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lg9dxf
|
While every other fruit juice is of the fruit’s color, why does apple juice instantly oxidize to brown?
|
Chemistry
|
explainlikeimfive
|
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"Apples have polyphenol oxidase, which breaks down into o-quinones, which then break down into [other stuff that happens to be brown]( URL_0 )."
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|
lg9gmp
|
Why do we hear a pop sound when pausing or resuming audio of low frequency?
|
Biology
|
explainlikeimfive
|
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"It depends on where in the waveform you were when you paused/unpaused it. A 50Hz sine wave will cross \"zero\" 100 times per second -- half the time, the wave will be positive, and half the time, it will be negative. If you happen to pause it when the wave is very close to zero, it will be silent. However, if you happen to pause it when the wave is at either peak (positive or negative), your nice sine wave gets chopped into a square wave. That's the pop you're hearing -- going from a high (positive or negative) sound level to nothing, and when you unpause, you go from nothing and shoot straight up to a high sound level again. Properly engineered audio systems can eliminate the pop by doing a gradual (well, gradual within a few milliseconds) smooth ramp-down in signal intensity, either in software or hardware, before actually pausing or unpausing. Alternatively, when you pause, they can wait a few milliseconds until the signal crosses the zero point before actually pausing it."
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lg9j0e
|
How do countries actually take control of another country once they occupy the capital?
|
Like, when the capital falls, how does the country fall under the control of the opponent? How does it actually work, can't the existing government just say "No we're not listening to you we're doing our own thing?" Not just the capital but like cities in general, when the city centre falls, what makes the whole city fall? Also, if I'm understanding this correctly, can countries just skip the actual war and just occupy the capital if that's how it works?
|
Other
|
explainlikeimfive
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"\"Occupy the capital\" probably implies that they've pushed their forces through the entire country and successfully reached the capital. \"Take control\" probably means either \"literally holding a gun to the leader's head until they 'voluntarily' declare that you're now in control\", or \"leaving troops all over the country, proclaiming that you're in control now, and daring anyone to argue with your soldiers and tanks and bombs\". There's no switch that's flipped or anything, it's just making a declaration, backing it up with either violence or the threat of violence, and being that way for long enough that people just get used to it and accept that you're in control now.",
"It depends on where the capital is and how it’s occupied. Is it in the middle of the country and you first have to devastate the defending forces and push through the entire nation to get it? That’s a crushing blow and the enemy will struggle to fight on. See: the fall of Berlin in 1945 Is it near the edge of the country and hard to defend, so the enemy withdraws quickly to mount a defense elsewhere? This is merely a symbolic victory with little military utility. See: the burning of the White House in 1812 Capturing Berlin required the german army to be shattered and routed by a superior force, and they did not resist afterwards. The US mounted only a light defense of Washington DC in the War of 1812, opting to withdraw into the much harder to capture mountainous interior of the country and force the British to fight in tougher terrain.",
"Throughout history most of the population doesn't really give a shit who's ruling them. Regular people have to go to work exactly the same whether it's Britain or America \"ruling\" them. If a military force takes the capital and kills or replaces the leaders, those new leaders still have the exact same amount of power as the old ones did. People can choose to actively disobey them, just like they always could. But there will still be consequences just like there always were. Lose your job, end up in jail, get shot. Unless the Invaders represent a huge ideological shift, like they force a new religion on you or something, to the average person it doesn't really matter that much who's in charge.",
"well basically....you either obey the occupation rule or you resist, caught and executed. the occupation force didn't just walk in the front door of the capital all nicely.",
"It depends, like, when the USA invaded Iraq we took control of all their government and started 'de-baathification' and replaced all of the people with others who were essentially an American puppet. This is the most extreme form of takeover and often, as it did for us, fail dramatically. The more common form of takeover is an empire, where the government isn't entirely replaced, I mean, what a pain in the ass! An example of this was East Germany, while the Soviet Politburo had an extreme level of influence over the East German government, the East Germans still executed the basic functions of government. They knew the Red Army was nearby, so they capitulated. A historical example is when the Norman French invaded England and took over the capital. In that case, a relatively small number of Norman French (this is important because Norman French were a different ethnicity than the typical Frankish French we think of) were able to subjugate the whole country by eliminating key nobleman and replacing them, while paying off others and elevating key individuals. It also helped that the Normans were fairly effective governors. The English people, themselves, would hardly have noticed a difference but for the castles got a lot nicer and they had to speak French in court, not that it mattered to nearly anyone. Mind you, this only happened after one key battle, but it was enough to eliminate any serious resistance. Similarly, when the USA took over Japan after WWII, they worked diligently to keep the civil authorities in basic control of the day to day functions of government while setting up the Japanese economy western style - to their benefit ultimately. The difference between Iraq and Japan couldn't have been more different, and the outcomes play that out."
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lg9tak
|
Why are an aging population and automation simultaneously a problem?
|
I understand each issues individually, but how can they coexist? We don’t have enough working age people so we need more people, but we don’t/won’t have enough jobs due to automation. They don’t cancel each other out? What am I missing?
|
Economics
|
explainlikeimfive
|
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"You're looking at one side of the problem...the labour side. And there, yes, they cancel each other out. Not enough workers, so automation closes the gap like /u/epideictic_possum notes. But that's not \\*the\\* problem...\\*the\\* problem is funding. Most countrys' entire tax/benefit structure assumes roughly comparable numbers of aging/retired people receiving benefits (medical, pension, etc.) and working people paying taxes to fund those systems. If the number of people using the benefits goes up and the number of working people goes down, the tax structure doesn't keep the budget balanced and robots don't pay taxes.",
"Automation reduces the number of people needed in jobs and an aging population means there are fewer people available to work. These together mean that there are fewer people paying income tax.",
"Basically, because we have some arbitrary structures built around the idea of \"money\", that keep the game running. These require that someone \"pay\" for anything we want done, even if the resources and labor to do that thing already exist and are eager and willing to do the thing."
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lgatxx
|
If space is a vacuum, how does propulsion work?
|
Random thought while at work; honestly though, how can a spacecraft/satellite turn from it's original course outside of planetary or star gravity?
|
Physics
|
explainlikeimfive
|
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"Propulsion doesn't need anything to \"push against\"; moving in a vacuum is perfectly simple. \"Every reaction has an equal and opposite reaction\", right? If Reaction 1 is \"engine sends stuff flying out the back of a spaceship\", then the equal and opposite Reaction 2 is \"ship moves forward with exactly the same force that stuff flew out the back with\".",
"Everything has an equal and opposite reaction. So when exhaust gasses are pushed out the opposite force is applied to the craft. It is the same principle as when the rocket takes off, they are not using the atmosphere to create lift, it is actually something that creates drag and makes it just a bit harder to lift off.",
"Imagine that two people float together in space. Both push against the other one simultaneously. What do you think will happen? They will be pushed appart from one another and keep moving away from the other one. Now, if what you push against is not another person but something much smaller, like a tennis ball, the result would be the same: both you and the ball would move away from the other, but the tennis ball would move a lot faster due to it being so light, you would move much slower (in relation to the position you started at). Propulsion in space is like that, it doesn't push air backwards like a plane, but instead throws matter back."
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lgc0dy
|
Why do some computer programs need to be "installed" whereas others will run from an .exe file?
|
Basically what the title says, sometimes I can run programs as a standalone .exe file, but sometimes the program needs to be installed instead. What is the difference between the two?
|
Technology
|
explainlikeimfive
|
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"Some programs are like an individual hot wheels car that you get when you behave on a shopping trip. You can play with it just all on its own. These programs are usually smaller, and don't need to rely on much else or make any special changes to your computer. Others are like hot wheels cars that come one of those boxed sets you get for your birthday. They come with tracks that have to be put together; you have to ask your dad for batteries, or you have to grab a chair and clamp the track to it; you have to put some ice water in the little container so the cars can change colors. These programs try to do a lot more, or work together with other bits of code, but they require more setup as a result.",
"A program that can be run straight from an .exe file needs to be fully self-contained...the computer is going to load the first instruction from the .exe file to memory, run it, and away you go. This doesn't mean it needs to be a single file, but if it's multiple files the .exe file needs to be hard coded with where the other files are or how to ask the OS where other files are. However, if the program needs other resources that may or may not be installed on the system, or needs to tell the OS various things to work (what kinds of files it opens), or needs information from the OS (what kinds of printers are out there, what other software is on this machine, etc.) then it needs to do more \"housekeeping\" to get that information, install anything that's missing, setup preferences, etc. That's what \"installing\" does.",
"some ...actually most programs rely on having supporting libraries, this can be handled in one of 2 ways: - \"bake\" these libraries into the executable, while this makes your program self-contained and wont require any installation, it increase the size of the final .exe file and forces the operating system to load the whole thing on startup which might be a problem if memory is limited.This also creates an issue if you want to actively support the software, as any update to the libraries you want to implement requires a full recompilation not to mention not all middleware providers actually allow you to do this as their software could be proprietary and could land you in legal trouble especially if your software is not free. - include references in your code that point for these libraries, in a \"relative\" directory and make calls to these libraries dynamic. this has the benefit of keeping your own code contained on itself, with its only outside connection being these calls, however this requires that when you distribute your program you must include its dependencies in the form of dynamic link library files aka .Dll files. this method also facilitates updates as an update is only required if the actual library call is changed. Because most Users do not want to have to manage possibly multiple versions of the same .dll, programmers develop installers that manage this for you while also changing any required options so that the program can do what's intended.",
"Windows developer of 15 years here. Most of the answers submitted here (so far) are based on specific experiences/use cases - or are just plain guesses and not right. Dependencies for example, does not mean you HAVE to use an installer. My best ELI5 is software applications are like home electronics. Some applications are microwaves (just plug it in and it will work) - these are EXE's, no complex setup required. However some applications are like home alarm systems, they require holes to be drilled, hardwiring to power and maybe connecting to the phone line. In the real world you would use an engineer to fit it, as it is very complicated and you (the user) could make a mistake. This is exactly what installers do in software, they take care of all of this work for you and ensure it's completed properly and can be reversed (uninstalled) in the future if required. Edit: A word",
"Imagine that apps are people you hire to come over to your house and do something for you. Some of them do simple tasks and are very organized. They bring everything in a backpack, take out just what they need, and put it back when they are done. That’s like an app that is a single .exe file; it has everything it needs in one place. Some have big jobs to do, and need lots of tools and equipment to do the job. Think of a painter who brings a truck full of ladders, tarps, and different colors of paint. The painter might move all this into your garage while they are working. That’s like an app that needs to install lots of files on your computer to function correctly. Of course, some people might be able to keep things in their backpack if they were organized, but when they show up they just spread out all their stuff over your living room. Some apps do that too, even though with a litte care they could have been made as just a single .exe file.",
"There's 2 main reasons to have an installer. The first is if there are dependencies, that is the program assumes something else is installed (in modern times, assuming Windows, this will likely be something like the .NET framework). The installer can check if this is already installed, and prompt you to install it if it isn't already there. The second that an installer isn't needed, but there's other typically expected things, like adding a start menu shortcut. There are also things like some programs can add options to your right-click menu on certain file types, and this is usually done during installation. It can also be considered more user friendly depending on the audience. Sometimes these programs will offer two versions, a stand alone version that you can unzip and run, and one with an installer. Another potential benefit of an installer is that it can include an uninstall that will remove the shortcuts it created, as well things like asking you if you want to remove the data created. It can also be useful when upgrading versions to have an installer update any existing files that are needed. If the official Windows installer framework was used to create the installer, it can also be aware of Windows system restore so when you restore to a point in time, that program can either be installed or uninstalled as appropriate. Many programs don't actually need an installer, but not having one can make your program look unprofessional if it's meant for a consumer audience.",
"Not much, usually applications have supporting external libraries and configuration files. These need be placed in relation to the executable. An installer usually handles this for the user, on Windows, it may also add registry entries.",
"Normally programs are a collection of EXE files (windows world), not just one. A simple one may be simply one EXE, but more complex ones will contain others that can be called upon depending on what the user is doing. So, what does the program have to do. If it can rely, 100%, on the operating system software (like a simple \"Ping\" program or something) then you only need the exe and maybe a simple config file. Say you have a more complicated program that is capable of scanning something, so as part of the 'installation' you have to register some DLLs (which are just 'libraries', think of them as tiny little programs that operate as shortcuts for developers, instead of coding everything from scratch you might load a DLL that someone else developed, without DLLs development would take FOREVER) and a device 'driver', or special program just to run a specific input or output device. Some installations will even go further and install a web server or something so you and other computers can access the program remotely. So, in that case, in addition to installing whatever special software you have designed, you also have to install httpD (or IIS, whatever). Think of the installation as 'prep work' for the program, the prep work is different for each program. If you are installing a SQL server, the prep work is extensive. If you are installing Notepad++ the prep work is trivial."
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lgccg9
|
Why do you preceive some kind of "pressure" when using noise canceling headphones?
|
So I was searching for posts concerning noise canceling headphones and I found a few posts about how they cancel out noise. As I understand, the headphones basically listen for incoming "noise" and send out the "opposite" wave. OK! Then I was wondering: if the two waves cancel each other out, why you perceive some kind of "pressure" especially when no music is played?
|
Biology
|
explainlikeimfive
|
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"This is a fun one. Our brains react to certain input from our senses based on instinct. When you put on noise canceling headphones they cancel out low-frequency outside sounds (and other frequencies). But that lack of low frequencies is also what happens naturally when there is a pressure difference between your inner and outer ear, and it triggered that feeling. It's an instinct reacting to what normally would be a good time to pop your ears, but its the headphones not climbing a mountain or whatever would normally cause a pressure difference."
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lgcdvx
|
How does a chemical buffer work?
|
If there is both a base and an acid in the solution, shouldn't they neutralise each other? So how does that make it able to use the acid or base and neutralise other acids or bases that might be added?
|
Chemistry
|
explainlikeimfive
|
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"A buffer solution is made of a weak acid/base and a solution of the “conjugate” base/acid You’d have to be a true mad lad to use HF as a buffer, but it is a simple weak acid that I’m going to use for demonstrating: Your buffer solution is a mixture of HF (hydrofluoric acid) and NaF (sodium fluoride) The NaF fully breaks down in water, pumping out Na+ and F- ions. The HF *doesn’t* break down very well in water, and remains mostly HF. So now what happens if you add a strong base? Pour in NaOH and it instantly splits into Na+ and OH- The Na+ wanders off to do nothing since the partners of strong acids and bases are pathetically weak in solution. The reactive OH- that we’re trying to buffer against yanks an H+ off the HF and converts to water. Let’s try a strong acid instead. Pour in HCl, it splits into H+ and Cl-. Like the Na+, the Cl- wanders off to do nothing interesting. The H+ finds a free F- in solution and binds up into HF, which as we’ve established doesn’t break apart easily. This way, the solution can absorb a strong acid *or* a strong base without a significant change in pH. Note that this doesn’t mean the solution is “safe” in any way, just that it’s not changing acidity when you add acid or base."
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lgcf6v
|
How do those Dyson fans with no blades work?
|
Technology
|
explainlikeimfive
|
{
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"text": [
"Through lies and deception. There are fan blades hidden in the base of the fan, take the fan apart and you can see a turbine in there."
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6
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lgcn6g
|
Why do human feet have so many bones, yet very little mobility compared to our other joints and appendages?
|
Biology
|
explainlikeimfive
|
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"Look at your hands. Do you see why your hands need a lot of bones in order to move in all the different ways that they do? Your hands and your feet are just variations on the same blueprint - that way your DNA can just store one blueprint, and then a set of simple \"adjustments\" to make a hand vs a foot, which is way simpler (from your DNA's perspective) than having two completely separate sets of instructions. So basically, your feet have a lot of bones because your hands have a lot of bones, and it's easier to build feet as kinda-crappy hands (more like \"hands built for standing on rather than picking stuff up\"; if your feet were as good at picking stuff up as your hands you wouldn't walk nearly as well). EDIT: another reason that your hands and feet both have so many fiddly bones in weird places (like all the different bits that make up your wrist, for example) is that the blueprint for how to build a hand/foot had to start with an older blueprint which had a lot of fiddly bits to make fins for fish to swim with (and crawl around in mud with).",
"Its way more effective for an animal that runs on two feet on the ground. Way back in our evolutionary history when we were climbing trees more feet could grab things and whatnot. But over a very long time as we developed into distance runners it became more advantageous to have sturdier feet. Very slowly over many generations we lost the finer control in favor of durability, but retained just enough to control balance.",
"A lot of talk about evolutionary processes here. I don't know much about that. I am, however, a martial artist and former massage therapist, and have spent the last 17 years learning about feet, how they move, what they do, and how they get sick and heal. So take my answer for what it's worth. Your feet SHOULD be almost as mobile as your hands. The movements are just a little different. They have a limited grasping ability if you're fully mobile and properly stretched and exercised. They have thick tendons and other connective tissues all along them to absorb weight and force. The structure is similar to your hands, but each part is a lot more robust. Think about an athlete like a basketball player running drills, and imagine if they were barefoot. Every time the player changes direction, makes a sudden start or stop, the foot grips the ground, and you can actually see the bones and joints spread out, absorb the impact, grab the ground, and then push off again similar to the way hands work when doing push ups. Cheap shoes, tight shoes, rigid shoes, or simply shoes with a heel that lifts too high will cause the entire foot to freeze up over time. When a person like this tries to walk barefoot, they will throw their foot in front of them on each step, like a rock attached to the end of their leg. It hurts after more than a few meters, and they can't really change directions at all; they have to stop, turn, and then start again. Most people like this will be so used to it that they won't notice at all. Healthy feet can propel the body in almost any direction at a moment's notice, and will support your body in a variety of weird postures. It's how a karate master looks like he has so much balance, standing on one foot and kicking - his feet hold him up. I hope this explains a little bit. There's a lot more to discuss, but this is the basics. Feel free to ask more questions!"
