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7hjzqr | In nature, why is it the generally the responsibility of the male to prove its fitness to the female? Is the offspring not just as susceptible to poor genes being passed from the female? | Biology | explainlikeimfive | {
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"Males can mate with a lot of females in a gestation period. Females can only (usually) mate with one male per gestation period, so they make it count. Consider a generic species. For males, the genetic 'best option' is to spread their seed far and wide, the idea being that *some* of their offspring will survive. If they can impregnate fifty females? Great! Their genetic legacy is secure. For females, the best option is to only accept the best they can get, to improve the chances of fit offspring. If they mate with a weak male, their offspring is going to have a hard time of it, and will probably die early -- not good, if you're putting a lot of energy into setting up a lineage. Females in this generic species have to know that the investment they're making -- in food, in time, in energy, and in the risk to their own health during pregnancy and birth -- is worth it, so they're likely to only accept the best they can get."
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7hjzt9 | what magnet, charter, and choice schools are in the USA | These terms occasionally come up in comments about education. | Other | explainlikeimfive | {
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"Standard public schools in the US take any student that lives in their assigned region and educates them. However, let's say you are a really talented musician, there is really not reason to think that the other talented musicians in your state live near you. So, the state (or county) might open a Magnet school for Music. Any student in the state/county can go there, but the school can select the best musicians. This is a very different system, but it's still apublic school run by the government. Let's say some parents want to have a school that adopts a non-standard teaching philosophy, for example boys-only and girls-only rather than co-ed. They can find some educational studies that show this works better for some students. With this justification they can apply to the state/county for a Charter to open a Charter School that adopts this educational paradigm. It's a controlled experiment, and usually they use the same books and tests as usual schools. Attendance at the charter school is voluntary, sometimes with a lottery if more kids want to go than there is space. Other times parents want a school choice that's not educationally based, the long-standing example is Catholic School. These schools teach the same content, but in addition they teach certain religious things. In most of the US, these are private schools, where the parents pay. However, in some areas with below average public schools there have been experiments with voucher programs where some of the tuition is paid with public money (because the student isn't taking up space in a public school). This is the most controversial aspect of the system.",
"Regular public schools have to take any students in their assigned district. Magnet school - it’s a “magnet” for the best students in a city. Either the best students overall, or the best in a specific field, like a science magnet school or performing arts magnet school. These don’t take everyone - you have to either apply, take a test, or for a performing arts school, you have to audition. Some magnets take 10% or less of the students that apply. Charter school - these are in the public school system but are run by people other than the regular board of education and its staff. They are usually in poor urban neighborhoods. Supporters of charter schools say that poor urban schools are usually terrible and that this is a chance to give those kids a better education. Opponents say that charter schools take power away from the community that has more of a say in the way its public schools are run, and also take resources away from public schools. School choice means that parents can pick from a number of public schools instead of just being assigned to their local district school. If too many kids apply to one school and too few to another, then not everyone would get their first choice. The stronger version of school choice is school vouchers, where each kid gets a voucher for a certain amount of money that can be used towards tuition in a private school or Catholic school or other religious school instead of attending public school. Many right-wing politicians have proposed school vouchers over the years, but its very rare that a community actually has them. People worry that the private schools would just take the best students and leave the more difficult students in the public schools (poor kids, non-English speakers, learning disabled, and kids with discipline problems)."
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7hk08r | the cost benefits of running central heating on auto through most of the day vs off and turning it on when you get home. | Economics | explainlikeimfive | {
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"Your house loses heat to the outside based on the temperature difference between it and the outside. The warmer it is inside the house, the more energy will be lost. The more energy lost to the outside, the more energy has to be put into the house by the heater. Therefore, it is nearly always better to turn it off during the day. The only exception is if it's so cold outside that turning it off would actually damage stuff inside the house. If the inside gets below freezing, for example, you could have pipes or valves burst. The same thing applies with AC in hot, humid areas: if it gets too humid inside for too long, you could get mold growth. But except for these extreme cases, you'll see lower costs by not leaving it on all day.",
"Most modern home heating systems run on a thermostat. They turn on until they reach roughly the temperature set-point, then they turn off. If the temperature drops a few degrees, they turn back on to bump it back up. If you run it all day, it runs just enough to keep the temperature near where you set it. If you cut it off for a long time and the temperature really drops (depends on how cold it is outside and how good your insulation is), it will take a lot of energy to get it back up to temperature. The bigger the house, the more time and energy it will take to warm up. The third option here is obviously to just set the thermostat lower when you are gone. That way you're using less energy, but also saving the energy you would need to warm up the system when it is completely cold."
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7hk5wi | Why does autotune sound so bad in 2017? | It’s 2017. We have smart-everything now. Autotune has sounded the same since 2000s. How come it hasn’t improved since? Side question; why does autotune sound so bad in the first place? | Technology | explainlikeimfive | {
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"Autotune has been used, unbeknownst to the public, long before Cher's Life After Love, which is commonly credited as the first song to employ apparent autotune. Before then, it was simply used to correct pitch in studio performances. When applied thusly, it is nigh unto undetectable. When you can hear the autotune, that's intentional.",
"99% of the time you don't hear autotune/pitch correction when it's used as a tool and not as an effect. It's gotten really, really good and it's integrated into most recording software. Back in the day you needed a hardware unit or third party software, now it's a standard feature and it's used so much you wouldn't believe it. It's primarily used when you have a take with a few notes that are out of tune slightly and need to be fixed, which is cheaper than booking studio time or a musician to redo the takes. When you hear it like you're talking about, it's used as an effect. You may think that it's a cheesy effect that sounds bad, but artists make a conscious decision to use it in that way because they think it sounds cool. It can be used as a callback to tunes they were influenced by or are trying to emulate from the early 2000s. But it's just that, an artistic effect. If you don't like it in music don't buy that music. The reason it sounds \"fake\" is twofold, the first is the actual pitch shift and the second is how it is applied to the audio. The sweeping majority of pitch correction software essentially time stretches the audio (without changing pitch) and then plays it back faster or slower by the same factor. Both stages will have artifacts, or add crap you didn't want. Time stretching without shifting pitch is an old idea (it was done back in the 50s) but one of the things that happens is transients (fast changes in the signal envelope) get smeared or shrunk in time, and in bad cases can even be repeated giving you some pops and blips. When you speed up the signal after stretching it, you have to filter it or else you get \"aliasing\" which is high frequency garbage on top, if you slow it down you naturally filter the signal which rolls off the high frequencies. Now *even if* you have no artifacts from the shift, you have a problem which is that the general curve of the frequency response is shifted up or down. This is not how a real instrument works, where the curve is fixed based on the acoustics of the instrument/voice, but the individual harmonics move up and down. This causes the timbre of the instrument to shift with the pitch changes, and it sounds alien and unnatural. In general the only way around those problems is to only use tiny pitch shifts. Which is where autotune excels today, it's great for fixing tracks that are out of tune, not for changing the melody entirely. Now when the shift is applied it is done with an envelope, meaning the pitch shift is applied over time. The signal will ramp up or down to the new pitch, it isn't instant. The longer that ramp time, the more natural it sounds. When it's very short you get that T-Pain sound, as the pitch correction kicks in almost instantly rather than how a voice would naturally change."
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7hk699 | Is there any advantage to put the power buttons on the side of laptops or embedding them into the keyboards? | Technology | explainlikeimfive | {
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"There are a number of reasons for the location of power buttons. Minimum length of connecting cables. Free space on the face maybe at a premium. Think of edge to edge screens. But hidden buttons by the keyboard are a great location. If you have ever accidentally turned off your phones display. Imagine doing that while working on your laptop without having your work saved. Some laptops allow you disable the power button. You can still power off, by holding for a longer time, but no more accidentally power offs.",
"Typically you would find these side power buttons on laptops that swivel all the way around to turn into a tablet. If you had the power button on the keyboard when a laptop is in tablet mode, it’d be an awkward push. Thus, it’s placed on the side for compromise. Source: I own a 2-in-1 laptop and it just makes the most sense."
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7hk6yf | Why do college basketball players who are injured and out for a game or two, sit on the bench in street clothes? | Think that happens in the NBA too. | Other | explainlikeimfive | {
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"It isn't just injured players in street clothes, you have the healthy scratches to. An NCAA Div I team can have as many players as they want (although only 13 full scholarships), but can only have 15 players available for a given game. Those players are allowed to \"dress\" in a uniform, while the inactive players must wear street clothes. Coaches are not required to decide who to dress until a little before game time, so they want all the players there. Also, even if they know a particular player won't dress, they are still part of the team and are there for support.",
"The players want to support their team even though they cant be there to play so they come and still cheer for their team",
"Only so many players are allowed to \"dress\" for a game, and most teams have more players than they can put on a game roster. If a player is injured, then the coaches can fill that roster spot with another player, like a back-up from the practice squad. In this case, the player that is taken out of the lineup cannot dress for the game. Injured players that can't dress for the game can still come to the game though, which is why they wear street clothes on the bench."
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7hkb2e | How does the U.S. government read the FCC comments? | Other | explainlikeimfive | {
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"Real simple, they don't. They aggregate similar letters and count them up and weight them to get a concensus. Then they disregard the letters and do what they want anyway, they don't have enough to answer to us. We don't sign their checks so why would they listen to our baseless opinions?",
"They are read by analysis computers. Most of the comments are cut-and-paste. The programs simply count how many copies of each version there are. Many comments have inaccurate contact information, these are segregated, as they don't really count. The unique ones are read by scanners looking to decide what side they are on, and how unique their argument is. These methods assure that the input positions are understood. Fairness is neither provided or promised."
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7hkc7n | Why and how does a Anti-Static wrist band protect and prevent our electronics from being damaged? | Why does static even ruin our electronics, and what exactly does an anti-static band do to prevent that from happening? | Physics | explainlikeimfive | {
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"Your body is not a very good conductor. It's ok, nothing special. Your clothes/shoes, on the other hand, are good insulators and they can charge you up to tens of thousands of volts. Discharging 15,000V into a computer circuit designed to run on 3.3V will fry it. The anti-static band uses your ok conductor body to bleed off the charge your clothes/shoes have built up. That makes you have only safe voltage on your skin, as long as your anti-static band is hooked to ground (through a resistor, for safety).",
"Think about what would happen if you designed a bridge that was able to support a couple people walking across it at the same time and then you drove a fully loaded semi across it. That's basically what static discharge does to electronics - you take something designed for a small load and you briefly put a load that is orders of magnitude larger across it. It might not fail immediately, but it is certainly weakened and highly more likely to fail in the future. [The huge amount of voltage being delivered into a fragile piece of metal can cause a significant part of the metal path to basically vaporize or turn into slag]( URL_0 ), which can cause power to go places where it isn't expected or not go where it is expected. Anti-static bands basically give electricity that has built up on you a path to leave. Your clothes rubbing together can build up static charge on you that can't overcome the insulating property of your shoes, but if you touch an electronic device that can conduct it will jump to that path of least resistance. Putting on an ESD strap always gives the static electricity that builds up on you an immediate and low-resistance path to leave you so that there is minimal if any build-up on you as you're working with those electronic devices."
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7hkd13 | Construction of numbers | I understand that the natural numbers can be constructed using set theory and are defined by the Peano Axioms. How do we get negative numbers (and thus the integers) from the naturals? How do we get the rationals from the integers? How do we get the reals from the rationals? How do we get the complex numbers from the reals? | Mathematics | explainlikeimfive | {
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"We can construct the integers as a set of equivalence classes of ordered pairs of natural numbers, with (a,b) representing a & minus;b. Two pairs (a,b) and (c,d) are equivalent if a+d=b+c. Now that we have integers, we can construct the rationals as a set of equivalence classes of ordered pairs of integers, with (a,b) representing a/b. Two pairs (a,b) and (c,d) are equivalent if ad=bc. We can then construct the reals as sets of rational numbers, where a real number is represented by the set of all rational numbers smaller than it. Then complex numbers are ordered pairs of real numbers, where (a,b) represents a+bi.",
"Assume we have just addition and positive integers at our disposal. How do we get subtraction and integers from here? One approach would be to start thinking of pair of numbers, (a, b). To add a pair like this, you add the first numbers together, and then second numbers together, forming new pair with just addition. So (1, 4) + (10, 2) = (11, 6), for example. To define integers, we just say that integers are all pairs like this, but so that we don't differentiate between two pairs if you can add same integer to first and second number of one pair and get the second pair. So for example, (5, 3) = (3, 1) because if we add 2 to both numbers in (3, 1), we get (5, 3) = (3 + 2, 1 + 2). Now we just can note that pair like (2,1) stands for natural number 1."
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7hkrs6 | Why do we pay for internet at home by speed, but for mobile internet by usage? | Other | explainlikeimfive | {
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"Phone companies cannot guarantee a consistent speed based on the mobile phones location as the coverage and strength of the signal can alter the speed. So they charge you what you use regardless of your location. You're not going to use much if you're on a mountain somewhere but probably use loads if you're in a city somewhere. Homes that have fixed broadband or fibre optics have more reliable connections so they charge you based on what the average or (up to) speed is in your area"
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7hkst8 | How do you determine the rate heat will expand an object? | In general, heat causes object to expand. Aside from differences in temperature, what determines the amount something will expand when heated up. | Chemistry | explainlikeimfive | {
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"What you're looking for is called the [coefficient of thermal expansion]( URL_1 ). It's different for every material, and is in units of K^(-1), or sometimes percentage per K. For example, a gas with a coefficient of 1%/K would expand by 10% if you raised the temperature by 10K. Since every material is different, you pretty much have to look up whatever your object is made out of in a table [like this]( URL_0 ). One unfortunate thing is that the coefficient is often different at different temperatures. So that material above might have a coefficient of 1%/K when at room temperature, but this might drop gradually to 0.1%/K as the temperature rises. You can usually find this behavior in a graph [like this]( URL_2 )."
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7hlmdo | How do screens produce the color black if it’s, physically speaking, just the absence of light? | Technology | explainlikeimfive | {
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"Exactly as you say. They don't emit any light. It you turn of a screen it is black so turning of the light is enough for the pixel to be black. In practice it is not as black as a turned off screen types because the back light is always on and make it darker with a LCD that can block the light. It might look darker then when a screen if of but that is because you compare it lit pixels beside it or previous scenes."
