If the city attempts to provide their own internet they would get sued. The only reason Google Fiber was able to become a thing is because Google could afford to build their own utilities and fight in court with a chance of winning. The American telecom industry is the poster child of corruption and bad morals and ethics. They are not satisfied with their 97% profit margins and don't care one bit about making the world a better, more connected place. It is because of Google Fiber that companies like Comcast are finally starting to improve their networks, because it is clear to both sides that the moment Google Fiber is available everybody will jump ship. These companies are fully aware of what they are doing and how damaging they are and are terrified that their monopoly will end.", "Most people here simply do not understand how absurdly expensive running fiber is here in the US. A lot of it is all the codes and standards, environmental protections etc. Just to give you an example. When we tried to build a single fiber run to a local school, the cost was $75,000. We got an estimate for wiring the entire small city for fiber (every home) and it came out to about $35 million. That's for about 15,000 people. That's almost $2400 per person if every single one of those 15,000 signs up. That's just the fiber and equipment, no bandwidth to backhaul providers, etc. And this involves no big greedy corporations who just want to charge you a ton of money because they are evil and diabolical as is the common belief on Reddit. And in the real world, this notion that bandwidth costs nothing is simply untrue. Sure there are some companies that trade bandwidth. So long as they are both sending each other the same amount of data each way, they don't charge each other for that mutual bandwidth. But its not very common for ISPs. The US is very vast and has lot of mountains in many areas. Those long distances cost a huge amount of money to cover, as do areas like mountains. So take the endless claims that it's all about big greedy corporations with a grain of salt. Feel free to do some research and see how much it would cost you if you were to build your own fiber network non-profit and you will see for yourself.", "You won't get 200Mbps on Telstra LTE most of the time unless you're very lucky. First of all, the guy is in Melbourne, speedtesting to a Telstra server. Telstra has its HQ in Melbourne, and they have very strong mobile reception here (plus in other cities). But outside of the bigger cities, or even in the suburbs, the mobile cells are further spaced out, so there's more congestion and generally the speeds drop off a bit. It is pretty good though, I'm currently getting 85Mbps inside my house (Melbourne suburbs, about 8km from the CBD). Telstra is a world leader in LTE technology, they're investing a lot of money in it. If you moved to another carrier, you wouldn't get as good service. However the fixed line internet in Australia is nowhere near as good, as other commenters have said. Also, mobile data is expensive here, especially with Telstra (best network, so they charge more). You get 10GB on a $120/month plan with an iPhone 7 (unlimited talk and text). And when you go over the 10GB, it doesn't throttle your speed, you get charged at a $10/GB rate. Source: I'm currently doing an internship at Telstra :)", "LOL, sure you can get those speeds in Aus, but i mean you have a max of like 25GB before you start paying $10 per GB over that. Source: Am an internet seller man", "America is where the technology is developed. As a result it's usually the first country to get things and gets technology 1.0. As the technology gets deployed people figure improvements, better ways to do stuff, upgrades, etc and technology 2.0 is developed. Usually this updated technology is deployed in the rest of the world after the USA. So why don't you just upgrade the technology? Well, upgrading usually costs more money, and technology 1.0 tends to be good enough. BTW, this doesn't just refer to LTE cell phones, but to credit card chips (which most of the world had before us), and other stuff that's deployed first to the US and later to the world.", "I work for T-Mobile as a project manager. We are the fastest in our area and many others but it really depends on the spectrum owned by the carrier. The US government (FCC) Is in charge of dividing up the available spectrum via auctions. 5MHZ of additional spectrum can cost billions of dollars per market (geographic area). That's the reason he carriers are always trying to merge or buy each other out. It isn't the towers, customers, or equipment. It's the spectrum. The carrier with the most bandwidth owns the speed and thus owns the customers. It's a vicious game.", "There's an Adam Ruins Everything on this. If I remember correctly the TLDR is that since the govt thought that I'd all be just a fad, they didn't stop monopalization- There's barely any competition so no pressure to get any better.", "Collusion. Companies spend the absolute bare minimum they need to maintain their networks and strike deals amongst themselves so as not to have to compete with anyone else. When someone like Google Fiber comes into the market, they use lawyers and politicians to help keep them out and protect their fiefdoms.", "The geographical area that is covered in other countries is is tiny compared to in the US. Even in countries that are larger than 1/50th of the US, they still only supply internet to their larger cities and metropolitan areas. Also, CDMA is an anti-competitive technology. Verizon is a CDMA company in the US. Everywhere else, GSM (Like T-Mobile and AT & T) is mandated and pretty much open to competitive forces which improve service and decrease consumer costs." ], "score": [ 423, 321, 235, 52, 22, 13, 9, 8, 8, 6, 3, 3, 3 ], "text_urls": [ [], [ "http://www.speedtest.net/my-result/i/1916489877" ], [], [], [], [], [], [], [], [], [], [], [] ] }
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5ld1ko
How are pop-up and generally annoying web ads viable?
Go to a news website, or any website in general, and you get bombarded with pop-up ads, ads that start playing videos automatically, etc. - how is this intrusive advertising even remotely beneficial to the advertiser anymore? It seems like this type of advertising would do more harm to their brand than help. Do they actually generate substantial traffic and revenue for the advertiser?
Other
explainlikeimfive
{ "a_id": [ "dbusu9z", "dbuynrr" ], "text": [ "The same reason you get viagra and penis pill spam in your email. Some people are unbelievably stupid and willing to spend money to prove it.", "> It seems like this type of advertising would do more harm to their brand than help I suspect most of us associate annoyance with the *ad* itself, but not the *brand* behind the ad (E.g., I know I don't hate Coke because of their annoying ads). It also doesn't matter much if ads are annoying. Half the job is making people remember. What annoying ads do? Make people remember. If we forgot them in 30 seconds they probably would be annoying in the first place. There's also a few interesting studies I've heard of about us being more receptive to the '*skip this ad in 5 sec*' type, because for that five second period we are paying attention to try and skip it asap, whereas on telly we zone out almost immediately. > Do they actually generate substantial traffic and revenue for the advertiser? They don't even need to generate revenue directly or immediately. Many marketing things are long term and look like they are losing money on paper. Primarily, they just need to make sure you are aware of that brand. Do you know how often I see ads to [Grammarly]( URL_0 )? Sure, I find the ads annoying. However, I now *know* about the product and if I wanted a service like that it's the first one that comes to mind. Because of those ads, before I even used the service or product, I have a 'stereotype' of that product. People often use these stereotypes when making purchases. In this case, I'd be making a comparison between a complete unknown and something I've seen on an ad. For many, that's enough to change their decision and behaviour." ], "score": [ 13, 4 ], "text_urls": [ [], [ "https://en.wikipedia.org/wiki/Grammarly" ] ] }
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5ld2d4
Why would a drug dealer lace their product with carfentanil, which is causing so many OD deaths? Aren't they reducing their own customer base?
I ask as a paramedic who responds to these ODs. We are getting more and more warnings about dangerous opiates that can even cause us to OD if we inadvertently come into contact with a trace amount.
Other
explainlikeimfive
{ "a_id": [ "dburzdt", "dbv0j8q", "dbus4os", "dbv1vpa" ], "text": [ "So, my source is an informational presentation from a law enforcement officer. If someone wants to add a different perspective, by all means... Dealers want to be known for having the strongest stuff around. Yes, people OD. They consider it advertising.", "Tldr it makes the drugs stronger and more addictive. It's easier to get hooked so they sell more", "Usually it's too either A) be more addictive, and/or B) be known to have the strongest and best shit around. So if someone overdoses, other people might assume its strong and possibly the best around. This will interest more people to buy from that dealer", "I just learned this. It's because when people OD the people buying drugs think that dudes stuff must be awesome and it actually gets them more customers vs others. Plus the stuff they put in is so much cheaper than the actual product that they make a much higher profit margin." ], "score": [ 5, 3, 3, 3 ], "text_urls": [ [], [], [], [] ] }
[ "url" ]
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5ld3ls
why does it hurt when you swallow a beverage "wrong" ?
Some people will say "oh it just went down the wrong tube..." what is the real reasoning behind this sharp pain?
Biology
explainlikeimfive
{ "a_id": [ "dbuvik6", "dbux4no", "dbv0r1z", "dbux23t", "dbv47le", "dbuzxoa", "dbuw5cn", "dbvajgc", "dbv1vig", "dbv0pkq", "dbv020o" ], "text": [ "When you take too big a swallow, it stretches your esophagus, causing it to spasm. This hurts.", "The OP is talking about two different things. In the title, we are lead to believe that the OP is talking about \"stretching your esophagus, causing it to spasm\" However, in the comment portion, OP is talking about \"There are two major \"tubes\" that your mouth leads into. One is the esophagus, while the other is the trachea.\"", "Sometimes it hurts even when the drink went down the \"right\" tube. This happens most often with carbonated drinks. The lower pressure outside of the can/bottle and the heat of your body makes carbon dioxide to come out of the soda/pop/coke as you drink it. This is what causes the fizzling effect. It's cool and tasty as long as it happens in your mouth. But what if the fizzling keeps going on after you've swallowed? Your esophagus was preparing to handle an ounce of liquid, but suddenly it has an ounce of liquid *and* a large volume of gas in it. It's as if you swallowed a deflated balloon and it somehow inflated itself while you were swallowing it! This causes painful stretching of the esophagus. [Edit] Obviously, this is more likely to happen when the drink hasn't had enough time to fizzle out before you swallow, like when you drink straight out of a freshly opened, cold can on a hot summer day.", "As I understand it, your esophagus works in tandem with your mouth to time when it needs to start contracting and relaxing to move food into your stomach. Think of this action like moving a bead from the bottom of your toothpaste container to the opening using both hands instead of one. When you swallow \"wrong\", you might grab some air instead of the soda at first, which causes some uncomfortable pressure on your esophagus as it moves the air down into your stomach ahead of the beverage. Ever notice you can give pretty rad burps after swallowing \"wrong\" like that, too?", "A lot of misinformation in this thread... It has nothing to do with water going down the wrong tube. What happens is that when you normally swallow, you initiate a series of muscular contractions in your throat all the way down to your lower esophageal sphincter. These contractions will normally work to push food/drink down the esophagus into the stomach (this is why you can swallow upside down and not have food/water come out of your mouth). Think of squeezing a pea out of a straw to visualize how it works. When you \"swallow wrong\", what happens is that the muscle contractions, instead of taking place right above the bolus to push it down, actually takes place at the bolus, causing pain as the muscles squeeze the bolus, instead of pushing it.", "There are two pipes in your throat: one for food/drink and one for air. When you normally swallow, your air tube closes off and food/drink goes into your food pipe. Two things can go wrong to cause an unpleasant sesnation: 1) food/drink enters your air tube by accident, making you cough and splutter, this is the body's natural response to protect your lungs. 2) the food/drink goes into your food pipe, but something holds it up and it becomes stuck, leading to pain/discomfort. Source: Medical Speech Pathologist specialising in swallowing disorders.", "There are two major \"tubes\" that your mouth leads into. One is the esophagus, while the other is the trachea. The esophagus is where foods and liquids go. The trachea leads to your lungs. When you swallow something, a tiny flap called the epiglottis prevents food particles from going into the trachea. However, sometimes this doesn't always work, and food and liquids will go down the wrong pipe (into the trachea instead of the esophagus). This causes nervous reflexes, such as coughing and choking, to get those particles out.", "For background, I'm a 4th year resident in otolaryngology, so this is right up my alley. To first understand your question more clearly, let's define a few things. Dysphasia: dysfunction of swallow Odynophagia: pain with swallow Aspiration: food/liquid/saliva entering your trachea Aspiration occurs when you have some type of dysfunction of your larynx (structure composed of and supporting vocal cords that elevates during swallow) and epiglottis (cartilage flap that closes over your larynx to protect airway when swallowing). Aspiration cause you to cough. Typically is not painful. This is what happens when people say \"it went down the wrong pipe.\" It can become an issue when it leads to aspiration pneumonia. Older folks and smokers (or other individuals whose lungs and windpipe cannot optimally clear mucus) can develop an infection of the lungs if bacteria continues to enter this area and is not cleared properly. Dysphasia can be divided up into a few different categories. Oral - involving the mouth, all voluntary muscle movement. Thing of someone with a paralyzed tongue trying to push a food bolus to the back of their mouth. Very difficult. Oropharyngeal - a combination of voluntary and involuntary muscle movement. This phase of swallowing is basically your active swallow initiation motion followed by involuntary motion of pharyngeal muscles. Elderly with weak pharyngeal muscles, or someone who has suffered a stroke affecting this area. Additionally, at this stage, if the epiglottis fails to descend properly, aspiration can occur. Esophageal - completely involuntary muscle movement. Dysphasia in this phase can be functional or mechanical. Mechanical occurs if there is some type of obstruction in the esophagus, like a ring, web, or tumor. This type of dysphasia occurs mainly with solid food and not liquid. Functional dysphagia occurs if there is some type of improper muscle motion, like lower esophageal sphincter spasm or diffuse esophageal spasm. It occurs with solid and liquid. Basically there is either a physiologic miscommunication among the nerves or a chronic problem. All these types of dysphagia can present with pain in different areas based on the location of the dysfunction. Typically in the morning, a short lived cramp/pain with swallowing is likely due to an esophageal spasm.", "When a beverage is swallowed \"wrong\" generally it is due to a pocket of air in the throat being trapped below the thing being swallowed. This air causes a slightly more dry spot directly below the object being swallowed and thus we feel it more dramatically. This feeling is basically due to the pocket of air, but is also potentially aided by a spasm of the throat.", "There's a slide that goes from your mouth to your tummy, but it's usually closed off by a little gate. When you're drinking juice, the gate opens so that Juice Man can slide down to your tummy. If you're not paying enough attention when you're drinking, the gates to the slide will forget to open. So when Juice Man jumps for the slide, he slams right through the gate. That's why it hurts when you swallow wrong.", "The muscles in your throat scramble to save you from it actually going down the wrong tube. To do that, that they have to do a lot more work than normal. And that puts unusual pressure on the nerves in the area and maybe even rips the muscles involved a bit.. both of those would cause pain that stands out from normal sensations, and would be easily noticed." ], "score": [ 1903, 1296, 532, 475, 86, 76, 66, 42, 7, 4, 3 ], "text_urls": [ [], [], [], [], [], [], [], [], [], [], [] ] }
[ "url" ]
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5ld5r4
Why do the instructions on pasta call for you to measure out water?
On pasta the bag/box will tell you to put 2 quarts, for example, of water in a pan. I always just put a generous amount of water in the pan to boil. Is there a reason I should be using 2 quarts and measure out the water when cooking pasta? Does anyone actually measure in this case?
Other
explainlikeimfive
{ "a_id": [ "dbuszzp", "dbuv26g", "dbuuumm" ], "text": [ "The less water you use the sooner it will boil and the less energy you use maintaining the boil. However too little water and you end up steaming the pasta or even burn the pasta and that is not what you want. So the right amount of water is just so that the pasta starts to appear over the water just as it is done, which is pretty close to the recommended amount.", "The directions need to give a safe minimum to the casual or untrained cook. However, you can find some new techniques that use less water. Alton Brown advocates cooking pasta in a minimum amount of water and adding the pasta while the water is cold. There are there are other techniques for making fresh pasta in a frying/saute pan with very little liquid.", "It's to make the instructions idiot-proof. It's easier to just give a specific amount of water than to try to explain how much to fill up the pot. Because some people do somehow manage to screw up boiling pasta." ], "score": [ 23, 16, 5 ], "text_urls": [ [], [], [] ] }
[ "url" ]
[ "url" ]
5ldcnk
Why is ventilation needed for indoor or underground rooms?
Technology
explainlikeimfive
{ "a_id": [ "dbuum0h" ], "text": [ "If you were placed in a sealed room with no pipes to the surface it would be like placing a bag over your face and waiting to suffocate. Eventually through breathing the oxygen level would drop and carbon dioxide levels will rise, you will feel sick, possibly dying if you stay long enough. For mines, underground parking and so on it's important to pump out the toxic air and replace it with fresh air from the outside, especially if oxygen supply is a concern. The reason underground areas need ventilation systems as opposed to say a highrise building is that there is no wind or natural airflow in those underground environments. If there was there would be no need for ventilation." ], "score": [ 5 ], "text_urls": [ [] ] }
[ "url" ]
[ "url" ]
5ldd1v
Why is ♡ considered a heart when a heart doesn't look like that? Also, how does it relate to love?
Other
explainlikeimfive
{ "a_id": [ "dbuviyu", "dbuyyu2", "dbuvmi2", "dbuvz40", "dbuvflx", "dbuv1ph", "dbv8yqf", "dbvg45u", "dbv948y", "dbv8r9p", "dbuykau", "dbvbp1n", "dbv32jg", "dbvj7uv" ], "text": [ "Human hearts can have significant differences in exterior morphology, but if you google images online - they mostly have a pointed lower end with two slightly bulbous areas on either side at the top with the left and right atria. That, along with the color red, isn't too far-fetched for a crude symbol. [e.g.]( URL_0 )", "The association of human emotions with internal organs come from antiquity-- the spleen is the source of malice (hence the dual meanings of \"bile\" and the term \"splenetic\" for an angry man) and the liver the source of cowardice (\"lily livered\") The heart is identified with love, and with courage, probably because people noticed that your heart beats fast in either instance. No matter what your emotion, you don't feel anything in your brain, but you do \"feel\" fear in your guts etc . . . so for a long time people associated these organs with feelings. The abstract and simple version of the heart is likely Christian in origin-- this particular simplified shape is the symbol used in the Catholic Devotion of the Sacred Heart", "From Wikipedia on Silphium. There has been some speculation about the connection between silphium and the traditional heart shape Silver coins from Cyrene of the 6–5th century BCE bear a similar design, sometimes accompanied by a silphium plant and understood to represent its seed or seed pod. Silphium is a now extinct plant that was important in antiquity and was probably used as a contraceptive. Other sources say that the romans harvested it into extinction for its contraceptive properties.", "It is actually a very old symbol dating back to at least the 14th century. We don't know why the shape looks like that and all the ideas are from modern times. It varies between the heart looks like sex organs (a butt or two breast, or two testicle, or a vulva), that the symbol looks like the seed of a plant that is now extinct, but used as a contraceptive which associated it with love and sex, or that the heart is an artist's interpretation of the human heart and it was described to the artist badly.", "I read something once that said the heart shape we use is actually 2 hearts put together and that's why it symbolizes love. If you google 2 hearts sewn together you should get a good pic demonstrating this. Sorry I don't know how to link to pics.", "On the subject of the heart shape, nobody really knows the origin. There are all kinds of theories as to where that came from. Perhaps somebody could expand on that, though, if they know anything more. On the relation to love, back in ancient times, specifically Egypt, the heart was thought of as the center of all emotion and reasoning. Since the heart is connected to all the various body parts using channels, they assumed that the heart must be what controls the body. You could assume how love came to be from this, considering love is an emotion.", "The heart is the shape of a women's lower back and butt. [Source]( URL_0 )", "There was an ancient plant Silphium, which the Romans used as a contraceptive to terminate pregnancies. The plant eventually became associated with love and sexuality. It was so popular they actually made the plant extinct! The seeds of the plant were in a heart shape. URL_0", "Have doggy style with a wide hips, slim waste woman and you can see where the heart shape originates.. ;-)", "I'm a cardiologist. I assure you, the ❤️ symbol doesn't look like an anatomical heart. My rudimentary understanding is that this symbol is the representation of a woman bending over, representing sensuality and sexuality.", "It's shaped that way because it looks like a well shaped woman's butt. I do not have source material. Some of you will think this is a joke. It is not. Don't believe me? Have a woman friend (*not a girl, a shapely woman) and have her sit on a dusty bench. Look at the shape left in the dust. ♡ booyah booty", "The heart symbol is what a girl looks like bent over which is what you see when you are making love to each other :-)", "I have always been told (well since I was an adult) the shape is a stylized form representing a woman's genitals. I can't really find any proof for this however: > According to Gloria Steinem in the 1998 introduction to the Vagina Monologue > > \"For example, the shape we call a heart—whose symmetry resembles the vulva far more than the asymmetry of the organ that shares its name—is probably a residual female genital symbol.\" > > An earlier suggestion by Tanzer (1969) that the shape was used as a symbol indicating brothels in ancient Pompeii). Tanzer (1969). The Common People of Pompeii. A study of the graffiti. With illustrations and a map — [wikipedia: heart symbol] ( URL_0 )", "...The heart does look like that, though. Obviously it's hyper-simplified, but how else would you draw a heart in just a second or two without a visual reference? The bottom of the two halves of the ♡ are the two ventricles, that come to a point (more or less) and have the artria bulging at the top. Just look at both side by side and you'll see the resemblance." ], "score": [ 793, 354, 159, 35, 31, 22, 14, 13, 12, 10, 7, 5, 5, 3 ], "text_urls": [ [ "https://anatomicalinnovations.com/wp-content/uploads/2014/09/real-human-heart1.png" ], [], [], [], [], [], [ "https://encrypted-tbn2.gstatic.com/images?q=tbn:ANd9GcQBFsEzApP7LIkIr8sSBxf22-IHpr7Bx2OzZL3ZNxuYFI_FcMG-" ], [ "https://en.wikipedia.org/wiki/Silphium" ], [], [], [], [], [ "https://en.wikipedia.org/wiki/Heart_%28symbol%29" ], [] ] }
[ "url" ]
[ "url" ]
5lde59
Why do vitamin C tablets say stuff like 800% your daily value? Does that mean the rest gets wasted?
I thought your body could only absorb so much vitamin C at a time.
Biology
explainlikeimfive
{ "a_id": [ "dbuuya8", "dbv26gr" ], "text": [ "100% equals the minimum daily amount recommended by the FDA. You can easily surpass this by eating vitamin rich foods or by taking a pill. It doesn't mean that is all your body can process", "vitamin C is very easily absorbed (contrary to what some ignorant commenter posted here), it's water soluble your body absorbs as much of what you give it as it needs - which varies according to your state of health - and passes out the rest when you ingest more than you can utilize it loosens your stools, you can get diarrhea from \"overdosing\" when one has a systemic infection like \"strep throat\", one can often easily take up to 4,000 mg every 4 hours, 24 grams/day, without overdosing, whereas when one is healthy even 2,000mg in a whole day can produce this saturated-and-passing-out-the-rest effect you can learn a lot experimenting with this the US RDA is iffy. the RDA for vitamin C may be that which was determined to prevent scurvy, not that which meets the demands of most people's lifestyles another example - they now say the RDA for vitamin D should be 5,000 IU and not 400 IU high percentages of the US RDA should in no way be alarming unless they're of vitamin A (or some minerals, other things), a fat soluble vitamin which can be toxic to take too much of in supplemental form 800%. of the RDA of vitamin C is less than 500mg, it's *nothing* happy new year, eat your weedies." ], "score": [ 8, 3 ], "text_urls": [ [], [] ] }
[ "url" ]
[ "url" ]
5ldlgf
Why were slaves treated so badly?
Other
explainlikeimfive