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lgd2yy
|
What happens to pacemakers, iron hips, and other implants in the cremation process?
|
Biology
|
explainlikeimfive
|
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"Silicone implants are often removed before cremation because they get sticky, and you don't want to hand over a ball of goopy ashes. Pacemakers contain lithium batteries which can explode so they are removed before cremation as well. Metal bits can be sifted out with an electromagnet after cremation if necessary.",
"Drs have to put on the cremation form/combined MCCD and cremation form to alert mortuary staff and undertakers if there is a pacemaker/ICD present. It also needs deactivating before removal - usually before someone dies Edit - I put ‘usually’ but on reflection, that isn’t true and it really depends, it must be fully discussed. More info here URL_0 . I don’t know what happens to the device after removal, ie which waste stream they go into or if they get dismantled and recycled",
"I am aware of council crematoria that can make a significant amount of money from recycling precious metals from surgical implants. Over a year the amount can be significant. Had a fascinating visit seeing behind the scenes including the machine that grinds down the ashes - it uses large metal balls to render the ash to a fine powder. Very sadly they also had a few dozen containers of remains never collected that they hung onto for years. Just sat on a shelf. Interesting and poignant they had some incredible tales. They once had a body delivered by the deceased son, in a cardboard coffin in the back of a rental van - after unloading his mum he refused to stay & left immediately. Dread to think of the story behind that.",
"My favourite opening line to a book \"It was the day my grandmother exploded...\" (from *The Crow Road* by Iain Banks) is about what happens when a pacemaker isn't removed (the line is about that, not the whole book)."
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lgd3kl
|
If your body sweats in order to keep cool, what causes it to sweat when you're cold?
|
Biology
|
explainlikeimfive
|
{
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"text": [
"The ELI5 for this is that you sweat for a number of reasons, and the mechanisms that control sweating aren’t only linked to temperature regulation. Certain chemicals or nerve impulses can cause you to sweat in response to a number of stimuli, even when you’re cold. You have sweat glands that, for example, are activated by the chemical your nerves release when you’re in the “fight or flight” mode",
"There are multiple reasons for a cold sweat, but one of the most common ones is a fever. A fever is triggered by an infection. By raising your body's temperature, it makes it harder for the bacteria or virus to survive. It also activates the immune system by speeding up the functioning of cells in your body. A fever is often accompanied by chills, which are kind of deceiving. You're not actually cold, temperaturewise. Your muscles keep expanding and contracting, while your blood vessels constrict, which reduces blood flow making you feel colder. The fever, however, is still raising your core body temperature, which is why you sweat. If anyone with more knowledge than myself can expand or correct, please do. TLDR; an infection causes fever and chills. The fever makes you sweat and the chills make you feel cold."
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lgdpmt
|
Does Earth's atmosphere also spin with the rotation of the Earth? Shouldn't we be able to observe Earth's spin by looking at the clouds?
|
Physics
|
explainlikeimfive
|
{
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"The atmosphere spins with us. If it didn’t, we’d be feeling huge winds all the time. Clouds move due to differences within the weather system. The planet’s spin doesn’t directly affect it, at least not in a small/local scale. If I’m remembering correctly the Coriolis effect might influence it but I don’t know for sure. If the atmosphere didn’t move with us, it would also have major implications for air flight.",
"The effect of Earth's spin on the atmosphere is to create the [prevailing winds]( URL_1 ), and the air movements you see in that article are not just purely from the spin, but also because of the Sun's energy (light) heating up different parts of the globe at different angles (with more or less heat) and also at different times of the day (the time zones), and because of geography (mountains, plains, etc.). For water, the spin (and other factors) cause the prevailing [ocean currents]( URL_0 )."
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|
[
"url"
] |
[
"url"
] |
|
lgdr37
|
Why do bats hang upside down while birds perch upright?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gmqzu31"
],
"text": [
"They seem to have evolved flight (and more relevantly to your question, landing apparatus) very differently. Flight evolved (at least) twice in dinosaurs, once in Microraptor (formerly thought to glide) and again in birds. We aren't exactly sure when or how the direct ancestors of birds developed flight, but with Microraptor its relatively safe to say that flight evolved from an active arboreal movement. Dromaeosaurs (raptors) flap their wings to help them climb and to help restrain prey, so once a raptor started living in trees and leaping between branches, using flapping to go further and then eventually fly wasn't as huge a change as it might appear. Bird flight is based on running and jumping, they are great at taking off. The origins of bats are a lot less clear than birds, but judging from their method of taking off it seems that they evolved from a more passive arboreal movement, such as gliding. Only a select few bats are specially adapted to take off from the ground, with very strong wings that they \"punch\" the ground with as they throw their body forwards in order to gain momentum, and even they are pretty bad at taking off. Bat flight is based on dropping off of a branch or ledge, and they are very bad at getting into the air on their own strength. PBS Eons has a great video looking into the origins of bats that might also lend some more insight: [ URL_0 ]( URL_0 )"
],
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43
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"text_urls": [
[
"https://www.youtube.com/watch?v=zWeYCULC0UQ"
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|
[
"url"
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[
"url"
] |
|
lgdtlq
|
if the oldest movable printing press exists in Korea, so does the oldest books from the printing press... why are the Germans credited with ‘inventing’ it?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"gmqtjrn",
"gmqwzny",
"gmqtaat",
"gmsdud5"
],
"text": [
"There were limited uses of it in China and Korea, but the Germans are the ones who really made mass production viable, kicking off the age of the mass-printed book. One big help is that they only needed the letters of the alphabet, so they could just make molds for only that many letters to make a huge amount of type for printing.",
"While the movable printing press were developed in East Asia long before Gutenberg it never really created the same sort of printing revolution as it did in Europe. There were several reasons for this. There were far too many letters in the alphabets to make the typesetting process faster then the carving process. There were also issues with finding the correct type of ink to produce good quality text when printed. And also the noble classes did not want this technology to fall into the hands of revolutionaries as they might mass produce works they disagreed with. In addition printing presses were used in banking to mark valuable papers with unique serial numbers which also made the technology secret. So the printing press you are mentioning, which is arguably the oldest, belonged to the king of Korea and were kept secret from his subjects. In fact owning a printing press in Korea at that time was prohibited by law. So there was only this one machine in the entire country. Meanwhile in China they had abandoned movable printing presses entirely because they were too slow and unreliable. So the East Asian inventions were not as significant culturally as the German invention. This is why we credit Gutenberg with his invention instead of any of the East Asian inventors.",
"Because it didn't gain world wide attention until the 1970s and was forgotten about until 2011. Historians, even when they are unbiased (which isn't a given) aren't omniscient. Point being, the people who wrote the history books crediting Gutenberg weren't aware of the Korean invention. Secondly, two people can independently invent the same thing. You don't have to be the *first* person to do it to be an inventor of it.",
"The printing press in Europe is an independent invention from the Asian printing presses. Contrary to what other people are saying here, printing _did_ cause quite a revolution of bookmaking and literacy in China. See this askhistorians thread for example URL_0 But Gutenberg's press is the ancestor of modern printing presses, the ones we use today which is why it gets all the press. It's also the press that European historians and schoolbook writers of the past tended to know the most about (since among other things you didn't have to wade through sources in Chinese or Korean to learn about it)"
],
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3
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}
|
[
"url"
] |
[
"url"
] |
|
lgen6a
|
How does a transistor in a computer get told what to do? (Turn on or off)
|
So from my understanding, a computer is composed of millions or even billions of microscopic transistors. These transistors are configured in elaborate ways to make different gates to interact with each other. My question is, fundamentally a transistor is basically a switch. But instead of a human turning the switch on or off with their hands, you have another wire doing it for you. Now, in a computer what is controlling these transistor gates to turn on or off? Is it other transistors?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"gmqy1o7"
],
"text": [
"Yes. Other transistors. It's a huge chain of them. This chain loops in many places as well. However, there are some external sources. First, peripherals. Keyboards, memory drives, cameras, and whatever else. Other networked computers, even. Alternatively, the clock. The clock is an oscillator, turning on and off regularly. This tells the computer when to begin the next operation, as well as keeping time for time-related activities. All computers have a clock. The clock is typically a quartz oscillator; a piece of quartz which vibrates like a tuning fork, driven by electricity."
],
"score": [
7
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
lgf8ib
|
Polarization and screens
|
I noticed that when wearing my polarized sunglasses I can't see my phone screen, but I turned my phone sideways and can now see clearly. Does anyone have a good explanation for this?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"gmr26re",
"gmr28ak"
],
"text": [
"Yes. Light is a wave. It is polarized perpendicular to the direction it moves. If it is moving up or down, then it is polarized in some horizontal direction. Part of how phone screens work involves polarizing all of the light. If your sunglasses and the screen polarize in the same direction, then you can see it. If they 'disagree' then your sunglasses will absorb the light instead.",
"Polarized glasses basically have very tiny straight lines on them. When light goes through the lenses, these lines stop any light that isn't already running in the same direction as those lines from getting through. This is polarization. Your screen has a polarized filter on it, so there light coming out is also polarized, running in the same direction as the tiny lines on it. If the lines on the phone run in the same direction as the lines on your glasses, you can see the images. If the lines are rotated 90 degrees, you see nothing at all."
],
"score": [
7,
5
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
lggk7y
|
Why does heat rise?
|
Physics
|
explainlikeimfive
|
{
"a_id": [
"gmr9qd3",
"gmr9oqk"
],
"text": [
"Hot air is less dense than cold air! When air is hotter, you can imagine the gas particles are bouncing around a lot more. That means, for any unit of space, there are fewer particles. Density is a measure of how much stuff there is in a unit of space, so less stuff for the same amount of space, means lower density. If something is less dense, it will rise because it is lighter.",
"Cold air is basically heavier/more dense than warm air so warm air fights to get above cold air and cold air fights to get under warm air. Thus causing heat to rise"
],
"score": [
8,
6
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
lgglkh
|
why do humans tie the umbilical cords of babies while it’s not a needed on other mammals?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gmraawv",
"gmrayn3",
"gmrevhk"
],
"text": [
"Humans don't really *need* to cut off and tie umbilical cords of babies. The natural thing would be to have the mother chew it in half and then let whatever length hangs off the baby gradually necrose and fall off at some point in the future. But humans have the ability to use tools and if there isn't a need to leave a nasty cord leaking goop all over your new baby, maybe just... don't?",
"Most other mammals chew the cord to cut it. They also lick their young to clean them up and very often eat the placenta.",
"There's a small chance of infection, and that could lead to problems. Why not prevent it by simply tying off the umbilical cord? Animals have no choice but to accept a high neonatal mortality rate but humans will do whatever is possible to keep the baby healthy and alive. Risk is low, but as with anything concerning saving babies' lives, people do it."
],
"score": [
31,
7,
6
],
"text_urls": [
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
lggpfr
|
Why are underwear white?
|
Given the proximity to areas that... well, have the possibility to easily stain a white undergarment it may not be the best color!
|
Other
|
explainlikeimfive
|
{
"a_id": [
"gmrbgqd",
"gmrci17",
"gmre7ve",
"gmrdjs7",
"gmre9bz"
],
"text": [
"Dyes and designed fabric are more expensive than white generic fabric. When it comes to undergarments (male/female/everyone else) tend to prefer comfort over style. This is why lace, cotton, designed patterns, etc are more expensive than \"tighty whities\" or \"grammy panties\" but it's these whities and panties that are more comfortable. Edit: so they are white because it is less expensive to make and they are being made for comfort instead of being seen.",
"Probably not the reason why they were designed white, but in more practical terms you can bleach them. Great for kids with any sort of bathroom related trouble, or from any age really.",
"Todays underwear evolved from renaissance era smocks, which were white linen that could be bleached clean.",
"Because you can throw them in the washer and wash on high temperature, and add bleaching agents if needed without worry about damaging colors",
"It’s easier to bleach. White socks, white underwear, white shirts can all be thrown together and washed with bleach to remove odors and stains. They are also cheaper. Colored briefs and boxer briefs are trendy and more expensive. If your buying underwear as a family it adds up. An 8 pack of white briefs are generally cheaper than a 3 pack of “fashion” briefs/boxers or boxer briefs. And there is a religious significance for some cultures that underwear must be white."
],
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11,
7,
4,
3,
3
],
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|
[
"url"
] |
[
"url"
] |
lggtrl
|
How are unions bad for Stocks?
|
So ya I've been reading one up on wall street, and one part it says that unions might be bad for a stock, and I really don't see how.
|
Economics
|
explainlikeimfive
|
{
"a_id": [
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"gmrbicv",
"gmrclhz",
"gmrbg2k"
],
"text": [
"The amount of money coming into a company is fixed by whatever products they make and what they can sell those products for. A bunch of that goes to pay for the raw materials and equipment and company expenses like insurance, utilities, etc. A bunch goes to paying employees (both direct pay and benefits). What's left can be invested in new stuff, go to shareholders, or some other more esoteric options. A union allows the employees to \"collectively bargain\" (bargain together) to get better benefits (pay, insurance, pension, etc.) than they otherwise would have had. That increases the money going to employees so less is left to go to shareholders, because math. This annoys shareholders, which can make the stock go down. Done correctly, a union can actually \\*increase\\* employee productivity and satisfaction enough to offset the cost increase and the company can do great (see: Southwest Airlines), in which case the shareholders also do great. Done incorrectly, it can suck so much money out of the company that nothing is left to invest or go to shareholders and you end up bankrupt (see: General Motors, United Airlines). Note: unions were NOT the sole factor in any of these cases, just one of many. I'm just pointing out that success/failure can happen with or without a union.",
"Because the workers being paid more means less profits for the company/investors, in theory. However there's a complex correlation between higher earning and productivity.",
"If a company's workers unionize, then their labor costs will likely go up and other expenses might be incurred (ie. spend more on PPE for employees, slow things down/lower worker quotas for worker safety). More costs for same revenue mean lower profits, lower P/E, and typically lower stock price.",
"Without knowing specifics like which stock and what the goals of the union are, I could be off base but I'd say that usually it's because the basic primary goal of a union is to increase the rewards available to the employees of a company with things like better pay, more vacation, better hours, stuff like that. That can sometimes cut into a company's bottom line in a way that impacts their overall profitability negatively, and that would traditionally drive the value of a stock down to some degree."
],
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6,
3,
3
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|
[
"url"
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[
"url"
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lggx7x
|
How did prehistoric early evolving humans cope with their toe nails?
|
I can’t imagine they would just wear down as they walked as fronts of toes don’t really scrape on the ground like that . Wouldn’t they rather become Ingrowing and painful
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gmrf4z8",
"gmrg9vy",
"gmsfbh8"
],
"text": [
"This is going to sound gross, but, I am capable of handing 90% of my nail care with my teeth. Isn't that normal? If it didn't wear away naturally, maybe they did it with their teeth?",
"I tare my toe nails with my finger nails. Almost never need a trimmer. Can also do my finger nails with the other hand.",
"Just walking on ground, no. But remember that when you walk barefoot in semi-dry environments, you're also walking through tall grass, rocks, and likely climbing trees regularly. With a good diet, finger- and toenails are very hard, and tend to chip off rather than tear away or grind down. You can see this with a lot of farmers or laborers hands even today - they have REALLY thick fingernails, and will often have ragged, chipped edges, and they rarely if ever need to cut or trim them."
],
"score": [
12,
8,
4
],
"text_urls": [
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|
[
"url"
] |
[
"url"
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lgh95z
|
Humans have spent countless years domesticating and selectively breeding crops in order to get the best possible produce, such as bananas and watermelons. So why is there still a giant ass pit in avocados even though basically every other crop is selectively bred for the best attributes?
|
I just thought of this and couldn't find anything on the internet as a cause for this phenomenon.
|
Biology
|
explainlikeimfive
|
{
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"text": [
"It takes time to breed plants for the traits you want, especially when avocado trees don't bear fruit for 5 to 13 years. That's a long time to wait. Avocados until recently had giant pits that took up most of the fruit. So the smaller pits we see now are a big advance on what they used to look like. Over time, the pits will get smaller and smaller and the edible part will get bigger and bigger. Sometimes you still get avocados in the store with ginormous pits, and other times with quite small pits. Check out this video that shows (near the end) wild avocados. Some are tiny like olives, others are larger but mostly pit, just a small layer of edible stuff. [ URL_0 ]( URL_0 )",
"One thing to note that no one has mentioned is that all commercial Hass avacados are grafts from a tree from 1926. They aren’t grown from seeds, they are clones, and clones of clones, so we can’t choose to plant the seeds from fruit that are smaller. (well we can, we just dont) So the answer to your question is that we haven’t actually selectively bred hass avacados for the last 100 years. Another thing to note is that it can take hundreds or even thousands of years of selective breeding to make a change like that naturally. With todays tech we can make that happen in a few years probably.",
"Because the #1 trait they breed for is matketability. Thats why the hass is standard in the us. Americans were willing to pay for the dark skin that hides damage during trasport and storage. Next are color, texture, and flavor. Size is one of the last. If you're interested, the California Cooperative Extension's avocado variety testing program documents from the 50s-70s are available online URL_0",
"Seedless avacados are not actually uncommon but are just small and are discarded by farmers typically. Due to the long time it takes seedlings to mature its difficult to breed new cultivars and most new varieties are accidental mutations. I buy pinkerton avacados and the seed to flesh ratio is great but it goes bad quickly off the tree and is bad for mass market. Hass avacadoes are the ones most people are familiar with I think. They produce a lot of fruits with seeds of varying size (but typically at least a third of the fruit is seed)and have a decent shelf life (for an avocado) I imagine the fruit is also resistant to mutations that affect seed size due to its evolutionary niche as food for megafauna which is why the pit is so large and the fruit so calorie dense.",
"As other people have mentioned, it takes time to be able to achieve the genetic modification you're after. The history of the avocado is quite interesting and I suggest you look into it. In essence - the avocado is really old. It's from the time that the Earth was covered with megafauna and megaflora (large plants and animals). The avocado tree relies on big animals to eat it and pass on the pit away from the tree, someplace new. 13000 years ago around 60-80% of the megafauna went extinct and so did the chances of the avocado to survive. Animals don't peel and eat just the fleshy part, they eat it whole and pass only the undigested pit. Not much animals were left capable of swallowing it whole and we can thank a select few for keeping it alive, at least until humans saw the potential and started growing it themselves. It's part of mexican culture for at least 2000 years, but it didn't really come close until the 19th century where it gained popularity, and the first half or the 20th century when people started creating varieties and mass producing it. But in the mind of the avocado pit it still relies on the big animals, so it may have been 200 years for us cultivating it, but it's gonna be hard for the avocado pit to get the memo that the thing it relied on for millennia to survive is no longer needed. Here are a couple of interesting posts about the history of the avocado: [why avocados should have gone extinct]( URL_1 ) [how avocados survived]( URL_0 ) (I apologise for formatting since I'm on mobile and I hope the links work, and I apologise for any language mistakes)",
"You can get seedless ones URL_0 Breeding for seedless things is tricky because obviously you can't breed them if they don't make seeds. Sometimes you can hybridize plants to produce infertile hybrids that don't produce seeds. This is how they make seedless watermelons. If you have a plant, like a banana, that can be grown from cuttings once you produce a seedless variety you can propagate it easily. But you can't really select for much in the way of changes, because each cutting is an identical clone. Finally, you can just prevent the flower from being fertilized, which in many plants will result in a fruit containing no seed. This is how they made those seedless avocados. It can be labor intensive to do this with every flower. The development of seedless avocados has probably been limited by a lack of suitable hybrids to breed with in order to try and make a sterile hybrid that will make a good tasting fruit which won't develop a seed or will produce only a reduced one. You can't breed for a trait you can't find in the population.",
"There's major factors you have to consider in things like selective breeding. * What climate are these crops sustainable at. * How long ago when selective breeding was started approx * How quick you can breed said crops * What how many traits are associated with breeding Just with a couple of those points you can gather; that even if the selective breeding process started awhile ago on avocados there's minimal places you can effectively grow it. Not only that but as someone mentioned avocados take awhile to grow, and the fact that there are other traits that come along with breeding it's not simple. Also you have to remember that even if say the seed size is small that could mean a few things, smaller produce, longer time to grow, and other things you can think of as well that might be a possibility. Ideally you want the best of both worlds.",
"Evolution takes time even when directed by humans selectively breeding things. If you have a plant that takes a year for each generation it is a lot faster than something that takes several years to bear fruit. To give you an idea how slow avocados are to adapting to new circumstances; the reason why there are such big seeds in avocados, is that they are optimized for passing though the digestive tract of giant animals. Avocados are the result of adaptation to giant sloths and armadillos the size small cars. You may notice if you live in the Americas that such animals are not currently present on the continent. They haven't been for many thousands of years. Those creatures became extinct shortly after humans started settling the continent in large numbers. It has been ten thousand years and avocados haven't really caught up to the fact that giant sloths are gone. The likely would have gone extinct too, if humans hadn't found them tasty and started farming them on purpose. Not a fast process."