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7hm6ae | Can hardware work without drivers? | Technology | explainlikeimfive | {
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"Short answer: No Imagine your computer is person A and your other hardware (Lets say a monitor) is person B. Person A wants to tell person B is to flick the light switch. The driver defines how they will communicate. Maybe it's English, maybe it's sign language. But without it, no matter what person A does, person B has no idea that person A wants them to turn on a light switch. And there is no way person B can tell person A that there is no light switch in the room. Plug and play hardware works because a bunch of companies got together and told everyone else that is going to make a generic type of device (eg monitors, mice, keyboards, etc) that they need to speak in english back and forth if they want generic functionality to work. If the need to do something fancy, like sing, they can write their own language. But if they want to talk, they need to speak in English. For a lot of stuff, like mice and keyboards, this is enough. For other stuff they actually need to sign... and dance... and throw pies in people's faces. They need their own language.",
"No. The drivers make the hardware work. Some operating systems put drivers in the kernel and some have them separate, but in most cases drivers are needed, like for printers and things like that.",
"A driver is, by definition, the software that allows your computer to interface with hardware. For modern operating systems that do not let programs directly access hardware, there must always be some sort of driver telling the OS how to use that hardware. That driver might be a generic driver that came with the OS rather than something specific to that piece of hardware (eg - standards compliant USB keyboards and mice or running a video card as a generic VGA adapter) but there's going to be a driver in there somewhere."
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7hm81t | Why couldn't taxes be the same for every level of income? Why do there have to be brackets? | Economics | explainlikeimfive | {
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"Even taxes across the board creates a heavier burden on lower income houses than on higher income ones because a larger percentage of your income goes to mandatory basic needs when you make less(food, shelter, transportation). There is a minimum on just how little you can live on, and living expenses don't scale linearly with income so higher income households have a larger discretionary budget, higher taxes cut into the discretionary budget which they don't like, but they are not at risk of not being able to meet basic food and housing needs due to the higher taxes as opposed to a lower income household",
"For starters, let me clear up a common misconception. Tax brackets apply to everyone on the money they earn in that bracket - you don't magically jump up to a higher rate on everything if you make that extra dollar. As an example, Let's say you've got a system with a 0% tax on income up to $10K, 25% on income up to $50k and 30% on everything over $50. If you make $10000 in a year, you pay 0% on that. If you make $10001, you pay 0% tax on the first $10k & you only pay 25% of that last dollar. If you make $20k, you pay 0% on the first $10k and 25% on the next $10k ($2500). If you make $100k, you pay 0% on the first $10k, 25% of 10-50k (10k) and 30% on 50-100k ($16667) for a total of $26,667. ---- With that out of the way, the argument for *progressive taxation* is that taxes are a bigger impact on the poor than they are on the rich. If you're only making $15k/yr, paying $3k in taxes *really* hurts you. If, OTOH, you're making $150k/yr, paying $30k in taxes isn't all that big of a deal.",
"If I make $100/week and you take $20/week, my life is MASSIVELY affected for things like \"paying rent\" or \"eating food\" If I make $10,000/week and you take $2,000/week, my life is vaguely affected, if affected at all. Like I'll have to shop around for my hotel in Aruba during my vacation, to make sure I get a good price, but that's about it. Maybe I might have to commute 15 more minutes to work. So what we do is we say \"Well, ok, the people making $100/wk don't have to pay as much. They need to use their money on, like, basic living things. Maybe we even help them out withs tuff\" Then once people are outside the \"Need to live\" amounts of money, we start going \"Ok, we'll take 5% of everything you make over the basics to live. You still keep most of it, because you worked hard and deserve luxury! But now you need to start giving back to the governing system that basically handles all of the public interest stuff\" Then eventually you get above the \"Can afford some quality of life stuff, and have a war chest for unforseen spending, that sort of thing\", and we go \"Ok you're doing well, we'll take 10% of everything you make over the little bit of luxury spending, and use it to build schools for everyone\" Eventually in a perfect world we'd also get to a point where we say things like \"You're a multi-millionaire, literally there is nothing that you would need to buy that you can't. There are maybe some things that you want to buy that you can't, but whatever. We'll take, like, 75% on everything you make over 5,000,000/year.\" And so on. It's been mentioned that when you get to a new bracket, you still keep everything that you make up to that bracket taxed at it's bracket rate. So if you make 1,000 and are taxed at 10% of it, you lose $100. If you make 1,500 and the 1,000-2,000 range is 20%, you lose $100 from the first 1,000, and $100 on the next $500.",
"Because you'd never have a fair rate. Set the rate to high and low-income families are doomed. If you earn $1000 a month, you need every dollar to life. If you earn $10.000 a month, the percentage that you can pay without really feeling like you are impacted are way higher. So if you'd set a low tax rate for everybody, you would get no taxes, because richer people play a small percentage, because it can't be set high due to all the poor people that couldn't pay that amount of taxes.",
"To everyone saying that we have it because having a progressive scheme is important, because it hurts poor people less, I have a few questions: 1. Is sales tax okay? It's a flat tax and it applies to everyone who buys the taxed products equally. 2. Are gas taxes okay? Another flat tax, and this clearly hurts poor people more because gas prices affect how far a person can drive to a job. 3. Are car registration fees okay? Not technically a tax, but same idea. 4. Are government stimuluses okay? By increasing the supply of money, the value of money is decreased (and by the same amount for everyone). This has the same kind of effect as a flat tax applied to everyone. 5. Is inflation okay? Should the government do something to stop it? Same idea as #4. Everyone's presenting this as if it's a *moral* issue to tax \"progressively,\" but all of these issues above are \"regressive\" in that they clearly hurt poor people much more than rich. Yet I never see any indignation about them on Reddit or the media."
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7hmbcw | Why do red clothes appear gray / black underneath red lights? | Physics | explainlikeimfive | {
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"If the room is only illuminated by red light, bright red pigment is indistinguishable from white pigment: they’re both reflecting nearly 100% of light falling on them (all of which is red). If you have a dark red shirt that reflects 10% of red light, it will look the same as a grey shirt that reflects 10% of all light. The fact that the grey shirt is also capable of reflecting green and blue light is irrelevant because there’s no green or blue light around.",
"The short answer is, they don't. They appear grey or black underneath *other* colours of light. White light is made up of an entire spectrum of colours -- think a rainbow, or a [Pink Floyd album cover]( URL_1 ). When you see something red in white light, what you're actually seeing is an object that absorbs all the other colours of light -- the green, the blue, the yellow, the orange, the whatever -- and bounces that specific red wavelength back to your eye. The red light is reflected for your eye to see. See [here]( URL_0 ) for a nifty little diagram. So, what happens if you don't use white light, but instead red? Well, a red item will look red still: the red light is being reflected back into your eye. But what about a green item? There's no green light to be reflected back into your eye, and all the red light is being absorbed, so the object will appear dark. (It's a little bit fuzzy here, because it would be very difficult to find a natural object that *only* reflected a very specific wavelength of light, but that's the principle behind it.) In short, a red item under white light should look the same as a white item under red light, if you can get the specific wavelengths to match up. So why would that make things darker? As far as I can see -- heh -- it wouldn't. What you're probably seeing is a psychological trick based on the fact that everything in red light is going to seem darker (after all, there's less light coming back into your eye, and it's not a situation you're used to). Surrounded by so many other dark items, and in lower lighting conditions, I'd say that's probably the reason why it might appear black or grey to you: a trick of the mind, not of physics."
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"https://www.sciencelearn.org.nz/system/images/images/000/000/043/full/Red-shirt-and-blue-shorts20150805-30610-1aagaua.jpg?1447040425",
"https://en.wikipedia.org/wiki/The_Dark_Side_of_the_Moon#/media/File:Dark_Side_of_the_Moon.png"
]
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7hmd75 | What is happening when a video lags and loses quality but continues to play? | Technology | explainlikeimfive | {
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"text": [
"> What is happening when a video lags and loses quality but continues to play? The streaming service has detected that there isn't enough throughput of data necessary to maintain a full resolution video stream to your computer, but that a lower quality video stream which consumes less bandwidth can be supported. It lags for a moment as the stream is converted to the new resolution but it keeps going afterwards."
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7hmi86 | Why are text and disclaimers in ads/commercials allowed to be so small? | Other | explainlikeimfive | {
"a_id": [
"dqs5h3j"
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"text": [
"The FTC governs this. There are not rules on exact fonts or sizes allowed, but the disclaimers must be in the same manner as the offer (ie, if the offer is text, the disclaimer must be in text, if the offer is verbal, the disclaimer must be verbal as well). The standard for being applicable or not is \"is it clear and conspicuous\". obviously this is hugely subjective, but it doesn't mean \"does it really stand out\" only \"would a reasonable person be able to notice it and, if they wanted to, understand it\". some disclaimers that are too unnoticable have been legally challenged and ruled against. you can notice most disclaimers, and if you try, understand them. The companies fudge the rules as much as possible to get is as small as possible while still probably being allowed."
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7hmpgb | What starts the pumping of the human heart and how does it keep going? | I guess I’m asking how the heart works, like what’s the power source? I keep thinking of an engine which needs a method to turn on and to keep going. I sound dumb. | Biology | explainlikeimfive | {
"a_id": [
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"dqscen8",
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"text": [
"You don't sound dumb. It's a good question. The heart has its own electrical system that keeps it pumping independent of brain function. Sometimes it misfires, though, and that can lead to things like heart attacks. Basically, as long as there's blood flowing through the heart to keep it alive it doesn't even need to be in the body. That's what they do for heart transplants.",
"The power source for the heart actually runs off of electricity. The heart is a muscle that receives an electrical signal as specialized cells rapidly change their electrical charge from positive to negative and back. If you have ever been shocked with electricity, when it occurs, your muscles contract rapidly. Every time this electrical signal travels through the heart tissue, the part of the heart that is “shocked” will contract. Your body has a cardiac conduction system which handles creating and regulating these signals. This heartpump runs automatically after your first heart beat when you are in the womb by receiving these electrical signals. Your body does it instinctually, so we never even have to think about it unless it beats out of rhythm, beats too rapidly, etc. Another way of understanding how the heart runs is to look at how a pacemaker works. The pacemaker is connected to sections of the heart. The “brains” of the pacemaker send out electrical signals from a battery at a set speed (beats per minute) to cause the muscles of the heart to contract in a specific order at a specific speed. This pacemaker behaves the way the cardiac conduction system is supposed to behave. Also, the heart and circulatory system is a closed system with a certain amount of blood in it. Think of it like squeezing a water balloon where the water is your blood, and your hand and the balloon are the heart. When your heart contracts, the blood has two directional choices to go, either away from the heart where it came from(backwards), or away from the heart moving forward in your circulatory system. Simultaneously, as your heart muscle contracts, a valve closes that keeps the blood from moving backwards in your circulatory system. At this point, the blood can only move forward in the system.",
"The heart has pacemaker cells in it that send an electric signal throw the top through the bottom of the organ once those cells has reach a threshold of sadism influx, it’s cause a contraction which pumps the blood through the body and the cells reset by pumping out the sodium only for it to hit threshold again and contract. This spot is called the SA Node."
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7hmq34 | What are protection rings? | I keep seeing people write Ring 0, Ring 3, Ring -2, and have no idea what they mean. A quick Google search brings up Wikipedia but I find the explanation confusing. What are protection rings, what function or use case do they have and what happens if something “breaches” a ring? | Technology | explainlikeimfive | {
"a_id": [
"dqs8vc0",
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"text": [
"To be honest (based on several decades of IT experience) this is one of those things where people invent overcomplicated terms for something rather than just explaining it. I believe this is done in order to make this easier to make colourful charts of so that non-technical people can pretend to understand it. Basically, an operating system has different levels of privileges. The highest privilege (or lowest \"ring\") has access to everything. Letting everything have that kind of access is obviously bad, so we reduce privileges for processes that don't need them. For example, a device driver would need *some* privileges, but not all, so you put it on a different \"ring\". An end-user program needs even less privileges, so you put it on an even farther ring, etc. Again, basically an overcomplicated way to \"simplify\" something that wasn't really complicated to begin with.",
"x86 hardware has a number of privilege levels. * Ring -3 is Intel AMT, a server management functionality. It allows remote control of the computer, even while it's sleeping. * Ring -2 is the System Management Mode. It's firmware that runs outside the control or oversight of the operating system. The code does things like fan control, reacting to hardware error events, emulating some old functionality like PS/2 mice and keyboards, etc. * Ring -1 is the hypervisor. It's used for virtualization. * Ring 0 is where the operating system runs. This includes device drivers. * Ring 1 is unused. * Ring 2 is unused. * Ring 3 is where applications run. This separation makes it impossible for your web browser to do any arbitrary thing it wants without going through the operating system. Rings lower than ring 0 are worrisome because they're outside of the control of the operating system and the user. The code is effectively invisible and undisclosed, and any vulnerabilities there make it possible to access the computer remotely in a way that's undetectable to any software running on it."
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7hmv6s | Why do movies have different release dates in different countries? | Other | explainlikeimfive | {
"a_id": [
"dqs989w"
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"text": [
"because some countries have other blockbuster movies on the same weekend as yours. and you don't want to compete against that. so you schedule your movie when there isn't that much competition"
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7hmyxi | why do tortillas cook flat on one side, and inflate rapidly on the other? | I love Mexican food | Physics | explainlikeimfive | {
"a_id": [
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"text": [
"Depending on the tortilla, there is likely stretchy proteins (like gluten) which are free to stretch in the area of least resistance (upwards, away from the heat). This is because the various proteins on the hot surface break down and begin to become firm in the process (leading to the crusty areas). So, one side is firm and the other is stretchy. As soon as the liquids begin to vaporize in the heat, bubbles are formed in the areas which will accommodate their expansion the easiest, leading to one-sided inflation."
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7hnfjm | If the common cold tends to be a different virus each time(hence why you can't necessarily prevent it), why do you have nearly the same symptoms each time? | Biology | explainlikeimfive | {
"a_id": [
"dqsdt2w"
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"text": [
"The symptoms are not the specific effects of the virus, the symptoms are the feelings caused by your body’s physical defenses. There may be a thousand different viruses out there that could be attacking you at any given time, but your immune system only really knows a dozen defense tactics. When a new virus comes in, the body tries what it knows... Can we cook this one off? (Fever) Does it go away if we secrete fluids to flush it out? (Mucous) Do we need to rush more blood cells to the infected area? (Inflammation) It’s getting into the airways, let’s try to force it out. (Coughing) The immune response itself causes the bulk of the symptoms, not the virus."
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7hngdb | Why is there a sensation of travelling, like being on a car or riding a train, after consuming alcohol? | I lie down and feel like I'm taking a train. This is when I know I'm drunk | Biology | explainlikeimfive | {
"a_id": [
"dqsd93c",
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"text": [
"Alcohol slows your brain down as it processes information from your inner ear (which is what tells you when you're moving)",
"Alcohol messes with your small brain. Your small brain is responsible for your sense of direction and balance. When you're drunk, your small brain doesn't get to do its job, but the vegetative part of your brain as well as your instinct try to counteract the false orientation and balance signals you're getting. The sensation of movement can only be felt if you are accelerating, or in other words, if your speed changes. When your small brain gets confused, it generally does not read smooth signals, but a rather chaotic set of impulses. This creates the signals that you're constantly changing your orientation at varying speeds, creating the sensation of movement. In other words, your brain is tricked. This is somewhat useful because you know it's time to stop unless you want to throw up. You might think that what you're thinking isn't physical because it is an illusion, but in reality, you still have chemicals flying around, creating a simulation of chaotic movement. The only difference is that the work your body does is not the same. Your brain sees it as real regardless."