{ "a_id": [ "dbuz4ph", "dbuwnsz", "dbuxi38", "dbuxttp", "dbuxb67", "dbuydls", "dbuwtq8", "dbuzf1x" ], "text": [ "Great question. I guess there are two prongs to this as I see it. Economically (and legally) slaves had no freedoms, they were property. Like others have said, they were treated poorly in the context of today's ethical codes. In the context of the time, they would've been cared for to the point at which it was necessary in order to maintain that resource. Psychologically, you'd be surprised how easily people can cherry pick what information they attend to (and therefore, their beliefs and emotional reactions to things around them). People tend to attend more to the information that supports their preexisting biases (this is called 'Confirmation Bias'). So if you were raised believing say, that slaves were subhuman or that indigenous people needed \"salvation\" through whatever means necessary, you'll sort the information in your world according to those biases. That natural part of ourselves (particularly in a community/time where critical thought might have not been encouraged) could go some way in explaining why people chose not to see the horrors of slavery. The same thing happens today with meat and dairy consumption and the impact of that industry on the environment but that's another topic for another time! Great question though!", "Nobody around you will think you any worse for taking your anger out on them. You will not be punished, some might even think better of you. Every other person you own will treat you with respect and terror. And it satisfies your primal urge to *power over the helpless.* The question is not why. The question is why not?", "I'd like to hear an informed answer. If I'm not mistaken, it was less likely for a slave to be treated like shit (as we have seen portrayed in popular media). I would assume that slaves developed more or less entire communities, generation after generation, and had a rather symbiotic relationship with the plantation owning family. Would love to hear some information on this.", "It's hard to understand now, but at the time there was a whole set of beliefs in place to justify enslaving black Africans, which set slavery in the Americas apart from other kinds of slavery. Essentially, people said that Africans were incapable of making civilization on their own, so keeping them as slaves was giving them a better life than they could ever otherwise hope to have. Being black and being a slave (or well suited to slave life) were synonymous. This idea was reinforced by the wealthy slave owners to prevent poorer white people from wanting to work together with slaves and overthrow them. At this level of dehumanization, it's easier to see why people would treat slaves cruelly. However, I do not know how common it was. /r/askhistorians has a lot of [great information]( URL_1 ) about this topic. According to [Wikipedia]( URL_0 ), the less slaves someone had, the kinder they tended to be.", "just keep in mind not ALL slaves were treated badly (yes being a slave is bad but im talking beyond that) this is a huge oversimplification and im not trying to make an accurate comparison but its sort of like pet owners. not everyone one is bad to their \"pets\" some treat them like family. in some cases i would imagine a wealthy owners slave got much better treatment than the common man depending on the era", "An argument I heard is they weren't always treated terribly because slaves were expensive. Treating slaves who were criminals could have a lot of cruelty because if you kill or maim a slave convict, it doesn't affect you. But a slave you bought, if you maim or kill them then you lose your investment. So people who owned slaves had an incentive to keep them alive and healthy. So punishments would probably be designed to cause pain and duress but not serious injuries or death.", "In the beginning, when slaves were plentiful, it was cheaper to buy a new slave than it was to take care of a current one. As the age progressed, it became cheaper to take care of the ones you had, and so life expectancy rose from a few weeks/months to a lifetime. They'd start them out on hard labor and eventually take them into the house for servant work. Many had children born in servitude, and many of those children had children. Yes, people still died, and there were some slave owners who were cruel or merciless in their punishments or indifferent to the plights of their slaves, but many owners were not. The kind of thing you see in movies is largely romanticized in order to vilify the trade. The slave trade is alive and well today, mostly in Africa.", "The idea behind slavery was black people and slavers were inferior creatures, a lesser animal and so couldn't and shouldn't be given anything other than a life of service. They were still tribal in Africa, because, being lesser animals, they were incapable of creating and being civilised. They were treated like animals (or worse) because for all intents and purposes they were considered animals. Nothing more than property to be bought and sold. To get into the mindset, think of them like a bike. If you bought a bike and decided to give it a good old kick, who am I to say how you ought to treat your bike. You bought it, it's your now. I don't have any right to critique your treatment of your own property. It's also worthing keeping in mind that we've become less violent in recent times. Life and people used to be a lot crueler in the olden days! It was only a few decades ago that schools all had corporal punishment with teachers whacking and smacking students with rulers and belts. The cultural norms of violence at the time were also an important factor in how poorly slaves were treated." ], "score": [ 19, 12, 8, 8, 6, 6, 3, 3 ], "text_urls": [ [], [], [], [ "https://en.wikipedia.org/wiki/Treatment_of_slaves_in_the_United_States", "https://www.reddit.com/r/AskHistorians/search?q=america+slavery+OR+american+slavery+&amp;restrict_sr=on&amp;sort=relevance&amp;t=all" ], [], [], [], [] ] }
[ "url" ]
[ "url" ]
5ldtde
Why do singers (*cough* Mariah Carey *cough*) have such a tough time when an earpiece or monitor isn't working, but the dancers are able to keep pace without anything?
Other
explainlikeimfive
{ "a_id": [ "dbuyiia" ], "text": [ "There is often a slight delay between her singing, her voice coming out of the speakers, and the sound echoing and coming back to her. This can result in what's called a [delayed auditory feedback]( URL_0 ) which can make talking or singing impossible. > Most delays that produce a noticeable effect are between 50-200ms. DAF usage (with a 175 millisecond delay) has been shown to induce mental stress. There are apps you can download to your phone to try yourself. I recommend trying to say something like the pledge of allegiance, to demonstrate how completely it can disrupt vocalizations. I'm not saying Mariah Carey isn't a \"has been with no talent left\", just that there's a scientific answer to your question." ], "score": [ 33 ], "text_urls": [ [ "https://en.m.wikipedia.org/wiki/Delayed_Auditory_Feedback" ] ] }
[ "url" ]
[ "url" ]
5ldu3c
Why is it so difficult to smell ourselves?
Biology
explainlikeimfive
{ "a_id": [ "dbuyh3b", "dbuznpn" ], "text": [ "Since we are always around our own scent we become used to it and no longer notice most of the time. If you burn a candle and stay in the room you will no longer really smell it because you have become accustom to it. We adapt to smells very quickly. Within the space of just a few breaths, we can lose our ability to detect new odors. It's called olfactory adaptation.", "The concept of habituation answers your question. Habituation is essentially when repeated stimuli are filtered our by our brains so that we no longer notice them. For smells, if you are continually exposed to the same smell, it will become less and less noticeable because your brain feels it needs to focus on other smells (possibly in order to detect stimuli that are more important to your immediate survival.) Similarly, habituation is also the reason why you don't generally feel your feet in your shoes unless you're specifically thinking about them." ], "score": [ 7, 6 ], "text_urls": [ [], [] ] }
[ "url" ]
[ "url" ]
5ldve0
Why do comedians repeat phrases of their jokes/stories every so often while performing on stage?
Other
explainlikeimfive
{ "a_id": [ "dbuyoww" ], "text": [ "If the audience is busy laughing, a good comedian will repeat the sentence they were busy laughing at so the audience has a chance to refocus and not miss the end of that sentence or the beginning of the enxy. I've seen some bad comedians that just can't read their audience and they keep going through their routine firing off jokes and when everyone laughs, the next joke falls flat because half the people in the audience didn't even get a chance to hear the preamble. Additionally, repetition can be a rhetorical tool to drive a particular point or create interest or simply to entertain. Or they could be used to repeating themselves for any of the reasons already mentioned even if the specific instance of them repeating themselves actually doesn't fit the criteria but they are just used to doing it anyway." ], "score": [ 5 ], "text_urls": [ [] ] }
[ "url" ]
[ "url" ]
5le984
What is happening when one commercial is interrupted by/for another?
When I am watching television and it goes to commercial, occasionally and not too infrequently, I will see what is clearly the first five or so seconds of a commercial, and then it will quickly fade out and be replaced with a commercial on a completely different subject. Why is it that these commercials are being interrupted? And why is it so often so rough rather than a smooth interruption/transition?
Other
explainlikeimfive
{ "a_id": [ "dbv1dqh" ], "text": [ "Those are national or at the least very large area commercials that get cut short. Companies who pay to have their commercials show over all of the regions that a particular cable company caters to sometimes get overwritten by \"local\" commercials. These spots cost less but won't show up everywhere, just a specific region. It sort of just plays over whatever commercial is on the national broadcast :)" ], "score": [ 12 ], "text_urls": [ [] ] }
[ "url" ]
[ "url" ]
5leazc
I just read that it takes 26 hours for New Year to pass all time zones, how can that happen?
Other
explainlikeimfive
{ "a_id": [ "dbv1wsk", "dbv2330" ], "text": [ "Because the time zones go from UTC-12 to UTC+14. Specifically, the cause is several islands in the Pacific Ocean such as Kiribati. Kiribati is an island nation whose islands are spread across three times zones. Normally, these time zones would have been UTC+12, UTC-11 and UTC-10. The problem is that it would put one part of Kiribati a day ahead of the rest of it. So instead they chose to move the rest of Kiribati one day ahead, so their time zones are UTC+13 and UTC+14 instead of UTC-11 and UTC-10. I'm not sure why they didn't just choose UTC-12, UTC-11 and UTC-10 instead, but I'm guessing it's so that they will be on the same days as the islands west of Kiribati instead of the islands east of it.", "There are two times zones east of the 180^o meridian. People there, with islands west of the meridian more than with North America, so they keep on the same day. That way they share the same weekends and weekdays, making it easier for business and government to interact. Also, this change was first made in 1995, no doubt in part to capitalize on being the first place on earth to see the year 2000." ], "score": [ 53, 4 ], "text_urls": [ [], [] ] }
[ "url" ]
[ "url" ]
5ledy7
How does Spotify and Apple Music pay artists?
Technology
explainlikeimfive
{ "a_id": [ "dbv646p" ], "text": [ "The streaming services collect all the money from subscriptions and ads, then each artist is paid their percent of the total streams. If there's only 100 streams that months, and Taylor Swift songs account for 10 of those, she gets 10% of the revenue that month. When you break it down, each streamed song gives the artist about $0.007. Spotify' analytics break this down better if you want to see their total streams and their policies and stuff. This is sad because then that sliver of he pie is broken down even more and divvied up between the record label, management, legal, and THEN the artist, which ends up being a fraction of a sliver of not a whole lot of money for your art. Which is still better than stealing the music, but not as good as actually buying the product and seeing your favorite artists live." ], "score": [ 9 ], "text_urls": [ [] ] }
[ "url" ]
[ "url" ]
5lefn5
how does someone like bill gates keep all of his money?
Economics
explainlikeimfive
{ "a_id": [ "dbv2kn1" ], "text": [ "His net worth is largely tied to his investment holdings with Microsoft, although he more than likely has investments elsewhere. As the share price of Microsoft fluctuates daily on the market, his net worth fluctuates with it. If Microsoft has a particularly bad quarter, he publicly lost a lot of money." ], "score": [ 4 ], "text_urls": [ [] ] }
[ "url" ]
[ "url" ]
5lesef
Why is it when we chew/swallow food or drink, we don't gag but if we have to have a medical procedure that involves something going down our airway or dentist, we don't gag?
Biology
explainlikeimfive
{ "a_id": [ "dbv4ou7", "dbv4t2l", "dbv4v2s" ], "text": [ "Because you have no gag reflex. You have likely lost your gag reflex through the repeated taking through your throat hole of various large objects. What these objects might have been we can only guess. It is possible that you are bulimic and have lost your gag reflex that way. Perhaps you're a sword swallower. But the fact that you do not gag under any of the circumstances you've described strongly suggests that you have suppressed your gag reflex in some way.", "The gag reflex is almost a defence against involuntary inhalation/ingestion of things. You're scenario where you don't gag on food, but do when the dentist tries to put stuff back there isn't quite right. When you \"don't gag on food\", it's because you're swallowing. As someone who has had tubes down their throats for medical procedures I can assure you that if you try and swallow while their putting the tubes in, it makes you stop gagging.", "The software in your brain differentiates between an unwanted intrusion, i.e. the dentist who you don't really know who sometimes causes extreme discomfort sticking things in there that you know normally dont go there, so you gag to try and expel it. Food you want otherwise it would make you gag too. Edited, spelling." ], "score": [ 5, 4, 3 ], "text_urls": [ [], [], [] ] }
[ "url" ]
[ "url" ]
5letsn
Why do newspapers often have random sentences where a l l t h e w o r d s a r e w r i t t e n l i k e t h i s?
Other
explainlikeimfive
{ "a_id": [ "dbv5ig7", "dbv4udy", "dbvl0rq", "dbv4v8u", "dbvi6hf" ], "text": [ "Newspaper columns are justified on both the left and right, which means that the left margin and the right margin are both straight (see [this image]( URL_0 ) for a visual explanation). There are a couple of techniques you can use to get both margins straight, and usually you use a combination of both: you can use hyphenation to break up longer words, and you can adjust the spacing between words, or between individual letters. In most publications you barely notice it, but newspapers typically use very narrow columns. Because they use such narrow columns, it's harder to get the text to justify correctly, and often words or letters are spaced out so far it becomes noticeable. In the days before computers were used to set type, this was done by hand, and it's a very difficult thing to get exactly right: newspapers had to be printed very quickly, so text justification was often done poorly. With modern technology, the process can be automated, but now the problem is getting the software to understand what looks neat and professional to a human, and what doesn't.", "The composition software they use to format the columns figures out how many words will fit on a line without hyphenating anything, and then evens out the spacing between the letters to exactly fill up the whole line. Sometimes a line doesn't have a lot of characters in it, so the spacing ends up really big. Source: I used to be a typesetter", "I worked at a company that published scientific journals. If the journal's style guide specified justified we would often spend an hour on a single article adjusting kerning to get words to bump to the next line to fix these kinds of issues.", "Formatting basically. Some words are double or triple spaced in order to fit them visually into a neat paragraph. Some newspapers will hyphenate words instead. > That was how she understood Chris- tmas", "We used to get weekly readers in elementary school. I noticed the weird typesetting and asked the teacher why it was like that. She explained that when a word couldn't be broken up with a hyphen, they would space the letters to make the column even on both sides. Before then I always thought that it was a way to show your eyes that this line had some kind of importance above all the others." ], "score": [ 372, 59, 13, 4, 3 ], "text_urls": [ [ "http://www.visionengravers.com/support/images/CNCEngravingGlossary/Justification.gif" ], [], [], [], [] ] }
[ "url" ]
[ "url" ]
5ley59
How does overuse of antibiotics actually lead to antibiotic resistant bacteria?
So I get that it kills off most bacteria, leaving some that are resistant to the drug... But the antibiotic doesn't change the bacteria to be resistant does it? And how does killing off the rest of them increase how quickly these resistant bacteria multiply, wouldn't they be there anyway? And if your body can't fight them, they will still be there and the antibiotics will still not be able to kill them?
Biology
explainlikeimfive
{ "a_id": [ "dbv5ucu", "dbv5mpk", "dbv6asv" ], "text": [ "The antibiotic doesn't change the bacteria to be resistant, but it creates selective pressure for resistant strains. In the absence of antibiotics, the resistance mutations would still arise but, as a very rare mutation conferring no survival advantage, they would persist in the population only at a very low level and likely die out by chance. When the resistant strains are the only ones that can survive, however, they come to dominate the population. When someone else who hasn't taken antibiotics yet catches the bug from you, they will catch the resistant strain and nothing else. From there on in the spread of that particular strain, it is 100% resistant. We say the resistance mutation has become \"fixed\" in the population - this would not happen without the selective pressure from the antibiotics.", "Everything competes for food, including bacteria. So basically the antibiotics kill off the competition, allowing the resistant strains to multiply much more and become the predominant strains.", "You're almost there! After the rest of the bacteria have been killed it's only the resistant ones left. When these ones reproduce they are significantly more likely to pass o the resistance. If this keeps on happening it the proportion of resistant bacteria builds to the point of become an issue." ], "score": [ 14, 3, 3 ], "text_urls": [ [], [], [] ] }
[ "url" ]
[ "url" ]
5lf0ro
How can the heart not tire out?
I know the why but how can the heart only stop beating when you die?
Biology
explainlikeimfive
{ "a_id": [ "dbv6463", "dbvfj6i" ], "text": [ "The heart is made of a special type of muscle tissue (cardiac muscle; the other two are skeletal or voluntary muscle, and smooth or involuntary muscle). Cardiac muscle cells have more mitochondria than other muscle cells, and mitochondria produce power for the muscles. The cardiac muscles are joined together in a way that lets them contract hard without tearing apart. So long as the heart is getting oxygen (a heart attack is when the heart stops getting oxygen), it's not going to get tired - it won't build up lactic acid, because it's being supplied with plenty of fuel, and it won't be damaged because it's not straining itself. Generally speaking, anyway - extreme stress (from being very obese, or from regularly straining your body with extreme exercise) can cause temporary or permanent wear to your heart.", "The heart does get tired, it can just function for a lot longer than other muscles before it wears out (props to tlndfors for pointing out that this is because cardiac muscle cells have more mitochondria and therefore more power and endurance). When we say a person dies of old age, what we mean is that they lived long enough for their heart to finally get tired and stop working." ], "score": [ 8, 3 ], "text_urls": [ [], [] ] }
[ "url" ]
[ "url" ]
5lf41k
Why can't devices (phones, laptops, etc) make our headphones noise-cancelling?
Noise-cancelling headphones record external noise and then creates sound waves that cancel these external noises. Why can we not use device internal microphones to record these external noises?
Technology
explainlikeimfive
{ "a_id": [ "dbv6wz0" ], "text": [ "Because you need the microphone to be right next to your ear for it to work. If the phone is in your pocket, it can't pick up the exact sounds it needs to cancel, because the sound at your hip is slightly different than at your ear. Additionally, there is the delay caused by the wire which would likely cause the cancellation noise to be too late to be effective. And then there is also that the headphone has dedicated hardware, allowing it to work very quickly, the phone does not, introducing an additional source of latency that greatly reduces its effectiveness. *Edit: Spelling" ], "score": [ 11 ], "text_urls": [ [] ] }
[ "url" ]
[ "url" ]
5lf5ih
Why are the atomic numbers of elements unique?
If the atomic number is the number of protons found in the nucleus of an atom of an element, why can't two elements have the same number of protons?
Chemistry
explainlikeimfive
{ "a_id": [ "dbv6t3p", "dbv6p62" ], "text": [ "If two atoms have the same number of protons, that's what makes them the same element. We identify elements primarily by the number of protons, as that's what makes them what they are. The number of electrons in a given element atom dictates whether or not it is charged, but electrons are much more fluid than protons, so will change from instant to instant. The number of neutrons in an atom can alter slightly within the definition of an element. For example deutrium is an isotope of hyrdogen consisting of a proton, a neutron and an electron. Because it has one proton, it's still considered hyrdogen, and can still form compounds in the same way that \"normal\" hydrogen can. Looking at it the other way, Deutrium is esentially another element with the same number of protons as hydrogen, but as a result it behaves so much like hydrogen, that it's called hydrogen.", "Atoms are classified into elements based on how they react chemically. This was done well before we even knew that protons existed. Later we discovered that the number of protons in an atom determines almost everything about its chemical behavior, so all of the atoms of each element have the same number of protons." ], "score": [ 7, 3 ], "text_urls": [ [], [] ] }
[ "url" ]
[ "url" ]
5lf6ni
How to type Korean?
Other
explainlikeimfive
{ "a_id": [ "dbv9aue", "dbv78jj" ], "text": [ "Korean uses an alphabet called hangul. Individual letters are composed into syllables, with each syllable occupying one block. This means that the computer needs to know when you have finished typing one syllable and want to start typing the next: fortunately, the Korean writing system has very strict and simple rules that are quite easy to program into a computer. A syllable must start with a consonant, and must contain at least one vowel; it can then have another consonant at the end. The consonant letter \"ㅇ\" is \"ng\" at the end of a syllable, but silent at the beginning of a syllable, so this lets you write syllables beginning with a vowel *sound* without breaking the rule that in written Korean, all syllables must begin with a consonant. In your example, \"saranghae\" is \"사랑해\", the three blocks representing the syllables \"sa-rang-hae\". First, you type an \"s\", which in Korean is \"ㅅ\". Next comes a vowel, \"ㅏ\"; when you type that, the \"ㅅ\" changes to \"사\", the syllable \"sa\". That's fine, but then you type the Korean \"r\", which is \"ㄹ\", but the computer initially thinks that you are typing the syllable \"sar\" or \"sal\", and so it gives you \"살\". At this point you panic, because that's not what you want. But don't worry, because the moment you type the next letter -- another \"ㅏ\" -- the software knows that you can't start a Korean syllable with a vowel letter. And so now it knows that the \"ㄹ\" needs to go in the second syllable, changes the \"살\" back to \"사\" and starts a new syllable \"라\". Now you type \"ㅇ\", and the \"라\" changes to \"랑\", the syllable \"rang\". Next, type \"ㅎ\". This is a consonant, so the computer knows that it can leave \"랑\" exactly as it is and start a new syllable. Finally, you type \"ㅐ\", the \"ㅎ\" changes to \"해\" and you're done. So in fact, if everything is working properly, you should just be able to type the Korean letters \"ㅅ\", \"ㅏ\", \"ㄹ\", \"ㅏ\", \"ㅇ\", \"ㅎ\" and \"ㅐ\", and the software will automatically convert it to \"사랑해\" without you having to do anything else. You do have to make sure you have a Korean keyboard and you have switched it to accept Korean (a Korean keyboard can be toggled between Korean and English input; for example, if you want to type a web address, you normally have to use English input mode).", "Korean isn't a logographic language like Chinese. It has an alphabet, just like English, made up of consonants and vowels. The major difference between Korean and English (and other alphabetic languages) is that in Korean, you group the letters of each syllable and write them on top of each other. 사랑해 (\"saranghae\") is just made up of three syllables - 사, 랑, 해 - and each of these is made up of two or three letters: * 사 = ㅅ + ㅏ * 랑 = ㄹ + ㅏ + ㅇ * 해 = ㅎ + ㅐ" ], "score": [ 11, 10 ], "text_urls": [ [], [] ] }
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5lf872
What is the point of Gerber Life? How does taking a life insurance policy out on your baby give them a good financial start?
Economics
explainlikeimfive
{ "a_id": [ "dbv7o5c", "dbvn62z", "dbvkbev", "dbvgzns", "dbv7omg" ], "text": [ "It doesn't. You don't need life insurance if no one is dependent on you. Babies don't have people depending on them. The product is basically bullshit.", "A whole lot of these comments show a lack of understanding on how different life insurance policies work. Gerber and the like sell whole life insurance which straddles the line between an investment and a life insurance policy. The payments you make toward the policy go toward a cash value which gains interest. You can cash out the policy to access that money but depending on the policy there may be restrictions or penalties to do that. So the policy can act as insurance in case the child does die to help with expenses, it could be cashed out in a time of need for the family(hardship, college, etc.), or you could continue contributing and keep the policy. As others have said, it can also be useful if your child develops a condition that would then prevent them from getting life insurance. Heart conditions, cancer, lung conditions, and a lot of others can make insurance much more expensive or even disqualify them. As long as you continue to make payments, the policy will stay valid even after a diagnosis like the above. The downsides is that it's more expensive than term life, and not usually as good of an investment as putting them money into stocks/bonds/indexes, as these policies tend to have pretty low rates on them.", "The main reason why it's marketed that way is because there's no good way to say \"buy this in case your kid dies\". Saying it gives them a \"good financial start\" is more palatable. Now, whether it's actually a sound investment is up to you to decide but, as many others pointed out in this thread, it's probably not.", "95% of the time it is a horrible option However, some of us developed cancer as young adults and are now functionally uninsurable. Edit* Dad got talked into a whole life insurance policy for me back in early 80s back when interest rates were astronomical. He has had a decent guaranteed rate of return for > 30 years and now it is the only life insurance policy I can ever get. Not a great investment for most everybody, but it worked out for me.", "It's whole life, which is a terrible investment. There are much better ways to invest for your child." ], "score": [ 29, 17, 8, 8, 5 ], "text_urls": [ [], [], [], [], [] ] }
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5lf8ga
Why is Norton hated so much? What makes an antivirus/antimalware program good or bad anyway?
Follow up questions: Given it's so notoriously bad for some reason, how come sales reps at electronics stores push it so hard? And also, what's the best antimalware software? Edit: Oops, sorry, I just found a previous question about Norton. I *did* search for it so tbh I'm not sure what's going on there. Consider the first question redundant then :)
Technology
explainlikeimfive