],
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16,
16,
5,
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3
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"text_urls": [
[
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],
[],
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],
[],
[
"https://www.google.com/amp/s/www.mic.com/p/avocados-should-be-extinct-not-ubiquitous-heres-how-they-survived-29898741/amp",
"https://www.smithsonianmag.com/arts-culture/why-the-avocado-should-have-gone-the-way-of-the-dodo-4976527/"
],
[
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],
[],
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}
|
[
"url"
] |
[
"url"
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lghgwf
|
Why does pinching on the soft part of your nose above the nostrils stop a nosebleed?
|
I've been plagued by hour-long nosebleeds all my life, I finally thought I may have been pinching wrong. I Googled how to pinch, it said to pinch the soft part above your nostrils. I did that and it stopped within 10 minutes. I can't believe this? How does that stop the nosebleed? I know nosebleeds stop with a clot or something, but it doesn't seem like pinching there would be anywhere close to the actual cut that causes it to bleed. I guess this is biology?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gmrhqnr"
],
"text": [
"The tip of your nose contains a rich supply of blood supply (known as Little's area). This is where most nosebleeds happen. By pinching this area, you're applying direct pressure on the bleeding vessel, which slows down the blood flow so that a clot can form more easily, thus stopping the bleed."
],
"score": [
8
],
"text_urls": [
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|
[
"url"
] |
[
"url"
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lghkuh
|
Sometimes when you stir a spoon inside a ceramic mug and it scrapes the sides, it leaves dark grey lines against the interior of a mug. What are those lines, and why can't they be washed off?
|
Other
|
explainlikeimfive
|
{
"a_id": [
"gmrh6wz",
"gmrg230"
],
"text": [
"We had this happen with a matte glaze and ended up doing a little experimenting. By adding 10% of our glossy clear glaze, the matte white became just a touch more glassy, toughening it against these scrapes. I would say the overall texture went from dull matte to dull satin, but pretty much indistinguishable if you didn’t know the difference. Pretty neat if you ask me! Edit: Whoops. I thought this was on the ceramics subreddit haha. Welp, I might not had added this little tidbit otherwise! The takeaway: the potters that make those pieces are also aware that it happens and there are tons of ways to go about tweaking your materials to fix it going forward",
"The lines are metal. Ceramic is \\*hard\\* and you're scraping a thin layer off the metal, like a very fine whetstone. They don't just wash off because you've physically embedded tiny metal particles in the ceramic, it's not on the surface where it can be washed off normally. You can sometimes get them out by chemically disolving them or converting them to something colourless...this is why many of the fixes involve baking soda, vinegar, or bleach."
],
"score": [
14,
9
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"text_urls": [
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|
[
"url"
] |
[
"url"
] |
|
lghlsh
|
What limits digital transmission speed in a usb port for example?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"gmrkvip",
"gms6zxy"
],
"text": [
"Any connection (not just USB) is limited by: * the number of wires used for data (the more wires, the more data can be sent at the same time, over separate wires). * the length of the cable (the devices that are connected via a cable must \"synchronize\" their electronics in order to transmit and receive properly, and the longer the cable is, the lower the maximum frequency of bytes that can be transmitted). These are physical limitations. In addition, you may have \"design\" limitations. For example, USB is a standard, meaning that everyone has agreed to follow the rules as designed by the [companies that originally designed it]( URL_0 ), in 1996 or 2011 or whatever. So because some years have passed, there may be artificial limits built into the USB standard that everyone has to follow because it's a standard. Phones and computers may be a lot faster now, but it's a standard so they can't transmit faster than the spec. for USB.",
"Oh man, let's go on a trip. The first thing that limits transmission rates is physical switching speed. Newer transistors can switch faster so therefore more speed. Back in the days of parallel ports we got more data across with more wires. But then something interesting happened. When you start switching too fast signals from wires next to each other cross over, kindof like how transformers pass energy from one coil to another. This of course screws up signals. So then we went back to serial data and just switching faster. Thus USB. At this point though you start running into problems with signal reflections and the actual quality of wire you are using. If the impedance (resistance to AC current) of a wire isn't constant over the wire you get reflections of the signal. It works kindof like how sound echoes. This can be worked around to a point by regulating the quality of connectors and wires. USB 1 you could probably run over telephone wire and be fine. USB 2 needs twisted pair (reduces noise interference) and shielding to get it's speeds) With USB 3 you get even more speed from multiple pairs of wires. Though unlike in the old parallel ports days each pair is individually twisted and shielded to prevent interference. In addition the hardware does a bit of signal analysis on the cable to compensate for differences in the cable. That's just a brief partial overview of USB. In a more general sense what limits transmission over copper. Frequency: Faster is better. Duh. Usually limited by current transistor technology. Impedance mismatches. When the cable changes impedance it screws with signal quality. This can be overcome with signal processing and quality control on the cable to a degree. Voltage used. Higher voltages can overcome resistance and capacitive losses in longer cables, or you can use multiple voltage levels to send more than just one bit at a time. It's harder to get voltage to swing over a larger range though so in general if you are using a higher transmit voltage you are loosing out on max frequency. External noise interference. Generally overcome with differential signalling and twisted pair wire and shielding. Wrapping signal wires in foil blocks external noise from stray radio waves, and more twists in a wire reduces external noise interference. More twists in a wire also increases capacitance and therefore needs more voltage to maintain the same max frequency so that's a trade-off as well. All these tradeoffs are why there's different standards for different types of data. Ethernet, HDMI, USB, PCIe, etc. They're all balancing range, speed, and cost to implement."
],
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4
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"text_urls": [
[
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|
[
"url"
] |
[
"url"
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|
lgiur1
|
Why is Neo Classical economics still globally prevalent in policy despite having been “debunked” years ago?
|
Economics
|
explainlikeimfive
|
{
"a_id": [
"gmrokks",
"gmrp0gu"
],
"text": [
"Because it makes rich people richer, and government policy largely follows the whims of the wealthy capitalist class that funds policymakers.",
"Certain theories become dogma if they’re embraced long enough and fiercely enough by mainstream academics. They cease to be subject to the basics of the Scientific Method and Logical Positivism. They become a form of religion."
],
"score": [
3,
3
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
lgj2d7
|
Why do things that cause pain or discomfort, such as bitterness and spiciness, cause pleasure?
|
Why have humans come to enjoy spicy and bitter foods, as well as other "painful" experiences as pleasurable?
|
Other
|
explainlikeimfive
|
{
"a_id": [
"gmrufua"
],
"text": [
"eating something spicy causes an endorphin rush while your brain tries to counteract the pain. kind of like adrenaline. very basic response. someone else will likely elaborate. i just love spicy food."
],
"score": [
3
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
lgjvqc
|
How do LED lights work and why do they last so long?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"gmrybn8"
],
"text": [
"LEDs work by using voltage to bring electrons up to a higher energy level in their atoms. When they drop back down, they have to lose energy and they do so by emitting light. They last a long time because they don't have the same failure mechanisms as incandescent or fluorescent lights. Incandescent bulbs get the filament very very hot so that it will glow brightly. That high heat leads to various failure mechanisms such as evaporation, and the transitions from hot to cold add more. Fluorescent bulbs create a mini-lightning bolt when started up and then rely on a plasma to operate. It's kind of amazing that either type of bulb lasts long at all, given the extreme conditions."
],
"score": [
3
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
lgk0qi
|
How does stomach acid dissolve food without destroying nutrients?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gmssz5o"
],
"text": [
"So, your stomach *acid* doesn’t actually do a lot of digesting, so to speak. The enzymes that hang out in your stomach (and small intestine, and mouth) do most of the heavy lifting. The enzymes in your stomach only work in acidic conditions, though, so your stomach secretes its own acid to keep your enzymes working well. But yeah, basically what the other commenter said. These enzymes each break down a specific kind of molecule, whether that’s carbohydrates (which are made of sugars), fats, or proteins (which are basically long strings of amino acids). The monomers, or small building blocks that make up these nutrients (also called macromolecules), can be either broken down to release energy, or assembled to form new compounds that your cells need. Not all enzymes will work on all molecules, because they’re often specially designed to break one specific molecule up. A *lipase* enzyme will break down fats, but not sugars or proteins. A simple example of your enzymes not working on all macromolecules is cellulose. Cellulose is a carbohydrate that can be found in pretty much any plant (or plant product, like paper or cotton), and it’s used to help a plant keep its structure. It basically looks like a long string of glucoses, which are tiny sugar molecules that your cells are very good at converting into energy. However, our stomachs lack *cellulase*, the enzyme that breaks cellulose down. Those cellulose strands stay intact, your body can’t extract any nutrients from them, and they pass right through your system. Other organisms can make cellulase (bacteria and fungi, mostly), but we can’t. Fun fact: cows, sheep, horses, and even termites have bacteria in their guts that produce cellulase for them!"
],
"score": [
3
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
lgk9qb
|
Aside from piracy, what are the other major implications of a games source code being leaked?
|
This situation with CD Projekt Red is crazy right now, but I don't understand why the games source code being leaked is such a big deal since it's a singleplayer offline DRM-free game. People could pirate it day 1, why does this make any difference? They can't find any exploits that would allow them to hack into peoples computers remotely, since it's an offline game. What are the actual negative implications of a source code leak?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"gmrx4dn",
"gms0oh1"
],
"text": [
"One perspective is that if a game's source code were to be leaked, it could be used to achieve a company's result of it's hard work that it paid for. Example aside from Cyberpunk 2077: Let's say a company produces a racing game with the most realistic car physics on the market. They've invested millions of dollars into creating this grade A experience for racing games. If that source code were to be leaked, it could be used by other studios without them needing to spend a dime. Even if it's not just copied and pasted, the ideology behind it could be applied, again, with someone else footing the bill. Hope this helps.",
"It mostly means the homebrew and mod community will be able to do a lot more things a lot more easily, and the publisher won't be able to do much to stop them."
],
"score": [
7,
5
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
lgkbeg
|
What is a 5% level of significance?
|
Mathematics
|
explainlikeimfive
|
{
"a_id": [
"gmrzb3m",
"gmrz5ni"
],
"text": [
"The level of significance is kinda likes the chance that even though your evidence seems to show something special, nothing special is actually happening and it was just luck that gave you the special result. For example: let's say you have a coin, and you want to test whether it is a normal coin, or a rigged coin that always shows heads when you flip it. If you flip it twice, and you get heads both times, maybe that means it's a rigged coin, but maybe you just got lucky with a normal coin and got heads twice. After all, there is a 25% chance of that happening. So, if you wanted to set up the experiment to have a 5% level of significance, you'll want to to flip the coin five times, because there is less than a 5% chance that you would get five heads in a row. If you flip five times and get five heads, you can safely say \"This is not a normal coin\" and there will be less than a 5% chance that you are wrong.",
"If the null hypothesis is correct, then your method have a 5% chance of falsely rejecting it."
],
"score": [
10,
3
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
lgkek9
|
Since we have microscopic organisms walking around on our skin, do those microscopic organisms have organisms that are microscopic to them walking on their skin and so on?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gmrzdj9",
"gms5ow4",
"gmu0tou"
],
"text": [
"Yes. Well, sort of. (Note - this can't be exactly ELI5. Forgive me for going ELI15.) There's a type of little tiny organic robot called a \"bacteriophage\". It's an organism, but it's so simple that we're not sure it's really alive. It's a virus that makes more copies of itself by landing on and injecting its innards into a certain types of bacteria, kind of like how certain types of mushroom only grow on certain types of trees. The injection takes over the bacterium's internal factories, and instead of keeping the bacterium healthy, those factories start churning out more bacteriophages instead. These burst out and spread the party around. So they don't really \"walk\" on the bacteria's \"skin\" (which is really just a simple little wall to keep the bacteria's innards in and the outards out - and yes 'outards' is not a word but it should be), but they do land and inject. P.S. They look a lot like some of the weird wrecked injector-bots you see in some Stephen Universe locations.",
"Dust mites are too small to see with the naked eye and there's plenty eating our skin cells, but they are still multi-celled animals and almost surely host to bacteria of their own. So here's one example of this definitely happening.",
"Great fleas have little fleas upon their backs to bite 'em, And little fleas have lesser fleas, and so ad infinitum. And the great fleas themselves, in turn, have greater fleas to go on; While these again have greater still, and greater still, and so on. [[citation]]( URL_0 )"
],
"score": [
32,
6,
3
],
"text_urls": [
[],
[],
[
"http://wiki.c2.com/?FleasAdInfinitum"
]
]
}
|
[
"url"
] |
[
"url"
] |
|
lgkrcd
|
Why do judges sentence criminals to more than life terms? - Ex: 2 life terms plus 65 years.
|
Other
|
explainlikeimfive
|
{
"a_id": [
"gmrzup8",
"gms0668"
],
"text": [
"A couple of reasons. It's important that you be punished for each crime in certain situations. Such as you killed 300 people, to honor the dead we need to give you 20 years per person. Second, sentences can get reduced due to various factors. So if we knock your sentence down from 20 years per victim to only 5 years per victim, the person still has a 0% chance of getting out alive.",
"Life sentences are rarely actually a life sentence. It is usually 15-25 years depending on the state. After that time, they can seek parole. Multiple life sentences can be served concurrently or on after the other,"
],
"score": [
9,
4
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
lgky0u
|
why you can’t (or can) Invest a large sum of money into a stock, stock rises due to this sell, profit, repeat.
|
Wouldn’t this be possible? Say I put $100 million into a stock, causing the price to go up, then I immediately sell. Wouldn’t that be guaranteed profit? ELI5 please.
|
Economics
|
explainlikeimfive
|
{
"a_id": [
"gmsllzw"
],
"text": [
"Well what really happens in a stock market is there are two prices, the Ask and the Bid. The stock market might look like this: - Alice, Carol and Edith each have shares of XYZ. Alice is selling 100 shares for $20.00, Carol is selling 200 shares for $20.05, and Edith is selling 800 shares for $20.10. The Ask price is $20.00. - Bob, Dan and Fred each want to buy shares of XYZ. Bob wants to buy 300 shares for $19.95, Dan wants to buy 400 shares for $19.90, and Fred wants to buy 600 shares for $19.85. The Bid price is $19.95. So if you buy 1000 shares of stock, you'll clean out Alice's and Carol's offers entirely, and deplete most of Edith's offer. The Ask price will have risen to $20.10, meaning the next share you buy costs $20.10 since Edith's offer is now the lowest asking price. However if you sell, you'll be selling to Bob for $19.95 -- less than you paid for any of your shares. In order to sell your stock at a profit, you have to wait to see if Bob, Dan, Fred, or anyone else decides to offer to buy it from you for more than you paid. There's no guarantee this will happen."