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7hnjdv | Why, when cooling foods in water, do we have to bring it to boil first, then lower to a simmer before putting the ingredients into the water? | Other | explainlikeimfive | {
"a_id": [
"dqsglvy",
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"text": [
"Do you mean when *cooking* foods in water? Some recipes require this method, others don't. The idea is to ensure that the water is hot before using it, so your food doesn't sit in not-hot water a long time, getting soggy and gross. (Or just throwing off the calculation for correct cooking time.)",
"nope, but water releases most energy when boiling. While its getting up to a boil the food will absorb energy that the water should get, making it take a lot longer to boil. Once it is boiling the water is 100 degrees and releasing energy whether it is simmering or boiling hard, so lowering it to a simmer really just helps you save water (because if you evaporate too much then it wont cover the food)."
],
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7hnl67 | Why do balloons heat up when stretched and cool down when relaxed again? | For example, if you hold a balloon against a part of your body sensitive to heat (I use my upper lip) and stretch it, you can feel heat, and when you let it compress again it rapidly cools. | Physics | explainlikeimfive | {
"a_id": [
"dqseaxk",
"dqsm4kt"
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"text": [
"You are breaking inter-molecular bonds when you stretch a polymer like latex, and reforming them when you release it. Breaking them lets out energy, and reforming them absorbs energy. Thats it really.",
"Its origin is in entropy. [Entropy]( URL_0 ) is a measurement of disorder. Now consider that a rubber is composed of a bunch of polymer strands (looking like a bowl of cooked spaghetti). When stretched the polymer strands should be more aligned and straighten out along the direction of the stretching. So when you relax it the strands go in all directions, or become more disordered. Entropy is related to heat, and during relaxation the entropy is increased. So if the system (aka balloon) heat is positive, heat must go into the strands of polymer. If the heat goes into the rubber, where does it come from? The heat comes from the environment - the balloon feels cold. [Source.]( URL_1 ) And when you stretch it, the reverse thing happens."
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"https://en.wikipedia.org/wiki/Entropy",
"https://depts.washington.edu/chem/facilserv/lecturedemo/EntropyofRubber-UWDept.ofChemistry.html"
]
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7hntv3 | Why do small stripes show up distorted when displayed on a screen in a picture or video? | Technology | explainlikeimfive | {
"a_id": [
"dqsglu8"
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"text": [
"Because a screen is made of many individual pixels. Imagine a classroom with 5 x 5 desks where each desk is a pixel on a screen. Now, you take a string and move it about the desks. If the string intersects a desk, that person stands up. It's easy to make lines of people that are horizontal and vertical. However, things get strange if you start making the string diagonal. You can have every person stand up but then the line looks fatter than usual. You can have fewer people stand up but then the line looks like it has breaks. This is known as aliasing. It's difficult to display small things (usually lines and edges) on screens simply because pixels have a certain size. By making pixels smaller, you can reduce this effect (phone screens have very high resolution despite their small size). Other methods such as anti-aliasing selectively blur these edges so they do not appear as distorted."
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7hnz8m | why do cyclones have names? And who names them? Why don’t earthquakes, tsunamis, etc. are not named? | Other | explainlikeimfive | {
"a_id": [
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"text": [
"In the US, the NOAA (National Oceanic and Atmospheric Administration) names hurricanes. I'm not sure about who handles naming cyclones/typhoons/regional-names-for-same-storms. These storms are named because they have lifespans of weeks, and during this lifetime meteorologists are able to watch these formations and make predictions about what they'll do. There are also usually a bunch going at any one time. Since they spend so much time talking about 'em, being able to tell them apart is important, hence the names. Tornadoes, Earthquakes and Tsunamis are much less predictable, and over much much faster. No name is needed since if you say \"the tornado\" can kinda assume \"the one that is happening\" or \"the one that just happened.\"",
"Tropical storms have names to make warnings about them easier to follow. In years like this one where there were a number of hurricanes active in the same area and the same time, it could quickly get confusing. You don't want confused audiences when you are trying to warn people from potentially lethal dangers. Somebody might mistakenly think that a hurricane warning does not concern them since it has already passed him by when the warning actually talks about the next hurricane or something like that. They could number them but numbers are not as memorable as names for most people. The solution is to simply name them alphabetically. The first tropical storm gets a name starting with A and the next after that get a name starting with B and so on. There are lists with the names that will get used decided for the next six years. After that lists gets reused again but especially bad hurricanes have their names retired and replaced by different names starting with the same letter. Earthquakes, tsunamis etc usually have much less warning in advance and are much rarer so there is less chance for confusion. Those type of disaster usually get named for when and where they happen so they can be easily distinguished when written and talked about later. Some especially big catastrophes get nicknames like the x-mas tsunami, which happened around x-mas and affected many different countries."
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7ho0qu | Why is it that when a limb falls asleep, sometimes it’s kind of painful (like pins and needles) and sometimes it’s gentle (like a sort of dull buzzing)? | Biology | explainlikeimfive | {
"a_id": [
"dqsj23y"
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"text": [
"From my experience, the painful part comes when the blood comes back into the limb, triggering the dormant nerves to panic about missing blood for a while. Someone please correct me if I'm wrong."
],
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7hocmw | How can cups stack within eachother without the cup getting smaller the higher you go? | When you stack plastic cups why do they fit in each other if they have the same shape and mass? I have no clue what flair this belongs in so please tell me. | Other | explainlikeimfive | {
"a_id": [
"dqsjyas",
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"text": [
"Stackable cups are *tapered* so that they're smaller at the bottom than at the top. They also stick out past the top of the lower cup somewhat, allowing them to regain the extra space lost by being inside the lower cup. If they had to completely fit *inside* the lower cup then, yes, they'd have to constantly get smaller.",
"Have you ever looked at a cup? They are small on the bottom and bigger on the top."
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7hopme | Why do downloads, file transfers and renders always seem to linger on 99% longer than any other percentage? | Technology | explainlikeimfive | {
"a_id": [
"dqslytz",
"dqsmtse"
],
"text": [
"I dont know how accurate this is, however at the end of the download i assume this is the whole package being checked for errors and any missed packets or segments are redownloaded to ensure it is complete",
"There can be a vast number of factors that affect progress reports including bugs, design flaws, and programmer laziness that may make progress bars behave illogically. Some bars could get stuck, go backwards, freeze, or spend inordinate amounts of time at certain percentages depending upon the implementation of the progress bar by the programmer making every progress bar unique. Often there could be a last routine run before 100% is reported to check for issues or perform an action which may take longer than each percentage point before 99%, for example, writing a file or log to the disk. The are innumerable factors, including your own confirmation bias."
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7hoy2m | Why does coffee make some people sleepy? | Biology | explainlikeimfive | {
"a_id": [
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"text": [
"Coffee dehydrates you a bit because it makes you pee more, so it's recommended to drink water to counter that after having that coffee, or whatever that keeps you more hydrated. Oldie arabian way of drinking coffee supposedly involved a bit of salt to keep the fluids in longer. If you're not hydrated enough you'll feel progressively more tired, your head will hurt and later you'll feel nauseous. But don't worry, that happens when you're in high temperatures environment without being hydrated enough, not after a couple of cups of coffee. Coffee with less water or other drinks might just make you a bit sleepy.",
"ELI5 version from the way I understand it... I'm possibly way off the mark here, so feel free to chime in and correct me: When your are tired there are certain chemicals released into your blood which are picked up by your brain, signalling that your body is tired and needs rest. These chemicals get to your brain through the blood/brain barrier, but there are only a limited number of 'gates' through which they can fit. It also takes a certain amount of time for them to be absorbed and the gate to become free/empty again. Caffeine blocks these gates so that the chemicals can't get through and reach your brain, and so consequently you don't get the response of feeling tired. However the chemicals are still in your blood, and once the caffeine wears off they are free to enter your brain again. Except this time you have more of these chemicals in the queue because they've still been produced by the body during the period where the caffeine prevented them from being absorbed. Boom, extra tired. Similarly, it's best to wait 1/2 hr or so after you wake to have your coffee so that your body has time to clear these sleepy chemicals from your brain. If you drink coffee immediately it won't have much effect because the gateway receptors are already blocked with the sleep chemicals that they are absorbing. This means you won't feel the benefits of the caffeine until the queue had been emptied and the room for the caffeine to hop into the gates."
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7hp1yl | How does the salt-and-ice challenge work? | Kids these days are doing a ton of challenges and one of them is the salt-and-ice challenge where you put salt and ice on your skin to burn yourself, but how do salt and ice do that? | Chemistry | explainlikeimfive | {
"a_id": [
"dqsnpnw"
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"text": [
"We did this back in the 90's also. \"Adding salt to ice or ice water actually lowers the temperature and makes it colder than the regular freezing temperature for water, 32 degrees F. The mixture soaks up heat from the surrounding skin cells, causing a second- or third-degree burn similar to frostbite.\" Edit: I have friends with marks still on them I would watch the knuckle heads do it and just let them win if your put in that situation."
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7hp3iv | Why is it that when you're cutting something in a sawing motion back and forth, it is easier to cut then just pushing down? | You're applying the same downward pressure both times but it is significantly easier to saw something. This is especially true with serrated blades. | Physics | explainlikeimfive | {
"a_id": [
"dqsp6a2",
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"text": [
"Mechanical engineering student here. When you're splitting something you're basically separating the microscopic adjacent layers that the object has into two parts. When you're sawing you're actually removing a layer bit by bit. The thickness of the removed layer is equal to the thickness of the sawblade. This is why when you saw a wooden log, you have some sawdust leftover. The sawdust is simply the amount of wood that was removed during the process. However, splitting the log with an axe doesn't leave remains. Now the next question is: what's the difference between removing a layer bit by bit and splitting two adjacent layers? I can't really tell you I'm afraid. That sounds to me like non-trivial materials engineering. I'm pretty sure it does have something to do with the direction that you're applying the force in.",
"A knife has very tiny teeth on its cutting blade. They are just natural imperfections in the metal. They are small enough that you can't see them without a microscope but large enough to act as a saw."
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7hp4yh | When you turn a bowl of soup, why do the contents not turn with the bowl? | Just eating some noodles today, and when I rotate the bowl the floating things refused to rotate... | Physics | explainlikeimfive | {
"a_id": [
"dqsol6d",
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"text": [
"Why should stuff rotate? Only the outermost molecules have contact with the bowl and experience a force due to friction. If you keep turning the bowl long enough you will see that the motion will eventually translate onto the inner content but it will take quite a while.",
"The soup has mass, therefore it has inertia. It wants to stay in place and requires force to start moving. There is very little drag between the soup and the walls of the bowl, so very little force is passed to the soup. Then the outer layers of the soup must pass it to the inner ones, which again, is a very weak process."
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7hp5p2 | How does a spray dryer work to produce a powder from a liquid? | I don’t understand how exposing the liquid to an immense temperature ends up producing a powder, there must be some kind of cooling process? | Chemistry | explainlikeimfive | {
"a_id": [
"dqsoknn"
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"text": [
"You start with a solution or a mixture, which is sprayed (and so dispersed in very little drops) through very hot gas (that could be air or nitrogen). Being the drops very little, they heat up very quickly: the solvent then evaporates, leaving only the dry solute in a tiny powder."
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7hp9bd | How do they get Cafeïne out of regular coffee making it decaf coffee ? | Other | explainlikeimfive | {
"a_id": [
"dqspak3"
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"text": [
"the beans are steamed for about 30 minutes in order to open their pores. Once the coffee beans are receptive to a solvent, they are repeatedly rinsed with either methylene chloride or ethyl acetate for about 10 hours to remove the caffeine.(because caffeine is more soluble in it)"
],
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7hpc61 | Coriolis. Please actually explain! | There have already been questions about the coriolis effect/deflection, but each one only gives an example of it (carousel). I know it's the reason storm cells in the northern hemisphere move clockwise and in the southern hemisphere move counterclockwise, but WHY?! | Physics | explainlikeimfive | {
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"Okay, I'm going to give you the version my physics teacher once gave me a long time ago. And just for clarification, I am nowadays a physicist myself so I do know what I am talking about. As you know, stuff that is in motion wants to stay in that same motion. Newton's laws, pretty simple. So imagine for example a missile being fired from the equator straight north. Now, compared to the axis around which the earth rotates (i.e. the axis that goes through the north and south poles), the rocket will also rotate around the axis, since it was fired from the equator, which is rotating around the axis. As the missile travels north, the radius of its rotation around the earth axis becomes smaller, but its speed around the axis remains the same. This means that *relative to the surface* the missile will start turning east. I am going to do some maths here: Originally, the rocket sits on the equator, and thus rotates around the earth on the equator in 24 h. The equator is ~40 000 km long, so the original missile speed around the axis is 40 000 km/24 h = 1667 km/h. Now, as the missile travels north, its path (cricle) around earth gets smaller, say only 30 000 km at some point, but the rocket is still traveling with a speed of 1667 km/h around the axis, while the surface of the earth is only traveling with a speed of 30 000 km/24 h = 1250 km/h. So the missile's speed relative to the surface of earth is 1667 km/h - 1250 km/h = 417 km/h east. This is actually not completely correct (I will show physics below). The same thing happens if you fire your missile from the equator southwards. If you on the other hand fire a missile *toward* the equator, the missile will turn east because its path around the axis will become longer. So stuff that goes *away* from the equator turns *east* and stuff that goes *toward* the equator turns west. If you want to go into more physics, this is called the conservation of angular momentum. Angular momentum is the product of the mass, velocity and radius of a thing that is rotating around an axis. So AM = mass*speed*radius. Now if you decrease the radius and the mass stays the same, the velocity increases. So the tangential velocity around the axis actually increases above 1667 km/h. The same stuff happens with moving air, and that is why storm cells rotate the way they do. Now, in order to see the Coriolis effect, the distances have to be large, in order for the change in rotating radius to be significant. The Coriolis effect cannot be seen in a sink, for example. Also, the further away you get from the equator, the stronger the effect gets, since the radius starts to change more rapidly the further away from the equator you go. Example: At the equator, if you go 1 m away from the equator, your radius has almost not changed at all. If you are on the south pole and go 1m away from the pole, your radius have increased with 1m. Go ahead and ask if something is unclear. This was hastily written and a pretty long answer... Edit: I messed up east/west. Should be correct now.",
"The earth rotate so the air on the equator has to rotate one revolution per day as the ground does to stay still.The air on on the north and south only have to rotate around its axis on one day. The rotational speed on the equator is 40075017m/(24*60*60s)=463.8m/s and the rotational speed on the poles are 0 m/s So of air moves a away from the equator is moves a small fraction faster then the ground and air that move towards it moves a bit slower. On the small scale the effect are not noticeable bur on large storms and wind patterns it have have a huge effect. There are lower air pressure in the center of a storm so air moves towards it. The air to the equator increase speed relative to the ground and move east and air from the polar side will move slower then the ground and move west. The result is that large storms will move to the east on the equator side and west on the polar side and that will result in counterclockwise rotation on the northernemisphere and clockwise in the southern. You can see a informative video on it here URL_0"
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7hpdwb | How is time only an illusion according to Einstein? "For us believing physicists, the distinction between past, present and future is only a stubbornly persistent illusion." | Physics | explainlikeimfive | {
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"This is a quote by Einstein on the death of his friend: he's using poetic language inspired by physics, but it's not intended to be precisely true. As Einstein well knew, some events definitely *do* occur in our past, and some definitely do occur in our future. But there's a category of events that could be seen as past, present, or future depending on how fast we're moving.(!) These events, at a \"spacelike interval\" from us, must be located far enough away in space, and close enough in time, that no signal from the event can have reached us yet (or vice versa). In the case of Einstein's eulogy, his friend definitely died before Einstein did. The only way that could *not* be true is if Einstein died so far away that neither Einstein nor his friend could have heard about each other's deaths. That's important because it means we don't have to worry about \"causality\": it would be really awkward if it were possible for Einstein to shoot his friend, but the friend died before the bullet was fired. Fortunately the universe is set up so that can't happen. URL_0"
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7hpkr3 | How do they program computers to play at different elo strengths in chess? | Mathematics | explainlikeimfive | {
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"The \"strength\" of a computer chess program is governed, generally, by two things: 1. How many moves ahead it calculates; 2. Whether or not it is programmed to select suboptimal moves. The further ahead the computer looks and the more optimal moves it makes, the harder it will be. The fewer moves ahead it looks and the less optimal moves it makes, the easier it will be. You can then calibrate the computer by having it play against ranked people and seeing how well it fairs."