{ "a_id": [ "dbv7856", "dbvdj0r", "dbvhfqm", "dbvh7vq", "dbvntjk", "dbvh2wn", "dbvn4mq", "dbvew3z" ], "text": [ "Nobody likes Norton because it is a resource hog that slows your computer down. It doesn't effectivly do it's job. Norton's CEO even admits that it only gets 40% of viruses at best. So why would people pay outrageous for a program that slows down their computer, and only does less than half the job. Stick with Microsoft Essentials; it is free and makes sense that Microsoft would know the in's and out's of their own code better than some 3rd party like norton. Norton is a complete waste of money.", "A good antivirus program is like having an amazing immune system. A bad antivirus program is like having severe, debilitating allergies.", "Back in the day Norton was the only game in town. Time were much simpler and it was a product that did one job and did it well. It's been a bloated POS for 20 years. It spreads it's tentacles into every nook and cranny of your system. I'm still salty about having to remove it piece-by-piece one time in 1999. Their endpoint AV, which is installed on company computers and controlled by the sysadmin, is pretty good. Very little resource usage and it seems to catch most things. Can't speak to how easy it is to use from the admin perspective but as a user I really didn't notice it was there. A final note; *Antivirus software is your last line of defense.* If you're worried about security there are many layers that go on top of the AV. Edge firewalls, OS firewalls, email filtering, ad blocking, DNS filtering, etc. If you're counting on *any* AV to protect you you're doing it wrong. A final, final note: [Norton's DNS service]( URL_0 ) is free for home users and seems pretty good at blocking malicious sites. Pick a protection level and plug those DNS addresses into your router. That way when your browser sends a request to resolve URL_1 Norton's name servers send back a \"Nope, this site ain't safe.\"", "There are a multitude of reasons that Norton is infamous, the most common of which is its malware style behavior when attempting to get you to resubscribe. It was basically windows 10. The last thing you want in an anti-malware program is for it to pester the shit out of you like malware itself does. To answer your second question without any intention of endorsement, malware-bytes is, in my opinion, the most effective available free anti-malware software. Like most consumer products, you get what you pay for.", "From earlier this year: [Google Found Disastrous Symantec and Norton Vulnerabilities That Are ‘As Bad As It Gets’]( URL_0 ) That is, installing Norton/Symantec has been **actively making users horribly less secure**. The one thing that article didn't mention was exactly how many years it's been doing this. > Given it's so notoriously bad for some reason, how come sales reps at electronics stores push it so hard? Norton is a business that cares about money above all else. Your security is near the bottom of their list. Prepackaging and partnering is a pretty central part of their business (\"first one's free\" (or really cheap) is their favorite thing). So they have a business deal with Best Buy to push Norton installs. That's all.", "I'd suggest MalwareBytes over Norton. It's free and reliable. Not only that, but there's a mobile app for your phone (at least for Samsungs) that does more than \"clean your phone.\"", "It acts like a virus. Sales reps are paid on commission, they usually get very little commission on the actual computer, they make tons of commission on anti virus and other accessories.", "People are stupid and stupid people just keep using stuff that works badly. Or making other people use it. The one that works very well is Frisk software F-Protect. It is much better at finding everything and includes an Artificial Intelligence engine for stopping things acting like a virus even with no positive ID." ], "score": [ 218, 33, 30, 27, 6, 4, 3, 3 ], "text_urls": [ [], [], [ "https://dns.norton.com/configureRouter.html", "maliciousfuckersinc.com.cn" ], [], [ "http://fortune.com/2016/06/29/symantec-norton-vulnerability/" ], [], [], [] ] }
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5lfah8
why is wearing something bright orange when hunting recommended? Doesn't that defeat the purpose of blending in?
I'm not a hunter at all, nor do I believe hunting for fun is okay, but I have multiple friends who do hunt and I lived in an "everyone hunts" city so I would see camo and bright orange all over the place. What's the point of wearing bright orange if it makes you stand out? Why even wear any camo then if you're just going to stand out?
Other
explainlikeimfive
{ "a_id": [ "dbv7jv6", "dbv7p7c", "dbv7ov8", "dbv90xo" ], "text": [ "If hunting deer it is recommended because deer are color blind. The orange is so other hunters can id you and not shoot you.", "You want to stand out because you don't want other hunters to accidentally shoot you. Yes, this might occasionally also make you stand out to some of the animals you are hunting (though not always cause not all animals perceive the world in the same way) but in the end, it's better for something to get away because it spotted you than for you to get shot.", "Many animals cannot perceive color in the same way as humans can. What is bright orange to us is a much more bland and less distinct color in relation to the colors around it to many animals. In this way to a deer or such a camouflage pattern with part of the color replaced with bright orange will function similarly to a regular camo pattern when seen by an animal.", "To add to these answers, in certain types of hunting you actually don't want to hide at all. For example in pheasant/quail hunting, where you have a lot of hunters moving around in tall grass trying to herd the birds, orange gear is immensely useful there." ], "score": [ 35, 18, 7, 4 ], "text_urls": [ [], [], [], [] ] }
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5lfcom
American Television Times (9/8c)
What are these even? I want to catch a new episode of my favorite show but don't know what time it is on since I live in Asia and we don't use this kind of time? I really don't know what to call it either. Please explain like I'm 5 thanks!
Other
explainlikeimfive
{ "a_id": [ "dbv87t1", "dbvcgp3", "dbvgnz1" ], "text": [ "The United States has several time zones. The 9 means it is on at 9:00 in the Eastern Time Zone, the 8 means it is on at 8:00 in the Central Time Zone, which is one hour earlier.", "the 8 c is for American central time zone it's UTC -6 most of Asia is anywhere from UTC+4 to UTC+9. so if a show airs Tuesday night at 9/8c for me for you it will air Wednesday sometime between 6 a.m. and 11 a.m. depending on what time zone your in. if your not familiar with UTC find you time zone [here]( URL_0 )", "Most broadcasters use two feeds. East and West. There are 4 timezones (not counting sparsely populated Alaska and the far outlier of Hawaii) So the show will air at 9 relative to those feeds. Central gets the east feed, which as already stated is an hour earlier. Mountain time gets the west feed, but the population in mountain time is less than half of any of the other time zones,especially when you have AZ blatantly ignoring the rest of the country's use of daylight saving time and being in sync with the west coast during the summer. So with such a relatively small population they just leave residents in mountain time to figure it out for themselves." ], "score": [ 14, 5, 3 ], "text_urls": [ [], [ "https://en.wikipedia.org/wiki/List_of_UTC_time_offsets" ], [] ] }
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5lfljz
If you were travelling faster than the speed of sound, what would happen if you screamed?
I know it seems irrational, but Felix Baumgartner! Thanks 😊 EDIT: Thanks everyone for all your replies :). Loving reading them! Just like to add, I know this can't happen without special clothing etc., like what Baumgartner wore, or being in a pressurised compartment such as a cockpit. I'm just wondering, theoretically ;). Thanks again :).
Physics
explainlikeimfive
{ "a_id": [ "dbvp8jl", "dbv9ykq", "dbw3y0g", "dbvqra0", "dbvo52a", "dbvjql1", "dbvpyfs", "dbvwa22" ], "text": [ "In a pressurised compartment or spacesuit or something, the air between your mouth and ears isn't moving relative to you, so things are normal. If the air is moving past you faster than the speed of sound, (either you or the air can be moving) the sound from your mouth may not be able to travel through the air to your ears. You might still hear something due to sound waves propagating through your bones, but it's more likely that you'd not because the air around your head would be pressurised by ram pressure and probably deafen you. This reasoning may well be invalid because air behaves differently when it is hitting your face at hundreds of metres per second to when it is unimpeded.", "Basically, nothing special. If you clapped your hands, you'd be displaced far enough that the sound will never reach your ear. If you screamed, some of the sound would reach your ear so it would be muffled.. This is assuming you weren't deaf from the air blowing past your face.", "Pilot here with the alternative answer as many others have given you your expected answer. I'm going to assume you have, without an aircraft or other pressurised container to protect you, somehow accelerated to a speed above 761mph, the speed of sound at sea level (Assuming 20°C or 68°F ambient temperature). Let's call it 800mph. Long before you even got anywhere near the 800mph mark, you would be dead. The faster you accelerated to the 800mph mark, the quicker you die, but die you would. Screaming would not happen. The how will vary greatly depending on the speed of your acceleration but many of the principles will be the same. The first thing to kill you is debatable and again, dependant on your speed of acceleration but at a moderately slow acceleration in my opinion the first thing to send you off this mortal coil would be breathing resistance. As you accelerated somewhere beyond the 400mph mark, the air pressure forcing against you would be too great for you to intake and expel air out of your lungs, even by turning your head away against the wind. You could wear a helmet of some kind to prevent this but then the air around your mouth is moving with you and thus breaks the rule of the question. But turning your head at this point in time is kind of moot. Because you wouldn't be able to. As you go faster and faster through earths atmosphere, you begin to bump up against air, because even though you can't see it, air has mass. The faster you go, the faster you bump up against it and eventually the air in front of you can't get out of your way fast enough. So the air starts to feel a lot more solid as it compresses. At 600mph it's pretty hard indeed. Too hard. Although there are many people who have ejected from fighter aircraft at speeds in this range and even higher, many of them suffer from horrendous injuries and most pilots will attempt to eject in a way that minimises their forward velocity if they are able to. [The fastest ejection ever to succeed took place at three times the speed of sound but the pilot had many aids to ensure it was possible]( URL_0 ). Most jet jockeys of slower aircraft don't have what he had. However even when they do eject, the air resistance slows the ejected pilot down pretty quick. But your not slowing down, your still accelerating to our magic 800mph. Bumping against that air faster and faster, the air cannot get out of the way any more so it does what a gas does when it can't move. It compresses. That makes it harder. And as it gets harder, it begins to get harder for whatever is compressing it to move through it. In this case we will assume your flying like superman, so it's your head on the firing line. It will be subject to around 3g of force (Three times the force of gravity). This doesn't sound like much but it's a constant force. This isn't a huge problem unless you move your head even just the tiniest little bit, in which case your neck snaps like a twig as you pass somewhere around the 650mph mark from the air resistance, which is too great for a human spine to endure (If your accelerating really fast, this will likely kill you first). Except you might not feel it because you might have cooked to death a few seconds before, and if you haven't then it won't be long before you will. Because when you begin to go so fast that air can't get out of your way fast enough, the side effect of it compressing is that it begins to heat up and it gets hotter the faster you go and the more it gets compressed. This is the same reason that spacecraft return modules and the shuttle will heat up to extremely hot temperatures as they return to earth, and why most comets and asteroids burn up in earths atmosphere. Now your not going anywhere near as fast as most spacecraft are when they re-enter earths atmosphere, but at 800mph the temperature is still going to be hot enough to kill a human. Aircraft use special composites and design techniques to bleed the heat off but at 800mph it's not too hot for an airframe to handle. It's definitely too hot for a human though. It's tough to give an exact temperature as it would depend on a huge range of factors but it would be somewhere between 200°F or around 93°C if not hotter. You would only survive a sustained few moments of that at most. How fast all this happens depends on how fast you accelerate but there's no doubt at 800mph your screaming days are over. If there was any screaming to be done, you did it involuntarily long before you broke the sound barrier.", "Is there a density level where the speed of sound is slow enough and the friction of the air is low enough that it is possible to experience it? Edit. If we can bare 100 mph wind speeds at sea level could we tolerate 0.1 atmospheres at 1000mph?", "Short answer is: your voice will propagate only within limited directions behind you. It will not propagate in front of you. The long answer is: If you traveling faster than speed of sound, at first, you will have the [bow-shock wave]( URL_1 ) in front of you. Second if you scream, the sound wave (which is the small perturbation) will propagate only inside [Mach cone]( URL_0 ), where the cone slope depends on your velocity and equals to sin(alpha) = c/v, where \"c\" is the speed of sound and \"v\" your velocity. Number v/c is called Mach number. Edit: add short answer.", "You'd hear it, because the air inside the cockpit and/or your helmet isn't moving at supersonic speed.", "Sound is just waves travelling through the air so you can visualise your question like this. Imagine you're on a speedboat, travelling at full speed. You drop a large stone off the front of the boat. That would be like making a sound (dropping the stone) while going faster than the sound can travel. The stone would make ripples (noise) but the boat would be going faster than the ripples can travel through the water. So the ripples/sound would quickly get left behind. You'd be able to see (hear) them as you travelled onwards.", "Your voice won't be able to escape past your lips causing you to choke on the very words you speak!" ], "score": [ 298, 211, 120, 34, 21, 13, 12, 5 ], "text_urls": [ [], [], [ "https://theaviationist.com/2015/03/17/sr-71-mid-air-disintegration/" ], [], [ "https://www.grc.nasa.gov/www/k-12/airplane/machang.html", "https://www.youtube.com/watch?v=QhlxH9XDW_A" ], [], [], [] ] }
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5lfr5p
When and how did green generally get associated with positiveness, and red as negativeness?
Other
explainlikeimfive
{ "a_id": [ "dbvdons" ], "text": [ "It's hardwired. Red is the color of blood and bleeding, green is healthy vegetation. On a biological level, we don't want to deal with injury and we do want a healthy fertile landscape where food and shelter can be found. So we instinctively like green and dislike red." ], "score": [ 35 ], "text_urls": [ [] ] }
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5lfsvr
Why is it "bad" to make tea in the microwave vs a kettle?
Okay so this is a bit of a silly/light-hearted one but I keep seeing it referenced occasionally and an wondering. Usually it's some sort of conversation between someone here in the US and our friends across the pond and they seem mock alarmed or horrified that Americans use the microwave to heat the water for their tea. My question is: why does it matter? It's just your method of heating the water right? Either way you're just going to pour the heated water in a cup and add the tea bag so it's not like the actual tea is going in the microwave. Edit: I forgot I posted this and can't catch up on answering everyone but thanks for all the input!
Other
explainlikeimfive
{ "a_id": [ "dbvble8", "dbvbg0e", "dbvbqtm", "dbviirk", "dbvfgpg", "dbvd5z6", "dbvwcp6", "dbw0k5n" ], "text": [ "Much like a small sect of coffee drinkers, there are tea ~~connoisseurs~~ snobs that will turn their nose at you if you don't brew your tea at the *proper* temperature. Tea pots are designed to heat water to a specific temperature, where the microwave can produce irregular and inconsistent results. In reality, most people will never know a difference and most tea consumers can't taste the difference. If you are among the few that can taste the difference or can't take the mockery, a teapot may be good for you. Otherwise, enjoy that quick heat from the microwave-induced vibrating water molecules.", "Oh good lord. Disclaimer: I am a tea snob. I'll start by saying there's nothing *inherently* wrong with using a microwave, *so long as you're only using it to get the water to the correct temperature*. Tea is a lot more delicate than most people think. You do not -- I repeat, **not** use boiling water for tea, and you never, *ever* boil the tea in the water! You need very specific temperatures, and very specific steeping times for different kinds of tea. For example, green tea needs to be steeped for 1-2 minutes in water that is 80 degrees C (175F). That too is generalised - some green teas must only be steeped for 30 seconds! Steeping the tea for too long will make it bitter. Same with the temperature being too high or too low! That's why people keep dumping sugar and milk in tea. If you make tea correctly, *you don't need to add anything to it* to make it delicious. Now if you're using some, shall we say, non-delicate tea, like the kind that comes in tea bags, then it's not a big deal since that's not going to be delicious anyway. And there are more resilient teas that can handle a wider range (in fact, there are some Display Teas that are designed to have hot water added to them for an entire night). As a sidenote: the people across the pond are in a glass house about tea. They know *nothing* about brewing. Unless \"the pond\" is the pacific ocean and you're going to China, and also 200+ years back in time.", "> My question is: why does it matter? It doesn't. > ...you're just going to pour the heated water in a cup and add the tea bag so it's not like the actual tea is going in the microwave. I always microwave the teabag in a cup of water; do it most every day, works just fine.", "Different teas need to be brewed at different temperatures and for different lengths of time to get their proper flavor. Black teas for example are usually steeped at higher temperatures (200-212F) for longer periods of time, whereas a white/green tea that is more delicate is generally steeped at 150-180F. Different teas have different chemical makeups which greatly affect the flavor of the tea, and how long and hot it can be brewed at before it gets bitter and ruins the taste. Brew your jasmine needle at 212F and you're gonna burn the hell out of it, making it bitter and disgusting. Many pre-packages teas that you would buy from the store (Lipton, store brands etc.) are very fine, sometimes powdery, and generally just low quality tea. The finer the particles are, the more surface area the water hits, and hence the faster the tannins and other flavors infuse into the water. The proper way to get the best quality tea in terms of flavor would be to: * use loose leaf teas (the higher the quality, the better the taste) * brew the tea at the proper temperature and length * use freshly brewed water, do not re-heat previously brewed water * use the highest quality water available to you (contaminants in the water can affect the taste) * store your tea in an air-tight storage container, away from other materials that may have a strong aroma (spices for example) * store your tea in a dark area (generally keeping it in a metal tin would do) Like /u/sterlingphoenix said, you want to avoid using boiling water, generally 205-210F at the hottest. If you are using a high quality loose leaf tea, and using water that isn't riddled with hard minerals, you should have a great tasting tea without any sweeteners. You can of course add sugar, honey, etc. but depending on what kind of sweetener you use, this will greatly affect the flavor of the tea, and in most cases, will hide the true taste of the tea. Good tea does not need to be sweetened, and it's healthier to avoid sweeteners anyhow. I HIGHLY suggest checking out Adagio Tea ( URL_0 ). They have a large variety of high quality tea available at an affordable price, plus they don't charge shipping over certain amounts. They also have a rewards programs, clubs (subscriptions) and more. They do a lot of free samples, and limited time tea variants etc. Been buying from them for years now and I am very happy with their prices and quality. The shipping is quick too. The reality is that there IS a proper way to get the BEST flavor out of the tea. If you are drinking tea to just have something hot to drink, that's fine, but you're really not getting the proper tea. It's kind of like playing your Skyrim on an Xbox instead of a PC :^)", "Because it flies in the face of tea tradition. Microwave ovens are associated with quick but poor-quality cooking. They're the things you use to heat up a frozen pizza pocket at 2:00 in the morning. Tea, on the other hand, is supposed to be a class apart -- you're supposed to put your regular life on hold, brew up a pot, and let your troubles slip away for the next little while. So you don't want to mix up your sublime tea experience with such mundane things as microwaves.", "Microwaves don't heat evenly, and hence there are several possible results, none perfect: cold spots in the water, superheated water that boils vigorously on contact with the tea, or water that's been heated long enough in the microwave to come to a rolling boil, at which point there's a good chance that the oxygen has been boiled out. All of these can affect the flavor of the tea. Most people who are into tea agree that most black teas should be seeped with water at 212°F(100°C). A tea kettle or hot pot, whether electric or stovetop, heats from the bottom, creating convection currents that stir the water, allowing the temperature to be uniform. Plus it's easier to know exactly when the water reaches the desired temperature. [Partial source]( URL_0 ) At the risk of being a tea snob, if you're adding a tea bag to a cup into which you've poured hot water, you're already compounding the problem. The water will cool off from the cup, so when you add the bag, you're dealing with water that's already colder than it should be. Whenever I use bagged tea (mostly just herbals), I always put the bag in first and then pour the water onto it.", "May also have something to do with the US using 120V mains power rather than 230/240V, I am told that electric kettles in the US take forever to boil whereas a kettle in the UK will take around a minute to make a couple of cups worth of boiling water. It is therefore a lot quicker for you to heat water in the microwave.", "Its to avoid the harrumphing of the Greater Spotted Tea Drinker. I myself am a Lesser Spotted Tea Drinker so while I use a kettle, microwaving the WATER is...ok but strange. However, sugar and teabag, then hot water, then teabag out and then milk. Adding milk with the teabag in is blasphemy and all who do so shall be first against the wall when the revolution comes." ], "score": [ 133, 44, 18, 16, 6, 6, 5, 4 ], "text_urls": [ [], [], [], [ "www.adagio.com" ], [], [ "http://www.slate.com/blogs/browbeat/2013/06/04/microwaving_water_for_tea_why_are_the_results_so_lousy.html" ], [], [] ] }
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5lg7s0
How do Youtubers earn money? I mean, how is revenue generated by simply watching a video. I understand it has something to do with the advertisements, but that is my question, how do ads help Youtubers earn money.
Technology
explainlikeimfive
{ "a_id": [ "dbvex5u", "dbvytvq", "dbveim5", "dbvqaq3" ], "text": [ "It's quite simple. Advertisers pay money to Google/Youtube for the rights to show an advertisement before (or during) a video. Google/Youtube takes a cut of the revenue, and the Youtuber earns the rest. The amount advertisers are willing to pay in terms of cost per click or cost per view, is dependent on many factors, including but not limited to: - The popularity of the Youtuber / video - The target audience of the Youtuber / video - How competitive (from an advertiser perspective) the video is (or its associated keywords are) Certain videos are not eligible for monetization (so Youtubers typically won't earn ad revenue from them). This includes, for example, many videos depicting nudity or sex and videos containing extremely foul language or controversial / offensive topics. If a video contains commercial music, sometimes the music publisher or record label will file a copyright claim over the video and instead of taking it down will request the Youtuber's revenue share instead. So, in these cases, the Youtuber is not penalized but also does not earn ad revenue from the video. Youtubers also make lots of money (much more than standard ad revenue) by negotiating product placement deals directly with advertisers to personally use and/or promote a product (such as a mobile app, web service, gadget, etc.) within their video.", "My girlfriend is a popular YouTube creator (currently between 150k-250k subscribers). There are three core ways YouTubers make money. (1.) YouTube AdSense: - This is purely getting paid for views on videos, because there are ads on videos, such as display ads (the ads next to the video), overlay ads (ads that pop up at the bottom on the videos), and skippable and non-skippable video ads before the actual content. Depending on the time of the year, the amount a creator is making is roughly between $1 to $2 per 1,000 views. YouTube does this because they are getting a cut of the revenues that the advertiser is paying for on the videos. Some videos are not \"monetizable\", so the creator will not earn anything for the views. This is generally because of offensive content within the video. (2.) Sponsored Content: - This is advertising within the video itself. This form of advertising can occur in many different forms, but a few examples would include companies paying for their products to be featured in videos, merely having the products mentioned in a video, or saying something along the line of \"this video is brought to you by [XYZ Company].\" (3.) Selling Branded Products: - This one is pretty obvious. Selling t-shirts, stickers, hats, etc. My girlfriend is only involved in (1.) & (2.) at the moment, and she made ~$50k in 2016. Each community within YouTube is different, but in her sphere, the majority of earnings come from sponsored content with AdSense being a nice bonus.", "Companies pay to advertise on YouTube, YouTube gives a portion of that money to the uploader of videos with ads on them. The amount companies pay to advertise depends on a bunch of factors, like views of course, if it's skippable after 5 or 15 seconds, how many comments/likes the video gets, etc.", "The ad makers pay YouTube to put their ads on YouTube videos. YouTube keeps a portion of that money (around 30% I think) and then pays the youtuber based on how many views they get. For a non-partnered youtuber, it's about 10 views for 1 cent, 100 views for 10 cents, 1,000 views for $1, and $2,000 for 1 million views (these are all estimates, it varies a lot). I'm not sure how different it is for partnered YouTubers, but I think it depends more on who they're partnered with. It also depends on your viewer base, and more specifically, how many viewers have Adblock. On videos over 10mins you can put extra ads, and therefor some extra money." ], "score": [ 126, 13, 4, 3 ], "text_urls": [ [], [], [], [] ] }
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5lg92k
What's that clicking sound in your ears everytime you yawn?
You don't have to yawn either, you just do this thing and you can make the same noise in your ears.
Biology
explainlikeimfive
{ "a_id": [ "dbvljiw", "dbvevke" ], "text": [ "It is your pharyngoltympanic tube (Eustachian tube) opening. It connects your middle ear to your throat. Opening it is also how you \"pop your eardrum\" or equalize pressure within the middle ear.", "Often, the bones in the jaw's joint, which is right near the ears, is not a nearly perfect sphere like it should be. The rubbing and catching of one part in the other makes the clicking noise. If it is painful, you have a problem and should see an oral surgeon. They call it TMJ (which is really just it's abbreviated name - tempo-mandibular joint) and some people needs surgery to alleviate the pain." ], "score": [ 6, 4 ], "text_urls": [ [], [] ] }
[ "url" ]
[ "url" ]
5lgb2h
How does Shutterfly make profit when it gives away so many discounts and free things?
Economics
explainlikeimfive