],
"score": [
4
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
lgkywg
|
- Considering the technological advancements in the last 50+ years, how comes the relative appearance of astronaut suits have remained the same since then?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"gms21vf"
],
"text": [
"Appearance has nothing to do with technology (check out the high fashion from the era of Louis the XIV's time), but there haven't really been any fundamental changes in suit technology. The requirements of the suit haven't changed and the tech stack hasn't really changed so the suits look basically the same. Materials have gotten better, so the newer suits are a little less bulky and a little cleaner looking, and the helmets got better with better transparencies, and the backpacks got smaller, but functionally there's very little difference between the newest suits and the Apollo suits. Humans didn't change size or needs. It's like asking why pants have looked basically the same for several centuries. The SpaceX suits were very deliberately designed to look more high tech but, ironically, the visual cues are all non-technical...they're pure fashion. A lot of the true tech changes, like seals or computing or materials, aren't changes you can see easily. A carbon fiber racing skull looks exactly like a wooden racing rowboat from 100 years ago until you get up really close and inspect it. Edit: typo"
],
"score": [
17
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
lglddq
|
Why do call companies get away with “reaching out about my expiring car warranty”?
|
Other
|
explainlikeimfive
|
{
"a_id": [
"gms8ew6",
"gmsdgt4",
"gmtf90z"
],
"text": [
"It's an automated \"program\" (for lack of a better word) that spams every number possible. You'll be redirected to someone in another country if you went through the prompt and therefore it's difficult to prosecute them.",
"Because there simply isn’t enough law enforcement to go around. It’s also very easy for scammers to hide their true phone numbers making them damn near impossible to track down.",
"If you want an ELI5 that goes on for 2 hours, I highly recommend the podcast Reply All, episodes 102 & 103 (Long Distance). They go deep on how these scams work, tracing them around the world. They also did a follow up episode last year, #164."
],
"score": [
24,
4,
4
],
"text_urls": [
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
lglkm8
|
How do broken bones heal?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gmt1cm0"
],
"text": [
"Bone healing occurs in three stages. The first is the inflammation stage, where clot forms between the fracture. The next is the repairing stage, where the clot is replaced with cartilaginous and fibrous tissues to stabilize the fracture, which are then gradually replaced by bony tissue to form an immature spongy bone mortar. The final stage is the remodeling stage, where the marginal spongy bone is replaced with the harder compact bone, leaving the bone basically as good as it was before fracture."
],
"score": [
29
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
lgllmv
|
Couldn't we just launch nuclear waste into the sun, how would that work and is it even possible?
|
Physics
|
explainlikeimfive
|
{
"a_id": [
"gms7bqq",
"gms5173",
"gms78ml",
"gms7xbk",
"gms5d9g"
],
"text": [
"Ignoring for a moment the threat posed by a catastrophic failure during launch through the atmosphere, once you get the waste out of Earth orbit there's no particular reason to hurl it into the Sun. It's actually really difficult to hit the Sun from Earth. The Earth orbits the Sun instead of falling into it because the Earth is moving sideways at 30 kilometers per second. If we want something to fall into the Sun, we can't just launch it into space and let go of it; we have to cancel out all of its orbital motion first, and that's really expensive in terms of rocketry. If we just want to be rid of the nuclear waste, we're better off going up than down—it requires far less energy to launch something up and out of the solar system forever than it does to crash the same item into the Sun.",
"i’m no scientist but i think it would be really expensive and all anyone cares about is money",
"Too expensive and dangerous (rockets do explode from time to time...) Tbh, dumping it in the ocean is safer and cheaper. I'm serious. Once it is in the concrete caskets, you could easily dump it into a deep part of the ocean with no risk of radiation leaking to the surface and minimal risk of it leaking to bottom dwelling creatures. The middle of the pacific is deep (ballpark average 10-15k ft straight down) and is relatively barren of fish and other marine life.",
"There's no good reason to do so. It's simpler, cheaper, and safer to bury it on Earth. Having said that, of course we *could*. Put it on a rocket aimed near Jupiter, á là the [Ulysses]( URL_0 ) probe, on a Sun-crossing trajectory. As long as several things go according to plan, the package is gone, out of reach.",
"It’s very far away. The money it would cost to get it there would be better spent researching other means of disposal. Plus what if something crashes into it and then there’s just some nuclear waste floating in space. I mean shit. Maybe that’s how life begins on other planets. Some space trash finds its way onto a lonely planet and billions of years later you have things like chicken nuggets and the bachelor. Eek. Might as well just not."
],
"score": [
22,
20,
5,
4,
4
],
"text_urls": [
[],
[],
[],
[
"https://en.wikipedia.org/wiki/Ulysses_(spacecraft\\)"
],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
lgluf5
|
If you put a 2L bottle of liquid in the fridge, does it cool faster, slower or at the same rate as 2L worth of cans?
|
Also a simple explanation as to why thx :)
|
Physics
|
explainlikeimfive
|
{
"a_id": [
"gms6tce"
],
"text": [
"Cans will cool faster because a. Metal transfers heat faster than plastic, and b. The 2l cans have greater surface area than a single 2l bottle."
],
"score": [
38
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
lgme5o
|
how/why do we instinctively know we're not supposed to do things such as running into a wall?
|
Other
|
explainlikeimfive
|
{
"a_id": [
"gmsa9go"
],
"text": [
"You don’t, you learn as you start to move around. This is really clear if you ever have a chance to spend time around a toddler. They learn pretty quickly sometimes."
],
"score": [
25
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
lgmjuv
|
Why is the air from your mouth warm when your lips are wide open, but cool when your lips are puckered?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gmsiqzi",
"gmse4ih",
"gmu5jtx",
"gmu5xrs"
],
"text": [
"Oh! I know this one! The most common answer is that its perceived temperatures is all about heat transfer, not the actual temp. The air molecules around your skin get warmed up by your skin, so it feels cool when those molecules are blown away and new ones come, which can start taking more heat from your body. Think of a fan pointed at you in the summer- its not blowing cool air, the air behind the fan is the same temperature as the rest of the room, its just the movement of the air that feels good. When you pucker your lips and blow, the air comes out a lot faster, so it can do a lot more heat transfer. BUT, if the air in your lungs is body-temp, how does that help transfer heat from your skin, which is also body temp? There is another important piece, which is entrainment. Anytime moving air goes through still air, the moving air starts to pick up a little of the still air along with it (basically because of friction). The faster it is moving, the more it picks up, so wide-open mouth breath only picks up a little, but pursed-lips breath picks up a lot. PLUS, pursed lips means you are getting a small amount of hot air to start with, so by the time it gets to your hand, its mostly cooler air. (Compared to an open-mouth breath, which is a lot of hot air that only picks up a little cool air). You can test this by blowing with pursed lips through a tube- without being able to entrain other air, your breath will still be fairly warm on the other side. Or to put it as an ELI1: When you blow air fast, the hot air from your body picks up lots of cool air friends, and they can kick the heat away from your body really well together.",
"You are probably testing it by blowing on your skin, that gives a false impression due to evaporation of the moisture differing in a fast narrow air stream and a broad, wide one. Try it with a thermometer and see if the effect is real.",
"Pv=nrt. P is pressure. V is volume. T is temp. Basically put when you move a large volume of air through a small hole the temperature decreases. It's called the venturi effect. Look up carborater icing.",
"Simplest and 'non technical' as i can put it is as follows, When our lips are wide open, there is no restriction to air flow coming out of our lungs. This air (which has taken up some of the body heat) has bit higher temperature than surrounding air and feels warm. But what happens when the lips are almost closed? To understand this we must understand the relationship between pressure and temperature. It can be described simply as 'whenever there is rapid drop in pressure, it also results in drop in temperature.' You can experience this while refilling a gas lighter with LPG gas canister, where temperature may reach almost close to zero degrees c. In our case, when lips are puckered, we put a 'restriction' on air flow out from the lungs. This restriction causes rise in air pressure inside our mouth. When this high pressure air escapes through a small opening in lips, there is a sudden drop in pressure, which in turn leads to drop in temperature, that's why this air feels cooler. this drop in pressure is great enough to sufficiently cool down the warm air from lungs. and by the way there is more of physics at work here than biology."
],
"score": [
17,
5,
4,
4
],
"text_urls": [
[],
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
lgmjwn
|
How and why scars disappear over decades ?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gmsc2lj"
],
"text": [
"Not really an answer to your question but fun fact. Scars aren't permanent tissue. They're an ongoing process. If you were to give yourself scurvy, the ongoing process would stop, the tissue you know as scar tissue would weaken, eventually fail and the wounds would reopen."
],
"score": [
3
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
lgmsxi
|
Why a horse need to be put down if it breaks a leg
|
Why do they kill horses if they ever Break a leg? Can't they heal it instead?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gmsd3iw",
"gmsd6j6",
"gmsqf1x",
"gmt4egx",
"gmt4gvf"
],
"text": [
"It's a very long healing process for a complex limb. Horses put a lot of weight on that limb and they can't just lie down and heal for weeks at a time. Horses are also fairly nervous and quite stupid. They will not take it easy. They will not like the cast. They will not stoically handle the pain. Most of the time, horses are just one little incident away from freaking out over something. The short of it is that it's extremely hard to help a horse recover from a broken limb and it's very likely that the horse will either develop complications from a poor healing process or simply break the limb again because it doesn't know how to take it easy. With the risk of failure being so high, it's usually not worth trying unless it's an extremely valuable horse that still has a breeding purpose that doesn't rely on it having a perfectly functional limb afterward.",
"The main reason is because it’s honestly not practical for a horse to walk around on 3 legs. Not only is that a major factor, but because it’s is such a problem, “healing” is an incredibly painful process because the horse has to be immobilized for such a long period of time that it’s body won’t be able to actually support it once the bones heal. And that’s only if the bones heal properly, fitting a cast/brace on a huge animal like that isn’t realistic because of their size and strength and how expensive that would become. And it’s a ton of money for something that won’t be a guaranteed success.",
"Its not impossible to heal a horses leg. Depending on the type of break some (very rich) owners elect to heal the leg instead. But it’s a very expensive and complicated process during which the horse can’t do anything but stand in its stable with its body leg supported by ropes and whatnot. So you need infrastructure to do it in the first place, money to have the vet over every other week or so to check on the leg, and money to pay for the horses upkeep without the possibility of getting any money back from competitions or breeding or whatever. The second problem is horses are dumb. They don’t like being locked up in a small space without being allowed to play with their friends or eat grass. So they’ll either get a bit wild and risk hurting themselves more, or get depressed. Even in the last stages of healing they can decide that a leaf on the floor is very scary, jump, and hurt themselves Last but not least an extended cast period is never good. Not using the limb leads to reduced muscle mass and the bones get more fragile. The chance of the break not healing well or re breaking during the healing process are rather high. Even if it does heal there’s a good chance the horse won’t be able to perform as well as before, or maybe won’t be able to be ridden at all. Unless it’s a good breeding mare most people don’t bother. TLDR: it’s more trouble than it’s worth. Low chances of successfully healing and a huge pain to go through both for the horse and owner (and vet for that matter). Most of the time the kindest thing to do is to put the horse down.",
"a horse can't lie in bed watching TV for six weeks while it's mom brings it ice cream. A horse can't use crutches to get around. A horse is an enormous animal that is built to stand on all 4 legs. Keeping it off a leg while it heals is nearly impossible. A very valuable stud racehorse with private full time vet care may be able to recover from a mild injury, but most horses can't get that kind of care.",
"These folks mostly covered it but I’d like to add laminitis to the answer. When a human or any smaller animal has an injury to one leg, they’ll favor the other....putting more weight on that leg and foot. When/if horses do that, it causes a lot of problems in the “good” foot. Their hooves expand slightly with weight and putting MORE weight on a hoof that can’t handle it causes a chain of reactions that can cause inflammation and damage in the tissues. At that point even if the broken leg had time to heal, the other foot would basically be ruined. Maybe sling them up while they heal you may ask? Horses don’t like that. And they are large and potentially dangerous to themselves and everyone around them when they are scared. And their gut is made to work by moving around while they digest. The pressure and lack of movement would eventually kill them or possibly cause issues not compatible with life as well. Same for say.....keeping them laying down while they heal....another thing that would cause problems not compatible with life. PSA: healthy horses DO lay down sometime. If you see a horse in a field laying down, don’t call the authorities or worry all day that it was ill. I’ve personally had the UPS/FedEx whatever guy stop at our house without a delivery to ask if one of my horses was okay. Of course said horse got up to come see why we were standing in the yard. Haha"
],
"score": [
76,
15,
14,
6,
6
],
"text_urls": [
[],
[],
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
lgn9i9
|
What exactly is a game's source code and how can stealing it be bad?
|
Some hours ago I came across a news about how CD PROJEKT RED was hacked and, among other things, had the source codes for three of their games stolen. What does it mean for the company to have something like this leaked?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"gmsl386",
"gmsflvh",
"gmslpg7"
],
"text": [
"Source code is kind of like coca-cola's \"secret formula.\" Anyone can buy a coke, drink it, try to determine what it tastes like, but without some very high tech and expensive equipment, you probably can't figure out exactly how it's made. If you were to break into coca-cola headquarters or wherever they store the recipe and steal it, you could start making your own coca-cola impostor soda, which would of course be bad for the original brand. So, as for the code side of that, like the other reply said, some awful people could plagiarize that code and use it to make their own games, therefore profiting off the honest work of other people. If the source code that was stolen is for games that aren't released yet, then that information can be used to leak what the games will be about, and how they run. Side note: There are some programs and games that are \"open source,\" meaning the source code is freely available, usually on places like [github]( URL_0 ). Anyone is free to use, modify, and usually redistribute these programs as they see fit, and it allows people to examine the code so they can see that it's safe to use/find out if it contains malware. The downside is that the original author of the code can't directly profit from selling it.",
"There's source code then there's compiled code. The source code is what the programmers write out. Other programmers familiar with the language it is written in can puzzle out what it does, and even use sections of it for themselves. The compiled code has been converted from the programming language humans understand into the 1s and 0s that computers work with. It is generally nigh impossible to puzzle out what each bit of code does. Your computer knows what to do with 1s and 0s, but someone trying to take those and use the code for their own game would have a very frustrating time to the point it's not even worth it. Someone with the source code for a game could pirate the game, more easily create cheats for the game, or copy the game's code to use in their own game. They probably could be sued if it is proven in court that they made use of someone else's code, but if the game that rips off that code is compiled, then it would be difficult to prove.",
"The source code of a piece of software is what the developers typed up to make the project. There are tons of examples of source code out on the internet to look at to see what it consists of, but it's just thousands and thousands and thousands of lines of written code that is proprietary material - meaning it's like a book someone wrote and it's their property unless they release it for public use. The reasons this can be bad include things like maybe the project isn't finished and they don't want someone to possibly steal their unique ideas or even use the code to enhance or release their own product before the original company does or can, or maybe the source code contains unique and innovative ways to approach challenging problems in the industry and they don't want competitors to gain that knowledge and have an upper hand like they do. The very simplest reason is that it's hard work put into a huge project that will allow them to make profit and stay in business, and they don't want their work to be taken from them."
],
"score": [
5,
4,
3
],
"text_urls": [
[
"https://github.com/git"
],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
lgntn9
|
could the M1 Bazookas in WW2 penetrate any German tanks? How do the warheads work?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"gmsi9pp",
"gmsq9rs"
],
"text": [
"It used what’s called a “shaped charge” warhead. There’s an explosive shaped like a funnel, wide end forward, in the warhead. The funnel is lined with metal. The fuze at the front sets off the explosive on contact. The explosive squeezed the metal lining into a very thin VERY high velocity jet of liquid metal, like squeezing a watermelon seed between your fingers. The jet is so fast and high pressure that it can blow right through solid armor.",
"Yes, but no. u/tdscanuck already explained how a bazooka explosive works. The bazooka could penetrate up to about 100mm of steel armor. That sounds like quite a lot, but the top tier German tanks, Panthers and Tigers, had that much frontal armor. Some of the tank destroyers had even more armour. As a result, although the bazooka was effective, it had real trouble getting through the frontal armour of the bigger German tanks and was only good against them from the sides and rear. The US did start developing a more powerful Bazooka towards the end of the year, in part based on the German much stronger Panzerfaust and Panzershrecks, but those didn't reach the front lines until after the war. Still, bazookas and other shaped charge weapons actually did make infantry much more dangerous to tanks."
],
"score": [
6,
3
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
lgo1yy
|
Why is flour considered “raw” and needs to be cooked when the rest of our produce just needs to be rinsed?
|
My roommates were discussing a Master Chef contestant who used “raw flour” to thicken mashed potatoes—to the horror of the judges—, and I realized I had never thought about the food safety of flour. When I looked it up, there were numerous sources confirming people can get Salmonella and E. Coli from un-cooked flower, but I don’t understand why that isn’t a concern for all other plants we eat as well.
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gmsjyzq",
"gmsmsrf"
],
"text": [
"Because flour is the ground up version of the plant. When you take a normal fruit or vegetable and leave it whole, it has its own natural defenses to keep bad stuff out, like a skin or peel or any kind of hard outer layer. To clean it, all you need to clean is that outer layer. But flour, flour is ground up grain. It’s impossible to just rinse or clean off. So it isn’t that every sack of flour is definitely going to be contaminated by something like E. Coli, just that there is no real way to “clean” the flour besides heating it up to high temperatures.",
"Flour is *literally* raw. It's raw, ground up grain. It's a health hazard because it's assumed that you'll sterilize the flour yourself. By cooking it. When you get other raw vegetables, you wash them to remove contamination on the surface. Flour is ground up, so it's *all* surface, and it can't be washed. Because then you'd be making dough. This is why a steak can be rare. The outside is where contaminants might be, so that gets cooked. The inside is *mostly* safe. It is much less safe to eat ground meat raw because it's *all* surface. This is also why you can't eat raw cookie dough. It ain't the egg that'll likely kill you, it's the raw flour."
],
"score": [
15,
7
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
lgod0l
|
Social media sites don't allow spam but do allow promoted content. What is the difference?
|
Other
|
explainlikeimfive
|
{
"a_id": [
"gmsm6uk",
"gmsuor3"
],
"text": [
"Promoted content is openly marked as such and often put through special paid channels to reach a site's users. Spam often doesn't declare itself to be promoted, and often uses less-than-legitimate channels to reach users. An ad campaign to put posts about a telescope in front of users who have shown interest in astronomy is different from sending a DM to every user saying \"buy my telescope!\".",
"Ads make the site money. Spam does not, and also lowers the value of the paid ad, leaving the paid ads wondering why they bothered paying when others are getting the same results for free. Think of it this way - Seller A has a kiosk at a shopping mall pays rent to be there. Seller B comes into the mall and sets up a cardboard box selling stuff. Seller A had to pay rent, but Seller B is not paying rent, and yet still selling things. The mall isn't going to allow that. It's bad faith for the people doing business legitimately."
