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5lchat
|
Why there was a 'leap second' added to the end of 2016?
|
[
"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."
] | null |
explainlikeimfive_other
| 0
|
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.
|
[
"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."
] | null |
explainlikeimfive_other
| 1
|
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!
|
[
"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."
] | null |
explainlikeimfive_technology
| 2
|
5lcr1h
|
Why is it that we calm down when we take a deep breath, hold it for a few seconds and exhale?
|
[
"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."
] | null |
explainlikeimfive_biology
| 3
|
5lcsyf
|
Why does 1080p on a 4k TV look better than 1080p on a 1080p TV?
|
[
"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."
] | null |
explainlikeimfive_technology
| 4
|
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
|
[
"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"
] | null |
explainlikeimfive_other
| 5
|
5ld008
|
Why does lights make a "blinking" effect when looking at them from far away?
|
[
"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."
] | null |
explainlikeimfive_other
| 6
|
5ld14u
|
Why are internet speeds in America so slow
|
[
"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"
] | null |
explainlikeimfive_technology
| 7
|
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?
|
[
"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."
] | null |
explainlikeimfive_other
| 8
|
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.
|
[
"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."
] | null |
explainlikeimfive_other
| 9
|
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?
|
[
"When you take too big a swallow, it stretches your esophagus, causing it to spasm. This hurts."
] | null |
explainlikeimfive_biology
| 10
|
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?
|
[
"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."
] | null |
explainlikeimfive_other
| 11
|
5ldcnk
|
Why is ventilation needed for indoor or underground rooms?
|
[
"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."
] | null |
explainlikeimfive_technology
| 12
|
5ldd1v
|
Why is ♡ considered a heart when a heart doesn't look like that? Also, how does it relate to love?
|
[
"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 )"
] | null |
explainlikeimfive_other
| 13
|
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.
|
[
"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"
] | null |
explainlikeimfive_biology
| 14
|
5ldlgf
|
Why were slaves treated so badly?
|
[
"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!"
] | null |
explainlikeimfive_other
| 15
|
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?
|
[
"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."
] | null |
explainlikeimfive_other
| 16
|
5ldu3c
|
Why is it so difficult to smell ourselves?
|
[
"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."
] | null |
explainlikeimfive_biology
| 17
|
5ldve0
|
Why do comedians repeat phrases of their jokes/stories every so often while performing on stage?
|
[
"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."
] | null |
explainlikeimfive_other
| 18
|
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?
|
[
"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 :)"
] | null |
explainlikeimfive_other
| 19
|
5leazc
|
I just read that it takes 26 hours for New Year to pass all time zones, how can that happen?
|
[
"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."
] | null |
explainlikeimfive_other
| 20
|
5ledy7
|
How does Spotify and Apple Music pay artists?
|
[
"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."
] | null |
explainlikeimfive_technology
| 21
|
5lefn5
|
how does someone like bill gates keep all of his money?
|
[
"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."
] | null |
explainlikeimfive_economics
| 22
|
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?
|
[
"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."
] | null |
explainlikeimfive_biology
| 23
|
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?
|
[
"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."
] | null |
explainlikeimfive_other
| 24
|
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?
|
[
"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."
] | null |
explainlikeimfive_biology
| 25
|
5lf0ro
|
How can the heart not tire out? I know the why but how can the heart only stop beating when you die?
|
[
"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."
] | null |
explainlikeimfive_biology
| 26
|
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?
|
[
"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"
] | null |
explainlikeimfive_technology
| 27
|
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?
|
[
"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."
] | null |
explainlikeimfive_chemistry
| 28
|
5lf6ni
|
How to type Korean?
|
[
"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)."
] | null |
explainlikeimfive_other
| 29
|
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?
|
[
"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."
] | null |
explainlikeimfive_economics
| 30
|
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 :)
|
[
"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."
] | null |
explainlikeimfive_technology
| 31
|
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?
|
[
"If hunting deer it is recommended because deer are color blind. The orange is so other hunters can id you and not shoot you."
] | null |
explainlikeimfive_other
| 32
|
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!
|
[
"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."
] | null |
explainlikeimfive_other
| 33
|
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 :).
|
[
"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."
] | null |
explainlikeimfive_physics
| 34
|
5lfr5p
|
When and how did green generally get associated with positiveness, and red as negativeness?
|
[
"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."