{ "a_id": [ "dbvfp8e", "dbvi89n" ], "text": [ "Hi, I'm going to offer you this pen! It's originally $100 but I'll give you a 90% discount. It's yours for the low, low price of $10!", "It's a combination of higher markup than the discounted price and/or using the discounts as loss-leaders. A loss-leader is selling something at a loss and relying on people's impulsive purchase habits to have them buy other things with higher markups that makes up for the loss. An example of a loss-leader is our local grocery chain had a \"buy 1 box of Velveeta cheese, get 2 cans of rotel tomato and pepper sauce\". If they give you the stuff to make a nice dip, you're going to need a bag of chips. They're gambling that you'll buy a bag or two of chips as well. So they give you $1.50 worth of rotel, and you buy $5 worth of chips. A Shutterfly specific instance of this would be when we got a free 8x8 picture book. My wife made one with pictures of our child to give to a great grandparent for Christmas. She then decided \"it would be nice if we had one, and if we had another one to another older relative.\" Not to mention, she added a couple of upgrades to some of the books. So their offer of a free 8x8 book got them $60+ in revenue." ], "score": [ 10, 9 ], "text_urls": [ [], [] ] }
[ "url" ]
[ "url" ]
5lgc5t
What is a tensor?
Mathematics
explainlikeimfive
{ "a_id": [ "dbvj2y6" ], "text": [ "A vector is an arrangement of values in one dimension, like this: V = [a, b, c, d, e] etc. A matrix is a vector of vectors. For example v1 = [ a, b, c ] v2 = [ d, e, f ] v3 = [ g, h, i ] v1, a, b, c, M = [ v2, ] = [ d, e, f, ] v3, g, h, i You can think of a matrix as a two dimensional arrangement of values. A tensor is a vector or matrix of matrices. You can think of it as a three or higher dimensional version of a matrix." ], "score": [ 10 ], "text_urls": [ [] ] }
[ "url" ]
[ "url" ]
5lgnew
The idea of space as a vacuum.
Cannot. Understand.
Physics
explainlikeimfive
{ "a_id": [ "dbviguq", "dbvlzm1" ], "text": [ "It is called that because space has nearly no atmosphere and extremely low pressure. Liquids and gasses always will flow from an area of high pressure to areas with lower pressure while no other forces hold them in place, this is how a vacuum works, by creating a low pressure system that pulls air from higher pressure systems around it until equilibrium is achieved. Space is so large and such low pressure that equilibrium can't be achieved and thus is a constant vacuum.", "Just turn it around. Having *air* around you isn't normal. The pressure inside you compensates the pressure outside you. That layer of air is tiny compared to the ball of rock you're on. As you go up and up, it *rapidly* gets thinner until there is nothing but a few stranded atoms. To you, this air is vital. To someone else, that air is poison. To someone, the pressure around you would crush them like a tin can on Venus. The air around you **is not normal**." ], "score": [ 8, 3 ], "text_urls": [ [], [] ] }
[ "url" ]
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5lgr8h
What determines the borders where each timezone starts? If I live on the line which timezone do I follow?
Let's say I live next to the line where timezones are split and I go to a doctor who is in the next state over in another timezone at a certain appointment time. Would he schedule my appointment as if it were a show preview on television with something like 7/8 central?
Other
explainlikeimfive
{ "a_id": [ "dbvj4xn" ], "text": [ "Time zone boundaries tend to follow the same boundaries as countries or subdivisions in order to keep time as constant as possible. If you had an appointment in another state, they would schedule you their time, not yours. Some businesses, who are close to a timezone difference, will always report their time with the timezone.. \"See you at 1PM Eastern Time, Mr. Duplexety\"." ], "score": [ 4 ], "text_urls": [ [] ] }
[ "url" ]
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5lgw1c
Why is there a separate security code on credit cards? If the three extra digits make it that much more secure, why not just make the number three digits longer?
Economics
explainlikeimfive
{ "a_id": [ "dbvogrg", "dbvkn60", "dbvn38j", "dbvus2z", "dbvzje9", "dbvvwuc", "dbwiz0k", "dbwewmk" ], "text": [ "In the olden days, credit cards were often not scanned with the mag strip, because the equipment was still too expensive for smaller retailers. What they did instead was use a carbon paper and a roller machine to take an imprint of the front of the credit card with the numbers. This was commonly part of the receipt, and one copy would be torn off and given to the customer. The problem with this, of course, is that now all these receipts you are just throwing away left and right have your whole card number on them. This is where the extra numbers on the back to confirm an online(or at the time, over the phone) purchase can be used, if you only had a receipt you found with the front of someone's card, you would not have all the numbers needed to complete a transaction.", "Two main reasons: 1. They're in a different spot than the main credit card number, so if you get a picture of the credit card you still can't use it because you don't have the security code. 2. On systems that save your credit card number, they are not supposed to save your security code, which means you need to type it in in order to place an order. That means that if someone else gets access to my computer or login, they can't order stuff for themselves because they don't have my security code. The same goes if the seller's system gets compromised, enabling hackers to access our credit card numbers - but they can't use them without the security code.", "To add to /u/Dacke comment... Android Pay is actually way more secure because when it transmits a credit card, it actually transmits a one-time credit card generated just for this transaction, so stealing it is pointless. As with any security system any time you have _static_ or non-changing information it is considered easy to individually compromise. The new chip in new credit cards in america means that you never actually transmit the credit card number to the payment system. Instead you transmit an identifier and a rolling code. The code is verified by the server to verify legitimacy. Since reading the code is pointless since it changes by algorithm every few seconds you have a much more foolproof system. So _at least_ the card readers in every store are no longer attack-vectors for credit card theft. Previously you hack a credit card reader provider and you get _everything_. edit: I'm sorry I think I mixed up android pay and the older Google wallet.", "It's not just three extra digits, it's a separate code that is used very differently. The credit card number identifies the card, can be read by card readers from the magnetic strip, and is stored by merchants' systems that store your card information. Or, if they use the old machines that make an imprint of the card, that number is on the imprint (which means the full credit card number is on the receipt). The CVV code (the three extra digits) is just written - on the back of the card, with no raised plastic, so it won't appear in imprints and won't be as easy for people to see or photograph. It is *not* stored when your card number is stored, and PCI (the standard in the US that companies that take credit card numbers are required to abide by) places more restrictions on where you can keep that number. It can only be temporarily kept for use during a single transaction, and that's it.", "There is a set of regulations that dictate the payment card industry called PCI. if you want to do anything with payment cards you have to be PCI compliant. One of the major things in PCI compliance is you cannot store the CVV (those digits). You also cannot store the mag stripe data. This makes it hard to copy a card from legitimate hardware. It also allows companies to tell how you used your card. Merchants are charged different rates for \"card present\" (you physically swiped your card) and \"card not present\" (you typed in your card number, like an online purchase). There are other categories and large companies can negotiate rates. The numbers are also present on the back of the card, which makes copying the numbers more difficult. If I wanted to steal your credit card number with the CVV I'd have to see both sides of your card. This means is most likely need physical possession of the card, I cannot sneak a picture. When you combine these features it makes it more difficult to steal someone's card number. It doesn't make it impossible but does out up enough barriers to stop a good amount of low-level thieves. Furthermore the way the numbers are used with mandatory industry standards they serve a purchase for the men behind the curtains that run the show. Lastly I've called the digits CVV but different companies and networks may have a different name for them. They serve the same purpose though.", "Those numbers are not \"stored\" or \"remembered\" by merchants. This makes purchases more safe by verifying that you likely have physical possession of the card. If you just added the three digits to the main card it would defeat the purpose of the security measure. Merchants who do not check this code each time are more likely to process orders with stolen credit card information. These codes are something for merchants to check, not to help you. What you(as a credit card user) just need to do, is check your money activity regularly. You can get your money back due to fraud via a backsies(a chargeback) as long as you notice it within 120 days(visa rules) from the transaction date. The money will then be taken from the merchant for being a meanie who ran your card. Even if the merchant checked your billing address(called AVS) and this code(CVV) they will still be responsible if you say it isn't you.", "there is a separate security code (CVV2) on the back of your credit card to allow there to be a different code for cardholder manual entered transactions (e.g. online and phone, not fallback) to those done with magnetic swipe (CVV) and in more recent times yet another one when the chip is used (iCVV). The most obvious of demonstrable reasons to have this is so that your card can't be skimmed and then used to do online or phone transactions. Unfortunately given it is static in nature its can obviously be bypassed by taking a photo of the back of the card. To add extra levels of security Visa\\Mastercard\\etc do have services like secret question\\answers etc. In regards to why they don't just make card numbers longer... quite a few reasons but a few are - - if they've stolen your number it doesn't matter if its 5 digits or 50 digits. - 16 is enough. thinking of just visa and cards starting with 4, theres 140 trillion valid card numbers or something. More than enough really. (Do note that the card number itself has its own check digit at the end) - it makes more sense to think of these CVVs (Card Verification Value) as codes to validate that the piece of plastic being read or referenced is actually from your bank. Technically the code is generated using a key known to your bank and the card scheme, the card number, the expiry date (in some format) and the service code (basics of what kind of card it is, and some rules. Generally this number is substituted so you get a different CVV codes)", "isn't the CVV also a checksum to ensure that a valid cards details are entered? from what I understand, this 3 digit number is not completely random, but is derived from an algorithm running through the 16 digits and expiry date of the card. the algorithm can reach any of a set of multiple 3 digit ids, though - one of this smaller set of numbers is assigned at random to every credit card. the way the checksum works is that when a credit card number is entered, the algorithm is played back in reverse to validate the details entered - this is usually done on the page itself." ], "score": [ 1465, 479, 55, 18, 6, 5, 4, 3 ], "text_urls": [ [], [], [], [], [], [], [], [] ] }
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5lgx81
how do people hold their breath for so long without passing out/dying
The official record for breath held underwater is 24 minutes and 3 seconds. HOW?!
Biology
explainlikeimfive
{ "a_id": [ "dbvm1nh", "dbvpucx" ], "text": [ "They train to perform well for their sport. If you do something that is challenging repeatedly your body adapts. So their bodies are more efficient with oxygen, and they probably have a large lung capacity and good control over their heart rate. Some of these records are also set by breathing in pure oxygen.", "There's a video out there of a ted talk David Blaine did explaining how he got his record of holding his breath under water. He talks about the process and training of it. Edit: here's the link URL_0" ], "score": [ 12, 3 ], "text_urls": [ [], [ "https://www.ted.com/talks/david_blaine_how_i_held_my_breath_for_17_min" ] ] }
[ "url" ]
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5lgxhi
A lifetime supply.
Economics
explainlikeimfive
{ "a_id": [ "dbvknsp" ], "text": [ "Depending on the product and company a lifetime supply would mean a certain amount each year for so many years. In this case vans which would probably be one pair per year. If the t & c stated 30 years for example it would be a total of 30 pairs in way of a voucher per pair maybe,then that person would give over the vouchers to the charity." ], "score": [ 3 ], "text_urls": [ [] ] }
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[ "url" ]
5lh577
Why do non-fighters collapse when they get elbowed in the head, but MMA fighters can take it with the punches so to speak?
Watching a UFC fight, you see fighters elbow as hard as possible against their opponents face. The fight goes on. Whereas when Metta World Peace elbowed James Harden, he was on the floor clutching his head and the game was stopped. Both muscular men throwing elbows. If anything the MMA elbow should be more effective in being a trained move.
Biology
explainlikeimfive
{ "a_id": [ "dbvnhw0", "dbvq2kz", "dbvmw05" ], "text": [ "Med student and martial arts buff here. Most people just aren't used to getting hit. It's a huge deal for most people because it's an egregious violation of all kinds of social norms, it destroys their pre-concieved notions about themselves and other people, and they just aren't accustomed to pain in any form. It doesn't take a lot of training to \"beat\" this reaction out of people. You can learn pretty quickly that getting hit in the head or face isn't necessarily the end of the world. It's never fun, but you can easily learn to deal with it, up to a point. Only up to a point, however. When you get hit hard enough, it can start to cause real problems, but the phenomenon you describe in the thread title is as much psychological as anything else.", "MMA fighters engage in a practice called sparring, in which they simulate a fight with a training partner- many times going much farther than a simulation and throwing punches and kicks 75 - 100% power (a practice that is now frowned upon in this more enlightened age of brain trauma in combat sports). This prepares them for the blows that they will receive in the actual fight, a typical fighter will engage in sparring multiple times in a week during a fight camp. What you saw in the James Harden incident was a man completely blindsided by a blow to the side of the head. Violence like this is rare in a basketball game and is not something that you can prepare for. He undoubtedly received a concussion from that, you simply can't train for being sucker-punched/elbowed by a giant. The punches that you see that knockout MMA fighters are the punches that they don't see coming, much easier to absorb a punch that you can at least try to block. Also, many times a lot of these guys are acting, putting on a little bit of the show for the referees so that they can get the offender ejected and giving their team an additional advantage, as well as soaking up some attention from a surprised crowd.", "I am *not* a doc or a fighter (more of a gadget lover) but I think this is more or less accurate. If you watch KO vids and know a bit of brain science, it's all about the axis of rotation of the head. A straight punch drives the brain back and forth along a single axis - a knockout blow (in any sport) is generally to the chin or temple which twists the head back *and* to the side violently - a two-axis rotation that torques the midbrain and causes the victim to lose consciousness. Watch the action of the victim's head in any KO video: two axes of motion = sleepytime." ], "score": [ 42, 4, 3 ], "text_urls": [ [], [], [] ] }
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5lh9ki
My brother looks exactly like my dad when my dad was a baby. I currently look like my dad at his current age. My brother and I do not look alike nor related. How does this happen?
Biology
explainlikeimfive
{ "a_id": [ "dbvpjoe" ], "text": [ "You each got 50% of your dad's genes, some overlap and some don't, some get activated earlier than others." ], "score": [ 7 ], "text_urls": [ [] ] }
[ "url" ]
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5lhaz8
How do rebreathers work?
I'm watching a documentary on the USS Atlanta and they mention the world record for the longest dive was 30 hours. I've dived before a decent amount of time but never worked with rebreathers, how are they able to stay under for so long without adverse effects?
Technology
explainlikeimfive
{ "a_id": [ "dbvwrp6", "dbvvki6", "dbwnmen" ], "text": [ "If you're suffocated by being locked in a small box, it's not actually the lack of oxygen which is the problem. Normally the cycle is 20.9% oxygen, 0.04% CO2 in, then 16% oxygen 4% CO2 is exhaled. Inhaling 1% is very uncomfortable, \"stuffy\" air. 7%-10% CO2 is toxic and will lead to suffocation *even if there's sufficient oxygen*. Excess CO2 will change blood pH and the body can't handle that. So if you exhaled into a bag along with a tank of pure O2, well you could add the equivalent of +4% pure O2 on one side and vent out 4% of the volume of gas on the other side, but the CO2 mixed into the air so you don't remove the 4% CO2. No, the new CO2 level after partial venting is 3.84%, still toxic. So we're got 3 problems here: 1. We can't maintain breathable air by just adding O2. 2. You can't breathe pure O2 when diving either, O2 is toxic at the increased pressures experienced while diving. We can't dilute it with CO2 either, it can ONLY be diluted with nitrogen or (rarely) with helium. 3. We don't want to waste any volume of air here other than the CO2, but we can't just vent CO2 selectively. Not only would we waste the remaining 16% O2, but a larger volume of inert nitrogen too, and we don't want to carry a huge volume of nitrogen. Same's true for spacecraft. Spacecraft can't tolerate high O2 either because it makes everything super-flammable. What we have is a CO2 scrubber of lithium hydroxide or sodium hydroxide. These adsorb ONLY CO2 from the air and form a carbonate, this does reduce the volume of air and and equivalent volume of O2 can be added. The nitrogen (78% on Earth, varies in diving and space ships) is not consumed nor regenerated. The CO2 is literally \"scrubbed\" out.", "Humans don't exhale solely waste gasses - in reality, there is still some oxygen in the gas mix that you breath out. Rebreathers function by allowing this gas to be recycled, adding appropriate amounts of oxygen from the tank to the recycled air, and by filtering out gasses such as CO2 (IIRC). I can't give you any exact numbers, but this is my understanding from reading the Wikipedia page a while back.", "I'm a certified rebreather diver. I dive the Poseidon MKVI and 7. The rebreather machine is basically a Nitrox mixing machine on my back. One of the small bottles is 100% O2. The other is regular air. On the surface it feeds me the pure O2. As I dive it blends more and more air into the system to keep the gas safe to breath. The breathing system is a closed loop. Bubbles only exit the system when I use the gas for buoyancy purposes. The O2 will get used up by my body to survive so there is a sensor that automatically replaces the O2 as my body metabolizes it. The CO2 my body produces is deadly so there is a chemical in the system that absorbs that CO2. That's called the scrubber. Mine is a prepackaged sodalime chemical that I can buy at any rebreather specific dive shop. That's about it. Rebreathers are great. They are totally silent. Fish don't run away when they see you. They seem to think you are just another fish instead of a bubble spewing monster. One very small 2L tank of O2 can last me three - four hours of diving. If you dive with regular divers that ends up being an entire weekend of 2 tank diving." ], "score": [ 91, 5, 4 ], "text_urls": [ [], [], [] ] }
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5lhb8h
How do card readers know that a card has a chip?
When I see people use their cards at places like convenience stores, sometimes they'll swipe their card and then be asked afterword by the machine to insert the chip instead. How does the machine know the card has a chip, and how can it tell the difference?
Technology
explainlikeimfive
{ "a_id": [ "dbvoph3" ], "text": [ "When you swipe your card, the machine is reading information on the card. One of the things it reads is a little message that says \"Hey! I have a chip on me!\" Now the machine knows, so it tells you to use the chip." ], "score": [ 48 ], "text_urls": [ [] ] }
[ "url" ]
[ "url" ]
5lhc44
Why do most spiders have many eyes, but poor vision?
Biology
explainlikeimfive
{ "a_id": [ "dbvw73y" ], "text": [ "Predatory [jumping spiders]( URL_0 ) actually have quite good vision, but that doesn't necessarily answer your question of why *other* species of spiders have so many eyes if they don't get good vision out of it. The \"secondary eyes\" apparently mostly detect the direction of light and/or movement, which is presumably useful enough that they don't atrophy completely over evolutionary time (some species that live in dark caves have no eyes at all). Having enough secondary eyes that they can monitor a 360° arc would then be useful." ], "score": [ 6 ], "text_urls": [ [ "https://en.wikipedia.org/wiki/Jumping_spider" ] ] }
[ "url" ]
[ "url" ]
5lhdgq
Memory assignment in hardware
When I write a line of code in C like int x = 5; How is that value physically written into the computers memory?
Technology
explainlikeimfive
{ "a_id": [ "dbvom3m" ], "text": [ "The C compiler will craft a request to the operating system to assign an available memory location to hold an integer. When it's time to store a number there, the CPU will put an electric signal on its address bus pins equal to the binary address of that memory location, and a signal on its data bus pins equal to the binary version of the number 5, and then briefly electrify the \"Store\" pin to tell the memory subsystem to accept this write request." ], "score": [ 7 ], "text_urls": [ [] ] }
[ "url" ]
[ "url" ]
5lhdts
Why do we capitalize "Happy New Year"?
Other
explainlikeimfive
{ "a_id": [ "dbvola3", "dbvol2y", "dbvt6sf" ], "text": [ "My guess is that happy is capitalized because it's the beginning of a sentence, and New Year is a proper noun (shorthand for New Year's Day).", "New Year's Day is the name of a holiday. Because of this it is capitalized like every other proper noun.", "I just had an \"aha\" moment reading some of these comments. Americans (or at least some of them) consider \"Happy New Year\" to be short for \"Happy New Year's Day\". Presumably this is why some say \"Happy New Year's\" (heard as \"Happy New Years\" to these British ears, which is mildly irritating). In the U.K. \"Happy New Year\" just means \"Happy New Year\". You are welcoming in the year, not the single day. At least, that's the way I've always thought of it. So good question by OP. My guess is we capitalise it just because it looks better. I wonder what the style manuals of the economist, the FT, the New York Times etc say. I'm going to guess the economist does not capitalise it, but could be wrong. Anyway, happy new year." ], "score": [ 25, 10, 7 ], "text_urls": [ [], [], [] ] }
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5lhh73
Why do mobile games suck, even though phones are more powerful than good handheld gaming systems like Gameboy?
Technology
explainlikeimfive
{ "a_id": [ "dbvpq8r", "dbvzxmi", "dbvq4h3" ], "text": [ "This might be a snarky response but: have you purchased any 30-40$ mobile games? If you can play a game for free, what you are playing is what someone could create on a fairly small budget, in a fairly small studio, and then sell to investors in order to produce. Most of these games are riddled with ads and microtransactions because those provide a source of income that is lost by not charging players for the initial purchase. Games with an initial charge make their money through game sales; those with very low costs rely either on volume or on other methods to pay for the costs of development. Triple-A hand-held games, like Pokemon, are developed and marketed by companies that are usually very large and have entire teams dedicated to promoting the game; they also cost more to buy up-front. Finally, note that while the gameplay may be limited in \"free\" games, the graphics and potential are much better than older handheld systems, with social capabilities that those older systems lacked due to the connected nature of smartphones.", "touch-screens are horrible for most games. Gameboy is way better. A solid set of buttons for controls is how games are meant to be played and CPU power does not make the game. Style of game-play does", "I assume because most mobile developers want to make as much money as possible. This means the target audience are largely nongamers. The best games that anyone can play are simple and repetitive to get as many people as addicted as possible. Complex stories, concepts, and challenges would largely scare away nongamers. In contrast, things like gameboy games need to be geared towards a gamer. Instead of just a way to spend $5 or waste 5 minutes, gamers want a deep and rich experience, something that will make you care about what's going on in the game world and get immersed in it." ], "score": [ 21, 3, 3 ], "text_urls": [ [], [], [] ] }
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5lhiq3
School Choice
Is it the ability to put their kids in any public school they want? That the government should pay for private schools? With school choice, will new private schools open? I don't understand, unless there are "open slots" in schools, isn't it just going to be people with influence get their kids in good schools, and others are left with the rest? Isn't educating the masses a positive for a country?
Other
explainlikeimfive
{ "a_id": [ "dbvu7el" ], "text": [ "I'm going to answer from an American perspective. The argument goes something like this. Public schools are really terrible. So the wealthy pay extra to get into private school. The less wealthy but still well off will move to areas where the public education is better than average. The poor get the worst public schools. But if everyone got vouchers, then the poor could go to a different school other than the public school they are assigned to. Because of this, schools will have to compete with each other in order to get more students, and therefore more money. No one will give their vouchers to the terrible schools, so they must change or die. The competition between the schools will lead to better education, and the poor will have more options. There are many different proposals on how to do this. Economists are generally split on the idea. But here's a recent survey so you can see the split yourself. URL_0" ], "score": [ 11 ], "text_urls": [ [ "http://www.igmchicago.org/surveys/education" ] ] }
[ "url" ]
[ "url" ]
5lhovu
What causes your nasal cavity to sometimes "burn" when there is liquid entering it, but other times it isn't painful?
I thought it had to do with the salinity of the liquid (hence why saline solutions work to clear your nasal passages) but I recently got that burning feeling from my own mucus. I had a very runny nose and while trying to blow it I got that burning feeling associated with getting water up your nose.
Biology
explainlikeimfive
{ "a_id": [ "dbvzqbb" ], "text": [ "You are very much correct. Fresh water will burn, but an isotonic saline solution that's close to your blood plasma will soak in and rinse through quite comfortably. The burn from runny nose mucus was probably concentrated enough to be TOO salty, which hurts just as much. Or else your mucous membranes were inflamed, which makes them very tender, so it might have been strictly physical irritation. I personally prefer a Neti pot over a squirt-bottle, with a pinch of baking soda in the salt mix. One thing to remember with this is that it's not directly sluicing up into your sinuses. It's hydrating your nostrils, and creating a mild vacuum to gently suck the snot out. But it's also less of a feeling of \"OH MY GOD I JUST STABBED MYSELF IN THE BACK OF MY EYES WITH A WATER JET.\" Your mileage may vary." ], "score": [ 3 ], "text_urls": [ [] ] }