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7hprcn | why do professional basketball teams score more points in a game than college basketball teams, but college football teams score more than professional football? | Other | explainlikeimfive | {
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"There are rule reasons and then there are talent reasons. For basketball, NBA Games are longer (48 minutes vs. 40 minutes for college), giving more time to score points. Also, much of offensive baseketball is a skill that just gets harder and harder to defend it as you get better and better at it. The best defenders in college are more able to stop the best offenses than they are in the pros. For football, the games are the same length, but there are a couple rule differences that matter. The clock stops after every first down in college, which means teams have more time to actually run plays, and as such more time to score. There are other slight rule changes that are generally more offense-leaning (for example, players only need to get a single foot inbounds for a catch to count in college, vs. both feet in the NFL. This means more passes that would gain no yardage in the NFL instead move down the field in college.) Additionally, talent disparity is enormous in college football. The NFL has 32 teams of 53 players, for about 1700 total players. Obviously it's not exact, but for sake of argument say these are the best 1700 football players on the planet. Meanwhile, there are 130 FBS schools with 85 players on scholarship, so let's again dumb it down and say these are the 11,000 best college football players on the planet. The talent difference between the best player and the 1700th best player is much lower than that between the best player and the 11,000th player. This allows for individual performances in college ball that would be completely unheard of in the NFL. Lastly, NFL playoffs are selected and seeded based on objective measures (wins and losses are #1, but there are other tiebreakers). A win by 20 points is essentially no different than a win by 60. When NFL games are in hand, teams sometimes sit their best players to keep them from getting hurt, run low-reward plays to wind down the clock, etc. Meanwhile, the NCAA still uses subjective rankings as important factors in who makes the playoff. In this case, it is often much better to win by 60 than to win by 20. So teams will purposefully run up the score when such a thing would rarely happen in an NFL game (at least on purpose)."
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7hpt8u | How can news outlets and others report on accusations? Even to the point they ruin peoples lives and careers before being found guilty... | Other | explainlikeimfive | {
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"There is no law against reporting such things. The press would be pointless if they could only report on things *after* the government has had its say. It would basically make the news outlets a tool of the government, reporting only on the outcomes the government has decided. Accusations are relevant and important. While people lament trial by media, the alternative is worse."
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7hq1v2 | How do they actually tell the genetics if someone is the father of a child | Biology | explainlikeimfive | {
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"If the child is a boy and the y-chromosome is a match then its likely they are father and son. But only then do you keep looking.",
"They look at a bunch of different short regions in the genome that are known to vary between individuals depending on how closely related they are (more related = shared sequence). There are probabilities attached to how many of these markers are likely to be shared between individuals by random chance. So the results of a DNA test are something like \"19 out of these 20 markers match, and the odds of that being a coincidence are one-in-a-million.\""
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7hq37z | What changes does your body go through when training to hold your breath for a long time? | Biology | explainlikeimfive | {
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"For humans, you increase blood cell count, slow heart rate, and increase your tolerance of increased acidity in the blood that is caused when CO2 turns into carbonic acid in your blood stream. You have sensors in your brain that measure acidity and will trigger you to breath faster and increase heart rate. I can also explain how animals like seals can dive for long periods of time if you're interested in that too."
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7hq5fj | How can medications change one's personality? | I've read some books and articles on how some medications were able to change someone's actual personality... can someone ELI5 how that can happen? (if it indeed can happen.) | Biology | explainlikeimfive | {
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"Simply put, anything that has an effect on brain chemistry, whether it be hormones, electrolytes, or energy, can possibly affect how you experience life and how you think. That can cause a change in personality.",
"All that is you, and your personality is nothing but bio chemical reactions in the brain. By adding new or foreign chemicals to the brain you can alter these reaction and change you.",
"This is a super broad question, so i can only give a broad answer. Medications are purposefully designed or naturally existing compounds (tiny bits of material) which can be recognized by our body. Our body has a HUGE amount of chemical signaling; practically every part of our body needs to communicate with another. The catch is that the signals are *very specific*, and the cells who can \"accept\" the signal have very specific areas on them to accept a perfectly fitting chemical (Signal). When something has bound to this area on the cell it causes what is called a cascade, a mutliple step process which gives instructions to various parts of our body (which can target one cell, or many cells, to produce something, to stop something, or to control something). Medications are implemented to bind to these specific signals areas on our cells, in specific areas of our body. Due to the fact cells often have specific receptors for these chemicals (either man-made, natural, or through our own production), we are able to \"force a change\" in someones body through their own internal environment. For personality changes, the cascade and specificity are critically important. Your body is wired so that all the organs and systems work together - adjusting one will often affect the other. Medications that target your brain will directly affect your personality, because these medications are telling your cells to behave a certain way by the sheer purpose of the drug. Moreover, medications which affect other systems, such as your cardiovascular system, can cause nutrients to move around your body faster (higher heart rate seen in coffee, for instance), which can force your brain to deal with an *abnormal* amount of desired nutrients for that cell (usually accidentally entering the cell through gradients). Your internal environment is being forced to behave in a specific way, and your body reacts to that change by sometimes making your personality change."
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7hq928 | Why do deep-water fish need eyes and what do they use them for? | Biology | explainlikeimfive | {
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"Mostly those eyes are vestigial (without function) however for many species they allow for bio luminescent communication or other tricks, such as anglers who can use their lure light to detect the motion of prey as it comes close. For many species however, including cave dwellers, the eyes remain but become functionless. Like our human appendix, it doesn't hurt your survival chances to have functionless eyes in the pitch dark, even if it is a tad wasteful on calorie intake"
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7hqdvl | Why does the perception of sound inside a shower differ so greatly between someone inside the shower and those not (IE singing)? | Physics | explainlikeimfive | {
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"The acoustic quality of the enclosed space makes the singing sound different (better?) To the person in the shower, as the sound is reflected back to them with little interference. Outside the shower, the sound has to get passed the curtains or door, which muffles and distorts the sound.",
"Hard surfaces reflect sound so you sound louder for longer. Also this longer lasting sound makes it sound like you're really holding that note like a pro. Then you get a bit of feedback or reverb that makes it sound like proper music because the sound bounces round.",
"It is easier to sing softly, part of being a good singer is being able to sing loudly. A small, enclosed room with hard, flat surfaces will make your singing seem louder. Also, the water from the shower produced white noise that makes it harder to hear your signing imperfections."
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7hqw8c | What causes light bulbs to spontaneously explode? | My light bulb in my dining room just spontaneously exploded and scared the crap out of me, with shards of glass all over the floor. ELI5 and make me believe it wasn't a ghost, but instead, some strange, simple electrical explanation. | Physics | explainlikeimfive | {
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"Are you in an old house? Slight power surge without proper surge detectors through an old lightbulb can product a lot of heat and make the lightbulb pop. I’d consider bringing in an electrician to look at your house, cause that could be dangerous",
"The light bulb is, somewhat simplified, a wolfram wire in a controlled environment that is encapsulated by a glass bulb. The controlled environment is sometimes gas, and sometimes just air with a different air pressure. When you light the bulb, you'll create heat inside the bulb. Heat changes the air pressure inside the bulb. For obvious reasons, the bulb is designed to handle the change of pressure. But sometimes they break anyway. And that could be because of a number of reasons: - the bulb gets a power surge that create an instant and sudden energy increase inside the bulb. - the glass bulb is damaged. And eventually it breaks. - The temperature difference on the sides of the glass (inside and outside) are too great, and the glass cracks. (indoors, this shouldn't be much of an issue. But bulbs intended for outdoor use tend to have a thicker glass, especially if they are sold to an arctic climate.)"
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7hr5ry | What does dialing 1 before an area code really do? | Other | explainlikeimfive | {
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"> The phone system often requires the caller to dial 1 first as a trunk prefix before the area code and number, to indicate to the phone system that the call requires a connection to another area. \"1\" is also the country code for the North American Numbering Plan, and therefore must likewise be dialed before the area code for international calls made to NANP countries. According to URL_0 I actually had no idea, so I looked it up out of curiosity.",
"While US phone numbers are access internationally with country code '1', the '1' you dial before the area code is *not* a country code. Long ago, dialing a '1' meant you were dialing 'long distance'. This, for the most part, meant you were going to dial a 10 digit number. For a while there were regions in the country where some parts of your area code were local, and some parts were 'long distance', and some parts of neighboring area codes were local. By dialing a 1 before the area code you acknowledged that the call was going to be expensive. If you dialed (xxx)-xxx-xxxx and the number was local, it would go through. If it was long distance (for you), you'd get a recording instructing you to dial 1 before placing the call. In those days, the phone system could tell if you were dialing a 7 or 10 digit number by looking at the 2nd digit you dialed. If the 2nd digit was '0' or '1', you were dialing 10 digits. If it was not, you were dialing 7 digits. Then, we ran out of phone numbers, so the restriction that an area code had to have a 0 or 1 as the 2nd digit and an exchange (the next 3 numbers) could not have 0 or 1 as the second digit was dropped. By this time the cost of 'long distance' calls had pretty much disappeared, so the 1 became a flag that you were dialing a 10 digit number. Now there are many places in the country with 'overlay' area codes. Two or more area codes serving the same geography. In those regions you must _always_ dial 10 digits, so the one is kinda pointless. Some systems require it, some don't. If you wanted to dial a country code, so as to make a long distance phone call, from a land line you dial 011-(country code)-xxxxx. I've never tried it, but I suspect you could dial 011 1 (10 digit us phone number) and make a call that way. Using a cell phone you dial +(country code)-xxxxxx. On your cell phone you can dial a + by pressing and holding the '0' key.",
"It lets the phone system know that you're going to make a phone call to another area with another area code, so it knows the next three digits will be the area code rather than just the first three digits of a number. Let's say you wanted to dial (212) 555-8715. (Made-up number). Without the 1, your phone might just start dialing after seven button presses and you'd end up calling 212-5558 within your own area code. Some carriers/areas don't actually require this. Other areas go so far as to require the area code even for local calls. It sort of depends on the specifics of how the infrastructure has been set up. Goes beyond my knowledge though. That also means that this business with the 1 mainly just applies to US/Canada; other countries will all have their own conventions for dealing with different area codes."
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7hrbzv | Why dont the eyeballs of animals like snow leopards that thrive at -30 degrees freeze over? Do they just blink every millisecond? | Biology | explainlikeimfive | {
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"Minerals (salt) in the eyewater - this reduces the freezing point. You can observe this when salt is put on frozen streets. It does not heat up the streets, but reduce the freezing point of the water on it, thus removing the ice.",
"Finland here. The coldest I've been out in is about -35°C (-31°F) and can absolutely confirm that your eyeballs don't freeze, probably due to the salt as others comment. However, you do have to blink slightly more often (I actually found myself squeezing my eyes closed a little, about once a minute, the same as you do when you've been staring intently and avoided blinking for a while and they get dry), and you can definitely feel that the fluids are denser. You'll also find that your breath instantly coats everything around it with frost. Frosty eyelashes are annoying as fuck. Anything warmer than -20°C is just like any other frosty day.",
"Picture a warm mug of coffee on a cold day. The outside is warmed from the inside. Warm blooded creatures like snow leopards (and you) generate heat. Skin and the surface of eyeballs doesn't get cold enough to freeze (hopefully).",
"I know nothing about eyeballs but a few things about heat transfer. It takes a lot of energy to change the temperature of water because of it's high heat capacity. It also takes additional energy to change the phase of water. Basically this means water can loose a lot of *heat* before it changes *temperature*. Also water is a good conductor of heat, so if the front of the eyeball is exposed to cold, but the back of the eyeball is exposed to a heat source, heat can be conducted from the back of the eyeball to the front to keep the whole eyeball at a somewhat uniform temperature. All of this was based on the assumption that an eyeball is a small bubble of water, which obviously can't be true. But I know they must also have blood vessels, which is an additional means of transferring heat around the eyeball.",
"Winnipeg Canada here. Can confirm eyeballs don't freeze even when it's below - 40 though everything on your face tends to get frosty and if you wear glasses almost instantly ice over. Once it's around - 50 with wind if you aren't in the right layers you got about 10 mins before you freeze like a popsicle.",
"Body temperature. Warm inside the body. Cold outside the body. Eye between. Body generates heat that keeps the eyes warm."