] | null |
explainlikeimfive_other
| 35
|
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!
|
[
"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."
] | null |
explainlikeimfive_other
| 36
|
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.
|
[
"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."
] | null |
explainlikeimfive_technology
| 37
|
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.
|
[
"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."
] | null |
explainlikeimfive_biology
| 38
|
5lgb2h
|
How does Shutterfly make profit when it gives away so many discounts and free things?
|
[
"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!"
] | null |
explainlikeimfive_economics
| 39
|
5lgc5t
|
What is a tensor?
|
[
"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."
] | null |
explainlikeimfive_mathematics
| 40
|
5lgnew
|
The idea of space as a vacuum. Cannot. Understand.
|
[
"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."
] | null |
explainlikeimfive_physics
| 41
|
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?
|
[
"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\"."
] | null |
explainlikeimfive_other
| 42
|
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?
|
[
"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."
] | null |
explainlikeimfive_economics
| 43
|
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?!
|
[
"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."
] | null |
explainlikeimfive_biology
| 44
|
5lgxhi
|
A lifetime supply.
|
[
"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."
] | null |
explainlikeimfive_economics
| 45
|
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.
|
[
"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."
] | null |
explainlikeimfive_biology
| 46
|
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?
|
[
"You each got 50% of your dad's genes, some overlap and some don't, some get activated earlier than others."
] | null |
explainlikeimfive_biology
| 47
|
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?
|
[
"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."
] | null |
explainlikeimfive_technology
| 48
|
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?
|
[
"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."
] | null |
explainlikeimfive_technology
| 49
|
5lhc44
|
Why do most spiders have many eyes, but poor vision?
|
[
"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."
] | null |
explainlikeimfive_biology
| 50
|
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?
|
[
"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."
] | null |
explainlikeimfive_technology
| 51
|
5lhdts
|
Why do we capitalize "Happy New Year"?
|
[
"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)."
] | null |
explainlikeimfive_other
| 52
|
5lhh73
|
Why do mobile games suck, even though phones are more powerful than good handheld gaming systems like Gameboy?
|
[
"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."
] | null |
explainlikeimfive_technology
| 53
|
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?
|
[
"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"
] | null |
explainlikeimfive_other
| 54
|
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.
|
[
"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."
] | null |
explainlikeimfive_biology
| 55
|
5lhrfu
|
Why are kinder eggs banned in America, but knockoffs aren't?
|
[
"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."
] | null |
explainlikeimfive_other
| 56
|
5lhtex
|
How was the canyon diablo meteorite, an object not from earth, used to determine the age of the earth?
|
[
"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."
] | null |
explainlikeimfive_biology
| 57
|
5li1yj
|
Why is the golden ratio common to so many things of different nature?
|
[
"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.\""
] | null |
explainlikeimfive_mathematics
| 58
|
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?
|
[
"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.)"
] | null |
explainlikeimfive_technology
| 59
|
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?
|
[
"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."
] | null |
explainlikeimfive_biology
| 60
|
5liavk
|
How do the police trace a bullet back to its gun?
|
[
"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."
] | null |
explainlikeimfive_other
| 61
|
5liqj4
|
Why is ice-cream that's melted then frozen much harder to scoop than fresh ice-cream?
|
[
"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'."
] | null |
explainlikeimfive_chemistry
| 62
|
5lirbu
|
How do life insurers make a profit?
|
[
"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."
] | null |
explainlikeimfive_economics
| 63
|
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?
|
[
"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."
] | null |
explainlikeimfive_physics
| 64
|
5lit0m
|
Why is your reflection upside-down when you look at a spoon on the side that is curved inwards?
|
[
"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"
] | null |
explainlikeimfive_other
| 65
|
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.
|
[
"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."
] | null |
explainlikeimfive_biology
| 66
|
5lj0oc
|
Why and how do Epsom Salts soothe sore muscles?
|
[
"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."
] | null |
explainlikeimfive_chemistry
| 67
|
5lj296
|
Bicameral legislatures - how do they work and why do they exist?
|
[
"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."
] | null |
explainlikeimfive_other
| 68
|
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?
|
[
"Your cable company is compressing the signal. Over-the-air transmissions are 100% pure, uncompressed video signals."