[ "url" ]
[ "url" ]
5lhrfu
Why are kinder eggs banned in America, but knockoffs aren't?
Other
explainlikeimfive
{ "a_id": [ "dbvs26h", "dbvrxe7", "dbw4x7s", "dbw4484", "dbwdj26", "dbw4r82", "dbw4iv3", "dbw5a57", "dbw4hud", "dbwmf5y", "dbwfge1", "dbw2t4f", "dbweysh" ], "text": [ "The regulations forbid embedding non-edible things inside food. While banning bits of plastic in chocolate bars is a good idea in general, it also catches kinder eggs. The legal versions have a ridge on the plastic capsule which sticks out of the chocolate, like [this]( URL_0 ). Legally, it's now two pieces of chocolate on the sides of a piece of plastic, not a piece of plastic embedded in a piece of chocolate.", "Do the knockoffs contain toys in their centre, surrounded by chocolate?", "Probably a stupid question, but what about fortune cookies? If they've banned edible items that contain non edible items, why are fortune cookies ok?", "The knockoffs circumvent the rule against a non-food prize entirely enclosed in chocolate. One version featured two chocolate halves surrounding a plastic core. The seam where the halves met was the plastic outer rim of the inner shell. Just today I saw that Kinder has finally solved the problem--sort of. They're now offering the Kinder \"Fun\" egg, which is two half-egg plastic pods. One side holds the toy prize, and the other holds Kinder chocolate paste and two crunchy candy balls. There's a small scoop between the halves you can use to eat the chocolate paste. Edit: seems I remembered the name wrong. Yes, it's \"Joy\" not \"Fun.\"", "The real question you should be asking is \"why are kinder eggs banned, but full auto assault rifles aren't?\" Just kidding no offence", "The only place I've seen the knockoffs is at mom and pop type marts and privately owned grocery stores. There was no plastic piece separating the chocolate like the picture posted above. It was small plastic toys inside a full chocolate hollowed egg. They were delicious but also probably bought illegally. Now if they realized it was illegal or not I have no idea. I bought the entire pack and my kid loved it!", "As a Canadian with full access to kinder eggs, I buy the kinder bars. The original kinder bars with the milk filling are basically the kinder egg chocolate but without the lame toy. Jolly ranchers are way more dangerous anyway. Don't give hard candy to children (or drunk people, people driving, walking, etc)", "We used to have wonderballs with toys in them but that got stopped in the 90's due to lawsuits.", "I always thought it was just because they're a hazard to unsupervised curious kids. Kinder used to have the tiny toys you had to assemble, where as the eggs now have stickers or assembled toys. I was one of those kids. My mom owned a store that sold them so I had access to hundreds of them. Unsupervised 4 year old me stuck a piece up my nose. Was up there 2 weeks before someone noticed a \"smell\". Had to have surgery to remove it, it was lodged that far up.", "On sad and tragic note, the creator of the Kinder Surprise eggs passed away a couple days ago. URL_0", "Because America is much more protectionist than people care to admit. It's the same way for lots of foreign products like cheese, they're protecting their farmer's industries", "They're not, technically. Ethnic Stores are exempt from certain laws involving food - including the one about toys inside of candy.", "There's a guy who owns the patent of closing chocolate that's been approved here in the states. He was on [Shark Tank]( URL_1 ) . Since he holds the patent that gets around the issue, everyone has to use his company. He explains himself pretty well during the [episode.]( URL_0 ) ." ], "score": [ 7016, 329, 93, 42, 28, 21, 14, 10, 10, 6, 5, 4, 3 ], "text_urls": [ [ "https://consumermediallc.files.wordpress.com/2013/03/chocolate-egg-with-capsule-and-ridge.png?w=680" ], [], [], [], [], [], [], [], [], [ "http://metro.co.uk/2016/12/31/the-inventor-of-the-kinder-surprise-has-died-at-the-age-of-83-6353568/" ], [], [], [ "https://youtu.be/6dz922-7LBg", "https://youtu.be/HLzpzK1I_Oo" ] ] }
[ "url" ]
[ "url" ]
5lhtex
How was the canyon diablo meteorite, an object not from earth, used to determine the age of the earth?
Biology
explainlikeimfive
{ "a_id": [ "dbvskv2" ], "text": [ "Basically, what it boils down to is that pretty much everything in our solar system [formed at about the same time]( URL_0 ). It turns out that this particular meteorite has a [particular composition that makes age estimations based on lead isotopes easier to measure]( URL_1 ). Thus, if we can get a precise estimate of when this meteorite formed, we can also get a more precise estimate of when the Earth formed." ], "score": [ 9 ], "text_urls": [ [ "https://en.wikipedia.org/wiki/Formation_and_evolution_of_the_Solar_System", "https://en.wikipedia.org/wiki/Age_of_the_Earth#Canyon_Diablo_meteorite" ] ] }
[ "url" ]
[ "url" ]
5li1yj
Why is the golden ratio common to so many things of different nature?
Mathematics
explainlikeimfive
{ "a_id": [ "dbvwzv5", "dbw84pl", "dbvyn15", "dbvy95k", "dbvvgem", "dbwns4d", "dbw271t" ], "text": [ "Say you have a seed. Deep down in the genetic code of the seed is the simple genetic code that says \"have these cells build more of themselves.\" If you let all those cells grow, the ratio between old cells and new cells will usually be the golden ratio. The golden ratio is so common in nature because it is the product of such a simple idea: the ratio between the first thing and the second thing is the same as the ratio between both those things and a third thing. It's what you always get when you tell cells or leaves or branches or scales to just \"grow more of yourself.\"", "The golden ratio is a beautiful mathematical *idea*, but it doesn't manifest in nature as much as is claimed in videos on youtube or books about the universality and even mystical significance of the ratio. It is 'pop' science, tenuously connected to a wide array of natural processes because people find that idea aesthetically pleasing. *Mathematically*, the golden ratio is fascinating. It is the irrational number with the simplest continued fraction expansion... > 1 + (1 / (1 + (1 / (1 + (1 / (1 + (1 / ... ... and it is the limit of the ratio of consecutive Fibonacci numbers. Fibonacci numbers *do* show up in science, in ((almost?) exclusively biological) natural processes, though this relationship also doesn't occur as much in nature as is often claimed. The number of spiral patterns in the arrangements of leaves around branches, petals around flowers, and scales around pine cones are often consecutive Fibonacci numbers - see [phyllotaxis]( URL_0 ) - and the higher those numbers get the closer the placement of elements around those spirals is related to the golden angle (the golden mean as applied to the circumference of a circle). This arrangement arises because it is the simplest and most efficient way to arrange petals (for example) such that they all get the maximum amount of sunlight with the least amount of work. In a sense the golden ratio is a lot like a Platonic 'ideal' - the idea that circles (for example) are always just approximations of some ideal perfect circle, that the forms of everything we see in nature are imperfect shadows of pure ideal forms that we cannot perceive directly. In that sense the golden ratio is the ideal, perfect relationship that is approximated in natural forms by the Fibonacci numbers. This leads some people to assume that there must be something universally important about the golden ratio, in the way that ideal-but-inaccessible forms were considered important to ancient Greek philosophers. But such ideas are in the realm of philosophy, not physics. tl,dr: the golden ratio is fascinating in mathematics as the eventual limit of the ratio of consecutive Fibonacci numbers, and as an organizing principle in some spiral biological processes. Claims that the golden ratio has some other significance or cosmic relevance might be interesting philosophically, but they have little to do with science.", "There's a good amount of debate but here's the unpopular truth: it doesn't play a big role in nature. There are many things that are close to the golden ratio but it does not crop up all over as is often claimed. Here's an article about the golden ratio in people. URL_0 And here's one about it in manmade stuff. URL_1", "[Vi Hart has an excellent 3 part video series explaining it better than I have ever seen it explained.]( URL_0 ) This is part 1. This ratio is the result of trying to maximize efficiency in using space. As she explains, it would be weird if these things *didn't* exhibit this pattern. The first part is mostly showing how the pattern occurs in nature, the explanation starts in part 2. The actual biological rather than mathematical explanation is in part 3.", "Because \"the golden ratio\" is a clever-sounding way of pointing out when something is approximately half-again bigger than something else. As you can imagine, such a vague concept can be interpreted to occur very frequently.", "Here's a recent article from Fast Company supporting the claim that the Golden Ratio, Fibonacci Sequence is man-made bullshit URL_0", "Actually it does not play a main role in nature. You can \"occasioannaly\" find something that roughly is under this ratio. Such an unfortunate myth that needs to go away." ], "score": [ 439, 107, 93, 35, 16, 4, 3 ], "text_urls": [ [], [ "https://en.wikipedia.org/wiki/Phyllotaxis" ], [ "http://www.independent.co.uk/news/science/mathematicians-dispute-claims-that-the-golden-ratio-is-a-natural-blueprint-for-beauty-10204354.html", "https://www.maa.org/external_archive/devlin/devlin_05_07.html" ], [ "https://www.youtube.com/watch?v=ahXIMUkSXX0" ], [], [ "https://www.fastcodesign.com/3044877/the-golden-ratio-designs-biggest-myth" ], [] ] }
[ "url" ]
[ "url" ]
5li5dj
What is the pixel resolution of regular eyesight and what minimum resolution would be needed for VR glasses to match a normal person's vision?
Technology
explainlikeimfive
{ "a_id": [ "dbvvbzc" ], "text": [ "Regular eyesight has a resolution equivalent to around __576 megapixels.__ This is the resolution that must be matched in order for VR to appear 100% real. (Although lower resolutions might suffice, too.)" ], "score": [ 3 ], "text_urls": [ [] ] }
[ "url" ]
[ "url" ]
5li6sn
Why is the moment of death always associated with "the light going out from one's eyes"? Does this actually happen or is it just a metaphor?
Biology
explainlikeimfive
{ "a_id": [ "dbvvkbl", "dbw6vrb", "dbvy5c3", "dbw1qhx", "dbvvmx8", "dbw723v", "dbvylf4", "dbw64sm", "dbwciko" ], "text": [ "Absolutely not. If you have ever looked into something's eyes when they die the pupils dilate and focus become unfixed. The eyes begin to look waxy. The spark of life you literally see leave their eyes. Its the most heartbreaking thing I have ever seen. I know this because I work with wild animals, wildlife. I have seen many animals die and it never ceases to be something that signifies the intake is dead. It's horrible. I hate it. But it's legitimately also metaphor for the soul leaving the body.", "The scientific reason is merely a cumulative effect of small, almost unnoticeable things. While alive the eyes constantly vibrate back and forth, unnoticeable to you (it's an evolutionary 'trick' that makes you not blind, associated with change detection). There's also dilation of the pupils in response to light and conscious movements on the part of the now deceased. When all of this stops suddenly due to the cessation of electrical signals from the now dead brain, it looks unnatural to your mind.", "I saw it when my mom passed. She died anf was just gone. There's no doubt about it, once life leaves what is left was just a shell.", "I watched my grandfather pass and seeing his natural luster in his eye just die, killed me. This is certainly not a metaphor, a certain sparkle is loss in the process of dying, you only realize it on their last breath though. I don't know the scientific reason, but from personal experience, the lights do go out. Why the moment of death is associated with this I'm not 100%, though my best guess is before stethoscopes and modern medical tech, people looked into somebody's eye to see if their were indeed dead. But that's my best guess.", "Idk if it's different with people but I was with my dog when she passed a few years ago and i think it's more metaphorical. You can see something though, Idk how to explain it really. It's kinda like you can see their eyes stop functioning, all those little movements, the way they focus on something, one second that's all there and the next everything is still and, well lifeless, almost like a machine powering down and coming to a complete stop. Not sure if this is correct or not but it's my experience with it.", "Your eyes are lubricated with fluids when you blink. The layer of fluid is thin and dries quickly, hence why we blink. After death you stop lubricating your eyes and the lubricant dries, resulting in a loss of sheen.", "In the Illiad, Homer describes several warriors' deaths with similar imagery. Examples: *And Eurypylus, son of Euaemon, killed Hypsenor, the son of noble Dolopion, who had been made priest of the river Scamander, and was honoured among the people as though he were a god. Eurypylus gave him chase as he was flying before him, smote him with his sword upon the arm, and lopped his strong hand from off it. The bloody hand fell to the ground, and the shades of death, with fate that no man can withstand, came over his eyes.* And (although Aeneas does not die here): *The hero fell on his knees, and propped himself with his hand resting on the ground till the darkness of night fell upon his eyes.* But actually in most of the epic, a death is described as someone \"falling to the ground.\" Interesting that the light leaving the eyes (which is how I interpret the shade/darkness falling on them) was associated with death even 3,000 years ago.", "I seen it in my grandmother when she passed away a few years back, it is literally like a light going out, one minute the eyes are there, focused on you, the next they aren't, the focus is gone, it's like they're looking straight through you, like wax model eyes. It's a strange feeling, to see it happen, the body just kinda switches off and that's it... nothing more, just a shell now. The scary part was when it happened to my dad when he was knocked out for some surgery, his eyes did the whole glaze thing and he went a bit limp, my eyes shot for the anaesthetist, he pointed at the ECG machine, heart still ticking, just sleeping. That scared me...", "There's an immediate change in the eye when someone dies, if their eyes are open, because there's no longer any focus to maintain, so there is a dramatic effect. But the \"light\" is somewhat of an exaggeration, naturally, based on the emotion of the experience. Having opened thousands of body bags, I can confirm that some dead people look just totally alive including the eyes. It's always a little creepy when you unzip and they just happen to be looking straight at you with clear eyes, because 19/20 times they're closed or not looking at you or deflated, bandaged etc. I have let out a small yelp when I was doing things mechanically whilst talking to a coworkers only to be met with a crisp fixed stare from the table." ], "score": [ 59, 31, 25, 24, 15, 8, 8, 5, 3 ], "text_urls": [ [], [], [], [], [], [], [], [], [] ] }
[ "url" ]
[ "url" ]
5liavk
How do the police trace a bullet back to its gun?
Other
explainlikeimfive
{ "a_id": [ "dbvx9x9", "dbvwfjh" ], "text": [ "They don't. That's the great TV/movie trope. Police don't trace the gun. They match the recovered casing or intact bullet to the gun they retrieved at the scene at the same time as the perpetrator is arrested. The firearm does impose a wear mark of the rifling of the barrel onto the bullet. The firearm does impose a mark from the impact of the firing pin on the primer. However neither of these two marks are registered in some master database that immediately gets you to the name of some person. Barrels are easily swappable without any tools. Firing pins are...Less easily swappable but does not require specialty tools. Firearms and their owners are not universally in some searchable database. Moreover, illegally possessed firearms are not going to be tied to their criminal persons. Some criminals do use the same gun in multiple crimes. If one of those crimes is tied to him, then there is some readable suspicion he might have committed the others, but that is very shaky evidence. So there's no possibility to take a casing or a bullet and seriously ask a CSI to find who owns the gun that would stand up to court of law.", "The chamber of every firearm has slight imperfections that are unique, similar to a fingerprint. By looking at the shell casings, this pattern can be identified, and then later matched, to find out if the currently examined weapon is in fact the one in question." ], "score": [ 16, 9 ], "text_urls": [ [], [] ] }
[ "url" ]
[ "url" ]
5liqj4
Why is ice-cream that's melted then frozen much harder to scoop than fresh ice-cream?
Chemistry
explainlikeimfive
{ "a_id": [ "dbw2c95" ], "text": [ "There are two things that make ice cream soft - the ice is in very small crystals, and tiny bubbles of air mixed into it. When you melt and refreze it, some of the air bubbles merge to create bigger bubbles with more solid material around them, and the ice crystals that form are much bigger, tying the mass together. So you end up with ice cream that is a lot harder and less 'creamy'." ], "score": [ 4 ], "text_urls": [ [] ] }
[ "url" ]
[ "url" ]
5lirbu
How do life insurers make a profit?
Economics
explainlikeimfive
{ "a_id": [ "dbw0xdk", "dbw08z2" ], "text": [ "They invest the money you give them and earn interest on it. And they don't always pay out so they keep that money too.", "Most people end up paying more in premiums then they get in return, accounting for inflation and return on the invested funds." ], "score": [ 5, 4 ], "text_urls": [ [], [] ] }
[ "url" ]
[ "url" ]
5lispj
Does the question "what was before the Big Bang?" even make sense?
If time and space were created at the Big Bang, then that question doesn't even make sense right? There was no space before the Big Bang, therefore there was nothing before the Big Bang because "things" and "stuff" can't exist without space, right? And there was no time before the Big Bang, therefore there wasn't a "before" the Big Bang because you need time in order to have a "before", right? There might be "something" before the Big Bang but it's no use even trying to explain or comprehend it since it wouldn't be time or space, so it'd pretty much just be "nothing" to our simple universe resident brains, right?
Physics
explainlikeimfive
{ "a_id": [ "dbw0qis" ], "text": [ "It's an interesting question because we want to know and understand as much as possible about our universe. But to your last point, you may well be right that we will never be able to really look beyond that origin point, and even if we could we might not make sense of it." ], "score": [ 6 ], "text_urls": [ [] ] }
[ "url" ]
[ "url" ]
5lit0m
Why is your reflection upside-down when you look at a spoon on the side that is curved inwards?
Other
explainlikeimfive
{ "a_id": [ "dbw1alq" ], "text": [ "Because the light coming off of your face is hitting the curved edge of the spoon and then reflecting off perpendicular to the surface. This makes it so the light that hits the top (from the top part of your head) is reflected downwards and the light that hits the bottom (from your chin) is reflected up. This creates an image on your eye that is upside down to what you'd expect. Diagram: URL_0 Credit: /u/TheWindeyMan" ], "score": [ 3 ], "text_urls": [ [ "http://m.imgur.com/NKo0BBX?r" ] ] }
[ "url" ]
[ "url" ]
5liy0i
How do fetishes work/how do you get them?
Is there any known explanation? I've been thinking about the fetishes I have (won't go further than that as I am on my main account) and I am confused at how they came to be for me. Any explanations are appreciated.
Biology
explainlikeimfive
{ "a_id": [ "dbw4b50", "dbx9bwx" ], "text": [ "No one knows for sure. But the leading theory is that somehow the pathways between sexual feelings and \"mundane\" objects and situations get crossed. So say you are five years old, and you see a lady wearing heels, your brain may \"glitch\" and a fetish is formed for high heels. Or they were pooping and it felt really good so bam! poop fetish. Now that isn't guaranteed of course. Actual, full-blown fetishes are very rare, but that's what the theory says.", "It's basically association. If you think about it, sexual attraction in general makes no real sense. Outside of a few physical characteristics that show a person is healthy and able to bear/provide for/protect offspring...what we find sexually attractive is basically fashion. Do you find blonde hair attractive? Blue Eyes? Long legs? Why? Why is one hair or eye colour sexier than another? Some people like women with lots of makeup, some people find no makeup attractive...in that sense you could say that person has a makeup fetish...but we only really describe things as a 'fetish' when it's away from the 'norm'...and things that are considered fetishes can quite easily become mainstream. For example, as a child of the 80's, I remember when shaved pubic hair was considered kinky and a 'fetish', today the total opposite is true. Tl;Dr : If you got your first boner at 11 years old from a flash of your birthday party clown's cleavage, you're probably going to have a clown fetish." ], "score": [ 6, 3 ], "text_urls": [ [], [] ] }
[ "url" ]
[ "url" ]
5lj0oc
Why and how do Epsom Salts soothe sore muscles?
Chemistry
explainlikeimfive
{ "a_id": [ "dbwcav4" ], "text": [ "I assume you're talking about epsom salt baths. In reality, relaxing in a warm bath relaxes you and relieves soreness. Epsom salt does nothing in this application." ], "score": [ 3 ], "text_urls": [ [] ] }
[ "url" ]
[ "url" ]
5lj296
Bicameral legislatures - how do they work and why do they exist?
Other
explainlikeimfive
{ "a_id": [ "dbw33ci" ], "text": [ "A bicameral legislature is a system in which two bodies are responsible for making laws. Both bodies must agree on and pass a bill before it can be signed by the PM/president/whatever and become a law. The United States is an example of a bicameral legislature. The two bodies that make up our congress are the Senate and House of Representatives. The Senate is composed of 100 senators--2 from each of the 50 states. The House of Representatives is composed of 435 reps, with the number of representatives from each state being decided based on the population of that state, but each state is guaranteed at least 1 representative. California is currently the most populous state so it has the most representatives. The purpose of doing this, at least in the US, is to try and strike a balance between the lawmaking power of highly and sparsely populated states. If we only had the HoR, then a few states where a lot of people live could dictate law to a larger number of states where fewer people live. If we only had the senate, then more populous states would have less voting power per citizen because each state has the same number of votes. Both of these situations are undesirable if your goal is to provide for as equal of representation as possible in the federal government, so we have both as a compromise." ], "score": [ 6 ], "text_urls": [ [] ] }
[ "url" ]
[ "url" ]
5lj9ns
Why is the HD quality that comes out of my $25 indoor antenna better than what I used to get through a cable box?
Technology
explainlikeimfive
{ "a_id": [ "dbw4z5c" ], "text": [ "Your cable company is compressing the signal. Over-the-air transmissions are 100% pure, uncompressed video signals." ], "score": [ 8 ], "text_urls": [ [] ] }
[ "url" ]
[ "url" ]
5lja4n
How do we know animals are not as self-conscious as humans?
Biology
explainlikeimfive
{ "a_id": [ "dbw5gll", "dbwjddb" ], "text": [ "Consciousness tests. Things like setting up a mirror and watching to see if the critter figures out that they're seeing themselves or if they think they're seeing another critter. There are plenty of others, but that one is basic and persuasive. And the answer is that several other species are self aware.", "Do you mean self-aware? Or self-conscious? /u/open_door_policy interpreted your question as self-aware, meaning an animal understanding that it's a thing by itself, distinct from others. It's difficult to define clearly, so it's easier to just say that it's what the [mirror test]( URL_0 ) and similar tests show. Self-conscious usually means being embarrassed in the presence of others, nervous that they're looking at you and know something embarrassing about you. I'm sure you can find pictures at r/aww and elsewhere that look like an animal is acting self-conscious, but that's anthropomorphizing. I don't know if there's any way to define or test for it scientifically, as how could you reliably distinguish between being afraid and being embarrassed?" ], "score": [ 26, 5 ], "text_urls": [ [], [ "https://en.m.wikipedia.org/wiki/Mirror_test" ] ] }
[ "url" ]
[ "url" ]
5ljevu
why credit cards are safer than debit cards?
Technology
explainlikeimfive
{ "a_id": [ "dbw63s0", "dbwctv7", "dbwcyg5" ], "text": [ "The key difference: With a credit card, the *card issuer* must fight to get *its* money back. With a debit card, *you* must fight to get *your* money back. If you report your card lost or stolen before any fraudulent transactions occur, your liability is zero. Many credit cards promise zero liability for all fraudulent transactions. ... The real difference between a debit card and a credit card when it comes to fraud is in how you get your money back. Having zero liability is safer than having liability, so credit is safer.", "A debit card is connected directly to your bank account. All the money on that card is money you already own. When you swipe a debit card, you're taking money directly out of your own bank account, immediately. So if a debit card is stolen, that person has access to all the money in your bank. A credit card is an I.O.U. to your bank. When you swipe a credit card, you're not paying any money at all; your bank is paying for whatever you're buying. Then at the end of the month, your bank will send you a bill for all the money it paid for when you swiped that card, and you pay it all at once out of your own bank account. If a credit card is stolen, that person has access to your bank's money, not yours. The big difference here is, if someone tries to spend a lot of money with the card, and your bank notices it and stops the card from being used, it's easier for them to say \"you don't have to pay us back for that time someone else used your credit card\" and remove the item from your bill, than it is for them to sort out which of the money in your bank account was spent by you, and which was spent by someone else.", "A couple reasons, that boil down to: debit cards are direct access to your money. Credit cards earn money from you (or, more money) so the companies are more likely to offer competitive offers such as charge-back insurance, which is basically when you tell Visa or MasterCard \"Hey, I didn't authorize Joe the mechanic to charge me that much, he was only supposed to do an oil change and report back but he went ahead and did $1300 of work and billed it to me\" and Visa goes \"I see, you've been a loyal customer, we believe you\" and unless Hal really thinks he has a case, it goes away. Another way it protects you is if, for some reason, someone has your card(s) and your PIN(s), the credit card has a delay and limit. If you check your online data every week or so, you'd see suspicious activity before it was deducted from your \"real money\" in the bank. But if the thief had your debit card, he might just empty your account and when you went to use your money, you'd find you had no money and it might be days or weeks before the bank 1) opens up and 2) does something about it. With the credit card, first you could have the charges reversed/canceled, and if for some reason that failed you could sever the relationship between your bank and the credit card company before the charges went through and deal with it through court. If you're not on the ball and only check your shit every few months, you'll be hosed no matter what." ], "score": [ 12, 3, 3 ], "text_urls": [ [], [], [] ] }