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7hrjxy | why are some electric toothbrushes cheap and others in triple figures ? Do they actually provide a oral hygienic difference? | Technology | explainlikeimfive | {
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"I currently use a Philips Sonicare. It cleans better than a cheap electric tooth brush and the vibrations are less course. So the difference between a cheaper and more expensive electric toothbrush is the method it uses move the bristles and the cheaper ones tend to be cruder. my dental hygienist noticed when I switched to the more expensive toothbrush and I usually require less scaling. I still have my wisdom teeth, so an electric toothbrush is the only effective way to clean back there",
"Some do, but it's mostly marketing. Phillips has funded studies that show their toothbrushes are better, and while statistically significant, the actual benefit to your health is marginal. In general, if someone is being watched during a scientific study, their oral hygene improved. They're less likely to skip brushing, a researcher is giving specific instructions on how to brush, etc. An electronic brush seems to be better than a boring brush. URL_1 But the specific brush requires a clinical trial to prove it's better than anything else. You certainly FEEL better if you believe your toothbrush is better because it's expensive. Placebo effects on health are a real thing. But to control how much is placebo vs. how much is the toothbrush, we need studies. Here's a study that shows Sonicare is superior to Oral-B. URL_0 But personally, sure, maybe the fancy toothbrush vibrates harder at a higher frequency, but I'd question the value of $250 for slightly whiter teeth. If you think that's worth it, feel free to splurge.",
"Both my dental hygienist and dentist could tell I switched to a sonicare before I told them. They said it was the best they've ever seen my teeth (I've always had a lot of dental issues). It makes a HUGE difference. Edit: thought this was askreddit so I didn't actually explain anything. The biggest difference I've noticed between the cheap and expensive ones is the amount of work you have to do. Most cheap electric brushes are basically just manual brushes that vibrate, so you still have to brush the way you would with a manual brush. With the sonicare you just gently touch the bristles against your teeth and slowly move it around your mouth. It vibrates every 30 seconds to indicate when you should switch quadrants. After 3 months of using it I had the least amount plaque on my teeth for any dental checkup in my life, and after using it for 2 years, it's the first time I've gone more than 2 checkups without a cavity. It has literally saved me thousands of dollars at the dentist.",
"While I'm not sure about them cleaning objectively better the more expensive ones will have rechargable batteries, Bluetooth integration, and replaceable heads."
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7hrloh | Why aren't there veins in the meat we eat? | Other | explainlikeimfive | {
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"Well there are still veins in it, bit we try to remove them as much as possible. Soucre: work in grocery store meat department There are probably more steps that remove more veins before it gets to our department as well.",
"there are if you have the right cut of meat and you look for it. you just haven't been looking hard enough. most supermarket cuts are already trimmed, and veins and connective tissue are tossed out. small blood vessels are tough to pick out if they're only the size of a needle down to size of a hair. but if you buy a whole section of untrimmed meat, you'll very likely find veins. next time you buy a chicken drumstick, look for the major blood vessels"
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7hrp1m | what is it about meat going bad that means it can no longer be eaten after being cooked? Doesn't the heat just kill any bad bacteria? | Biology | explainlikeimfive | {
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"If you're having a difficult time wrapping your head around u/cdb03b or u/WRSaunders answers, try thinking about it more abstractly. We use water to \"kill\" fire. If a building catches on fire, we call the firemen. The fireman puts out the fire with water. The fireman/water does not also repair the damage already caused by the fire, it just kills the fire. The roof caved in and all the contents are utterly destroyed by the fire, but at least the fire is gone now.",
"Heat might kill the bacteria, but it doesn't remove the toxic byproducts that the bacteria produced before they got killed. Eating all that bacteria-poop is also bad for you.",
"The live bacteria are not always the threat. In fact more often it is the toxins they produce as a waste product and as they die that are the threat. Once a certain volume of these toxins has been reached the food is no longer safe to consume."
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7hrq9b | How can businesses immediately tell you that your card has been declined? Are all card readers connected to the internet and what is the universal network they’re all connected to? | Technology | explainlikeimfive | {
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"Yes, card readers communicate to the bank over the Internet to validate transactions in real-time. It used to be phone lines but today it's almost all IP in the US and Europe.",
"Yes. Credit cards and debti card machines, when they say \"Authorizing...\" they're phoning home to query if you have a balance large enough for what you are trying to buy. They don't phone YOUR bank directly, they're phoning through a network. Here in Canada its Interac, a big one in the US is the Plus network... there are most likely caching servers on their network that have just your balance and daily withdrawl limit saved. When your bank updates your balance, they probably send a new balance to the network. Theres intrabank networks in every country (because banking laws tend to be at the national level), but VISA and MasterCard run global networks.",
"Yes, they're all online. The card reader calls the credit card company's computer system with the card info and the amount to be charged, and the system says \"yes\" or \"no\" depending on various factors. If you don't have enough credit left or if the card is frozen, then the answer that comes back is \"no\" and the sale doesn't happen."
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7hrv5a | Why Does DNA Form A Helix? | Biology | explainlikeimfive | {
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"I don't know that this can be a \"why\" question. The chemistry of DNA gives a molecule that has a helix as it's lowest energy arrangement. Just like benzine makes a ring or water makes a Mickey Mouse Head.",
"It is all in the chemistry. The nucleobases (A,G,C,T) form the rungs of the ladder, to which they are bonded to the sugar-phosphate backbone (just a type of arrangement of molecules). That Sugar-phosphate backbone can participate in bonding to itself, which is due to how the atoms are oriented in the sugar-nucleobase structure. The bonds (sugar-phosphate adjacent-bonding) want to be close because the force of attraction between them is so great, that they have no other option than squeeze close together. Once you squeeze an oddly shaped ladder, it has 1 of 2 options... one is to helix, and the other is form a lumpy-helix-entangled mess. We know complexes (such as the sugar backbone) want to be at the lower energy state, and so a lumpy-helix-mess is not good for molecule kinetics. It chooses to be a tightly \"twisted\" ladder because that is the best orientation for its shape and the pressures administered onto it. I should add: The regular nature of the backbone and the shape of both the backbone contribute to the likelihood of spontaneous helix formation."
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7hs3zh | why does the heart never need rest? | Biology | explainlikeimfive | {
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"Your heart is made out of a different kind of muscle than the skeletal muscles in your body. Cardiac muscle, which the heart is made of, can work very hard for a very long time without getting broken down or tired out like the rest of your muscles. So why aren't all of our muscles built this way? Because the heart muscle needs a *huge* amount of energy and bloodflow to keep going, way more than the rest of your muscles. So while it can work for decades upon decades without ever stopping, it needs a constant flow of energy and nutrients to do that job. Another muscle like your biceps, for example, needs lots of energy while its doing work, but when resting doesn't actually need too much maintenance. So in that sense, they're much more efficient. If your entire body was made of cardiac muscle, you'd probably need an 8,000 calorie/day diet and a very high blood pressure to keep things going. The setup we have means that we can get tired, but we can survive with less food as long as our body can keep that heart going."
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7hsoji | How do goats have such good balance/fearlessness for jumping on precarious ledges? | Biology | explainlikeimfive | {
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"They evolved in a region that had that terrain and survival dictated that they become skilled at that type of thing or they would be eaten. Those that were not balanced fell and died and eventually those with the skills were the ones that reproduced and the entire population obtained the skills.",
"The interiors of their hooves are softer than the exteriors, creating a suction cup effect. Also, walking on 4 legs instead of 2 is more stable and lowers the center of gravity.",
"You have multiple levels of explanation for a question like this: What in the development of a goat makes it good at balancing/fearlessness? What mechanism gives the goat good balance/fearlessness? What evolutionary process led to goats having good balance/fearlessness? Why did evolution lead to that process? Since you didn't specify, I'll answer them all to the best of my ability: Development: Practice, familiarity, goats do it a lot so they get good at doing it. Go watch a video of kids playing, it's very cute. Mechanism: Goats likely have very good inner ears for balance as well as strong leg muscles for it. Evolutionary process: Goats that don't have good balance are more likely to fall down the hills and mountains they live on and so more likely to die and not have more kids."
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7hsugh | Why does it feel so much colder outside in humid climates versus dry climates? | Chemistry | explainlikeimfive | {
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"More humid air is better at retaining heat. It is denser than less humid air, and the water it is holding absorbs heat better than drier air. So as you stand outside, more of your heat is being absorbed by the more humid atmosphere than if you were in a drier climate."
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7hswo5 | When to use a Chi Square (Goodness of fit) test vs. Matched pair T-Test vs. normal T-test | I have a big exam tomorrow and I get how to do these tests, just not when to use one over the other. Thanks! | Mathematics | explainlikeimfive | {
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"So when you say normal t-test, that's pretty vague to be honest, since there are like, 3 different types or something around there A standard t-test is one which tests if a sample differs from a population: are the men from los Angeles taller than the average American male height, does Mr. Thompson's algebra class have an average grade lower than the school average, etc. It tests whether a sample is likely to be part of a larger population A 2-sample independent t-test tests whether two distinct populations are statistically different: the weight of Latino men Vs the weight of Asian men, the proportion of stomach cancer in Japanese people in Hawaii Vs Japanese people in Japan, etc. A 2-sample paired t-test tests whether two data points from the same sample are statistically different: the amount of cholesterol in your body before and after you ate, your weight when you woke up vs when you're going to sleep, etc. A chi-square test for goodness of fit is used to determine whether your sample data fits the expected population. It can be thought of as an extension of the one sample t-test with respect to proportions, but it can applied to data sets when you have more than one sample proportion of interest (more than 2 categories): rolling a 6-sided die to see if it's fair"
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7ht50e | What's freight forwarding | Economics | explainlikeimfive | {
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"Freight forwarders are middle men who specialize in getting goods to destinations. Lets say that you area woodworker and you get an order for a complete, 16 seat dining room table and chairs from someone in China. You want to take the job, but you have no idea how to get that material to China when you are done - its not like you can just drop it off at a UPS box. You could contract with a freight forwarder who, for a fee, will organize the logistics of getting the goods from you to the recipient in China so you don't have to worry about it."
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7ht8n2 | How was the Playstation 3 able to perform so well with only 256MB of RAM? | The PS3 and the Xbox 360 were able to run games like GTA V and only had 256MB and 512MB of RAM, while on PC the minimum requirements are 4 GB of RAM. | Technology | explainlikeimfive | {
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"PC run Windows OS that multipurpose generic OS that will consume 2+ GB of RAM on it's own plus there is other software running at the same time so with 4GB of there is not even 2GB left for the game. The game on console can be fine tuned to specific configuration of the console. On PC it must be prepared to work with different configurations. PS3 has lower details. The thing about computational complexity (how it is hard to compute something) doesn't have to be linear."
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7htcpn | Project Stages for beginners (Initiation, Discovery, Design, Build, Test, Sign Off, Warranty). | I need to present this to some people who have never come across project management principles before, and while I know it, I'm really struggling to break it down. | Other | explainlikeimfive | {
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"Initiation - Let's build a truck (or whatever thing) Discovery - What should it do, what's needed or wanted Design - Here's how we should make it Build - Make it Test - Does it work as intended? Sign Off - Customer agrees it works and it's done Warranty - Fix anything that doesn't work later"
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7htdsd | Why do certain sounds ‘go through’ us? | Why do sounds like a knife on a plate go through some people and not others, and why do sounds go through us in the first place? | Physics | explainlikeimfive | {
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"This is physiology, not physics. Those sounds you mention have a similar spectrum to baby's cries, and our brains and ears have evolved to be tuned to those sounds and to produce a response."
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7hte80 | Why is it that so many of us humans have this fascination for violence (at least to some extent) even when we may deem it unethical? | Other | explainlikeimfive | {
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"We're an inherently violent species. Historically humans hunted animals for their food, and fought other humans for access to resources (like food, space, mates, water supplies, shelter).",
"Because humans evolved as omnivores and during long periods of tribal warfare. We have an instinct for violence, even social violence. We understand violence on an instinctual level because we had to beat things to death to eat them. We can distance ourselves from the act of killing because it filled our ancestor's bellies. If we couldn't we wouldn't be here - or at least we wouldn't be able to eat meat because we'd have evolved into pure herbivores. For social violence it's the same way a wolf pack leader keeps the wolves in line - mild violence with the threat of death. A lot of people feel good on a very basic level when someone they deem 'bad' gets hurt. Little kids learn very quickly that lashing out in anger gets some kind of result. It takes decades to train the violence out of a person - and half of them still support the death penalty and prison rape. People enjoy 'combat sports' because they like to see 'their guy' beat the shit out of 'the other guy' or 'the outsider'. This is a very tribal instinct - you want to see your team win, your champion win, and watching them beat the shit out of someone makes you feel better for your team because you're obviously winning.",
"If it weren't attractive, we wouldn't need to consider it immoral. Violence, aggression and dominance are all wired into the human psyche; we're primates after all. And fantasizing about committing acts of violence is always going to hold a certain fascination. The fact that we suppress or sublime those impulses for the sake of a better big-picture outcome doesn't contradict that, any more than enjoying the sight of rich food despite being on a diet."
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7htgfw | How does the genotyping process that 23andMe use work? | I was considering trying out 23andMe but would love to have a simple explanation to start me off. Thanks! | Biology | explainlikeimfive | {
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"Check out Smarter Every Day's video for a behind the scenes at the factory with loads of useful info: URL_0",
"[SmarterEveryDay did an episode on this]( URL_0 ) when 23andme wanted to sponsor an episode. TL;DW Genotyping looks for the presence of specific genes using a gene sequence probe. However, genotyping is also dependent on the accuracy and fullness of the non-biological information provided by the respondents.",
"23andMe uses a type of sequencing called [SNP genotyping]( URL_0 ) to look for general trends in your genome that indicate genetic history. It relies of the concept of SNPs (Single Nucleotide Polymorphisms), which are single positions in the genome that tend to vary between populations. Picture a double-stranded molecule of DNA. Unwind it, and you end up with what basically looks like a ladder. You can then assign every base pair (\"rung\" of the ladder) a number, from one to ~6.2 billion, moving from one end of the molecule to another. The very first base is position one, the next is two, and so on. Each position can be one of the four bases (A,T,C, or G). As it turns out, there are certain positions in the genome (based on the numbered order) that stay relatively constant between people that are more evolutionarily similar, and vary between other populations. For example (and I'm just making all of these up to illustrate) let's say that at the 512,431st position in the genome most people from Eastern Europe have an A, the Middle East have a C, South America a T, and North Africa a G in that position. If I know which of the four bases is in your genome, I can compare it to a library that tells me which populations have that same base pair. Multiply that by ~~thousands~~ (Edit: about 600,000 SNPs for 23andMe) of these SNPs throughout the genome and you can get a fairly accurate sense of someone's ancestry without having to sequence and compare the entire genome."
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7htgse | Symmetry makes a face pretty, what makes a voice pretty? | Biology | explainlikeimfive | {
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"Timbre(pronounced Tamber). It's the property that give non-pure tones, such as human voice, its unique character with harmonic overtones and undertones. Most everyone can say or sing in the same frequencies, but they'll all sound different due to physical differences and techniques. Those differences give timbre to the sound. Because the human brain is very good at picking up patterns, it finds harmonious sound(has distinct patterns in multiples of frequencies) pleasing compared to dissonant sounds(the frequency patterns that sound 'off') in a similar way that brain prefers symmetrical facial features to a facial feature that looks 'off'. On the side note, preference to symmetrical face is also due to correlation between genetic abnormality and/or upbringing environment and face symmetry, which has some influence in attracting mates. Preference in certain vocal qualitities may also be related to that."