] | null |
explainlikeimfive_technology
| 69
|
5lja4n
|
How do we know animals are not as self-conscious as humans?
|
[
"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."
] | null |
explainlikeimfive_biology
| 70
|
5ljevu
|
why credit cards are safer than debit cards?
|
[
"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."
] | null |
explainlikeimfive_technology
| 71
|
5ljg3b
|
Why headlights can be seen from a mile away but only illuminate a few hundred feet in front of the car.
|
[
"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"
] | null |
explainlikeimfive_physics
| 72
|
5ljjal
|
Why does a mere air bubble in the circulatory system prove to be fatal?
|
[
"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."
] | null |
explainlikeimfive_biology
| 73
|
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?
|
[
"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"
] | null |
explainlikeimfive_biology
| 74
|
5ljz8f
|
If fat is stored energy, why can't fat people not eat for a few days, be fine, and consume the fat
|
[
"It can be done, with proper supervision. See the story of Angus Barbieri... URL_0"
] | null |
explainlikeimfive_biology
| 75
|
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?
|
[
"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."
] | null |
explainlikeimfive_other
| 76
|
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?
|
[
"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."
] | null |
explainlikeimfive_other
| 77
|
5lkcvi
|
why goats climb on top of stuff, please.
|
[
"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."
] | null |
explainlikeimfive_other
| 78
|
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?
|
[
"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."
] | null |
explainlikeimfive_biology
| 79
|
5lkql6
|
People who wake up after a head injury with a new ability (for example fluency in a foreign language)
|
[
"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."
] | null |
explainlikeimfive_other
| 80
|
5lksbc
|
What happens to our bodies when we don't get enough sleep over a long period of time?
|
[
"our body is engineered to save energy where we can best... that means shutting down some organs to preserve energy. mental problems soon follow"
] | null |
explainlikeimfive_biology
| 81
|
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.
|
[
"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."
] | null |
explainlikeimfive_biology
| 82
|
5lkvjy
|
In the past, chopping off a hand was a common punishment for thieves. What exactly happens afterwards?
|
[
"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."
] | null |
explainlikeimfive_biology
| 83
|
5lkvt4
|
Why does the face get so many more pimples when the hands/feet/arms are in much more contact with dirt etc.?
|
[
"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"
] | null |
explainlikeimfive_other
| 84
|
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%??
|
[
"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."
] | null |
explainlikeimfive_biology
| 85
|
5lkxek
|
Why do we remember some dreams, sometimes for years, but tend to forget others right away?
|
[
"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."
] | null |
explainlikeimfive_other
| 86
|
5ll4g2
|
Why do roads have unnecessary bends?
|
[
"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."
] | null |
explainlikeimfive_other
| 87
|
5ll6g5
|
In a box of tissue paper, how does the next piece of tissue come out when you pull out the one above it?
|
[
"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."
] | null |
explainlikeimfive_other
| 88
|
5ll7i3
|
Why are floppy discs called "Floppy" if they're not floppy?
|
[
"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."
] | null |
explainlikeimfive_technology
| 89
|
5ll9e4
|
Shadowbanning
|
[
"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."
] | null |
explainlikeimfive_other
| 90
|
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?
|
[
"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."
] | null |
explainlikeimfive_mathematics
| 91
|
5llbaq
|
What happens with plane after emergency landing on water?
|
[
"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."
] | null |
explainlikeimfive_technology
| 92
|
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.
|
[
"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..."
] | null |
explainlikeimfive_technology
| 93
|
5llgje
|
In WW2 movies and RL videos some soldiers salute and some use nazi salute. Why is that?
|
[
"Nazi salute (with straight right hand) was mandatory for civilians but optional for military. Soldiers mostly used traditional salute."
] | null |
explainlikeimfive_other
| 94
|
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.
|
[
"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 )"
] | null |
explainlikeimfive_chemistry
| 95
|
5lljm1
|
Why do we salivate and gulp when we are nervous or put on the spot?
|
[
"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."
] | null |
explainlikeimfive_biology
| 96
|
5lllev
|
Why does slow motion video of car headlights look like they are blinking rapidly?
|
[
"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."
] | null |
explainlikeimfive_technology
| 97
|
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?
|
[
"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."
] | null |
explainlikeimfive_chemistry
| 98
|
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?
|
[
"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."
] | null |
explainlikeimfive_other
| 99
|
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