],
"score": [
6,
5
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
lgomsx
|
Why do your fingerprints not scar when cut / burned and always grow back into the same "print"?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gmsn7dx"
],
"text": [
"Yea that’s a load of bullshit I cut about a third of the tip of my thumb off including part of the print and it’s gone it just shows up as a weird wrinkly patch in fingerprints"
],
"score": [
3
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
lgp3yb
|
How do tattoos work?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gmsp1m1"
],
"text": [
"Your outer layer of skin is constantly being shed and regenerated, but your inner layers are not being regenerated anywhere near as much. The ink in a tattoo is in this deeper layer so it rarely gets messed with, but is visible through the outer layer of skin. It does get affected by regenerated over time though which is why tattoos fade over time as a person ages."
],
"score": [
6
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
lgpooa
|
Why is it better to buy a course from an educational site when you can find it on the internet on some shady sites for free?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"gmss0pm",
"gmsrlsm"
],
"text": [
"If you're asking: Why should I pay for something, when I could just *steal* it, and get it for free. Then I'm sure you know the answer. If you're asking: Why should I pay for something, when there are free alternatives? I'd say it depends on the context. The advantage of a paid product, can be that it's maintained and updated - also a financial investment in something, can help with motivation:) Whereas with an old free course from 2015, you could easily run into problems like dead links and so on. But there definitely are a lot of free good sources for a lot of subjects.",
"Just two reasons I can think of. 1) It supports the creator of that content when you buy their course. 2) Those shady sites are usually illegal."
],
"score": [
9,
5
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
lgptei
|
What is the reason we still do not have a vaccine for HIV, but scientists could develop several for Covid-19 in relatively little time?
|
They are both viruses. Can they not use the same methods they used with Covid to create one for HIV?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gmtkihg"
],
"text": [
"Because of the unstable nature of HIV's genetic material, the virus changes it's receptors (the parts that it uses to interact with our body's cells) very quickly. This means that we can't effectively create a vaccine for HIV because a vaccine works by attacking that specific \"shape\" of the virusses receptor. By the time the vaccine would be completed, it would no longer be effective."
],
"score": [
5
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
lgpwai
|
Why do our eyes have to adjust to darkness?
|
If our retinas can expand and contract so quickly, and if our cone cells can identify different colors in an instant, why do our rod cells take so much time to adjust to low light?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gmstw85"
],
"text": [
"There are 2 types of cells in your eyes that detect light. Cones for color and bright environments and rods that are for dark conditions but can only do greyscale. When you are in the light the rods are inactive. They need a chemical called rhodopsin to work but they don't save that. It takes up to one our to produce this chemical in sufficient amounts to saturate all rods in your eyes and give you optimal vision."
],
"score": [
9
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
lgqf4n
|
what is the scientific/chemical explanation for why we feel so calm when petting animals?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gmtk6ml",
"gmt422r",
"gmt64zn",
"gmthsiw",
"gmt754j",
"gmtky9r",
"gmufl3z",
"gmtihn1",
"gmu7frb"
],
"text": [
"Humans evolved to have pleasurable feelings associated with activities that are good for survival (being warm, eating energy rich food, sex etc.). There are two of these that come with petting animals: 1) pets (especially cats and dogs) behave in ways we interpret as affectionate, so our brain thinks \"this creature likes me\" 2) some aspects of pet mammals (small, soft, large heads relative to their bodies) remind us of human children, so petting an animal feels like looking after a child, another activity which is good for survival of the species so evolution selects for it. What we describe as \"cute\" often essentially means \"resembling a human child\".",
"The brain releases the neurotransmitter oxytocin, which signals pleasure centers of the brain.",
"Eli5 here: they're cute and fuzzy and that makes you release chemicals in your head the makes you feel good. Some people have the opposite reaction and get scared.",
"Humans are social animals and we evolved responses to social activities like cuddling that benefit us. Two hormones play a role here in this, called oxytocin (sometimes referred to as the love hormone) and cortisol (a stress hormone). Oxytocin is released in situations like romantic love (people “in love” have higher levels, thinking about or being with a romantic partner increases those levels, touch included), parent-child bonding (for example it is very strongly released in “skin-to-skin” time post-birth and breast feeding), and petting animals or cuddling in general (you can even get some of its effects cuddling yourself). Oxytocin is released from the brain (the posterior pituitary, after being first created in the hypothalamus). It is part of a positive feedback loop in the body when most hormones are part of negative feedback loops. This means that more oxytocin leads to the release of even more oxytocin (rather than it causing decreasing levels). Physiologically, when petting animals, oxytocin binds to receptors in the heart and blood vessels that leads to lower blood pressure and heart rate. Psychologically, it produces anti-depressant-like effects and elevates mood. The other important hormone here is cortisol. Cortisol is released from the adrenal glands located in one’s abdomen/stomach and it’s release is controlled by a complex network that includes the brain (the hypothalamus-pituitary-adrenal cortex). It is a steroid hormone involved in the stress response, including the fight-or-flight response. Petting animals actually decreases this hormone, leading to a blunting of this stress response, decreased heart rate, decreased blood pressure, feeling more calm. Basically, petting animals increases oxytocin (love hormone) and decreases cortisol (stress hormone), resulting in relaxation, elevated mood, lower blood pressure, lower heart rate, etc.",
"I think this is based on your schema of the animal in question. So some people have that reaction. They see an animal and they touch the fur and the brain releases the oxytocin because they've had a generally positive reaction with that animal over their lifetime. Some people haven't had such good experiences, and so they freak out (ie. Panic, get scared etc.) instead.",
"I read that elephants have similar chemical reactions when they see humans as we do when we see puppies. So basically they think we’re cute 🥺 Not all humans of course; I think it also said that they can differentiate between a poacher and a non threatening person, and have different calls to alert the herd. I’ll try and find the article, I hope I haven’t got it completely wrong haha *edit* Turns out it’s unproven. I really want an elephant to think I’m cute 😭 URL_0",
"When you pet your cat or dog, your blood pressure goes down and your heart beats slower. You feel less stress. The more and the longer you pet, the stronger these effects. The risk of cardiovascular diseases gets smaller. If it's a dog and you walk him several times a day, the health profit is even bigger.",
"This is just a pet theory of mine, but I think there’s something to be said for the focused, repetitive tactile experience that can induce oxytocin. Repeatedly touching fur (or any textured surface) is very calming, and in some instances can be grounding for people in the middle of panic attacks or other traumatic episodes. I also think this is similar to the ASMR that some people experience when listening closely to soft sounds, or watching small movements: there is something relaxing about focusing on non-complex sensory experiences. It’s very similar to meditation, or prayer, or what we now call mindfulness.",
"Petting reduces Cortisol (Stress Hormone) & increases Oxytocin (Love Hormone) most likely explanation is that our ”Monkey Brains” cannot differentiate between puppies 🐶 and human babies 👶 URL_1 URL_0"
],
"score": [
820,
286,
96,
25,
23,
7,
5,
4,
3
],
"text_urls": [
[],
[],
[],
[],
[],
[
"https://www.snopes.com/fact-check/elephants-think-humans-cute/"
],
[],
[],
[
"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5645535/",
"https://www.hopkinsmedicine.org/health/wellness-and-prevention/the-friend-who-keeps-you-young"
]
]
}
|
[
"url"
] |
[
"url"
] |
|
lgr6jy
|
How does brushing with Toothpaste improve the health of your mouth?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gmt06qg"
],
"text": [
"The brush is doing most of the work by scrubbing your teeth and gums clean of bits of food. The toothpaste has helps with the scrubbing, but it also repairs the outside of your teeth with flouride."
],
"score": [
8
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
lgrrqj
|
If the purpose of cooking meat is to kill bacteria, how come it's still not safe to cook and eat once it's off?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gmt1qdt",
"gmt1n8f",
"gmt1x1v"
],
"text": [
"> If the purpose of cooking meat is to kill bacteria, how come it's still not safe to cook and eat once it's off? That's not the purpose of cooking meat, it's a welcome side effect. Cooking meat results in denaturing most of its proteins, making it more digestible. Killing all living organisms in food that has \"gone off\" will not necessarily get rid of all the waste products they produced in the meantime. The food may have acquired an unpleasant taste or even be toxic for consumption as a result.",
"When the bacteria eats meat it produces(poop) a toxin that's dangerous to eat. So while the bacteria dies of the heat the toxins they produces is still there.",
"100% could be wrong, but I was lead to believe It generally isn't the bacteria that make you sick. It's the toxins they release, cooking will kill the bacteria but not remove the toxins already on the food."
],
"score": [
22,
10,
5
],
"text_urls": [
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
lgs356
|
Why does the bottle don’t fog up on the surface where the text is printed on?
|
I have a soda stream bottle which stood in the sun. When I picked it up I noticed that the condensated water was everywhere inside the bottle, except for the places where text is printed on. Is it because the text is black or is there another reason? [The bottle looks like this.]( URL_0 )
|
Physics
|
explainlikeimfive
|
{
"a_id": [
"gmt3rvx",
"gmtca4n"
],
"text": [
"The black text absorbed radiant heat, making that area slightly warmer than the rest of the bottle. The condensation gathers because of the cold surfaces. The more complicated answer: the rest of the bottle was below the Dew Point for the humid conditions created after much of the liquid evaporated inside the sealed bottle. The sun kept that small area slightly above dew point. You can take a look at the Psychometric Chart to see what Dew Point looks like at various conditions, look up an annotated copy that explains what is going on. It looks complicated, but it's fairly straightforward once you know what you're looking at. Edit: autocorrect",
"\\*Why doesn't a bottle fog up on the surface that has text printed on it? FTFY"
],
"score": [
10,
4
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
lgsotp
|
Why do toddlers stick their tongues out when you try to wipe their face?
|
It’s both funny and inconvenient. Why do they do it??
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gmt8gzu"
],
"text": [
"It's part of the tongue-thrust reflex. They do this to prevent themselves from choking and to help them latch onto a nipple when breastfeeding."
],
"score": [
7
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
lgtnml
|
Old phones use antennas to get their signal in and out. What is the replacement for the antenna in modern cellphones and how does that work?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"gmtbphs",
"gmtb8ru",
"gmtc6ad"
],
"text": [
"It took some time for cell phone designers to find out how properly place an antenna inside the cell phone itself. The antenna is effected by the metal chassis, wires, battery, the users hand, etc. So it is much easier and better to have the antenna stick out of the phone. And designers still get the antennas wrong, as Apple demonstrated a few years ago. But with modern materials, miniturization of electronics and antenna simulations we have become pretty good at designing antennas that work from inside the phone itself. In addition to this we now have far better cell coverage so we are not relying so much on good antennas and the frequencies of the cell phone networks have gone up which means the antennas have gotten much smaller.",
"I’m pretty certain they still have antennae, they’re just built onto the inside of the phone chassis instead of protruding from it.",
"Antenna bands. Phones still use antennas they're just hidden. Fun fact: most phones don't have radio antennas, but you can replicate an antenna system by plugging in a set of wired earbuds"
],
"score": [
9,
7,
3
],
"text_urls": [
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
lgttg2
|
How is "fake news" not illegal?
|
Other
|
explainlikeimfive
|
{
"a_id": [
"gmtci7r",
"gmteiqj",
"gmtfbmv"
],
"text": [
"The US has very strong legal protections for speech, and *especially* political speech. Speech is only illegal under a very narrow set of circumstances, and generally only when it causes obvious, direct, immediate and quantifiable damage.",
"First of all, we need to be clear on what actually Fake News means. Is this news that is completely made up? Is it news that is based upon a factually true event, but then told in a way that distorts what happened (this is most prevalent with most TV news shows)? Is it a collection of news that only shows the good things about one political party while showing only the negative things about the other (this is what most TV news stations do)?",
"Because true and false are very difficult concepts to discern and allow for interpretations. For the following affirmations tell me which one you would consider false or fake. - it is now 2pm in the UK, - trees are green, - the sky is blue, - immigration is the cause of unemployment, - black people run faster than white people. For political topics, let’s say a US president gives the affirmation « Mexicans steal our jobs ». - is it true because it’s always true ? - is it true because it’s true is some cases ? - is it false because it’s not always true ?"
],
"score": [
9,
3,
3
],
"text_urls": [
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
lgtyii
|
Considering Chess provides perfect information of its board state and has zero randomness, how come the game isn't 'solved' yet?
|
It seems that there are still chess bots/AI being developed and being improved until now. Seeing as how all possible actions can be calculated and saved in a database ahead of time, why isn't the game solved by just 1 Chess Bot that has all the best moves to win/draw the game everytime?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"gmtdkf3",
"gmte9cg",
"gmtdr06",
"gmtitb8",
"gmua0ym"
],
"text": [
"There are far too many possible actions that we couldn't get close to calculating and storing them all. The number of possible board positions is somewhere in the same region as the number of atoms in the Milky Way galaxy.",
"\"Solved\" is a very tricky word. There is a fairly massive database of endgame positions which are solved in the sense of the word you are describing. For each one of these positions, every possible line has been simulated, and every modern chess engine is equipped to play perfectly to the inevitable loss, win, or draw. But these are all positions with relatively few pieces on the board. When a computer engine evaluates a position with many pieces on the board, it is actually horribly inefficient to perform such a brute-force calculation. There is simply not enough time in the universe for a machine - no matter how fast - to run a brute-force calculation from the starting position. So engines evaluate opening, middlegame, and many endgame positions from a set of qualitative criteria, as well as through advanced AI algorithms where they learn how to play the game.",
"Because there are practically infinite amount of states. White has 20 possible moves at the start of the game. Black has 20 possible responses. So that's already 400 states. But then it becomes even bigger and more complex. There are such a massive number of possible states that it becomes unfeasible to compute them all. So yes, chess is solvable. You could compute all possible states and find an optimal strategy, but it isn't solved because we are technologically limited.",
"Eli5 answer: Our best computers beat humans at chess every time. It has been many years since a human has beaten a top chess computer. Right now, our technology limits us and we cannot completely solve the game yet. There isn't enough time to calculate and store all the information. But perhaps when computers get faster and have more memory in the future, we could solve it. Chess computers use advanced \"pruning\" techniques. Solving the game would require searching through every possible board state and finding the optimal strategy for it. We cut or \"prune\" a lot of those board states out, however, because they seem like they shouldn't happen when the chess computers are playing well. So the computer only looks at board states it thinks are likely to come up in the next several moves, rather than all of them. This way, it can make a move much faster. Remember, official chess is played with a clock!",
"The game tree (every possible move) is far too deep and cycles back on itself (i.e. there's nothing stopping players ending up in an infinite loop of just about any size). But the sheer size of that tree is the reason. That a computer can win now is quite amazing, there's a reason that IBM Deep Blue was such an achievement. If you think that's incredible, the game tree for Go is several hundreds of orders greater, so Go, despite looking a much simpler game, is almost impossible to build a game tree for in the foreseeable future. Which is why Google's AlphaGo is DAMN incredible. These machines are some of the most powerful on Earth with stupendous amounts of storage. And neither are enough to store and analyse the entire game tree for chess or Go (chess is feasible... it may actually have been done already and I'm not aware, but Go will likely never be done with any number of conventional computers). We're talking numbers like 10 to the power of 360 - ridiculously more game positions than even atoms that exist in the universe (10 to the power of 80), and things like that."
],
"score": [
46,
21,
7,
7,
3
],
"text_urls": [
[],
[],
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
lgu1n3
|
Why are videogame cutscenes, intros and menu scenes rendered in real time instead of using a pre-recorded video?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"gmtduxx",
"gmtdzwx",
"gmtfaku",
"gmthfxk",
"gmte6cf",
"gmtps2z"
],
"text": [
"You might have different armour on when the cutscene happens, or if it’s a different time of day in game? It should look fairly consistent with the game as you’re playing it when you trigger the cutscene.",
"It saves space (videos are big) and allows characters to be customized - with the gear you have on type of thing.",
"Historically going back to the days before optical media became the dominant form of distributing games, it was a limitation of just how little storage capacity flash NAND cartridges or floppy disks had. It cost only a fraction of the storage space to script everything to happen in-engine using all the game assets you had anyway, than it was to package a video of that happening. It was only once optical media like CD's started appearing with huge gains to storage capacity (if at a performance cost, load times are now a thing) that you started to see video assets in games, most notably with the entire FMV (Full Motion Video) genre. Which did kick off an era of pre-rendered cutscenes. You can now include high quality rendered cutscenes that in no way could the hardware of the time actually run in real-time. Final Fantasy as a series did this a lot early on, though it had a lot of janky in-engine cutscenes as well because CD/DVD can only hold so much. That held until recently, when hardware with the previous and current generation really started to make high quality scenes runnable in real time *and* now storage space is starting to matter again since digital downloads are becoming a dominant means of distribution.",
"There is one main reason for using pre-rendered cutscenes, which is that they can look better than in-engine ones, due to having more time and resources to render more detailed models, advanced effects, and more complex environments. Conversely there are several benefits to using in-engine scenes. 1) File size - video files are much larger than a set of scripted animations. Most of the scenery and assets in the cutscene will be the same as used in game, so don't take up any more data (there will be exceptions where scenes take place in areas that aren't playable, for example, but even then they will use less data than video). 2) Adapatability - scenes can be dynamically adjusted depending on the game state. For example the gear your character is wearing or has equipped, which NPCs or party members are present, the time of day, or even the actual location of the scene. Doing this in pre-rendered scenes would require rendering multiple versions of the scene to account for differences. 3) Seamless transitions - the game can switch smoothly from gameplay to cutscene and vice-versa, which can be more immersive. 4) They can look better. Strange one this, as it is exactly the same benefit I claimed for pre-rendered scenes, but in many cases those don't look as good as they could. They may have been rendered at lower resolution or framerates to save time/costs, or have heavy compression to save space. Especially in the late 2000s/early 2010s, it wasn't unusual for it to be obvious that you'd entered a cutscene as the resolution dropped from 1080p to 720p, frame rate from 60 to 30 or 24, and suddenly you were seeing a lot of compression artefacts.",
"It can only be pre-recorded if no dynamic parts are in it. So if a character wears a custom outfits, or any parts of the cutscene can be influenced in any way it must be created in real time",
"- Cost and complexity. Pre-rendered scenes typically have a completely separate production process and sometimes are done by an outside studio. It's a lot simpler and cheaper to just have an in-house dev script the models and scenes you already have. - Space. Before games on CD's started to go mainstream in the mid-1990's, games simply didn't have enough space to store movies (and PC's didn't have the processing power to display them). - Dynamicness. In-engine cutscenes can show different versions, e.g. if your character doesn't look exactly the same (e.g. custom armor / outfit, or you can choose a different character / party each time you play)"
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lgu59d
|
Why do cosmic bodies such as planets and galaxies move circularly and not wiggly or straight?