[ "url" ]
[ "url" ]
5ljg3b
Why headlights can be seen from a mile away but only illuminate a few hundred feet in front of the car.
Physics
explainlikeimfive
{ "a_id": [ "dbw6z8s", "dbwb089" ], "text": [ "1/Distance^2 (As distance increases the luminosity gets exponentially smaller) Basically the further out the light is shined, the less luminosity it has. While the direct light source can be seen easily from a distance, the surrounding area that is lit up is very hard to observe from a distance while the driver can easily see the immediate surrounding much easier. My terminology may be completely incorrect and same with the formula. I pretty much just pulled it out of the back of my head from very distant memories from physics class in high school lol", "Most materials reflect a fairly small amount of incoming light. As an extreme example, [vantablack]( URL_2 ) will show virtually nothing. More importantly, light that is reflected is scattered in all directions, actually more away from you than towards you (the [specular]( URL_0 ) or mirror-like component, as opposed to [diffuse]( URL_3 )). What would be a bright point light blinding you if you were standing there is literally diluted, making only a small amount reach back to the lamp. Adding to the above is that your light hits the road at a very oblique angle. Any bit of light is spread over a large area, making even the diffuse component quite dark. [Retroreflectors]( URL_1 ) compensate to some extent by reflecting more of the light back to your general vicinity. That's how signs treated that way light up so much from your perspective when you shine a light on them." ], "score": [ 3, 3 ], "text_urls": [ [], [ "https://en.wikipedia.org/wiki/Specular_reflection", "https://en.wikipedia.org/wiki/Retroreflector", "https://en.wikipedia.org/wiki/Vantablack", "https://en.wikipedia.org/wiki/Diffuse_reflection" ] ] }
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5ljjal
Why does a mere air bubble in the circulatory system prove to be fatal?
Biology
explainlikeimfive
{ "a_id": [ "dbw8r8t" ], "text": [ "Because an air bubble can function and cause the same problems as a clot formed of other materials. Collectively, it is known as an embolism and can be made of things like clotted blood, fatty tissue, or even an air bubble. The principle is simple, the air bubble travels down the blood vessels, which get progressively narrower as they travel further away from the body, and then the vessel gets too narrow and the bubble gets wedged in the pipe, so to speak. It blocks the entire flow, preventing the blood from continuing down the path. Now if this blocks a vessel that's extremely vital, such as the ones that provide blood supply to the heart tissue or say the blood vessel that feeds into the lungs to pick up oxygen, then you're going to have a very bad time. It should be noted that air bubbles in the bloodstream are not as dangerous as people make it out. It is still a risk, hence why medical professionals will take care not to accidentally inject air, but it's not a case of 'the tiniest air bubble will kill you' sort of thing. Gases do dissolve into the blood stream, it's a slow process but it does happen. And your venous blood system is full of valves that assist with blood flow, but will also break up bubbles. In addition, the bubble has to go somewhere important and that's all entirely up to chance - it could spend it's entire time just circulating through large blood vessels and then gets stuck somewhere in your leg where collateral blood flow (other blood vessels) prevents any serious harm from happening. Edit: I should clarify that the most crucial component is which part of the blood system the air enters. The venous system is far more tolerant than the arterial blood supply, as explained above with things such as valves and the general fact that veins get larger in diameter as you flow downstream, whereas arteries getting narrower. In a hospital setting, most injections and bloodwork is done via the venous system, and you won't see people trying to access arterial bloodflow outside of specialized procedures because of these inherent risks. Air can also enter the bloodstream through trauma." ], "score": [ 11 ], "text_urls": [ [] ] }
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5ljtay
Does being out in the "cold" without a coat actually make you more prone to being sick?
I generally like cooler weather, and can easily go out in the "cold" (winter in the North Eastern United States) with no jacket at all, or a coat if it's really cold... However, I'm constantly being told to "put a coat on!" Or "HURRY up and come inside, you'll catch a cold!" Yet I rarely get sick. On the contrary, the people telling me this and "bundling up" when outside and avoiding prolonged exposure to being outside in winter get sick very often. So, ELI5... does cold weather make you sick or lower your immune system?
Biology
explainlikeimfive
{ "a_id": [ "dbwafin", "dbw9dxo", "dbw9ky7", "dbwafgm" ], "text": [ "Many answers here are misguided. Think of your body as a machine. When it's cold out it's occupied trying to warm you up. It pulls resources away from other areas for this. At body temperature, the cells responded with a sophisticated defense, sending out warning signals to uninfected cells around them. Those cells prepared an arsenal of antiviral proteins, which they used to destroy the rhinoviruses. > But at a relatively cool 91.4 degrees Fahrenheit, Dr. Iwasaki and her colleagues found, things changed. > The neighboring cells only managed a weak defense, allowing the rhinoviruses to invade them and multiply. This result pointed to an explanation for why rhinoviruses plague humans at low temperatures: In cool conditions, the immune system somehow falters URL_0", "Nope, the common cold is a result of infection with rhinovirus or some other viruses. You could stay in a (disinfected previously) freezer at -20°C for a while and get out, and the only thing you'll get is hypothermia.", "you are pretty close...its not the temperature that gets you sick...its the viruses that are more easily spread in the winter months because people are spending nearly all their time in close quarters indoors.", "I wrote a paper on this early in masters peogram, iirc the consensus is that cold exposure can alter neuro, endo, and immuno function slightly perhaps, and prolonged cold exposure likely caused a slight increase in our susceptibility, but as others posted it is most likely close quarters, runny noses, etc that create the cold and flu season timing with cold weatjer" ], "score": [ 67, 8, 4, 3 ], "text_urls": [ [ "http://www.pbs.org/wgbh/nova/next/body/scientists-finally-prove-cold-weather-makes-sick/" ], [], [], [] ] }
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5ljz8f
If fat is stored energy, why can't fat people not eat for a few days, be fine, and consume the fat
Biology
explainlikeimfive
{ "a_id": [ "dbwaitk", "dbwa9me", "dbweyu7", "dbwalhr" ], "text": [ "It can be done, with proper supervision. See the story of Angus Barbieri... URL_0", "Fat isn't a complete source of everything we need. It is great to supplement an insufficient supply of food but not enough to completely replace all food. We would lack vitamins and minerals, etc.", "They can. They just don't. Also you need pretty close medical supervision for any water fast longer than a week or so. Weirdly, it's also healthier to exercise moderately when fasting rather than sitting doing nothing. It aids ketosis to kick in, otherwise your body burns \"useless\" muscle. Then you're in trouble.", "Although serious adverse health effects would occur, a fat person *could* not eat for a few days and just live on the fat reserves. From June 19 to July 14, I didn't eat anything beyond a bite or two a day (and sometimes not even that). We're talking a piece of bread, an egg ,or a small cookie. I lost 30 pounds (245 to 215) over 25 days. Thanks major depression. I would faint all the time after any sort of physical activity (including walking for an extended period). I was very physically weak, and unable to utilize much of the strength I had. I can lift my body weight relatively easily, but during that month I found it hard to lift more than 50 pounds. I was very tired as well. I felt awful, really. Can't say if that's because of the adverse effects of the malnutrition or if it was just the major depressive spell I was under." ], "score": [ 9, 9, 3, 3 ], "text_urls": [ [ "https://www.eveningtelegraph.co.uk/fp/tale-angus-barbieri-fasted-year-lost-21-stone/" ], [], [], [] ] }
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5lk1jq
US college football bowls
As a non-American who loves NFL I am confused to no end about how the different bowls (sugar, rose, outback etc) relate to each other. How are the teams selected? Is there one bowl that rules them all (I.e. Crowns #1 in the country)? Where does the names of the different bowls come from? What else should I know about this complex system?
Other
explainlikeimfive
{ "a_id": [ "dbwee6y", "dbwbi9s" ], "text": [ "The larger bowl games (Rose, Sugar, Orange, Peach, Cotton, Fiesta) are traditionally given to the champions of each conference. For example, the Rose Bowl is traditionally between the conference champions from the Big Ten and the Pac-12. Each one is different, some are conference champ vs conference champ, while some are against an at-large opponent. These are generally played on/around New Year's Day. Each year [two out of those 6 bowl games are selected to be semifinals]( URL_0 ) based off of a rotation. This means that tradition is just thrown aside from these two games, and the 4 most highly ranked teams in the nation, regardless of conference, face each other in a 4-team playoff. This year, the Fiesta and Peach Bowls were the semifinal games, and the winners of each will play in the National Championship Game. The championship game itself doesn’t have a \"bowl\" associated with it, it's just called the National Championship Game. Aside from the two playoff games and the other traditional bowl games mentioned above, the remaining 39 bowl games are distributed based off of record and final rankings, and don't necessarily have a lot of meaning behind them. To be bowl eligible, a team needs to have a record of at least 6-6 at the end of the regular season. At times, not enough teams meet the 6-6 requirement, so teams with losing (5-7) records may be used to fill in the empty spots. Teams just squeezing past the requirements get stuck in games like the \"Dollar General Bowl\" or \"Famous Idaho Potato Bowl\", which don't mean much unless your team is in it. The Outback Bowl or Citrus Bowl would be more desirable, but require a higher rank/record to be placed into. It's sort of confusing really, with the playoff system being added into the existing bowl games just recently. Plus all the sponsorship doesn't really help, some Bowls get renamed quite a bit thanks to that. Tl;Dr: 6-6 record is needed to become eligible for a bowl. They are assigned based off of a combination of record, rank, and sometimes tradition. [These are the ones what you want your team to play in.]( URL_0 ) If your team isn't in one of those 6, just hope they're in one sponsored by a big company.", "Post-season play in college football is a tricky topic that is perpetually subject to scrutiny and debate. Currently, post-season games (Bowls) are chosen based on the College Football Playoff rankings. While these rankings may often seem arbitrary and subjective, they are based on a number of metrics designed to create as objective a system as possible. Still, fans have never and will never be completely sold on the objectivity of the rankings. Only the top 4 places in the year-end rankings compete for the National Championship. They play in a bracketed playoff with a 1-4 matchup and a 2-3 matchup. This year, those games were the Peach Bowl and the Fiesta Bowl, respectively. The winners, Alabama and Clemson, will play for the National Championship. Still, this leaves the rest of the the bowl games. This is where things get really confusing. Many of these games are played between conference champions (or conference runner-ups, if the champion is in the playoff). That is the case of this year's Rose Bowl between Big Ten Champion Penn State and Pac-12 runner up USC. However, Ohio State played in the CFP Playoff, despite losing the head-to-head against Penn State and finishing behind Penn State in the Big Ten Conference. Hence, the subjectivity. Other bowls are awarded to teams who played exceptionally well in non-power conferences. Such is the case in this year's Cotton Bowl where Western Michigan (from the inconsequential Mid-American Conference) will play the Big Ten Runner-Up Wisconsin. Unfortunately, the bowl game system has also fallen victim to American corporate culture. Any company with enough money can sponsor a bowl game of no consequence. On one hand, this provides an annual goal for teams of a lower caliber (a team only needs to finish with 6 wins to become bowl eligible). On the other hand, who really wants to watch the Meineke Car Care Bowl? In conclusion, the whole thing is a crap shoot. You basically have to go undefeated to secure a spot in the playoff, so every game matters. College football is one of the last things we are allowed to be completely fanatic about. Nothing beats tailgating at 8 am on a Saturday in October with some buddies and a case of Natty Light. There's a sense of hope in college football that doesn't exist elsewhere. It's a fucked up system where any year could be the year. Be sure to tune in to the Rose Bowl tomorrow. We are." ], "score": [ 6, 5 ], "text_urls": [ [ "https://en.m.wikipedia.org/wiki/List_of_College_Football_Playoff_games" ], [] ] }
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5lk6pt
Will sovereign states/countries ever shift from being republics to some different system of government just like how monarchies were slowly phased out? Why or why not?
Other
explainlikeimfive
{ "a_id": [ "dbwcsry" ], "text": [ "On the one hand, modern liberal democracy is regarded as \"the end of history\", with no other system to follow it. But it's as arrogant as it sounds. The ancient Greeks observed *anacyclosis*, a constant cycle of tyranny-oligarchy-democracy. Tyrants eventually die or get overthrown by their inner circle of advisors, who form a ruling clique; a competing group wants to take them down, and, to get enough political firepower, they vest the populace with more power. However, the resulting democracy inevitably comes to a political deadlock, where the only option is to put a strongman in charge. Rinse and repeat. The United States of America, for example, have come through three full and largely non-violent cycles: the tyrants were Washington, Lincoln and FDR. And, if this year is anything to go by, we're about to get a fourth one - and this even has nothing to do with Trump." ], "score": [ 5 ], "text_urls": [ [] ] }
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5lkcvi
why goats climb on top of stuff, please.
Other
explainlikeimfive
{ "a_id": [ "dbwcvq6", "dbwdk0y" ], "text": [ "This just my guess but most animals try to climb on to stuff so they can see more. That way they can see predators that might come and attack them, and find prey (if they need to) or other food sources much easier.", "Put simply, practice makes perfect. Goats are mountain animals. Mountain animals need to know how to climb or they fall and die. Goats and their kids are programmed to practice this at all stages of life because it results in higher survival. Similar to how horses and foals like to run around because they are animals that tend to run from danger and practicing helps!" ], "score": [ 4, 4 ], "text_urls": [ [], [] ] }
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5lkdo1
Why does driving long distances make people tired?
It occurred to me while driving home from work one day. I noticed the drive home will seem to drain me the longer I am on the road. Leaving me basically exhausted by the time I get home. Even though I am not performing anything I consider to be physically demanding. Why is it that I am left tired after the drive?
Biology
explainlikeimfive
{ "a_id": [ "dbwcypr" ], "text": [ "Driving is pretty taxing mentally, especially on a busy road you're constant at a peak awareness to make sure you don't crash and die. Mentally tired is something that can happen too." ], "score": [ 8 ], "text_urls": [ [] ] }
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5lkql6
People who wake up after a head injury with a new ability (for example fluency in a foreign language)
Other
explainlikeimfive
{ "a_id": [ "dbwio3s", "dbwitmn" ], "text": [ "Acquired Savant Syndrome. There's only 30 or so cases ever known. This [Popular Science article]( URL_0 ) has some information but we're not particularly close to figuring out how it works, let alone being able to recreate the effect.", "There have not been confirmed cases of people getting in an accident and suddenly speaking a foreign language (maybe if they already were learning it...). It's mostly urban myth." ], "score": [ 5, 4 ], "text_urls": [ [ "http://www.popsci.com/science/article/2013-02/when-brain-damage-unlocks-genius-within" ], [] ] }
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[ "url" ]
5lksbc
What happens to our bodies when we don't get enough sleep over a long period of time?
Biology
explainlikeimfive
{ "a_id": [ "dbwgoer" ], "text": [ "our body is engineered to save energy where we can best... that means shutting down some organs to preserve energy. mental problems soon follow" ], "score": [ 3 ], "text_urls": [ [] ] }
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5lkuig
Why is salt iodized?
What do our bodies need salt for? And why aren't we getting enough of it? And most importantly, why is it added to salt in particular. Why not put it in multivitamins, or some other food.
Biology
explainlikeimfive
{ "a_id": [ "dbwfrgy", "dbwmfcy", "dbwnwi3" ], "text": [ "Iodine is necessary and deficiency cause goiter. A swelling of the thyroid (not thymus) in the neck. It was added to salt because it is something that every household has and regularly uses. Multivitamins are not something every family has. It should be recognized that this concept is decades old now from a time when the vast majority of foods were home cooked. These days with meals for one and fast food it doesn't seem as obvious. As well as a health food push to market uniodized salt as healthier. Which ironically has caused an increase in goiter in the middle class. Edit: just a little more. There was suggestion of adding it to bread where I'm from. Not sure if this went through or not. More edits: As pointed out it's for the thyroid not thymus.", "Others have already answered the rest of your question but to elaborate a bit, Iodine is used by your Thyroid gland to create Thyroid hormones (T3 and T4). These exert their effects on essentially all tissue and serve to increase the metabolic rate of cells (the rate at which cells produce energy and function), increase sensitivity to (nor)adrenaline effects in the body, increase heart rate/contraction, and increase heat production. A severe enough iodine deficiency can lead to hypothyroidism, which can involve weight gain, tiredness, feelings of cold, dry skin, and a puffy face among other things. It's also crucial to brain development in children, as such, cases of untreated childhood hypothyroidism can lead to mental retardation. Goitres can occur but are also potentially present in hyperthyroidism. EDIT: if you were asking what we need salt itself for, salt is sodium chloride, which when dissolved becomes sodium and chloride ions. Both are crucial electrolytes used in electrochemical gradients, which are the things your nerves use to send impulses, among many other critical functions in basically all tissue in your body.", "It's added to salt because it is a salt itself (in the form of potassium iodide). You can get it in tablet form as well (for people with deficiencies or when there is radioactive contamination), but it's more convenient to just add it to what you are already eating." ], "score": [ 12, 4, 3 ], "text_urls": [ [], [], [] ] }
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5lkvjy
In the past, chopping off a hand was a common punishment for thieves. What exactly happens afterwards?
Biology
explainlikeimfive
{ "a_id": [ "dbwgqts", "dbwg2hh" ], "text": [ "Blood arteries and veins have a natural reaction to being severed that closes them up quite rapidly. Amputations is usually not considered a vital injury in first aid. There can be complications with infections but if done with a clean wound that is bandaged properly you lower the risk of infections. If you have damaged blood vessels and not severed ones there is much more blood and you can bleed out very quickly so you need to apply a tourniquet to stop the blood flow before you start the first aid procedure. Not that long ago amputations were preferred to treating serious wounds because of the lower risk of complications.", "It still is a punishment in some places. A tourniquet and direct pressure will control the bleeding long enough to stop it properly." ], "score": [ 16, 6 ], "text_urls": [ [], [] ] }
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5lkvt4
Why does the face get so many more pimples when the hands/feet/arms are in much more contact with dirt etc.?
Other
explainlikeimfive
{ "a_id": [ "dbwr5jz", "dbwgie5", "dbwgphs", "dbwvqnp", "dbwstmv" ], "text": [ "Acne is a \"multi-factor\" process. Dirt/bacteria from the environment isn't the only or biggest reason for acne. 1. Sebum 2. Androgen/Testerone 3. P. Acnes Bacteria 4. Keratin 5. Dead skin cells 6. Clogged pore First you have Sebaceous glands that release sebum which help lubricate your face for protection to keep foreign bodies, but when sebum gets stuck in the gland it's like glue. Androgen (male) hormones help push the sebum out of your glands, but when you have a change in hormone levels, sebum is pushed out more rapidly and if the gland is blocked, the sebum is collecting inside while not being pushed out. In our bodies we have the P. Acnes bacteria: it is an anaerobic bacteria and therefore cannot survive in an environment with oxygen. So the P. Acnes bacteria thrives when the gland is blocked because there is no oxygen and it feeds off of our sebum. Keratin makes parts of our bodies harder (heh). The mixture of sebum, bacteria and keratin becomes a hard plug under the skin. Just to add to the fun, dead skin cells also collect inside, especially if they are not washed off correctly. When the gland remains closed off, nothing can secrete out of it. The clogged gland is at this point, filled with P. Acnes bacteria, old sebum, dead skin cells, hard keratin and androgen hormones are trying to push it all out on schedule but everything is stuck inside the gland with nowhere to go. This is what forms a pimple/pustule. That is the basic process of acne. The sebaceous glands are only located on certain parts of your body and therefore are not effected by this process. So your hands and feet aren't going to form pimples just because they touch dirt. One could say the main cause is the P. Acnes bacteria. But the right conditions need to be met in order for a pimple to form. Source: Had cystic acne", "Not an expert here but I believe it is caused by the sebaceous glands becoming blocked. Since there are many more sebaceous glands on the face, more chances for them to become blocked. Sebaceous glands excrete oil, known as sebum, to help lubricate the skin. When they become clogged, the gland continues excreting sebum. With the gland clogged, it becomes inflamed and thus, a pimple.", "I'll take a swing at a possible explanation, albeit I'm no expert on the subject so maybe I can give something to think about until the experts roll in. So for starters, pimples are caused by inflammation of your pores. This is typically due to a bacterial infection, where the bacteria seep in to the pore, then your body attacks it which causes the redness, swelling, and puss. Although the pore itself may become blocked by oil which also results in pimples. Now as to why it specifically happens more on the face, the answer is it generally doesn't. Acne occurs primarily in areas which are ripe in hair follicles. Thus why back acne, and pubic acne exist, and you may sometimes find acne on your arms and bum. This is due to the sebaceous glands, which secrete sebum, or oil, on to the hair follicle. Because of them neighboring so close together, there's the greater chance of bacteria getting in, although it's attacked pretty quickly and doesn't penetrate further. Along with that, sebum can sometimes get blocked up and cause acne that way as well. While hair follicles are found throughout the body, sebaceous glands are primarily found in the facial, chest, and pubic regions. Thus why they're more prevalent in these areas.", "Acne is, basically, a clogged pore (hair follicle) that becomes infected (by a specific strain of bacteria). Factors that reduce the frequency of infection include: * desquamation (exfoliation) * sebum production (how much oil your skin exudes) * hygiene (how sanitary your skin is) Some reasons acne is more common on the face: * The skin on your face is thinner than skin on most other parts of the body. * The skin on your face also produces more sebum than other parts of your body. * We don't exfoliate our faces as much (friction from clothing helps with body).", "Found that changing out your pillowcase often (daily is best) helps prevent some acne from developing. Pass it on..." ], "score": [ 128, 87, 9, 5, 4 ], "text_urls": [ [], [], [], [], [] ] }
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5lkwes
How come full siblings share only 50% genetic with each other and not 100% since they both have the same parents?
Someone told me that full siblings with the same parents only share 50% genetic material, but why wouldn't it be 100% since they both have the same parents and are both getting 50% from the same mom and 50% from the same dad? Isn't it true that they're getting 100% of the same amount of DNA from the same genetic source (their parents)? What makes it only 50%??
Biology
explainlikeimfive
{ "a_id": [ "dbwgaci", "dbwgcvp", "dbwgb7e", "dbwnx9l" ], "text": [ "During conception you get 50% of your genes from your father and 50% from your mother. But you still have the same number of genes so there is 50% of the genes from each parent you do not get. Your siblings will have the same distribution of genes. So of the 50% of the genes you get from each parent your sibling will have on average 50% of them and 50% of the genes your parents have not given you. So you end up sharing 50% of your genes with your sibling. For instance your dad have a gene for developing testicles which makes you into a man, however there is still a 50% chance that this trait is the same in your sibling then in you. To better visualize how this works. You take a deck of cards and divide it into red and black suits. This represents the genes of your parents. Now on random chose 13 cards at random from each of those decks numbered 2 to A. The new deck will have equally many black and red suits. This represents your genes. Now repeat the task with another deck of cards and you end up with a deck for your sibling. Since you picked the cards at random you now share half the cards in the decks.", "You get around 50% of each parent's genes. Which genes you get from which parent is random. So a sibling probably won't get the same combination of genes you do. About half will be the same ones you got, and about half will be from the other parent.", "> > Isn't it true that they're getting 100% of the same amount of DNA from the same genetic source (their parents)? no humans have 46 chromosomes , and get 23 from each parent. your parents each have 46 chromosomes. so they give their kids only half of their chromosomes. chances are you aren't going to get the exact same 23 from both parents as your siblings get since the choice is random", "There's also crossing over to consider. The 46 chromosomes in a human are arranged in pairs. During the process where cells become sperm or egg (meiosis) the legs of the pairs kind of wrap around each other and trade little pieces of genetic material. This is called crossing over, it ensures diversity. It's another reason why siblings look different even though the genetic material comes from the same source. Even if you got the same chromosomes from each parent as your siblings, the chromosomes themselves would be different. No two egg or sperm are exactly alike, not even in the case of identical twins. That happens when a fertilized egg splits into two embryos during early development. I mean...statistically speaking they could be, but like someone earlier said, the chances are astronomical." ], "score": [ 38, 20, 14, 7 ], "text_urls": [ [], [], [], [] ] }