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7htm09 | why do distant objects appear greyish blue? | Biology | explainlikeimfive | {
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"When objects are far enough away, the same light scattering effect that makes the sky a hazy blue starts making the air between you and the distant object look hazy blue too. This occurs because some of the air molecules in Earth's atmosphere are just the right size to preferentially deflect blue light but pass all the others. The effect is slight, so you typically don't notice it unless it's compounded over hundreds or thousands of meters."
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7hto3k | how can animals know when something is edible and when is not | Biology | explainlikeimfive | {
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"The answer varies depending on which animals we are talking about. Mammals learn what to hunt and eat and what to fear from their parents. A baby gorilla will learn what is safe and good to eat the same way you did. It's mother will eat the plant and hand some to the baby. Whether you are a panda or a hedgehog this is basically the process, learning from your parents how to live, until they become adults and may sample new foods if they smell good, your nose is a tool that for the past billion years or so has evolved to allowed you to identify thousands of chemicals in an effort to keep you alive, it is decent at identifying things that you shouldn't eat. The smell of rotting meat makes you gag to get you to remove any rotten meat you might have accidentally eaten from your stomach. However for other creatures without parental care it is all instinctual, a rattle snake will strike at a mouse pretty much from birth it is hardwired with the knowledge that small warm bodied fuzzy creatures that smell like rodents are food. Some, like a jellyfish, just get lucky they make no effort to avoid predators or find food it is a floating trap and some certainly die from catching the [wrong creature]( URL_0 ) in their tentacles.",
"Actually.. they don't. People use to use dogs to test which mushrooms were poisonous. They would feed them to a dog. If the dog died, they were poisonous. Lots of pet owners have pets die every year because they eat poisonous plants. Dogs mostly, but horses, cattle, and sheep too. It's mostly plants that can be poisonous (not talking about when a person intentionally poisons something to kill an animal).. so the animals that eat plants are the ones most likely to eat something poisonous and die from it. I just read about a girl who had 4 horses die from eating Lychee nuts. She had moved to a farm this spring and had no idea they were poisonous, one after an other her horses started dying. The necropsy (autopsy for animals) indicated that this was likely the cause. Box Elder is also poisonous for horses. In some cases though the poisonous plants taste nasty, bitter, so the animals might nibble them and not like them so they don't eat enough to be killed."
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7htp6k | Why are spray deodorants or any spray cold and not room temperature? | Physics | explainlikeimfive | {
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"A few reasons. First of all, what we *perceive* as being hot/cold is not really about temperature--it's about the *transfer* of energy. When you wake up on a winter morning and step from your carpeted living room to the cold tile of your kitchen floor, the tile isn't any colder than the carpet--it's just better at conducting your warm body heat out from under your feet. Deodorant cans are metal and are better conductors than plastic rub on deodorants. Secondly, the deodorant spray (and can) cools as you release the deodorant. As the spray expands outside of the container, it loses energy as energy is required to expand the volume of the material. The temperature of an object is really just the average of the kinetic energy of its molecules. Conversely, if you were able to recapture all the gas of the propellant used in the spray can and force it into a tiny space, it would heat up--the energy it gains comes from the energy you put in to compress it back into a tiny space.",
"The content in the bottle is under a lot of presure. When you free up some air, you release pressure and this also drops the temperature following the PV=NRT rule Pressure and volume =(quantity of molexule), designated constant for the molecule and temperature."
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7hu6wt | the difference between terrestrial molloscs and crustaceans respiratory systems compared to their ocean dwelling counter parts. | Biology | explainlikeimfive | {
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"No ones answered so ill try to explain. Crustaceans are all arthropods which originated from the sea, and different arthropods devealoped different ways of breathing air. Insects dont have blood or veins like you would think of them, the absorb oxygen directly and it diffuses into their body without any imput from them, insects are small because this method can only keep up with a small surfacearea/volume ratio, and tissue far from the exoskeleton. Insects used to be very large before widespread nonaquatic fauna because the oxygen content in the air was so high. Crustations deal with these size limitations by having modified gills, normal gills need water flowing through them to open up and collect oxygen, and without water their gills will stay closed and be unable to have air pass through them. One method is to have slight webbing in the gill tissue which keep the gills open in the air, which they have been modified to \"breath\". The other method is keeping many small gills and lungs which will not close so easily. I hope that helps"
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7hugho | How do erasable pens work? | Chemistry | explainlikeimfive | {
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"text": [
"The ink doesn't \"disintegrate\" the ink but the heat from friction actually changes the chemical composition of the ink to make it transparent. Try erasing the ink first, then put it back in the freezer overnight - this will make the ink visible again (bit faded though), as the composition returns back to its original colour. Look up thermochromism on wikipedia. Mood rings use the same principal."
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7hujic | How does a sexual assault case proceed in court? With all of the "he-said," "she-said" how do they get to the bottom of the incident, both on the prosecution and defense side? | Other | explainlikeimfive | {
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"Generally, if the *only* evidence of a case is 'he said, she said', it doesn't get to court. The vast majority of sexual assault cases never go to court exactly because proving them is so incredibly hard. Beyond that, a sexual assault case can use any sort of evidence another case uses. Witness testimony, people testifying about what people have said to them about the incident (was there any bragging), DNA evidence if someone completely denies the sexual contact (important in case where the sex couldn't be consensual), any video/photographic evidence, text evidence, stuff like defensive wounds etc."
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7huxgb | Given the brutality of World War 2, how have relations between the major Allied and Axis powers continued to be so positive? Why are the alliances between the U.S. and Japan/Germany, in particular, so strong? What was different about WW2 from other wars that prevented ongoing tension/conflict? | Other | explainlikeimfive | {
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"It wasn't the war, it was the recovery. The Allied powers knew that the harsh reparations leveled on Germany after WW1 had *directly* lead to WW2. They were much softer with reparations and lead a significant rebuilding effort in the Axis countries after the war to ensure they got back on their feet with fewer hard feelings than last time around. Japan was also pretty well stripped of their military and told they had to focus economically and were given a ton of help to do so. This meant that any resentment that there may be wouldn't materialize as war again, though Japan's stance on the events of WW2 is still a bit ... *odd*",
"The post-World War 2 political environment encouraged the United States (and other allies, more reluctantly) to focus on reconstruction of the other Axis powers. For example, during the war, many American policymakers had planned to dismantle much of German industry. But shortly thereafter the U.S. pushed for the quick establishment and rearmament of a new German state out of the occupation zones in western Germany to counter Soviet influence in eastern Germany. West Germany joined organizations like the European Community for Coal and Steel and NATO and so became a more-or-less equal partner in Europe. Japan played a similar role in East Asia. China and Korea were both at danger of falling to Communist revolution; the U.S. occupied the Japanese home islands and preferred them to be a bulwark of stability. Like Germany's joining of NATO, treaties were signed with the reformed Japanese government that made it a useful tool to serve American interests. It helps to keep in mind that many of the sources of tension that led to World War 2 did not survive the war. In Europe, an ethnic cleansing occurred that saw most German minorities outside the present borders of Germany expelled. Japan lost its colonial possessions and its military was reduced to a size where it could not seriously influence politics, while a democratic constitution was imposed (retaining the monarchy only symbolically) that was very popular."
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7huyee | How does “I want my lawyer” work when being interrogated? | Other | explainlikeimfive | {
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"In the US, the right to remain silent and a request for a lawyer usually go hand and hand. You are basically saying, \"I'm not talking anymore, move on to the next step or release me. If you are arrested, you are either released after the arrest, or a bond is set. You don't need a lawyer for either of those things, although a lawyer could argue for reduction or elimination of bail. They can also persuade the police to not charge you. If your timing is bad, you can wind up spending a night or two in jail, but that is more about waiting for a judge to set bail than finding a lawyer. The lawyer comes into play when: * you want to talk to the police, but be protected from yourself * you want to negotiate with the district attorney * you are on trial"
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7hvh9r | What are the similarites and differences of the various rates dV/dr, dV/dh, dr/dV, dr/dh, dh/dV, dh/dr, dV/dt, dh/dt, dr/dt? | Im currently taking calculus but i don't understand the notation. V means volume and r is radius. The best i know is that they are rates in respect to time but i do not fully grasp the concept. Edit: Thanks for helping! I have a fairly good understanding now! | Mathematics | explainlikeimfive | {
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"It’s just notationnn Okay, so just think of “d” as meaning “really small change in” (infinitely small). So, remember how y=f(x) (technically, f is a function of x and y is f(x). y(x) is when y is a function of x but whatever)? This means *y is a function of x* meaning that it acts on only x The slope of two points on this function is given by: The *change in* y/ the *change in* x Or... delta y/delta x Now... let’s make that change infinitely small. So remember how “d” was infinitely small? The slope now becomes: dy/dx That’s derivative notation, it means infinitely small change in y over infinitely small change in x... or, take the derivative of the function y with respect to x and treat all other variables as constants, OR find the instantaneous slope of y which is a *function of x*, it ONLY acts on x so you regard everything else as a constant because they are not changing from y. Like, y doesn’t do anything to them (later if you do multi variable calc, you’ll see y(x,z) which now shows y as acting on both x and z) So if you have dV/dr, or V’(r), take the derivative of the volume function with respect to the radius and treat all other variables like constants. dV/dh, take the derivative of volume with respect to height. dCupcake/dLove, take the derivative of cupcakes with respect to love because cupcakes only act on love (¿¿ this was unintentionally deep) And so on I hope I helped! :) Edit: and all the examples I gave are not rates with respect to time. dV/dt is a rare with respect to time. dC/dt, dr/dt, these are rates with respect to time... notice a similarity?",
"The d notations say how fast the top thing is changing when the bottom thing is changing. So dV/dt is how fast the volume changes when you change the time. dV/dr is how fast the volume changes when you change the radius. Just apply this to any notation like this and it gives a general idea of what it means."
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7hvj8u | What is the point of having a spoiler on a car? | Physics | explainlikeimfive | {
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"text": [
"The primary reason is to spoil unfavorable airflow that contributes to the drag force on your vehicle, thus improving fuel economy and performance. They also have aesthetic appeal."
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7hvvsy | Why is it that we can transmit sight and sound over the Internet but not smell, taste, or touch? | Technology | explainlikeimfive | {
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"Sight and sound are senses designed to detect waves of energy coming from far away. Smell and taste only detect real molecules that actually *get into your head,* nothing remote about that. Touch could be simulated, and there are some prototype devices that do it.",
"Sound is really simple. Air vibrates with a certain simple one dimensional wave, it simply goes up and down in pressure over time. This is sound. We simply record the pressure at a very fast interval. We then send it as a string of numbers. On the other end we have a variable voltage source match these values, it drives an electromagnet near a diaphragm with a magnet on it (aka speaker), the diagram vibrates just like the original air, it pushes the air to vibrate with it. If you want to get complex, you can have a left and right channel, or even more, but it's still just a string of numbers. In short, audio is just a string of numbers telling you the air pressure at time intervals, and that's all sound is. Sight is slightly more complex. We take a grid of light sensor, each sensor records the intensity of the light falling on it, and we record this as numbers. This means we have a number for each sensor (aka pixel). That only gets us a single still image though. We then repeat these light intensity measurements at a certain time interval (aka frame rate) and we get a video. We send this much large string of numbers over the internet. And on the other end, we simply use these intensity values to adjust the brightness of a bunch of small light arranged in a grid again. If you want to get fancy, you record the light intensity of red, green, and blue seperately, and you get colour video. In short, video is just a string of numbers for mutiple locations telling you the light intensity at time intervals, and that's all sight is. Touch we can and do transmit. Ever used a videogames controller? That rumbling, that's touch transmitted over the internet if your playing an online game. Same goes for the vibrate on your phone. We could go more complex, but you'd need a masisve full body suite that can apply pressure and temperature all over you body. You really could make this suit and transit a string of numbers for pressure and temperature on every inch of your body over the intenet. It's not really an internet limitation, just a cost and practicality issue on the receiving end to reproduce it. Smell and taste are pretty much the same thing. A chemical that our body reacts to a gives a sence. So while we could easily transmit a string of numbers coded for chemicals over the internet, how would you get the chemicals on the other end? Well, you could make a machine with a large amount of the chemicals you can smell/taste and have them emitted on command. Again, it's not really an internet limitation, just a cost and practicality issue on the receiving end to reproduce it. We do crappy job of transmitting smell with \"scratch and sniff\" paper, you could easily do basically the same thing over the internet. Have a robot taking commands over the internet scratch the right one. That's (very limited) smell over the internet I guess. That said, if we could interface with our nervous system, that is fake senses with electrical impulses our nerves could read, then we could send whatever sence we wanted over the internet. However, we don't understand our nervous system well enough to do that. So for now, transmitting senses means you need to actually recreate the physical condition on the other end. Moving air or turning on some coloured light bulbs is easy. Actually touching and warming or cooling every inch of someone's body is not. Nor is releasing a plethora of chemicals from a vast storage vault of all possible smells/tastes on demand into a room or someone's mouth. TL;DR:. We could easily send a list of chemicals over the internet (smell/taste) or a list of temperatures/pressures and locations (touch) over the internet. It's really not that much harder than a list of air pressure (sound) or light intensity and location (sight). The issue isn't transmitting over internet, it's recreating them on the other end."