|
Or any shape for that matter
|
Physics
|
explainlikeimfive
|
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"They do move straight... as they have inertia. It’s space-time that’s curved. It can’t be wiggly because for something to wiggle, something else must cause it to wiggle. That said things do certainly tumble. It may also appear to wiggle when passing by certain objects as the curvature of space may cause a slight deviation.",
"Because of gravity, typically the gravity of the star they orbit around. And as far as \"how does gravity work\" there are multiple theories. The basic Newtonian theory is that gravity is a force, and what's happening is similar to tying a rock to a rope and whirling it above your head, you hold the rope with a force, and that force keeps the rock going in a mostly circular orbit around your fist. So gravity being a force acts he same way, even though it's invisible (the rope is not there). The more advanced (Einstein's) theory is that matter bends space and time in such a way that straight lines actually become circles around the object / material causing this bending of space and time. Similarly to how you can start driving in a perfectly straight line with your car, but because the Earth is a globe, if you were to film yourself driving from a camera out there in space, you'd see your car complete a circle around the Earth, even though your own eyes would tell you that you've been driving \"straight\" the entire time. With this theory, gravity is not a force, but just an effect of space and time being curved by matter (by stars and planets).",
"They move in a circular motion (more often an ellipse) because there is some other planet or star attracting it. It's like tying a thread to a ball and you swing it with your hand. The ball will move in circular motion because the thread is pulling it. Gravity is like the thread"
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lgu6ax
|
How are video game AIs programmed? Is it a just a long series of "If Then" statements? Why are some AIs good and others terrible?
|
Technology
|
explainlikeimfive
|
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"There are multiple ways to do it. Generally your if-then statement is close to reality. (Often it's Event based, to allow changes when new information is available rather than static checking what to do once previous commands are finished). Having lists of priorities is also common, to let the AI take the most important of the currently available options. AI skill is hard to get correct depending on the game. Strategy games are notorious for having terrible AI because it lacks creativity to adjust to any strategy the player might choose. In other games a good AI easily outclasses even pro players when not carefully reduced to human reflexes/perception Making a very good AI without allowing it to cheat (having more information than the Player for example) is a lot of Work and rarely done because just cranking up the numbers also makes the game harder for the Player without any effort for the programmers.",
"I read about a really cool simple AI in the old 8-bit Micro Machines racing game. The entire track was covered in invisible arrows. The computer controlled cars would just go in the direction of whatever arrow they happened to be on. When you shove a computer car off the track or push it behind an obstacle, it would literally be sitting on instructions on how to get back into the race.",
"Traditionally most simple AI's aren't necessarily just a chain of *if* statements. Rather, you would look at the actions an actor can do and calculate a motivation for them to do each one. The highest motivation wins. For instance, in The Sims, you might have a motivation score for Hunger, for using the bathroom, and for a few other things. Over time the motivation scores for hunger and bathroom go up until you're more motivated to use the bathroom or to eat than to do other tasks. You can make any specific motivation score as complicated as you want. Maybe your motivation to use the bathroom is higher when you're in proximity to one, so if you're going from A to B you might decide to use the bathroom on the way.",
"Different games require different AIs. AIs in a game like Dark Souls are basically complex If-Then statements. The enemy takes in their position, the enemy position, maybe a few other variables, and chooses a move to execute based on that, usually with some random chance in so it's not too gameable. AIs in a game like Total War are much more complex. There are many more factors that it needs to keep in mind, and often times the AI just can't handle the sheer amount of decision making. A big thing to keep in mind is that AI's need to run in realtime. in a game like total war, the AI could be made to be better, but then the calculations might take so long that the AI can no longer run in real time and you get a pause in the game frequently as the AI would need to make a decision. But that isn't fun gameplay.",
"As with anything involving programming, you can do it however you want. A common one is called a \"finite state machine,\" where you store a block of code in the current `state` variable (look up \"function pointers\" if you are interested in doing it yourself), then every frame you tell the game to run whatever is currently in the `state` variable. If certain conditions are met, then you swap out what's in the `state` variable with new code for a different behavior. For an example let's use a turret enemy. It rotates back and forth until it sees the player, then it shoots the player until it can no longer see them. In this case, we would have 2 states: Idle and attacking. We start with the code for \"idle\" stored in `state` which rotates back and forth, then checks if it can see the player. If the player is spotted, then it sets `state = attacking` and the next frame the attacking code is run. The attacking code will attack until it loses site of the player, at which point it will set `state = idle` and the cycle repeats. I don't know how familiar with code you are so I tried to keep it as close to ELI5 as I could, but if you want more detail I can. As for why some are good and some are bad, that's more of a design issue. It's like asking why some movies are good and some are bad. With games it comes down to knowledge of what makes an enemy fun to fight, programming skill, and time spent programming. Sometimes things are rushed, or the programmer just didn't care and we end up with a bad AI.",
"Or by \"machine learning\", which is just the programmer programming the AI to play the game itself before playing vs human. Example - I made a hangman game. The \"ai\" can play the game itself but starts with only the alphabet. It takes guesses in sequence, noting a correctly guessed letter each time and the word + word length each time it dies. By the end of 1000 iterations, it guesses the correct word 70% of the time. It always starts with 'e' as it came up the most times in its previous games. To make it more efficient, you would add extra 'lists' to be filled and keep track of, like word length x letter used - narrowing down the selection to choose from. You can then go further - after every successful guess, search your word list for matching words. And so forth. In the end, it is just the program storing information in different ways that is then used.",
"As said by others, it's mostly IF-THEN, together with ranking the possible options and taking the one which has the best \"value\". Machine learning is also a possibility, but up to my knowledge it is rarely used by major game companies. & #x200B; > Why are some AIs good and others terrible? 1. Games with secret information (like fog of war in wargames, hidden hands in cards games) are much more difficult to handle that games without secret informations (like chess). This mean that a common problem for AIs is that they \"forget\" informations they had 5min ago but they no longer have access to.Often, the devs just chose to make the AI cheat by looking at the secret information, and compensate by making the AI play suboptimally so that the player doesn't realise the AI is cheating. The more difficult solution is that on top of handling the current state of the game, the computer has to handle all the different informations that are known by the AI, and try to make deductions. 2. Games in real time give a huge advantage to AIs compared to turn base games. The AI can effectively act instantly thousand of time per second, so unless the devs willingly reduces the AI's capability to a more \"human-like\" level, the AI is potentially OP. 3. On the other hand, a lot of games have absurd amount of informations, which our brain is much more effective at approximating than AIs. There might not be that much difference for you between a game where you move from a square to another square (like chess) and a game where you have continuous movement (like Starcraft), but that's a huge complexity overload for an AI. 4. Having a stupid AI that cheats and have big bonuses (like free resources, etc) is much easier to code (allowing the team to focus on new contents, bug fixing, and DLCs), and the huge majority of players don't see the difference. As such, a lot of companies publish their game with very poor AIs. This is even more the case for games where it is assumed that experienced players will play against other humans, not AIs.",
"For a non ELI5 version, I would read up on \"behavior trees\". To summarize, you can just think of the kids of activities the AI does, and then imagine how you would decide to switch between activities. The switching is basically an \"event\" that happens, and ultimately you detect it with some if statements. But as the programmer you write a tiny function that triggers the event with if statements, and from then on you think of it as an event instead of the if statements that created it. Activities and Transitions * Patrolling - Starts in this mode. This is further broken down into sub steps, that basically boil down to: * Walk to the next spot in the route. How it does this isn't part of the AI, it's just a pathing algorithm * Once within some short distance of the goal, change what \"next spot\" means to be the one after that * Chasing - Once the player is detected, move toward them. This uses the same pathing algorithm as patrolling, and may choose to have them run by setting the move speed faster. The faster movement is one signal to the player that they are being chased. You can also enrich the experience by having the AI say, \"hey!\" or something. If they become undetected, chase where you last detected them. If the AI gets out of range of some distance or zone, revert to patrolling, which means find a path from wherever you are to the next patrol point and start walking, and maybe say something like, \"must have been the wind\" * Fighting - If you are in combat range of the player, do whatever abilities you have. Often there is a minimum time between any actions, called a global cooldown, and a minimum time between the same action, which is the action cooldown. This prevents them from doing everything at once and controls how often. You can make a whole behavior tree within this space to include things like evading or hiding when you are reloading or whatever. You think about this the same way you do this overall tree. This is a structure for one way you might design an AI. The behavior tree is an algorithm that lets you organize the activities of your AI in a way that mirrors how we behave, and it doesn't have to be that complicated for it to appear intelligent superficially. Gamers often observe the AI and start to recognize the patterns and learn to manipulate the AI to unintelligent things. When you break down any pattern or algorithm in computers, at the finest grain level it is all a bunch of if-else type statements, because at a processor level, testing and branching depending on the result is the fundamental way to control program flow. We often build up base patterns or algorithms to let us think about it in a more convenient way even though at a low level the test and branch pattern is everywhere.",
"As an AI researcher that plays a lot of games in my spare time, this always baffled me. From what i have gathered the state of the art in the games industry are still decision trees, which are as you describe it, simple if than statements. Those work great for first person shooter enemies, overarching directors, like in left for dead 2 the number and intensity of zombies spawning, and the alien in alien:isolation. So why is this the case? Why not simply train up a good network that will be better than all the decision trees you can come up with? After all, we can basically play dota and starcraft at pro level now with enough resources. The answer I gathered from multiple videos and thinking about it myself is, that in games, gamedesign is always king. You can only ever have really smart AI if the gamedesign allows for it. Take the Alien from Alien:Isolation i.e. You do not want it to be smart, because if its only goal where to kill the player, the game would not be fun. You also want it to be predictable, so that the player can learn its behaviours. A trained AI however will not play \"fair\" and predictable, so to speak. If you give it a goal, it will kill you, it will do so in the fastest and unfairest way possible and the end result is you not playing the game anymore, because you died 6 times in a row without any counter. You could probably make the alien more stupid, by restricting the information it gets, but now you need to basically balance the game in an indirect manner and bugfixing will be a nightmare. Imagine the balancing act multiplayergames have to go through but for a singleplayer game that needs to be ready and fun on release and also adding all the exploits a godlike AI can find in your game on top of it. & #x200B; The only time where an actual smart AI would be useful is, when it is supposed to mimic the way a human would play. This could be the case in computer controlled enemies in multiplayer games. But this is almost the only case, where you want actual smart AI. If you are interested in the topic and want to dig a bit deeper, I highly recommend the following videos/youtube channels: Gamemakers Toolkit: What makes good AI. [ URL_0 ]( URL_0 ) & #x200B; AI and Games: Behaviour trees 101 [ URL_1 ]( URL_1 )"
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lguqbk
|
Why do our eyes fill up when we are emotional?
|
I cannot think of an explanation why this physiological response is stimulated and what role our eyes have in this whole scenario. Also, do animals cry too? With tears and all i mean.
|
Biology
|
explainlikeimfive
|
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"We're social animals, so communicating with others was important enough for survival that we evolved things like laughing, yawning, crying, and other facial cues to how we feel and how others feel.",
"It is an emotional response in the brain that stimulates our lacrimal (tear) glands to increase tear production/excretion. It does have a part to do with social interaction and is potentially why emotionally increased levels of production are a thing. Additionally, your tear ducts (in the corner of your eye closest to your nose) actually drain into your nose which is why crying also causes congestion. Animals have tear glands to keep their eyes moist but I can't answer whether they shed emotional tears or not though."
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4
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lgussy
|
Advanced concepts of Big O with examples (except O(n), O(1))
|
Technology
|
explainlikeimfive
|
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"If you wanted to sort a list of numbers, one of the simplest ways you could do it is to find the smallest number, put it at the beginning, find the second smallest number, put it at the second position, and keep repeating until the list is in order. Finding the smallest number is a ***O(n)*** task, because it takes longer proportional to the length of the list you're searching, and you're repeating the task ***n*** times. So this form of \"insertion sort\" is ***O(n^2)***. If you used a more efficient algorithm, breaking the list apart in clever ways, sorting the sub-lists, and recombining them, you could get the total time down to ***O(n log n)***. The explanation of why it's less than n^2 is a little hard to explain so I'll leave it out unless you need it, but the point is that \"divide and conquer\" is a good working strategy. If you wanted to solve the \"travelling salesman\" problem, of how to plan a trip to n different cities with the least travel time, searching every possible combination and ordering of cities would take ***O(n!)*** time, which quickly becomes enormous. That's why it's really important in such problems to find a good heuristic to use that might ignore better possibilities, but will give you an answer that's close to the best answer, in a fraction of the time."
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lguyiu
|
If energy is mass, why same weight of food can have different calories count?
|
Biology
|
explainlikeimfive
|
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"Energy as mass (E=mc^2) is related to nuclear fission, that is splitting apart the atoms. Calories are derived from simple reactions, like digestion or combustion.",
"*tl;dr - Because people don't contain nuclear or antimatter reactors. We only get out a tiny amount of the energy in our food.* Energy and mass are equivalent; put simply, *mass is a way energy expresses itself*. But turning that mass into energy (i.e. getting all the energy out of something) is very difficult. The best way is to *annihilate* the mass by combining it with an equal amount of antimatter. That would get out *all* the energy (as there would be no mass left). But that would take a lot of antimatter. Only a few nanograms of antimatter have ever been made by humans. Your digestive system isn't going to be able to do that. The next best way is through a *nuclear reaction*. That is messing around with the things at the heart of atoms (protons and neutrons). There are two main types of nuclear reaction; either taking big, unstable nuclei and breaking them down into smaller, more stable ones (fission) or taking really small nuclei and smashing them together to create larger, more stable ones (fusion). When you do this, the mass of the thing you end up with is slightly less than the mass you started with, and that missing mass, or \"mass defect\", comes out in the form of energy. But your digestive system isn't capable of running nuclear reactions either. The energy we get out of food doesn't come from either of these processes. It comes from *chemical* reactions, rather than physics ones. That is, it comes from breaking apart molecules and combining them in more stable or more energy-efficient ways. But this extracts only a tiny part of the total energy of the thing. Google tells me that 100g of sugar contains ~400 kilocalories, which is about 1.7 MJ of energy. 100g of mass would give you about 10 billion MJ of energy if completely annihilated via equivalent antimatter (note you'd get 20 billion MJ energy out, as you'd also be annihilating 100g of antimatter). For comparison, 100g of uranium-235 (the standard thing for nuclear fission) would get you about 10 million MJ of energy out (if you really want I could do the calculations for hydrogen and nuclear fusion). So when food labels the calories in it, it isn't saying the total theoretical energy extractable from the food if you completely annihilated it, it is saying how much chemical energy your digestive system can get out of it. And given how complicated the chemistry of different foods is that will depend much more on the chemical composition of the food (so the type of food) than the mass. 1kg of sugar will give you more energy than 1g of sugar, but 1g of sugar may give you more energy than 100g of something else (because sugar is really easy to break apart for energy chemically). In theory, when you eat food and extract energy from it, you do decrease its overall mass by the appropriate amount. But using the rough numbers above, you're only affecting a 10 billionth of the total mass (even a nuclear reaction isn't going to change the mass by much more than a thousandth). Actually measuring that (particularly given how messy the whole process is) is going to be very difficult."
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"url"
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|
lgvw0i
|
What is Diffie–Hellman key exchange protocol in Messaging App.
|
Technology
|
explainlikeimfive
|
{
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"text": [
"Diffie-Hellman is a way for two people to share just enough information that they can each generate a secret key for use in encryption but not enough information for an eavesedropper to also generate that key. A good analogy is paint. Paint is easy to mix but impossible to unmix. You and I each secretly choose a paint color. (Let's call those colors A and B) Then we each decide and agree on a public paint color. (We'll call this color C). Then we each mix the public color (C) with our secret color (A and B). At this point I have a mixture of A and C and you have a mixture of B and C. We exchange our mixtures. Since paint is impossible to unmixed, anyone witnessing this exchange cannot extra A from AC nor can they extract B from BC, even if they know what C is. We then add our own secret color to the mixture given to us by the other person. So I add A to the BC you gave me and you add B to the AC I gave you. In the end, we both have the same mixture: ABC. Diffie-Hellman does this, but with math. The mathematical operates are chosen to be easy to do in one direction, but extremely hard to undo. That way, you and I can exchange information and perform mathematical operations that independently give us the same answers, but an eavesdropper cannot extract the appropriate information from our public exchanges to do the same thing."
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lgvy49
|
How is end to end encryption actually safe? Can't someone just steal the key?
|
Lemme explain my question. Disclaimer: My question would sound like a 5 year old's explaination itself but bear with me. Say I was texting my friend on a service that is "end to end encrypted" so basically when I hit the send button after typing, it locks it and the key to the lock is with only me and my friend. **But,** a hacker can just find the key because our service made it for us so there must be a universal 'recipe' to make that key that the service uses throughout everyone's chat and the hacker can just find the recipe and make the key. Making a random key wouldn't be useful since I would have to 'tell' my friend the key and the hacker can just intercept that. So how on earth is it possible to make something completely unreadable to others?
|
Technology
|
explainlikeimfive
|
{
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"It's called Public Key/Private key encryption. The service you are using gives each user a Private and Public key. It's randomly generated, but the public keys stored on their servers so that they can make the communication work. The way Public Key/Private key encryption works, is that if I want to send someone a message, I encrypt it using their public key. Then when they receive it, they decrypt it using their private key. Only the private key can unencrypt the message. So in your case, your app will ask their servers for the public key of your friend. Then use that public key to encrypt your text message. Your friend's app will use it's private key to decrypt the message. The private keys shouldn't be stored on the server for maximum security."