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5lkxek
Why do we remember some dreams, sometimes for years, but tend to forget others right away?
Other
explainlikeimfive
{ "a_id": [ "dbwgasa" ], "text": [ "We forget almost everything. Most of what you learn is school you forget. Where you have been. What you did yesterday. Dreams are no exception. We remember things specifically useful for survival. Everyone recalls the details of an escape, or a close encounter with danger. Now is the time of my brain exultation. Paul Allen is funding brain research. The chosen test animal is the trusty old mouse. Attempts are being made to understand mouse brains. They are trying to totally analyze a bit of brain the size of a grain of sand, tracing the connections in that bit. It will take a few years. The human brain is a thousand times as big." ], "score": [ 4 ], "text_urls": [ [] ] }
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5ll4g2
Why do roads have unnecessary bends?
Other
explainlikeimfive
{ "a_id": [ "dbwhnrr", "dbwhl8a", "dbwozxs", "dbwipiq" ], "text": [ "I think the premise is false - just because it seems unnecessary, it's highly unlikely anybody is going to build needlessly curvy roads. Obvious factors would be geography (Sometimes cheaper to simply avoid a big rock formation than to go through it), land ownership (maybe they couldn't acquire the land, or again, it was cheaper to go around), following a previous road/trail rather than trying to re engineer it, avoiding any other obstacles and, finally, some roads are built deliberately curvy to increase driver concentration.", "Many very long roads add \"unnecessary\" bends in order to keep drivers awake and alert. Long stretches of straight road tend to put tired drivers to sleep, which is obviously a safety hazard.", "There's a multitude of reasons why road designers do this. Chasing the straight is the biggest reason. Roads that wind through uneven areas will often chase the straightest path that involves the engineers having to do the least amount of work levelling the ground. It's often cheaper and easier to extend the road a few hundred meters or even miles than it is to have to bring in the engineering resources to level the ground to build the road. The next most common reason is a winding road is easier to travel up/down a gradient. Let's imagine you are at the foot of a steep hill. You can walk up that hill one of two ways. You can walk up it in a straight line and fight the gradient all the way up, or you can walk a \"Wavy\" indirect path that extends the distance you have to walk but decreases the gradient, making it easier, if a bit longer. Just like your legs, a vehicles engine and brakes will have an easier time of it ascending or descending the gradient if it does this. The third most common reason is that sometimes its just easier to avoid something that the engineers knew was there but is not immediately obvious to you. Like marshy ground beneath the surface. In the UK there is a motorway called the M62 that is bisected by a [lone farm and looks extremely odd]( URL_0 ). Many people believe that the farm is still there because the owners refused to sell their land. The real reason is the ground around the farm is so marshy its unsuitable for a road, the engineers simply went round it and did not need to demolish the farm, so they left them there. There was some flawed research many years ago that led to the thinking that drivers are less likely to fall asleep if they are forced to drive to a curve. This was quickly debunked but it led to a common myth that motorways developed during the 60's and 70's where designed with this research prompting the constant curves in them. The real reason is that they where designed with shallow curves to eliminate the amount of sharper curving that might be required and thus maintain higher speeds and prevent slow-down or braking pinch points. A similar myth often leads to the belief that roads are sometimes designed with curves/bends to force drivers to obey a speed limit. No road designer would ever do this. All roads are designed to be navigated as fast as possible as an efficiency metric. Any road that is by design slowing the traffic down is inherently inefficient and will cause problems. Believe it or not, property ownership is rarely a barrier to a roads construction and it rarely dictates the path a road has to take. If a road is considered necessary, many compulsory purchase laws exist in most countries that allow the land in question to be compulsory purchased from the land owner to allow the road to proceed. As I alluded to above, many people believe this is the reason the [farm that bisects the M62 in the UK]( URL_0 ) remains where it is in its odd location. The real reason is the engineers didn't want it as it was a unsuitable path for the road to take. Had they wanted it, they would have gotten it (Just like they compulsory purchased all the houses and farms that surrounded it).", "Many times because you can't see and are completly unaware of why. This includes geological formations, various barriers of material, utilities that need to be run, grading and drainage issues and a myriad of planning that goes into road engineering. A properly built road takes those factors in, it doesn't just appear." ], "score": [ 61, 21, 20, 17 ], "text_urls": [ [], [], [ "https://www.google.co.uk/maps/@53.641355,-1.9517334,358m/data=!3m1!1e3" ], [] ] }
[ "url" ]
[ "url" ]
5ll6g5
In a box of tissue paper, how does the next piece of tissue come out when you pull out the one above it?
Other
explainlikeimfive
{ "a_id": [ "dbwhsd0" ], "text": [ "Some fairly clever origami. Each tissue in the box is folded both to fit better in the box and to have a little flap that connects to the next tissue. When you grab the top tissue, the next tissue starts to come too. Eventually the friction force holding the next tissue to the tissue that you are pulling is smaller than the friction force of it being dragged through the opening. When this happens, the next tissue stops partway out of the box and separates from the tissue that you are pulling, leaving one tissue in your hand and the next tissue poking out of the box for convenient grabbing." ], "score": [ 23 ], "text_urls": [ [] ] }
[ "url" ]
[ "url" ]
5ll7i3
Why are floppy discs called "Floppy" if they're not floppy?
Technology
explainlikeimfive
{ "a_id": [ "dbwhrdn", "dbwk1uu", "dbwhovn" ], "text": [ "They were floppy when they were first created. If you look at URL_0 , which has the three most common sizes of floppy disks, the largest (8-inch) and the middle (5.25-inch) ones are housed in flexible plastic. By the time the smallest (3.5-inch) version, which is housed in hard plastic, came about, the name had already become established. They all also share the same flexible magnetic media on the inside, so they all have a \"floppy\" component even if their outer shell is made of hard plastic.", "Holy shit you know you're old when people don't know the answer to this. Back in the day, 5.25 inch disks were bendable/floppy. The name stuck even when they got smaller/harder.", "Because the original ones *were* floppy. The discs you're picturing are the rigid 3.5 inch 1.44MB variety - but before those were 5.25 inch ones which were pretty flexible." ], "score": [ 17, 6, 5 ], "text_urls": [ [ "https://en.wikipedia.org/wiki/Floppy_disk#/media/File:Floppy_disk_2009_G1.jpg" ], [], [] ] }
[ "url" ]
[ "url" ]
5ll9e4
Shadowbanning
Other
explainlikeimfive
{ "a_id": [ "dbwi8rm" ], "text": [ "Have you ever gotten into situations, where you are technically within a social group, but that group simply let's you tag along, while ignoring you completely? That's basically what shadowbanning is." ], "score": [ 3 ], "text_urls": [ [] ] }
[ "url" ]
[ "url" ]
5ll9me
How do data collectors account for people who put random answers in surveys?
I just had to take a one question survey before watching a YouTube video and I just put a random answer without looking at the question just to get to my video faster. I know I am not the only one who does this and I know that it happens A LOT. Like realistically, how many people are actually answering that YouTube survey honestly? Wouldn't this cause the data to be quite inaccurate and unreliable?
Mathematics
explainlikeimfive
{ "a_id": [ "dbwp95r", "dbwjssg", "dbwo2bp", "dbwirrr", "dbwziy4", "dbwmket" ], "text": [ "Hi, I am a mod at /r/surveyresearch and a full time survey researcher. There is inherent noise in all data we collect. However, generally when people answer surveys they mostly tell the truth, this is backed up with empirical research where we have administrative data on the people surveyed and we compare what the participant says and what the records say. Most of the time their responses align with the responses of the \"truth\". Error is mostly associated with trouble with recall or understanding the question rather than purposeful inattention. We also call this phenomenon of answering randomly or answering with malicious intent, \"Satisficing.\" It is an area of intense research from academics in the field of survey research. We can't catch it all, but we can setup various tricks to catch and remove answers that are intentionally wrong. * Randomization: If you randomize your question order and response order, a person who would pick randomly or pick the first response for each question would just appear as noise in the data, rather than a particular bias. * Logic checks: We can ask the same questions twice in different ways or we can ask a chain of questions that logically go together (i.e.,Are you a frequent smoker? Yes, How often do you smoke? Never). This would flag data for removal. * Meta/Paradata- If you complete a 20 minute survey in 5 minutes, we can kick your data out. If you straight line your answers, we can kick your data out. etc. * Attentional Checks: \"How often do you smoke?(Select the 3rd answer to continue)\". \"Do you use [Brand that does not exist]?\" We run the risk of deleting real honest responses, so these checks do not always occur. But it is available if there is concern with data quality. That being said, recent research shows that data cleaning really doesn't change the results that much for most questions. On average, it evens out as long as you have a large enough sample size. I would strongly encourage to answer surveys and answer them honestly. You have the ability to represent your interests and sway the opinion of companies and even governments by the answers you provide. Data collection isn't cheap, decision makers put a lot of value in these surveys and they will design products and even political positions around the data they get from these surveys. For a nationally representative US survey, your single response roughly represents ~606,177 adults. Your response has the power to represent, statistically speaking, an INFINITE amount of people. It is an incredible opportunity, don't waste it.", "EDIT- listen to the guy up there at the top for reals. If you're filling in online surveys odds are you're getting assigned an advertiser ID associated with you via various combinations of IP and MAC address, account details, cookies etc. If you fill in enough surveys to significantly affect things you'll start getting surveys with subtly bogus answers in them now and again and if you select the bogus answers regularly your entire answer history will get written off as done by a bot, clicker or randomly by a user not paying attention. Examples include asking you about a shop or service that doesn't exist. This is something a whole bunch of Google Opinion Rewards users have ran into. They fill in answers at random for a few months and then they hit the \"which fleeble did you gronk regenty? A) flarb B) gonk C) deeble D) none of the above\" question and answer flarb. No more survey questions for you.", "In larger surveys, and in any type of validated questionnaire, such as psych testing measures, etc. there are validation questions: questions that are similar to other questions. If you don't answer them consistently, then the form can get tossed because the response isn't valid.", "All legitimate survey results allow for a certain amount of accuracy. That's why \"survey size\" is vital in legitimizing the accuracy of a survey. Too small of a group, or too large in rare instances, will skew the results due to people not answering honestly or not understanding the question. Where the survey is taken is also a factor. Those who commission or actually take these surveys know this, and either determine a percent of accuracy, or use it to sway the survey in their desired direction.", "I never really contribute to these threads but I have a story about Google rewards that might be relevant. I was using it for pokemon go, but if you're not familiar with Google rewards it will ask you questions about places youve visited recently and will give you google wallet funds for your answers. Now pokemon go takes you to a lot of different places so I was getting a lot of surveys and just giving the answers they wanted to hear. One day a new survey pops up for me and asks me if I ever went to some funny sounding water park before. I say yes, and they ask me what my favorite attraction there was. I choose some random name of some random water slide, which leads the survey to tell me the locations I just submitted were fake and made up just to test the integrity of my answers. I have never had a new survey since.", "When data is compiled for surveys as well as for other research, it is put through a number of mathematical tests to determine if there are any patterns or if the data points all fall within a certain range, etc. If they size of the survey is large enough, most studies discard the outlying data points with what they assume is a reasonable amount of confidence. This is, of course, operating under the assumption that only a few and not the majority of the responders issued fake answers." ], "score": [ 317, 114, 11, 10, 6, 3 ], "text_urls": [ [], [], [], [], [], [] ] }
[ "url" ]
[ "url" ]
5llbaq
What happens with plane after emergency landing on water?
Technology
explainlikeimfive
{ "a_id": [ "dbwt2bw", "dbwihvn", "dbwk8rd" ], "text": [ "Pilot here. Landing on water is quite possibly the worst scenario a pilot can face when a forced landing is on the cards. It's a lot worse for some aircraft than it is for others, but regardless of the aircraft your in, it's a bad day no matter what. The first problem the pilot has to worry about is water isn't solid. It's also incompressible. That means anything entering the water is going to slow down really, really fast. That's a problem for most planes because almost all of them have something hanging from the bottom that will dig into the water well before the body of the plane hits the water. For large jet aircraft, this most often tends to be the engines sitting under the wings that act like giant water scoops. For smaller aircraft, it's often the bottom of the propellers and indeed some smaller aircraft have fixed non retractable undercarriage. The trouble is when these things hit the water, they basically act like a scoop causing instant drag and smashing the body of the aircraft into the water. Often quite hard. It's this near instant de acceleration to a stop that causes the aircraft to break up and the many fatalities on board. To counter this, pilots are taught that when forced to land on water, they should keep the nose extremely high which forces the tail to go extremely low. Hopefully the tail glances along the water first and slows the plane down enough so that when the plane \"Digs in\" to the water, it's going at much slower speed.You may be surprised to know most airlines do not extensively train their pilots for water based landings, if even at all. If there was ever a plane to be in for a forced water landing, it's one where the engines are mounted on the body of the aircraft [like this example]( URL_0 ). This means there's nothing to hit the water before the body of the aircraft does, thereby decreasing your chances of a fatal break up. Should the pilot get the aircraft down in one piece, it's surprising to most people to learn that a plane will float quite well, though it likely would not remain afloat forever. This is because some of the same reasons that keep it flying in the air also help to float on water. A broad weight distribution across a large surface area. Another reason is either the air or the fuel in its tanks is lighter than water and thus aid its buoyancy. It tends to be water rushing into the aircraft via windows/doors/breaks that forces it to sink. This was evidenced by the [aircraft that came down in the Hudson river]( URL_1 ) and how long it took to sink.", "It sinks and depends on where it went down divers or recovery crews are sent to recover the black boxes to see why the plane failed. If a plane sinks the cost of repairing the water and impact damage usualy makes the idea of refusbishing the plane and putting it back in to service quite unrealistic.", "Wikipedia has an [excellent article on this]( URL_0 ) and it's worth readin if you want to get a sense of how rare successful water landings are. Planes are normally irrecoverable in terms of being able to make them flight worthy again. Black boxes and scrap metal are the only things worth dredging them back up, typically." ], "score": [ 8, 5, 4 ], "text_urls": [ [ "https://s-media-cache-ak0.pinimg.com/originals/17/6b/98/176b98bf4a7f119545d0127ad4870cb2.jpg", "https://en.wikipedia.org/wiki/US_Airways_Flight_1549" ], [], [ "https://en.wikipedia.org/wiki/Water_landing" ] ] }
[ "url" ]
[ "url" ]
5lle8u
Why "flare" effects in game actually feel blinding.
Like in a game when I look into a sun, it feels like it's actually blinding my eyes, even if it isn't real sunlight.
Technology
explainlikeimfive
{ "a_id": [ "dbwjtzv" ], "text": [ "For two reasons. 1. Your mind associates the game visual with known experiences. So it triggers the memories of being blinded by sunlight 2. Your autonomic nervous system learns to react based on previous experience. So your pupils will constrict to minimise light intake. So for a split second you do actually see less light..." ], "score": [ 3 ], "text_urls": [ [] ] }
[ "url" ]
[ "url" ]
5llgje
In WW2 movies and RL videos some soldiers salute and some use nazi salute. Why is that?
Other
explainlikeimfive
{ "a_id": [ "dbwjf3k" ], "text": [ "Nazi salute (with straight right hand) was mandatory for civilians but optional for military. Soldiers mostly used traditional salute." ], "score": [ 3 ], "text_urls": [ [] ] }
[ "url" ]
[ "url" ]
5llgq8
What are the "natural flavors" listed in some of these zero calorie drinks?
I've seen it listed in my flavored sparkling water. That just seems like a very vague term.
Chemistry
explainlikeimfive
{ "a_id": [ "dbwrhhh" ], "text": [ "I always assume it is advertising shorthand for \"you don't want to know\" For example: \"Natural flavourings\" sounds a lot better than [\"beaver anal gland extract\"]( URL_0 )" ], "score": [ 8 ], "text_urls": [ [ "https://en.m.wikipedia.org/wiki/Castoreum" ] ] }
[ "url" ]
[ "url" ]
5lljm1
Why do we salivate and gulp when we are nervous or put on the spot?
Biology
explainlikeimfive
{ "a_id": [ "dbwohcg", "dbwxgbr" ], "text": [ "When you're in fight or flight response and your sympathetic nervous system is activated. Activation of the sympathetic nervous system actually shuts down saliva production, digestion and other rest and digest functions so you can use all your available energy to fight or run away. Some people think the nervous swallow is because saliva was building up before production was shut off, I personally believe it's a nervous reaction like saying 'umm'. It gives you that extra second before you need to respond.", "I've always seen this in cartoons etc but have never experienced it myself. Is this reaction common?" ], "score": [ 20, 4 ], "text_urls": [ [], [] ] }
[ "url" ]
[ "url" ]
5lllev
Why does slow motion video of car headlights look like they are blinking rapidly?
Technology
explainlikeimfive
{ "a_id": [ "dbwlxfd" ], "text": [ "A lot of modern cars use LEDs, now LEDs don't really dim, they actually just flash on and off really fast to give the perception of them being dimmer. So, if the same bulb is used for the high beams, then the regular headlight brightness will be achieved by dimming." ], "score": [ 6 ], "text_urls": [ [] ] }
[ "url" ]
[ "url" ]
5llsho
Why do companies use such low amounts of natural juice in soda, is there a reason for this? And are all the other components really necessary in such amount?
Chemistry
explainlikeimfive
{ "a_id": [ "dbwlrhy", "dbwowlh", "dbwnek6", "dbwnsby", "dbwtcz3", "dbwqlh8", "dbwrbc1", "dbwphv7", "dbwp6yx", "dbwogag", "dbwo2s6", "dbwrc3f", "dbwqofu", "dbwsbta", "dbwnmg3", "dbwv8cj", "dbwsodz", "dbwnmw1", "dbws1fe", "dbwu2ml" ], "text": [ "Natural juice is expensive compared to just high fructose corn syrup or powdered asorbic acid. You're not thinking in bulk. A difference of even 1 cent per bottle multiplied by 6.5 billion bottles of Coca-Cola sold annually makes a big difference.", "It mostly boils down to cost. Natural fruit juice is expensive and usually does not have a long shelf life (longer shelf life is usually a good thing because it leads to less waste and more important less write-offs (a write-off meaning a product has reached the sell-by date and now either has to be 'sold' for free or thrown away, depending on laws and store policy). Even if they have high amounts of actual juice it's often concentrated apple juice because apple juice is relatively cheap (especially if it's from concentrated juice) and it also has a quite neutral taste so it doesn't overtake the other fruits in taste. This way they can legally claim \"80% real fruit juice\" even though 95% of that is apple juice and only 5% is the actual fruit they are marketing.", "It's mostly a case of cost savings and the public being used to it. In Germany, for example, you can get a drink called Apfelschorle, which is half soda water and half apple juice. For example, [this]( URL_0 ) brand uses a mixture of 57% apple juice, 3% lemon juice, 40% soda water and some extra apple flavouring.", "The other issue that hasn't been mentioned is seasonality. Sure, juice can be stored and packaged year round (orange juice is one of the most \"processed\" foods, not matter how much branding goes into making it seem like it was picked yesterday), but the fruit is only harvested in certain months of the year, and every harvest produces juice with different acid and sugar levels that have to be adjusted.", "Beverage chemist here. It's marketing. All marketing. Some here have said cost but if it was done *exclusively* for cost, said juice would not even be in there. HFCS and sugar was way cheaper on a *solids* basis. As far as the other ingredients in there, some ingredients (ascorbic acid (vitamin C), sucralose, cyanocobalamin (vitamin B12) are effective at very low doses (think milligrams & micrograms worth). If you're drinking tea that you've purchased, there's a good chance that there is only a small amount of \"spray dried\" tea in there and caramel color added. Drink water. (not alkaline water... more marketing).", "When the question is \"Why do companies...\" The answer will almost always be \"To reduce costs.\"", "Also, don't overlook the fact that there is nothing magical about juice. It's fructose instead of sucrose, which is a minimal difference, plus water. There are a few water soluble vitamins, which no American/European is deficient in. Juice has to be harvested from a plant, though, which makes it more expensive. Apple juice is not \"healthy\" in any way, and I hate to see patients putting it in their kiddo's bottles. It's just flavored sugar water.", "Drink scientist here, specializing in natural juice sodas. The main reason is shelf stability. Natural juices dont hold color very long at all. The taste goes faster too. Natural juices are more expensive as well . the whole thing results in a cascade of increasing costs in the supply chain.", "Money. Why do companies do anything? Money. The answer is always money.", "Food companies use small amounts of real fruit juice let's say a table spoon per ten gallons. Since they added the tiny amount of fruit juice they can display on the label \"made with real fruit juice\". Your fruity drink consists almost entirely of sugar from concentrate.", "One reason is so they can call it something like \"apple juice drink\" or whatever so that in the minds of the general public it registers as apple juice. As long as it's that color and has an apple on the label many if not most people don't question it and just assume it's good for you.", "In addition to what everyone is saying, when Faygo first put out their pineapple flavored pop, stores at an issue with the bottles exploding. This was because they used real pineapple juice, and the said juice was fermenting, causing the bottles to explode. As you can guess, avoiding juice avoids exploding bottles.", "As others have said, I imagine it is because they wish to maximize profits. By using the absolute cheapest materials are available they do that. You can also factor in that they wish to make their product as addictive as possible. Caffeine is addictive, sugar is addictive, I imagine several of the other ingredients are also addictive.", "There are \"sodas\" from smaller companies that use more fruit juice. Izze is fruit juice and sparkling water. URL_0", "You're asking the wrong question, because you start with the unfounded premise that sodas are supposed to be made mostly from natural juice. A better question is why sodas contain natural juice at all, and I think it's because of marketing reasons. If it contains at least some natural juice they can put that on the packaging and pretend it's somewhat healthy.", "My grandfather was a chemist who worked on foods. He told me it was because if a competitor tried to break down their formulas, the natural flavors will reveal hundreds of compounds and it make it difficult to determine the recipe.", "I feel like everyone has misinterpreted the question. Why is there say 5% juice in soda, or %1, and not 0.? Does that 1% juice really do anything to the flavor or marketability of the product? Of course we know that natural fruit juice is expensive.", "Companies make what people buy, and do so at the highest profit margin they can achieve. That's not a bad thing, that's just how making money works. In the U.S. at least, \"natural\" sodas and such drinks don't sell well. People don't really want them, so it doesn't make sense to make them. Natural ingredients are more expensive, so if customers are okay with it they will use manufactured substitutes where possible. At the end of the day, the customer preferences are why soda is unhealthy and unnatural.", "I visited thailand last week and i qas shocked how a normal coke has 49 g suggar / 100 ml compared to 9 g per 100 ml in germany but the taste was nearly identical it qas insane!", "Fruit juice extract contains only the pure flavor of that particular fruit. The rest of it boils down to amino acids, varying types of sucrose and water. The extracts are then shipped from anywhere to where the bottling factory is, taking all of the other substances out that you can easily add back later at the factory, this saves shipping costs tremendously. They add water, amino acids, preservatives and sucrose (or sweeteners like stevia) back together with a small amount of extract and there it is again." ], "score": [ 889, 352, 251, 95, 57, 39, 34, 31, 18, 18, 12, 11, 8, 6, 6, 5, 5, 5, 3, 3 ], "text_urls": [ [], [], [ "http://das-ist-drin.de/ja-Apfelschorle-0-5-l--429106/" ], [], [], [], [], [], [], [], [], [], [], [ "http://www.izze.com/products/izze-sparkling-grapefruit-2/" ], [], [], [], [], [], [] ] }
[ "url" ]
[ "url" ]
5llsqo
How does the Queen decide who to knight? There's 1000s of people on this year's honor list how are they aware of them all to know if they deserve an award? Also how do they decide who deserves a CBE vs an OBE vs an MBE etc?
Other
explainlikeimfive
{ "a_id": [ "dbwm29y" ], "text": [ "Anyone can nominate someone for an honour, and a series of [committees]( URL_0 ) reviews the nominations. They make recommendations to the Prime Minister, who makes recommendations to the Queen. The exception is the Royal Victorian Order, which is given for personal service to the monarch." ], "score": [ 7 ], "text_urls": [ [ "https://www.gov.uk/guidance/honours-committees" ] ] }
[ "url" ]
[ "url" ]
End of preview (truncated to 100 rows)