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7hw838 | Why does chronic inflammation, such as in IBD, cause tissue damage? | Biology | explainlikeimfive | {
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"Think of chronic imflammation as a war situation. And you are trying to grow and harvest crops when there is an ongoing war over the soil (tissues). There is constantly bombs and fire going on (the citokines), as well as soldiers(neurophiles) fighting each other and dead bodies all over the place (neutrophiles and other dead cells). The tissue needs to remove dead cells via grinders(macrophages) and the soil is not getting the necessary nutrients or any fertilizer (blood flow and oxygen) while all these events are happening. Because of all these factors, the soil gets damaged over time, until the war is gone. Also the soil has its own limits too. after a certain time, if the inflammation takes too long, it doesnt recover to its full potential or may even become barren.",
"Chronic inflammation is related to tissue damage in two main ways. 1. The inflammation can be a result of tissue damage itself. That is to say that tissue damage actually calls the body's 'defence and repair' system to action. One of the ways the body repairs itself is through launching an inflammatory response. 2. When the body's 'defence and repair' system gets too active, like in IBD, the continuous inflammation can lead to further tissue damage. This is due to a whole heap of different mechanisms that all play a small role in damaging tissues. Immune cells \"white blood cells\" can have trouble telling healthy tissue apart from sick tissue and so some healthy tissue can be caught up in the clean up. 3. When healthy cells get killed they tell the body's 'defence and repair' system to try fight whatever is causing the damage thus causing further inflammation. So in illnesses like IBD the cycle of inflammation causes healthy cells to be caught up in the cross fire, which leads to more inflammation, which leads to more healthy cells being caught up in the cross fire and so on and so forth. Thats why when we treat illnesses like IBD we use medicine that makes the immune system stop being so active which gives healthy cells a chance to recoup. Source: final year medstudent.",
"This might be not 5 year old level. Sorry. Chronic inflammation refers to process where you have all stages of inflammation and repair happening at the same time for an extended period. The short answer is the tissue damage comes from the whatever caused the initial injury or insult and then keeps occurring due to the body trying to repair itself. You have areas that have just been damaged recruiting signaling cells to increase blood flow and bring in the troops. These troops destroy damaged cells so they can be replaced by other cells later. Tissue damage You have areas undergoing various stages of proliferation and resolution in an attempt to repair older injuries. Like any fresh injury this area is at increased risk of damage and this a return to acute inflammation. Tissue damage And then you have areas that have been repaired previously. Usually less organised repair because rhe body is doing this stuff on the fly. So you'll get some scar tissue and the it won't work as well as before. And you guessed it it is easier to damage in the future. Especially if there is active inflammation going on right next to it. Tissue damage. The original insult can be many things or anything. In your example, IBD, I am taking this as inflammatory bowel disease. So Chrons or UC. These 2 diseases are autoimmune in nature (at best guess and with caveats that most diseases are multifactorial) so the body starts attacking itself thinking it is foreign matter. This starts the inflammation process which then becomes chronic if not treated adequately."
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7hwe6p | how does the 3DS's 3D work? | Technology | explainlikeimfive | {
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"Your brain sees 3D normally by combining the separate pictures it gets from each of your eyes. The basic idea behind 3D graphics is to display two different images, one in each eye. If you make the two images slightly different, then the brain interprets them in the same way as your normal sight, and makes them look 3D. With 3D movies, this is done by displaying two pictures interlaced with each other so that every alternate line on the screen is a different picture and using polarised light. When you put on the glasses, the polarised lenses cancel out one of the images in one eye, so your brain gets two different pictures and makes them 3D. With the 3DS, the two images are displayed in interlaced vertical lines, and then to make sure that each eye sees a different picture, the 3DS has tiny walls that block your left eye seeing the right eye's pictures and vice versa. This diagram shows how that works: URL_0 As you move the 3D slider, the images separate or overlap more, and the walls become opaque or transparent."
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7hwizm | how does "mind uploading" qualify as a valid form of life extension? Wouldn't it simply be a digital copy of yourself, and not a continuation of your original existence? | Technology | explainlikeimfive | {
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"Any form of “life extension” that breaks continuity of self is a complicated subject, as the extension only applies to the new continuity and is broken for the old one. It’s a matter of personal opinion. Going to sleep and waking up does not break continuity of self, nor does general anaesthetic. However, if you made a perfect copy of yourself and then killed your original self, continuity would be broken. The 2015 video game SOMA is a fun game that focuses on this subject, too."
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7hwqva | why do people tell you not to "lock your knees" when standing for a long time and what does it mean? | Biology | explainlikeimfive | {
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"Stand up and bend your knees slightly. Then slowly straighten them out to their full extension. You’ll feel your joint settle into place once your knees are fully straight and your knees will stay straight without as much work from your muscles. That’s locking your knees. The problem is that it isn’t particularly good for your circulation. If your knees are locked for an extended period of time, then you can get blood pooling in your legs, depriving your brain of blood. The solution is to stand with your knees not locked. That is, hold your knees ever so slightly forward. That engages your muscles ever so slightly and helps get your blood moving. The moving blood won’t feel like anything, but that’s because now your circulation is normal, versus restricted.",
"Even while you stand perfectly still, you brain still automatically coordinates micro movements to keep equilibrium and posture. By locking your knees, you put your legs into a more stable position that needs less micro-movements to stay in place, so it feels more confortable because your muscles are effectively working less. However, blood in the leg veins has to flow against gravity and can't count on blood pressure from the heart like the arteries do (it would make capillaries burst), so it solves this issue by having one-way valves that stop the blood from going backwards and relies on various means to push the blood upwards, the main of them is the contraction of the surrouding muscles which squeeze the veins, since valves stop blood in one directio, this makes it go upwards. If you reduce how much your muscles contract, you also make harder for blood to return to the heart, which makes you leg feel numb after a while. If others bad conditions are present you can faint too."
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7hwyeu | Negative effects on children from a gluten and dairy free diet? | Are there any positives? Is there such a thing as a leaky gut? | Biology | explainlikeimfive | {
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"No diet is harmful so long as you get all the nutrients you need. If, starting from a balanced diet, you reduce your dairy intake, you'll have to compensate for the reduced intake of macronutrients like carbs, fats and proteins, and micronutrients like calcium and vitamins B2 and B12. You'll also have to get some of your fluids from elsewhere. None of these nutrients are particularly hard to replace though. The same goes for gluten, which itself isn't a nutrient that your body specifically needs. It is found of course in many baked goods and other products made with grains like wheat, barley, rye or oat. So with gluten you're cutting out a more diverse selection of foods and its harder to give a specific answer. But there are lots of gluten-free alternatives these days to replace those foods with, and afaik there isn't any specific food with gluten in it that contains nutrients that can't be found anywhere else. As for positives, people who are lactose intolerant will obviously benefit from cutting down on dairy. Those who have celiac disease need to follow a strict gluten-free diet because gluten damages their gut. There is also evidence for a condition known as \"non-celiac gluten sensitivity\". People who have this get symptoms similar to irritable bowel syndrome when they consume gluten, but to them gluten isn't nearly as harmful as to people who have celiac disease, and there is no medical need to abstain from gluten entirely. Also the diagnosis isn't very clear because it's based purely on symptoms correlating with gluten intake, and some people may be misdiagnosed who actually have a wheat allergy or sensitivity to other things in grains. And there also seems to be a bit of a \"fad-component\" to it with lots of people self-diagnosing a gluten-sensitivity based on tenuous evidence, because it's something they've heard about that can explain a variety of symptoms. There appears to be no good evidence for the condition known as \"leaky gut syndrome\"."
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7hwyla | How does a computer unset a bit (set it from 1 to 0) in memory/storage? | Technology | explainlikeimfive | {
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"It depends on the particular kind of storage. In magnetic storage, like a spinning-disk hard drive, it magnetizes the region storing the bit in the opposite direction. (In practice, hard drives write entire blocks at a time, but the technology could theoretically be managed a bit at a time.) In typical flash storage, like in solid-state drives or external flash drives, it can't write a single bit at a time. In order to change a bit from a 1 to a 0, it erases an entire block of memory, then rewrites the new data into it. In DRAM, which is the typical kind of RAM in a computer, it connects the capacitor holding the bit to a current drain, which allows it to discharge. (Similarly to others, standard DRAM actually can only write a whole line at a time, so switching a single bit means writing the previous value into all the other bits.) In SRAM, which is typically used for things like on-CPU caches, the bit line is set to 0 and then the write line is set to 1. The transistors switch into the alternative configuration, and then the write line is set back to 0, which causes them to maintain their current configuration until written again.",
"Depends on the method of storage. Hard drives are known as magnetic memory. They consist of large plates that have tiny tiny sections which can be individually magnetized by something called the \"drive head.\" It is magnetized similarly to how a nail is magnetized when you rub a magnet against it, though this process may also demagnetize it if done correctly. Reading it is simple, as the drive head flies over the magnetic section, the moving magnet generates an electric current in the drive head, which is transmitted to the computer itself. If magnetic then 1, if not then 0. RAM is a different story. Hard drives are slow so RAM exists as a fast cache that is used because the CPU needs fast memory to do its thing. So RAM exists for this purpose. At its simplest, it uses capacitors. These are kinda like rechargeable batteries with a few main differences, they are fast, can't hold much, and can't hold for long. Here, it is pretty simple to do. Charge in capacitor = 1, no charge = 0. The interesting thing is the convoluted setup this requires. Capacitors must be discharged to be read, so reading requires discharging it then reloading the capacitor. Capacitors also can't hold charge for more than a few milliseconds at best when disconnected from a power source, so every few nanoseconds, the machinery reads the bit and recharges the capacitor if it is a 1. Lastly is flash storage, something that uses something called a floating gate transistor. A transistor is an electronic switch in most cases, it isn't meant to be as a form of storage of charge, but we found some witchcraft that no one knows how works where we can store electric charge in a transistor for mostly indefinite time. This too requires discharging to read but once again a similar strategy is used here. This is used in SSDs, flash drives, and other \"flash storage.\""
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7hwze8 | Does low temperature really make us ill and if so - why and how? | Biology | explainlikeimfive | {
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"No, you must have the germ to become ill. However, viruses—like those that cause flu—travel in liquid particles, which survive better in dry, cold climates, the authors theorize. This type of air absorbs extra moisture, leaving the particles light enough to stay airborne. That means they’re more accessible for someone else to breathe in—and catch something from. The cold, dry air also increases mucus secretions in even healthy individuals, but if they become sick, you could say the cold makes the spread easier due to increased secretion.",
"Low temperatures reduce or nullify the action of the immune system, leaving bacterias and virus with more time to do their work without being bothered. Edit: low temperatures also make you stay indoors more often, so the contact with other people with some nasty organisms increases, leaving you vulnerable to get some contagious disease.",
"If you're speaking of \"flu-season\" or the like, it isn't the temperature that makes us sick. The cold actually weakens our immune system making us more prone to acquiring a virus."
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7hwzid | Why is it "healthier" to drink room temperature water than cold water? | Biology | explainlikeimfive | {
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"It's not healthier. It was thought that cold water would cool down the stomach, and disrupt whatever digestive processes were going on there. However, a half pound of water wrapped in a hundred pounds of warmer (mainly) water won't stay cool long enough to make a difference.",
"As far as I know, it isn't healthier. Drinking cold water is speculated to increase metabolism as your body has to work to lower the temperature of the water or your body. Similar to the idea that being cold is better for metabolism in general.",
"It's not a fact. It's also not a fact that walking barefoot on cold floors will make you sick. It's just an uncomfortable chill. Avoid too many extremes, however: Too much very cold water or too much time on very cold floors isn't going to have a positive effect. But within usual ranges, there is no effect.",
"Not \"healthier,\" but for singers warm water is preferred as your vocal cords contract/shrink when you hit them with cold water.",
"I always learned the opposite. That you're only supposed to drink cold water because otherwise there was a bigger risk of particles being carried over from old pipings. I dunno about that, but I do know that cold water always tasted way better than any other temperature of water anyway. 😋",
"It's not. Your body warms up the water as it processes it, consuming a few calories. This is the only possible way someone could think it's less healthy; just by considering calories burned to also mean unhealthy, which is stupid. Where did you even hear this?",
"In the military I was told that drinking room temperature water is in many cases better than cold water (outside, in the field, etc.). Your body don't \"waste\" its energy on warming up the water you put in your belly. Instead this energy is better spent elsewhere."
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7hx4mi | If sucralose contains no calories and causes no tooth decay, why are we still using regular sugar? | If we replaced all regular sugar with sucralose, it would help fight obesity, plus it's safe for diabetics. It seems great to me. So why is regular sugar still a thing? | Chemistry | explainlikeimfive | {
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"It doesn't actually taste like sugar or have the same mouthfeel. People like sugar because it's sugar. No known sugar substitute effectively replaces sugar. They might be sweet but none of them are perfect substitutes. It might be better than other sweeteners but it is definitely not a 100% replacement - try a soda with sucralose to understand for yourself. Honestly, the best replacements involve *reducing* sugar and uses non-nutritive substitutes to balance it out. It's way more satisfying to have 30% of the calories than 0% with a fake sugar."
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7hx6k1 | when lightning hits the sea, why doesn’t everyone and anything gets electrocuted since water is a conductor? | Physics | explainlikeimfive | {
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"The voltage lowers with distance. Therefore only everything in the area where the lightning hit gets electrocuted."
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7hxed6 | Why do we hear a weird high-pitched noise when there’s silence? | Biology | explainlikeimfive | {
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"That subtle low volume sound is always there. It’s called tinnitus and most of the time it is masked by ambient sound. Unfortunately as we age it becomes more noticeable and can be quite annoying to older people.",
"Follow up ELI5: Why are my ears popping/crinkling when I swallow? Edit: I mean every time I swallow it happens. Started happening about a month ago when I was listening to metal while sick (might have to do with it but likely not the sick part)",
"From what I understand these hair follicles are very sensitive to the vibrations and pressure changes which will later be translated into sounds. Tinnitus is just a symptom of a condition in which these follicles or the circulatory system have been damaged. That ringing that dies out is these follicles being unable to translate specific frequencies because of the damage. As we get older we wont be able to hear frequencies other younger people can (Adults can hear 0.02 khz - 16khz).",
"tinnitus source: spend a few years in the military specifically listening for high-pitched noises",
"Are there actually people out there somewhere who don’t hear even a slight high-pitched noise when there is silence? I think I have always had a very quiet high-pitced noise when I’m in a silent room, and I have always assumed that everyone has that noise in some degree, and that hearing damage tinnitus is just a lot worse version of it.",
"So I have another idea - dehydration. I have suffered from the same low level high pitched noise on and off most of my life. You can only really hear it when your in a quiet room etc and its a high pitched barely audible whine. I noticed that it comes and goes and during the summer where i graft outdoors and it got even worse to the point it was starting to piss me off. So i started tracking when it got really bad and what i noticed was it was absent in the morning when i woke up but within about 10-20 mins of being upright, it would start whistling. I also noticed it would come on louder after eating or drinking certain foods. Tea and porridge are two main offenders and pretty much within 5-10 mins of consuming both, the whistling would start. So putting it together I thought about how the fluids in my body changed with angle etc and noticed that the amount of water in my body directly affected the noise. If i had a pint of water before i went to bed at night (and didn't piss myself lol) I could get relief for most of the following day. As soon as I introduced a desiccant into my system, or exerted myself it would start again. Same with stopping drinking water - the noise returned. The conclusion i came to was that my body is like a sponge and the hairs in my ears were not floating as they should be, but are instead lying on their sides because the auditory canal or whatever you call it isn't submerged as it should be. In order to get that ear canal fully saturated and working I had to drink water then get horizontal in order to allow the water to \"osmosis\" all the way up to my ears. Keeping those hairs floating is a real problem. I have to drink a lot of water. But doing so cures my ear whistling. I have tested this several times and it works 100%. It's like my body is telling me it needs re-hydrated. TL/DR Drink more water then have a sleep",
"Follow up ELI5: why do we hear that random loud ringing in our ears ? I heard that it’s our brains primitive response to alerting us of danger in our surroundings—I.e,. It’s our cue to pay attention at the moment. What truth is there to this and can someone explain it for me? Also, sorry to hear about your hearing issues OP",
"URL_0 I was taught about 50hz Hum years ago, could it also be that? Background noise from appliances",
"Really regret not taking better care of my ears but I was uneducated about tinnitus and NIHL and didn’t know any better. I went to a few concerts without earplugs and used to listen to music on those Apple EarPods above 60% on the slider on a daily basis. Only thing I can do now is protect what’s left and spread the message to people who don’t know.",
"Great. This post made me think of my tinnitus... which makes me notice it more, which makes the ringing that much louder now that I’m thinking about it.",
"The ringing could be temporary tinnitus. The ringing is the ear's natural method of desensitization in the presence of constant noise. Mechanisms of desensitization are ubiquitous in biological systems that aim for homeostasis and equilibrium. If you were just in a bright room and went to a dark room, you would see a bit of glow. Similarly, if you went from a noisy environment to a silent one, you would hear some background ringing. But you would find that as the silence persists, the ringing would eventually drop down.",
"Yeah same here, mild tinnitus (sp?) from 10 years ago. Sometimes it seems worse because I use ear plugs at work and this makes it much more noticeable while the ear plugs are in. If only I'd used ear plugs in the past...",
"Have you ever noticed when your headphones or speakers are turned up all the way, but the device isn't playing anything, there's a kind of staticky background noise? It's the interference between the sound chip and the other parts of the device (with some background radiation). What you are describing is the same thing, but on the level of *The Matrix.*",
"When it is silent your ears might not like it and they make a sound to compensate for the lost sense"
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7hxgnk | How android is still controlled by Google though it is an open source project | Other | explainlikeimfive | {
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"They can release it in the sense that it would be available on their own website but they don't have the ability to push an update to peoples phones. I can tell you in great detail about all the objects in my house and their location but even with that information you can't change my house layout without my key to get into my house. You're free to go away and build your own house and have it match my house identically and maybe even change it to how you like but again I can't change your house without having the key to get inside.",
"> How android is still controlled by Google though it is an open source project? It's Google's project, so they control it. You can download it. You can change your copy however you want. You can release your copies to anyone. But you can't put your changes into Google's official copy unless they approve it. If you do submit changes to the official copy, they don't belong to you (they belong to everyone). Only Google's version gets pushed out to people's Android phones. > Why can an another company not develop on its own using open source codebase ? Why can't they release a new android version like Android Popsicle (v9.0) before Google does the same? Another company can do this. Many companies have developed their own version of Android and released it on their devices, but they can't release it with the \"Android\" name because that name is trademarked. In general, no one is going to install a non-official OS on their device because 1) why would they? 2) it's generally very technical process 3) if anything goes wrong, no one is going to help them fix it."