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lgw94l
|
What is 'fitness'? As in, why is working out easier the more you work out?
|
Let's assume you have two twins. One gets regular exercise and hits the gym every day. The other is a couch potato. Let's also assume that the fitter twin eats more calories and does only cardio, so they more or less have similar weight and muscle mass. Still, the one who gets regular exercise is able to run for longer, will break less of a sweat and have a lower heart rate. What are the physiological differences when someone is 'fit' versus 'out of shape'?
|
Biology
|
explainlikeimfive
|
{
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"text": [
"When we do cardio, blood is more directed towards the muscles you are working out (and away from places that aren’t doing a whole lot at that time). The blood flow is increased. The volume of blood is also increased when it is returning to the heart. Over time, the left ventricle enlarges to adapt to the larger blood flow. Now this ventricle can hold more blood and eject more blood per beat (even when resting). This decreases the heart rate over time. There is also evidence that exercise stimulates the production of new blood vessels. This creates more efficient circulation. Also, there is evidence that at the same time that cardio increases the number of blood vessels, resistance training increases the size of those blood vessels. This allows for fewer blockages and more efficient blood flow. The new blood flow (with fresh oxygenated blood) helps keep your other body parts healthy (like your organs).",
"Your organs adjust according to how they are used. So the more you use your muscles, the larger they will become. Same with heart (which is also a muscle really) etc. it makes sense - if something is not used, then it is probably not needed, so there’s no sense for the body to put resources into maintaining it.",
"There are two main channels. The first is that the body adapts to do the things we require of it. The cardiovascular system becomes more efficient at extracting oxygen from the air and distributing it to muscles. The relevant muscles may not become huge as in body-building, but they still become stronger and better able to handle repetitive stress. The same holds true for the heart, which is after all a muscle too. The second is practice. Lots of time spent doing an activity like running makes you better at running in both conscious and unconscious ways. An experienced runner will be more aware of their pace, breathing, and stride. They will also have significant muscle memory that lets them take particularly efficient strides. If your hypothetical fit twin *only* trained in running, they would be a much better runner, but only a somewhat better swimmer, than their twin.",
"The cardiovascular system changes just like muscles on a weight-lifter change. If the perceived effort to your body is low, then you won't need responses like sweating, increased heart rate, and heavy breathing like you would to keep up with a high degree of perceived effort. There's also biomechanical efficiency aspects at play. When you do something often like run or swim or bike you learn to relax and use better form and hold it even when you're getting tired. You can get \"more bang for the buck\" from the energy you do have by moving more efficiently. The \"couch potato\" will be less efficient with his energy to begin with then break proper form faster when they start to feel tired."
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lgxa7c
|
How are guys like LeBron James and Tom Brady coming about in this era and completely annihilating multiple records that were maybe held by one person previously? Even if we assume it's PED's, those have been around for a long time too. What changed?
|
Biology
|
explainlikeimfive
|
{
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"text": [
"A lot has changed. Our understanding of sports medicine and our ability to successfully repair and rehabilitate injury is dramatically better than even the 1990s. Athletes can train harder and play longer. The pipeline has gotten better, elite athletes are identified and trained to specialize earlier. The rules have changed to protect players from injury - and sometimes prioritize scoring. Of course LeBron will score more than anyone who played before the shot clock era and Tom Brady will play longer than QBs who got driven through the Earth’s crust five times a game."
],
"score": [
12
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"text_urls": [
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|
[
"url"
] |
[
"url"
] |
|
lgxdpy
|
Do trees feel pain?
|
Earth Science
|
explainlikeimfive
|
{
"a_id": [
"gmtypgf",
"gmtyh0y"
],
"text": [
"Well we have to define \"pain\". What we call pain isn't even agreed upon by all people (see masocists). So taking the general definition of recognizing stimuli that represent environments not conducive to our survival, then yes plants feel pain. They can recognize if they try to grow into an always shady spot and will try to avoid it. They recognize ground that is too salty or otherwise inhospitable and won't deploy as many roots there, etc.",
"It’s my understanding that a fully functioning central nervous system is needed in order to ‘feel’ as we do. I’m aware that plants don’t have those, but that’s not to say that they’re incapable of feeling. Certain types of fungi actually have the capacity to reach out to other living things in their proximity as their biomechanics allow them the knowledge that another living organism is within their reach. As far as I know, we don’t even have a catalyst for determination to find out whether or not plants have the capacity to ‘feel’."
],
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5,
5
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|
[
"url"
] |
[
"url"
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|
lgxvz8
|
Why can you eat some types of cheese with mold (blue cheese) but not others (Gouda)?
|
So some cheeses seem to be toxic for you if you eat them when they have mold on them, while others are mainly being consumed when they get moldy. Why is it so that some types of cheese will make you sick, while you can eat others without a problem?
|
Chemistry
|
explainlikeimfive
|
{
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"gmv9wk8",
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"text": [
"So it's not necessarily the cheese itself that makes you sick, rather the properties of the cheese and the types of mold growing. Mold spores are all around us and on our food. When a mold spore lands on food it starts to grow little microscopic filaments called mycelia. These are sort of like roots. For very hard cheeses, these roots can't really penetrate into the cheese that well, so in general you can cut the mold away and eat the cheese with little worry of ingesting any mold. In the case of soft cheese, the roots are able to penetrate much deeper into the cheese and often will remain present in the cheese even if you cut away the visible mold. Blue cheese - and other cheeses that are sold moldy - is a special example of cheese that you can eat moldy. In the cheese making process, a particular type of mold ([Penicillium roqueforti - a close member to the mold we use to make penicillin]( URL_0 )) is introduced into the cheese which is safe to eat. This mold actually changes the texture of the cheese as well, making it more creamy. Importantly, the cheese makers also keep a close eye on the cheese during this process to make sure no dangerous molds are growing. Keep in mind, however, that even though it's safe to eat the mold in blue cheese, you should keep an eye out for any new smells or colors in cheese that's been in your fridge for too long because that can indicate the presence of harmful molds taking over which may make you sick through the [toxins]( URL_1 ) they release. Edit: Typos, and a couple of links to other comments for more info. Edit 2: Since I only briefly said in the last sentence and didn't explicitly state/people aren't reading the linked comment: Some molds produce dangerous/toxic byproducts into its surroundings that make us sick when eaten, whereas others do not and are fine to consume. Because you won't know the type of mold growing on your cheese or whether its harmful it can be dangerous to eat moldy cheese that isn't sold moldy.",
"The type of mould that makes a blue cheese blue is different from the type of mould you will find in a lump of Gouda left in your fridge for too long. Some mushrooms are safe to eat, while others are hugely dangerous and will kill you if you eat them - mould is the same. Blue cheese is made in such a way as to grow certain types of good mould, while the stuff that appears naturally in your fridge is the bad stuff that can make you ill.",
"It depends on the type of mold. Different molds produce different waste products. The waste produced by the mold in blue cheese isn't toxic to us. The waste created by other types of mold are toxic to us.",
"I was as a cheesemaker for 2 years (until covid) - finally a use for a lot of now useless knowledge! When we make blue cheese we add bacteria to the milk that introduces blue mould spores. The bacteria comes from labs and we know it's safe to eat so when that cheese starts growing blue fur, we know even though it looks mouldy, it's safe to eat. If you take home a Gouda and it grows blue mould in your fridge, you don't necessarily know where that mould came from because it's not in a controlled environment, so it isn't guaranteed to be safe to eat. If a Gouda in our dairy sits too close to a blue cheese and starts growing blue mould it's just as safe to eat as our blue cheese because it's in a controlled environment and we know where the blue came from. TLDR: Blue mould from cheesemaker = good. Blue mould from your fridge = bad. Doesn't really matter what the cheese is.",
"There are many types of mold (aka fungus) that can grow on cheese, some types of mold are harmless while others can be toxic. In the cheese making process, the cheesemakers can tightly control the environmental conditions and encourage the correct type of mold to grow. If you get mold on a cheese that isn't meant to me moldy, it could be any type of fungus and potentially a harmful one.",
"Most molds that grow on non intentionally moldy cheese is non toxic aspergillus or penicillin molds. I usually just cut or scrape it off.",
"Short version: The mold that grows on Bleu Cheese is a very very specific species of mold that isn't toxic to humans. But if you leave it any food out for too long (cheese or any food, really), some random wild mold floating through the air will land on the food and start growing. This wild mold is not the safe species from bleu, so it can be toxic to humans.",
"The same reason that you can eat mushrooms but no death caps. Both are fungus. The mold on cheese is also a fungus. Some of them are delicious some are deadly. Many centuries ago people found out which molds are mit Dangerous and they saw, that If theese molds grow on their food it prevented other molds from growing. So the food was longer edible by adding the right Kind of mold.",
"cheese is super confusing. mold, no mold is one thing. Stinky is sometimes ok, sometimes not ok. The worst part for me is knowing when to eat or not eat the rind. I've started eating it on most cheeses now and haven't died yet, but sometimes it does taste pretty waxy.",
"Let me be the first to tell you that blue-veined gouda exists and it is DELICIOUS. My favorite cheese I ever had was a blue-veined gouda, but sadly I cannot find it now because my local cheese shop closed last year.",
"A related subject about which molds that grow on compressed tea \"designed\" for storage are dangerous keeps going over a similar issue. All of those molds are seen as a bad thing, but one common take is that you can brush off a white mold version but anything green or yellow is more dangerous, and you need to throw that \"cake\" (bing, or disk) away. The other take is that the mold is growing inside the tea too, and even white mold is dangerous, and you should throw the tea away (pu'er, that type). A type of yellow mold is actually seen as positive in other hei cha (a broader compressed tea category), and is intentionally inoculated. In all these cases the molds aren't regarded as a poison that will kill you, like cyanide, but are toxic, and cause health problems in other ways, including being carcinogenic, or potentially damaging internal organs. Except for that \"good\" yellow mold; that is said to have no negative effect.",
"It’s the milk, from which cheese is made that can be a problem. Raw (unpasteurized) milk can carry Listeria, Brucella, Salmonella and other seriously bad bacteria. Pasteurizing the milk kills those germs. Any cheese made from unpasteurized milk might be risky, visible mold or not. Mold that grows on cheese usually is not toxic. Blue mold is usually from the Penicillum family (penicillin was the very first antibiotic used on humans). Some molds and bacteria are used to make and/or flavor cheese. For instance, Camembert and Brie uses Penicillum camberti (a bacteria, not a mold) and often they have a coating of white surface molds that is harmless and many find it yummy. Rules of thumb. Crumbled or soft cheese (Gouda is a semi-soft cheese) that shows abnormal mold (blue mold on blue cheese is just fine) should be tossed. Mold on hard cheeses should be cut away, about 1” deep and 1” all around. Mold has trouble growing deep into hard cheese, but easily into soft or semi-soft cheese. Black mold on any cheese should be tossed for it could be Aspergillus niger, a toxic mold.",
"Mold is a type of fungus - a group which includes mushrooms. Just as some mushrooms are delicious and others may harm you, some mold improves a cheese and some mold may make you sick.",
"There are actually some Gouda cheeses with a blue mold. URL_0"
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|
[
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] |
[
"url"
] |
lgxybe
|
Is there any truth to the “5 second rule” when you drop food on a dirty surface. Does the bacteria/germs transfer instantly or is there a grace period? & if so, why would this become so popular if food is not contaminated?
|
Other
|
explainlikeimfive
|
{
"a_id": [
"gmu2ch5"
],
"text": [
"No there’s no truth to it. Most bacteria is on the dropped food almost immediately. It’s popular because it’s a funny thing to say and lots of people still want to eat the thing they dropped."
],
"score": [
12
],
"text_urls": [
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|
[
"url"
] |
[
"url"
] |
|
lgz2sc
|
Money stopped representing gold in the 1970's (I think).. So What does it represent now? Does this mean the goverment can just make infinite ammount of cash?
|
Money is just digits nowadays, it doesn't represent the total gold the state has. So can banks and goverment just change the digits?
|
Economics
|
explainlikeimfive
|
{
"a_id": [
"gmu9kh4",
"gmuag9q",
"gmua1nk"
],
"text": [
"Governments could theoretically change the digits but it wouldn’t actually change the value of things. If the US government decided to add two digits to the dollar so $1 is $100, the price of everything would just rise by an equal amount. Ultimately, what gives money value is everyone agreeing it has value. A dollar is worth a dollar because we all accept dollars as payment. But a more tangible reason is that everyone needs it to pay taxes every year. It doesn’t really matter if the government takes dollars, gold, or seashells. If you have to come up with $10,000 in seashells or go to prison, seashells have value.",
"Yes, governments can basically create money out of thin air. But the rub is that everyone else has to believe that the new money has real value or that it soon will. If people don’t believe that the new money has any value then all the money (the newly created money and the money that was there originally) loses value. That’s what happened recently in Venezuela, the government there created more money but nobody accepted the new money as having real value, so they simply increased the prices on everything. When the US created new money recently, the prices of everything did not go up mainly because people believe that the new money will get people to invest in new things that will ultimately create more value. But if this fails to happen, then prices will start increasing in the US as well.",
"That is correct. The central [banks can print money out of thin air]( URL_0 ). That will lead the currency to lose its value and, consequently, inflation. This means you will need more money tomorrow to buy the [same things you do today]( URL_1 )."
],
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22,
6,
4
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"text_urls": [
[],
[],
[
"https://eu.usatoday.com/in-depth/money/2020/05/12/coronavirushow-u-s-printing-dollars-save-economy-during-crisis-fed/3038117001/",
"https://i.imgur.com/kLH0i9g.png"
]
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}
|
[
"url"
] |
[
"url"
] |
lgz4pr
|
Why is it that when you look at a completly foreign place, it looks completly different then when you see it for a second + time?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gmu9199",
"gmuutix",
"gmubuje"
],
"text": [
"Why before you meet someone you don’t know them but after you meet them you know them?",
"The best I can answer is that your eyes/brain are overwhelmed by all the new details, it's unfamiliar. The more you look at it, the more the \"new\" details settle in as familiar and maybe you start noticing the subtle features of the place/picture. Maybe the uglier things even start to pop out to you. Eventually, it all becomes completely familiar and your brain ignores it.",
"I understand mate. I've tried to ask other people this. The usual response I get is \"what?\""
],
"score": [
8,
4,
3
],
"text_urls": [
[],
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}
|
[
"url"
] |
[
"url"
] |
|
lgz54l
|
If I buy shares at one value then later sell them at a higher value, who/what is funding that profit to me? Is someone/thing out poorer as a result?
|
~~out~~
|
Economics
|
explainlikeimfive
|
{
"a_id": [
"gmu9o1e",
"gmua65x"
],
"text": [
"In theory, the company itself is funding the increase. When you bought it, everyone believed the company was worth $50 a share. Since then, the company has done something to increase their profits and now everyone believes the company is worth $65 a share. You have made $15, but nobody has *lost* $15 - the value of the company has increased because they’re providing a service customers are more willing to pay for. Long term investing isn’t “zero” sum, everyone can win. Now if you bought a stock in a certain stop for games and then sold it to some idiots for 400x its value, then they’re gonna lose money when they find out that nobody else will pay that price. There are also more complex things like stock options where you’re directly betting against another trader, and that does have losers.",
"It’s like buying a car, keeping it for a long time and then deciding to sell it, only to find out that it’s a vintage car in very good shape, and is now worth more than what you paid for it. Whoever buys it from you is not “poorer”, they simply decided that they would pay the price for that car. When you bought it it was worth an amount you were willing to pay, and now it is worth an amount that someone else is willing to pay. If no one wanted to buy it at the higher price, it would not be worth that value"
],
"score": [
15,
4
],
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|
[
"url"
] |
[
"url"
] |
lgz7fw
|
Can I use shampoo in place of body wash?
|
Chemistry
|
explainlikeimfive
|
{
"a_id": [
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"gmubreq",
"gmu9ni4",
"gmue4s9",
"gmvfcn0",
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"text": [
"Take every response with a grain of salt. Some people have scalp issues. Some have dry skin issues. Some have excessive oil in the hair. Some have hair that's more/less difficult to manage. Some have excessive BO, while others don't have this issue. In short, washing yourself is about removing unpleasantness without creating imbalance. Some shampoos will strip more than desired, and can leave you with really dry skin (perhaps seasonal). You can damage your hair if you strip it too much, which is where conditioner can help rebalance. If you can wash your hair, and clean the rest of your body, and leave it smelling fine for an appropriate amount of time, there's nothing bad about doing that. I started doing this in high school when I was taking 2-3 showers a day (morning, after gym, after sports practice). And yet, it doesn't work for some friends and family because they have different levels of skin dryness, hair properties, body odor...",
"I learned to use head and shoulders as a body wash when I was living in the Caribbean. There is a skin bug you can pick up that will blotch your body sometimes very badly. The chemical in it (H & S) kills the bug. Plus you never get dandruff!",
"I do it all the time, have for years. I find that when I’m truly dirty if I grab the dedicated body wash I come out feeling fresher, but on a regular basis I just soap my hair and then use the excess to do the rest of my body and have never had any issue or complaints from anyone around me. Girlfriend often comments that I smell good so she doesn’t seem to have any URL_0 the end they are both soaps, most, if not all the difference is marketing.",
"It depends on tho shampoo. In general it is all just soap so there is no issue with using shampoo to wash your body. However there may be different things in shampoo that may not be suitable for the rest of your body. These are the chemicals which makes different shampoos do different things to your hair. For example anti-dandruff shampoo will have just the same effect on the rest of the skin on your body as it does to your scalp. And this might not do your skin very good.",
"I use shampoo as basically 'head wash' I have a big beard, so the only thing above my neck that isn't hair is my eyes, nose, and ears. I figure they get covered in shampoo anyways so why not give them a scrub",
"You can find 2-in-1 body wash and shampoo or 3-in-1 with conditioner on most store shelves. There may be some differences in high-end products, but most of it is marketing. Edit: Apparently while I thought I was pointing out that the existence of 2-in-1 implies there’s no real difference between the two, I mistakenly suggested that you buy 2-in-1. Not intended.",
"About 2 years ago I had run out of shaving cream and wasn't able to go but some. I did a quick google search to see if I could use shampoo and it seemed like it would be OK. If was great. So much so that I made it permanent. Specifically I use head and shoulders, but I assume any would work.",
"The answer to this, is yes, if you like the results. Everyone's skin is different. Our skin is different in how thick it is, how quickly it sheds, how dry it is, and how much oil we produce. Because we are all different, everybody needs just a little bit different care than other people. Most of our shampoos, conditioners, soaps, lotions, body washes, scrubs, and so on are tested against a sample of people and are then adjusted in little ways to get better results with whatever group they decided to test the product. This means that not every product is going to actually be good for every person. That's why there are shampoos specifically targeted to those with Asian, African, or Middle Eastern/Indian backgrounds here in the US-- because most of these product testers are assumed to be \"typical\" people, i.e. Caucasian people in the US, who have very different needs than other people around the world. So that means that, if you're a dry skin guy, but the product you used happened to be tested on really oily people, it might be too strong for you and might make you end up drier and itchier. But if you're very oily, or work around a lot of dirt and grease all day, you might find that a gentle shampoo does just about nothing for you. This is also why most people shouldn't use body wash on their hair-- skin on your head is more sensitive than the skin on your body, so chances are, the body wash is too strong for your head skin. So basically, try using your shampoo as a body wash and see if it works out. If you're happy with how clean you feel, if your skin stays healthy, if you aren't too oily or too dry and you don't break out in pimples, redness, or rash, then it'll probably work for you. But if you do end up with a result you don't want, then I would say try something else."