Dataset Card for ELI5-Category

Dataset Summary

The ELI5-Category dataset is a smaller but newer and categorized version of the original ELI5 dataset. It's an English-language dataset of questions and answers gathered from the r/explainlikeimfive subreddit where users ask factual questions requiring paragraph-length or longer answers. After 2017, a tagging system was introduced to this subreddit so that the questions can be categorized into different topics according to their tags. Since the training and validation set is built by questions in different topics, the dataset is expected to alleviate the train/validation overlapping issue in the original ELI5 dataset.

Supported Tasks and Leaderboards

  • abstractive-qa, open-domain-abstractive-qa: The dataset can be used to train a model for Open Domain Long Form Question Answering. An LFQA model is presented with a non-factoid and asked to retrieve relevant information from a knowledge source (such as Wikipedia), then use it to generate a multi-sentence answer.

Languages

The text in the dataset is in English, as spoken by Reddit users on the r/explainlikeimfive subreddit. The associated BCP-47 code is en.

Dataset Structure

Data Instances

The structure of this dataset is very similar to the original ELI5 dataset. A typical data point comprises a question, with a title containing the main question and a selftext which sometimes elaborates on it, and a list of answers from the forum sorted by scores they obtained. Additionally, the URLs in each of the text fields have been extracted to respective lists and replaced by generic tokens in the text.
In addition to the original ELI5 dataset, the data point also has a category field. There are 11 common values of category in this dataset: Biology,Chemistry,Culture,Earth Science,Economics,Engineering,Mathematics,Other,Physics,Psychology,Technology, and a special category: Repost indicates the same question has been asked before.

An example from the ELI5-Category set looks as follows:

{'q_id': '5lcm18',
 'title': 'Why do old games running on new hardware still have technical issues ?',
 'selftext': 'I am playing some mega man games on my Xbox One and experience slowdown when there are a lot of enemies on screen . but the Xbox One is significantly more powerful than the NES , so why is there still slowdown on this hardware ?',
 'category': 'Engineering',
 'subreddit': 'explainlikeimfive',
 'answers': {'a_id': ['dbuo48e', 'dbusfve'],
  'text': ["The XBox is emulating NES hardware and running the emulation at a set speed . If it ran it at as fast as possible , then it would be several times faster than the original NES game and would be unplayable . I ca n't speak for Mega Man exactly , but older games tended to run on a cycle locked to the screen refresh which was a fixed 60Hz or 50Hz . There was only one piece of hardware they ran on , so there was no need to adjust for different hardware speeds .",
            "In that case , it 's probably on purpose - they want to emulate the experience as closely as possible , even including the slowdown and sprite flickering . Some emulators let you turn it off , but it 's usually turned on by default . In other cases , like if you 're trying to emulate PS2 games on your PC , the game might just run really slow in general . Even though your PC is way more powerful than a PS2 , it has to \" translate \" from PS2 language to PC language in realtime , which is much more difficult than running PS2 code on the PS2 itself ."],
  'score': [13, 3],
  'text_urls': [[],[]]},
 'title_urls': {'url': []},
 'selftext_urls': {'url': []}}

Data Fields

  • q_id: a string question identifier for each example, corresponding to its ID in the Pushshift.io Reddit submission dumps
  • subreddit: always explainlikeimfive, indicating which subreddit the question came from
  • category: tag of the question, the possible values are listed above.
  • title: title of the question, with URLs extracted and replaced by URL_n tokens
  • title_urls: list of the extracted URLs, the nth element of the list was replaced by URL_n
  • selftext: either an empty string or an elaboration of the question
  • selftext_urls: similar to title_urls but for self_text
  • answers: a list of answers, each answer has:
    • a_id: a string answer identifier for each answer, corresponding to its ID in the Pushshift.io Reddit comments dumps.
    • text: the answer text with the URLs normalized
    • score: the number of upvotes - the number of downvotes the answer had received when the dumps were created
    • text_urls: lists of the extracted URLs for every answer

Data Splits

In order to avoid having duplicate questions across sets, three non-overlapping subsets of category are used in the training, validation and test set. Also, a special validation set contains all the questions in the Repost category. A valid retriever-generator model should have consistent performances on both validation sets.
The final split sizes are as follows:

Train Valid Valid2 Test
Biology 32769
Chemistry 6633
Culture 5446
Earth Science 677
Economics 5901
Engineering 5411
Mathematics 1912
Other 19312
Physics 10196
Psychology 338
Technology 14034
Repost 2375
Total 91772 5446 2375 5411

Dataset Creation

Curation Rationale

ELI5-Category was built to provide a testbed for machines to learn how to answer more complex questions, which requires them to find and combine the information in a coherent manner. The dataset was built by gathering questions that were asked by community members of three subreddits, including r/explainlikeimfive, along with the answers that were provided by other users. The rules of the subreddit make this data particularly well suited to training a model for abstractive question answering: the questions need to seek an objective explanation about well-established facts, and the answers provided need to be understandable to a layperson without any particular knowledge domain.

Source Data

Initial Data Collection and Normalization

The data was obtained by filtering submissions and comments from the subreddits of interest from the XML dumps of the Reddit forum hosted on Pushshift.io.

In order to further improve the quality of the selected examples, only questions with a score of at least 2 and at least one answer with a score of at least 2 were selected for the dataset. The dataset questions and answers span a period from January 2017 to June 2021.

Who are the source language producers?

The language producers are users of the r/explainlikeimfive subreddit between 2017 and 2021. No further demographic information was available from the data source.

Annotations

The dataset contains the category as an additional annotation for the topics of questions.

Annotation process

The dataset is auto-annotated by the tags of posts in the Reddit forum.

Who are the annotators?

The annotators are users/administrators of the r/explainlikeimfive subreddit between 2017 and 2021. No further demographic information was available from the data source.

Personal and Sensitive Information

The authors removed the speaker IDs from the Pushshift.io dumps but did not otherwise anonymize the data. Some questions and answers are about contemporary public figures or individuals who appeared in the news.

Considerations for Using the Data

Social Impact of Dataset

The dataset has a similar social impact to the original ELI5 dataset Social Impact of Dataset.

Discussion of Biases

The dataset has similar considerations of biases to the original ELI5 dataset Discussion of Biases.

Other Known Limitations

The dataset has similar limitations to the original ELI5 dataset Other Known Limitations.

Additional Information

Dataset Curators

The dataset was initially created by Jingsong Gao, Qinren Zhou, Rui Qiu, during a course project of ANLY 580: NLP for Data Analytics at Georgetown University.

Licensing Information

The licensing status of the dataset hinges on the legal status of the Pushshift.io data which is unclear.

Citation Information

@inproceedings{eli5-category,
  author    = {Jingsong Gao and
               Qingren Zhou and
               Rui Qiu},
  title     = {{ELI5-Category:} A categorized open-domain QA dataset},
  year      = {2021}
}

Contributions

Thanks to @jingshenSN2, @QinrenZhou, @rexarski for adding this dataset.

Update on GitHub

Models trained or fine-tuned on eli5_category