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7hxkbq | Why do enzymes in saliva only break down food and not our mouths? | Biology | explainlikeimfive | {
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"Enzymes can only bind to certain substrates. The ones in our mouths for instance can bind to strach and other food molecules but not to the proteins that form our cells.",
"The alimentary canal has cells all along it, called goblet cells, which release mucus, which is a kind of lubricant. But, it also forms a covering over the cells of the canal, and protect the cells from being digested by the enzymes. Hope that helped!"
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7hxly6 | why wild fires like the one in LA are so hard to contain | Chemistry | explainlikeimfive | {
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"text": [
"There are 3 ways to put out a fire. 1- Remove oxygen, 2- Remove heat, 3-remove fuel. We can't remove oxygen from the atmosphere so that's out. To cool it down you can spray water but that isn't feasible for the length of the fire. You can hit small sections with air tankers, helicopters or fire trucks but it is only for high value areas like houses. You don't have enough water, pumps and hoses to spray down every inch, so the main option is to remove fuel. How? Bulldozers or crews with chainsaws and hand tools create a fire break. You can clear brush and dig a fire break down to about 3 feet wide and 6\" deep to the dirt clear out the dead leaves, grass, roots, etc that will burn. That way the fire burns until it hits the line and has nothing left to burn, and it puts itself out. You can also create a smaller, more controlled fire to burn up all the fuel before the fire burns it in an out of control manner, but that is where the phrase \"back fire\" comes from. But if the wind carries burning embers or a tree falls across the fire line the fire will escape and continue to spread. If there is a strong wind it is too dangerous to dig line and it easily crosses the line you already built. That is why you rely on rain, calm winds and cooler weather to help, because there simply isn't enough resources to possibly stop a raging fire on our own.",
"A combination of rural and semi-rural areas which are far from main roads, or easy sources of water. Strong winds (called Santa Ana winds) which accelerates the spread of the fire. Lots of dry grasses and bushes from regular rapid growth/drying cycles."
],
"score": [
7,
6
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
|
7hxm2e | Why is it easier to open the lid of the pasta sauce bottle if I tapped it in the bottom? | Physics | explainlikeimfive | {
"a_id": [
"dqujeix"
],
"text": [
"It helps release some of the air bubbles trapped in the pasta sauce, and brings it to the top. The air at the top creates a buffer between the sauce and the lid so it's easier to open."
],
"score": [
3
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
7hxygq | What direction does the z axis go: up and down (height) or back and forth (depth)? | Mathematics | explainlikeimfive | {
"a_id": [
"dqulxl7",
"dqulwob"
],
"text": [
"The only real rule is to follow the right hand rule. [Specifically follow the direction here to orient it with respect to x and y]( URL_0 ), it also points out there are left hand coordinates where it's flipped, but you don't see that often.",
"It doesnt matter. The label is arbitrary. Typically the z axis goes perpendicular to both the x and y axis, which are perpendicular to eachother. Once that is set it doesn’t matter. I believe most people use z for height as they tend to view planes as top down."
],
"score": [
7,
3
],
"text_urls": [
[
"https://en.wikipedia.org/wiki/Right-hand_rule"
],
[]
]
} | [
"url"
] | [
"url"
] |
|
7hyawq | How does "8-dimensional" music work? | There are numerous so-called "8-dimensional" music tracks or sound sequences to be listened to with regular headphones, like [this here]( URL_0 ) (music) or [this]( URL_1 ) (barber shop). Despite ones musical taste, I find these impressive - but they are made for 2 speakers, and Stereo is a quite ancient technology we had for a long time, so how does this effect work? | Technology | explainlikeimfive | {
"a_id": [
"dququai"
],
"text": [
"It has to do with the ways our brains interpret position and distance of sounds based on the sounds each ear receives. There are two main important aspects: First the shape of your ear and ear canal actually subtly modifies the frequencies of the sound that enters it, depending on which direction the sound has entered from. The frequency profile of the sound that reaches your eardrum will be slightly different if the sound enters from behind vs from front. It'll be even more different if it comes from the other side, as some of the vibrations have to go around your head or even through your head. Your brain is very sensitive to those subtle differences and can use them to determine the position of the sound in space. This is often called HRTF - head-related transfer function. Second important cue is the time difference of the same sound arriving to each of your ears. Because the sound waves travel at finite distance, sound arriving from the left will arrive to your ear a few milliseconds sooner than to your right for example. These subtle effects can be captured using special binaural microphones, that [look something like this]( URL_0 ). They essentially model human ear and ear canal, with a microphone where the eardrum is and have the ears positioned about the same distance apart as you would. That means that the captured audio has both these spatial cues already \"baked in\", so when it is played back, your brain thinks the sound is coming from a certain point in space, even though its source is right next to your ears, sort of like a perceptual audio illusion! The effects can also be simulated in software, essentially as a form of audio filter, so you can produce artificial sounds that seem to be coming from certain point in space. This is very useful for virtual reality applications for example. Hope this helps!"
],
"score": [
4
],
"text_urls": [
[
"http://www.basvangeuns.nl/wp-content/uploads/2016/12/FreeSpace_5_WebReady_grande.jpg"
]
]
} | [
"url"
] | [
"url"
] |
7hyces | Why does the moon appear larger at the horizon than when it’s higher in the sky? | Other | explainlikeimfive | {
"a_id": [
"dqur73k"
],
"text": [
"How big something looks to us depends on how far away we think it is. The image of the moon on your retina (in the back of your eye) is always the same, but your brain needs to figure out how far away it is. Our brain has a lot of trouble figuring out the distance of faraway things in the sky. For things that distant, the brain cannot rely on \"parallax\", which is the effect that objects cast slightly shifted images on your two eyes. For very nearby objects, the shift is very large, but as you go further away, the shift pretty much disappears, to the point where the image of a very distant object looks the same in both eyes. So instead, the brain has to rely on contextual cues, and there aren't many of those in the sky. And because the brain doesn't have much experience with extreme distances, it assumes that things like stars, very high clouds, or the moon, are all about equally distant, and closer than they really are. So you tend to see the sky as a kind of dome all around you that is wider than it is high, instead of the vast unending space that it really is. When the moon is close to the horizon, the brain can tell that it's further away than any of the things that are in front of the horizon, like buildings and roads, so it doesn't underestimate the distance of the moon as much. You still don't really perceive the true size of the moon though, because there are no contextual cues to convince the brain that the moon is further away than just beyond the horizon, (which is typically a few km), rather than the actual distance of nearly 400,000 km."
],
"score": [
6
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
7hypwb | How does Whatsapp make money/profit? | Technology | explainlikeimfive | {
"a_id": [
"dqusgzp"
],
"text": [
"When a product is free, you are the product. Despite facebook telling us it's secure, I'm pretty sure they run a ton of analytics algorithms on your contact list, most used words, hours of sleep, ..."
],
"score": [
6
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
7hytt3 | Why do people still use i3 and a lot of i5 CPU when i7 is available? | Technology | explainlikeimfive | {
"a_id": [
"dqusmv5"
],
"text": [
"1. For most casual users and even a lot of gamers and such, hyperthreading (the main advantage of i7s) will make little to no difference. Beyond that, an i5 and i7 really aren't notably different performance-wise if you're comparing like clock speeds. Hyperthreading basically means that for any physical processor core, the processor essentially has two 'cores' the operating system can address. This doesn't mean it works twice as fast, it just means that if an application is hogging a core but not actually doing something at the moment, another application can utilize the core. As a result, you'll ONLY see any difference if you're significantly utilizing more than 4 cores. Generally speaking, casual users and gamers really won't, as the vast majority of applications (even games) only use one or at MOST two cores at a time. So at most, the operating system and any background tasks might use one core, your game might use at MOST two, and any other random stuff on your computer can use the fourth core on your i5. Adding 4 more virtual cores does nothing. You could add 4 more physical cores and see no difference. 2. An i5 will generally be ~$100 more than an i3. and an i7 will generally be $100 more than an i5. If you aren't oozing money out of your pores, that extra $100 if you don't need hyperthreading or $200 if you don't need a couple extra cores means you can put that money into something that will make a lot more difference for the task you'll be using your computer for, like a faster SSD or a better graphics card."
],
"score": [
5
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
7hzihz | How was the transition to the Euro so easy? How did the currency have any value when it started and how were they able to make everyone switch to it so quickly? | And was the money people had before worth anything after the Euro was introduced? How did foreign countries recognize the value of the Euro if it was just being introduced? | Economics | explainlikeimfive | {
"a_id": [
"dquy3f8",
"dquz761"
],
"text": [
"It wasn't easy, it was a lot of work. The currency had value because it could be exchanged for other currencies, and because (like any fiat currency) the governments agreed to accept as payment for taxes and fees.",
"I actually lived in Europe there during the transition. One day I went to the ATM and I got Euros and the screen showed my balance in Euros and everything just kinda worked. It was pretty impressive, actually. So first off, the Euro, like the US dollar, is *fiat currency*. It has value because the state says it does. It's designated as legal tender, which means that it must be accepted as payment of debts (more accurately, if I have a debt to you you cannot say that I didn't try to pay it if I offer you Euros and you refuse them). So the Euro has value because people think it does (technically that's true of almost all kinds of money...even gold-backed currencies only have value because people think gold has value beyond its intrinsic chemical properties). As for the transition: the Euro was in use \"on paper\" for years before the general population switched. The various countries of the Eurozone pegged their currencies to the Euro (e.g. the Italian lira was pegged to, say, 400 Euro per Lira). Bank-to-bank transactions were all conducted in Euros, government budgets and such were calculated in Euros, etc. When the time came to switch the physical currency, massive amounts of coins were minted and bills were printed and were distributed to banks and other institutions. Businesses were asked for months to prior to the switch to post prices in both the old currency and Euros, and then to accept payment in the old currency and make change in Euros for a while. The old currency was deposited with banks which then converted them to Euros and destroyed the old currency. Eventually, the various countries demonitized their old currency, meaning it was no longer legal tender and could not be forced to be taken as payment of debts and could not be deposited in the bank. This was done after months more of warning, to ensure people had plenty of opportunity to take their money to the bank and exchange it."
],
"score": [
10,
6
],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
7i0ze5 | Does light exist in 3 Dimensions or 4? | I've been sniffing around for answers but they are either insufficient or over my head. | Physics | explainlikeimfive | {
"a_id": [
"dqv972r"
],
"text": [
"Everything in our universe exists in 3 spatial dimensions plus 1 time dimension, for a total of 4."
],
"score": [
15
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
7i1izy | How is Moviepass making money, or even staying afloat? | Economics | explainlikeimfive | {
"a_id": [
"dqvegt3"
],
"text": [
"Moviepass is a private company, so it's financials are not available to the public. It's likely that it's not making money. The company is a bet that the data collected about its clients will end up being more valuable to the company (both selling additional services and selling information about movie viewers watching and buying habits) than the cost of the movie tickets they make available for a monthly fee. Remember, if you're not paying for the product, you are (or your data is) the product."
],
"score": [
19
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
|
7i1xyz | Why do airlines charge less for flights out of small cities (stopping over in a major hub) and more JUST from that major city? | I want to go to Las Vegas, so I started looking at flights. A flight from Victoria, BC to Las Vegas with a stopover in Vancouver is $250 round trip. Yet when I change my location to Vancouver, for the exact same flight (minus the flight from Victoria to Vancouver, so it should be cheaper) it's $330. Why is the airline charging $80 more for me to go through the major hub I'd be going through anyways? Thanks in advance team of reddit geniuses :) | Economics | explainlikeimfive | {
"a_id": [
"dqvn80o"
],
"text": [
"It has to do with competition. A flight from city A to city B to city C is not competing with flights from city B to city C. It’s competing with A-D-C with different stopovers and A-C nonstop. If one airline dominates airport B (which is the case for many large US airports; just not the few largest like NY’s and LA’s) that will make flights out of B more expensive. But that doesn’t apply to other flights using B as a stopover, so if airport A has more competition between airlines than B, then A-B-C will often be cheaper than B-C."
],
"score": [
6
],
"text_urls": [
[]
]
} | [
"url"
] | [
"url"
] |
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