],
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|
[
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[
"url"
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|
lh0kkl
|
Why aren’t multivitamins a substitute for a well-balanced diet?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gmuk90j",
"gmuk9ll",
"gmuisoq"
],
"text": [
"Imagine you were tasked to build a robot that was extremely good at removing nails from wood. After some trial and error, you settle on a design that uses a crowbar attached to a robotic arm. The robot can remove nails faster than any human, and with less damage to the wood. It excels at the thing it was designed for. Now imagine you gave the robot a pile of loose nails just sitting on a plate. This would be way easier to a human, but the robot struggles. The nails move around too easily and it can't push against the wood the way its used to. Other nails keep getting in the way. Even though the challenge seemed easier, the robot is actually much slower and breaks more nails than when they're embedded in wood. The human body evolved to extract nutrients from food. It is incredibly efficient at that task, but multivitamins are different. They are suspended in different compounds and may have very tiny chemical differences. The machinery of the human body just isn't very efficient at extracting them and putting them to use.",
"They only provide vitamins and minerals, but not the carbohydrates, fats, proteins, fiber, water, etc. that your body also needs to function properly. The vitamin and minerals help your body operate to utilize the food it takes in, converting it to energy, fighting germs, etc. What you're proposing would be akin to wondering why you can run your car on oil changes and not filling it with gas.",
"You need carbs, protein, minerals, fibre and fats too. Nutritional needs aren't substitutes for each other - all the nutrients are needed."
],
"score": [
19,
5,
4
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|
[
"url"
] |
[
"url"
] |
|
lh23qs
|
Why are blue-eyed people a little more sensitive to bright lights?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gmurthg"
],
"text": [
"People with lighter eyes (like blue eyes) have less pigmentation in their eyes, and we know that pigments absorb like. This is why things that are colored black get hotter on a bright sunny day than something that is white. So, people who's eyes have more pigment have more light absorbed by the different layer of the eye before the light hits the retina (the sensitive part that captures the light info and sends it to the brain.) People with lighter eyes have eyes that let through a bit more light, leading to a slight general increase to light sensitivity."
],
"score": [
3
],
"text_urls": [
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|
[
"url"
] |
[
"url"
] |
|
lh2em2
|
Why there are products despite heavy marketing, good quality, good design, they cannot sell well in the market?
|
Economics
|
explainlikeimfive
|
{
"a_id": [
"gmuur6c",
"gmutctd",
"gmuwog2",
"gmvnuum"
],
"text": [
"1) Price. 2) Availability of substitutes / crowding out. Releasing the best cereal in the world? 3) Poor market research, lack of market to begin with. Selling air conditioners in Iceland? 4) Perception/Reputation of the manufacturer. Kia might make an objectively superior car but people prefer BMWs. 5) Switching costs (real or perceived). For example being familiar with Apple vs Android. Or having all your friends on Facebook means switching to another platform might be difficult. 6) Timing. There are products with very short life and very seasonal demand. Releasing the best Christmas gift on New Year's day is likely to make the product unsuccessful",
"Usually because there isn't a market for the product. You can make the most incredible, self-balancing unicycle in the world, but no matter how cool and well made and well publicised it is, most people would rather just ride a bike.",
"Those qualities might not be what's most important to buyers vs. cost, ease of buying. Or there may be existing brand perceptions that advertising and shifts in quality cannot overcome. It took time (from 60's to 90's) for Honda and Toyota to shift from \"cheap\" cars to \"reliable\" cars. Now the Korean brands are trying to make same leap. Hyundai cars are very reliable, but many still remember the $5,995 super cheap cars from a generation ago. Or it could be something people just don't see the value in paying more for... say you make the most beautiful bathroom plunger, that works great, but costs $100. The vast majority of people are going to be fine with the $8 Home Depot one no matter how great yours is or how much you market it.",
"For the same reason some people like vanilla ice cream. You can't account for personal taste as it's subjective and chaotic. Example, try selling a 45 year old on new technology. No matter how effecient or time saving you have about 50/50 odds of him buying into it or saying \"why fix what aint broken\". Another example is android V iphone. It doesnt matter how technically superior, effecient and versatile android is; some folks continue to incorrectly purchase apple."
],
"score": [
12,
9,
5,
3
],
"text_urls": [
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|
[
"url"
] |
[
"url"
] |
|
lh2pve
|
When describing our culinary likes and dislikes, do we all taste the same thing and have preferences, or do we actually taste different things?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gmuw6tx",
"gmvbg3m"
],
"text": [
"I know for a fact that some people can taste certain bitter flavors that others can’t, it’s a genetic ability. I remember we all got tested for it in grade school while being taught about genetics. I couldn’t taste anything while the kid next to me looked like he was about to vomit. Anyway, we all don’t taste the same things but there’s enough similarity that most people can roughly agree on what things taste like, though preferences certainly vary by person and culture.",
"I actually just heard today ( I have no idea how true it is) that cilantro is something people taste vastly different. To some people it taste like soap!?!?!?"
],
"score": [
5,
3
],
"text_urls": [
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}
|
[
"url"
] |
[
"url"
] |
|
lh2ua6
|
Why is it common for teachers and nurses to unionize, but not, e.g., architects or lawyers?
|
Economics
|
explainlikeimfive
|
{
"a_id": [
"gmuxz6p",
"gmuw88d",
"gmux9ta"
],
"text": [
"When you have a lot of people working for a single employer there arises the possibility where the employer could impose unfair wages or bad working conditions. So the workers collectively bargain with the employer to have better working conditions and pay - they form a union. Architects are mostly self-employed or work in small studios, so there isn't a critical mass of workers that need to be organized. The same applies for lawyers in smaller law firms. Engineers (IT mostly) and Lawyers in bigger law firms are highly sought after and work in a competitive field. They have the luxury of going away and working for someone else (in contrast to nurses and doctors - there are only so many hospitals). Companies compete in providing the best perks to employees just to lure more of them in. So there is no need to form unions. At least not right now :)",
"Well, to start with lawyers and architects tend to be self employed, so there's no need. Nurses and teachers almost exclusively work for someone else so there's more benefit to collective bargaining as a group for them. If a lawyer wants to change his fees, he just does it.",
"The professions generally don't unionize because there's not much incentive to do so; they're already typically paid rather well, and thus the two primary things Unions exist to lobby for (i.e. compensation and better working conditions) aren't really that big of a deal. Nurses are actually kind of the odd-man-out in that, in major part because nursing *does* tend to have lower compensation than the other professions, and because nursing inevitably deals with the harshest working conditions of all of the professions *by far*. Teaching is kind of odd in that it actually has a lot in common with the professions (e.g. licensure), but at the same time isn't standardized enough to be a \"true\" profession. Regardless, teaching generally has a lot of the same issues as nursing, in the form of low pay and stressful working conditions."
],
"score": [
15,
6,
3
],
"text_urls": [
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
lh38pu
|
What exactly is a voltage controlled amplifier, and why is it important?
|
We're working on a VCV board in my class, connecting a ton of cables to make sounds, and the teacher stressed the importance of VCA. He said that audio source and envelope generators multiply to create audio output; why is this important? What exactly is VCA anyway?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"gmuzn7w"
],
"text": [
"VCA = Voltage Controlled Amplifier. You can think of a VCA as basically an automated volume knob. An audio signal is passing through it, being volume-controlled by a control voltage signal. a high control voltage turns the volume up, a low CV turns the volume down. Volume control is very important in synthesizers, because it lets you determine the \"shape\" of a sound - like whether it should have a short, sharp attack, or a long, slow swell."
],
"score": [
4
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
lh3zon
|
why do snow storms not produce lighting like traditional thunderstorms?
|
It’s snowing and I just blew my own mind with the realization that I’ve never heard or seen lightening during snow storms, even severe ones. My thought is that it’s the same amount of moisture as a rain storm, so would it be due to pressure or temp differences?
|
Other
|
explainlikeimfive
|
{
"a_id": [
"gmv3acb",
"gmvchtq",
"gmvc4dq"
],
"text": [
"It can thunder and lighting during a snow storm. It's called Thundersnow. The Science Also known as thunder snowstorms or winter thunderstorms, a thundersnow only happens when a rare set of conditions occur. In fact, people only witness about 6.3 thundersnow events each year. Typically between late winter and early spring when the air beneath the clouds is warmer near the ground than the air in the upper cloud layers. The cumulonimbus cloud (towering mass with a flat base at fairly low altitude and often a flat top, as in thunderstorms) must be lower than a typical thunderstorm, and the warmer air temperature must still be cold enough to form snow. Thunder snowstorms usually create snowflakes, soft snow pellets, hail and strong “gravity wave” currents of air similar to ocean waves. The lightning produced appears in purplish-blue flashes.",
"Usually just because a temperature gradient causes fast, hot air to rise and collide with cold dropping air. You can't see them collide of course, but the billions of water molecules knocking into each other builds up a charge in the cloud, just like when you rub your socks on a fuzzy carpet. But when it's cold there's much less movement. It's more like rubbing socks on a tile floor, it won't build up any charge because there's much less friction. As someone else said, thundersnow exists but is rare. It requires a mix of freezing cold and *even colder* air to still create that temperature gradient. I wonder how frequent they are during ice ages.",
"Lightning is usually generated when moist warm air flows upward into cold icy air, friction between the two generating chargers. A snow storm lacks the upward motion, temperature gradient, and interaction between warm moist air and ice particles so no charge is generated and no lightning triggered."
],
"score": [
54,
12,
3
],
"text_urls": [
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
lh44eb
|
How Do Honey Bees Control the Temperature Inside of a Hive?
|
Other
|
explainlikeimfive
|
{
"a_id": [
"gmvgdaf"
],
"text": [
"They vibrate to keep themselves warm. When it gets very cold, they will form a cluster around the queen to keep her and themselves warm and minimize heat loss. When it's warm, they use their wings to fan the air out of the hive to generate a breeze to cool it. And lastly, if it's still too hot, many of them will sit outside, creating a \"beard,\" to stay cool and prevent their body heat from warming the hive even more."
],
"score": [
5
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
lh4azv
|
Why is the scientific definition of a mole the number of carbon-12 atoms to make 12g rather than the number of protons/neutrons to make 1g?
|
Chemistry
|
explainlikeimfive
|
{
"a_id": [
"gmv6wge",
"gmv4e9x",
"gmv5hv4"
],
"text": [
"It isn't. The scientific definition of a mole is 1 mol = 6.022 140 76 * 10^23 particles. Your definition was the former definition, though. How they came to that old definition was already explained in this thread.",
"A mole is a specific number of atoms. The “12” in carbon-12 takes into account the number of protons and neutrons (6 of each). If everything was based off of 1 g instead of a specific number of atoms, then we’d get differing amounts as the elements are heavier. It makes chemical equations harder than if we had even amount of everything.",
"Because a free neutron or proton has more mass than the protons and neutrons in atoms do, and carbon-12 - which is easy to isolate and common and whose usage would line up nicely with the old definition of the unit - turned out to be a useful reference point. Hydrogen-1, with one proton and one electron, turns out to not be exactly 1 Dalton (the unit of weight used for the \"12\" in carbon-12); it's actually about 1.007, while a free neutron is about 1.008. (And in fact, the mole *isn't* that number. It's very close, but the gram has been redefined since the term *mole* was, so there are only approximately a mole of Carbon-12 atoms in 12g. The difference is small enough not to be relevant for chemistry most of the time though.)"
],
"score": [
8,
5,
5
],
"text_urls": [
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
lh4kqw
|
What is the difference between regular exercise that is healthy, and laborious excerise(manual labor etc) that causes joint/muscle issues down the road?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gmv6x02",
"gmv7a5v",
"gmv7b6g",
"gmvicz2"
],
"text": [
"In a very general statement, not much. It is possible to overstrain and injure oneself during exercise just as it is possible to do so in manual labor. Manual labor might be more prone to be repetitive (for just a few joints/muscles), last much longer at one go, require long periods at the same posture (sitting, hunching) and not allow for sufficient recovery periods - and this has a high likelihood of causing later problems. But not all manual labor is like that. And as you recognize, not all exercise is healthy either.",
"If you're doing exercise for fun, and you start to feel crap, you can stop. If you're doing exercise to make money, you can't stop just because you feel bad. You can't take a day off when you don't sleep well. You have to push through and keep going. Also with work, you tend to be doing a repetitive activity that targets on particular area of the body. Fun exercise, you would ideally spread it over the whole body, not just do one exercise day-in, day-out. The concentration of exercise in one area is punishing, which is why pitcher's tear rotator cuffs more often than any other position in baseball.",
"One of the main differences is that when you’re doing manual labor, you probably aren’t using good “form” like you would when exercising. So you get more back injuries doing manual labor than when exercising properly. Another big difference is the repetitive nature of manual labor. If you are only bench pressing until exhaustion every day, you would get hurt in the same way that would if you moved boxes or dug holes all day.",
"A proper exercise system is intentionally designed to reduce the risk of injury and long-term physical damage. We have a pretty good scientific understanding of how to exercise the body in the most efficient and least-risky ways, as well as the best ways to prepare for exercise and recover from it to reduce injury. Obviously, there's always some amount of risk, but if I'm running on an elliptical or bench-pressing a barbell, I have the luxury of performing that exercise in the most optimally safe and healthy manner that I can. Heavy manual labor often doesn't allow us to use those optimal techniques, though. It has a different focus other than maximizing safety. If I'm cutting down trees and hauling them away, I've got to do what's best to get those trees cut and moved, not what's best to keep my back properly aligned every time I lift a branch or push my chainsaw. Sure, I can try to be as safe as possible, but that's always going to have to give way at least a little bit to the practical needs of the job that I'm trying to do. Combine those practical demands with the more social and economic pressures of labor -- if I take a break every time I get fatigued, I'll make less money or get fired -- and you can easily see why physical labor is much more dangerous than controlled exercise."
],
"score": [
20,
13,
8,
3
],
"text_urls": [
[],
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
lh5knk
|
Why are watch bodies, safes, metal keyboard cases etc carved out of solid blocks of metal instead of melting the metal and pouring it in a mould for the item?
|
Other
|
explainlikeimfive
|
{
"a_id": [
"gmvd14c",
"gmvfmdp",
"gmvezgj",
"gmvw4sj"
],
"text": [
"Because keyboards and other things need a certain amount of precision that molds do not give. If you actually tried to mold metal, you would see it's won't come out perfect. Also it wouldn't be as cost effective as you think. Melting metal at a large scale isn't cheap",
"Most of these items are cast or forged into a shape closely resembling the finished product. Because these processes are less precise than needed, extra material is left (something that is 1\" thick is left at 1.030\". That extra material is machined away to very precise sizes leaving a finished product. Very little is made from a solid chunk of material unless it is already close to the size and shape of the finished product. You are wasting money buying material that is essentially waste, machining time (opportunity cost) removing extra material, extra labor, and extra energy to do so.",
"There is a limit to how accurate we can cast metal. The problem is that the metal will shrink and warp in weird ways as it cools. In addition it is very hard to find materials for the mold which can withstand extremely high temperatures but at the same time keep its shape to exactly what we want. So a common manufacturing technique is to first cast something but make sure it is too big and then cut away the excess material. This leaves a very smooth and precise surface instead of the rough cast. Especially with materials such as aluminium which are almost impossible to cast but very soft to cut. Of course there are plenty of other options for how to make things with metal which reduces the amount of metal you have to cut away. Aluminium but also steel is often found in extrusions which are pulled out of its liquid vat in a specific cross section. You can also wield pieces together but there is a limit to how deep a wield will penetrate. A very common manufacturing technique is to stamp out the shapes but again there is a limit to how thick the metal can be. There is also forging which basically involves someone beating a hot piece of metal until it have the right shape. This is used when you need a strong consistent crystal structure in the metal and metal forges can make enormous things so it is not inconceivable to make a forged safe, even a forged bank vault is possible.",
"Casting only works with specific materials, is relatively slow, and fairly imprecise. It is also quite limited in available shapes; you can't easily make thin sheets with casting. Machining allows us to get precise shapes in many materials that don't cast nicely, or produce difficult-to-cast shapes with small amounts of effort. Typically, the rough shape will be cast and then the final shape will be machined out. If only one or two of an object are being made, then the casting process is more trouble than it's worth and normal stock is used instead."
],
"score": [
8,
5,
4,
3
],
"text_urls": [
[],
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
lh5my9
|
Why can’t a helicopter just hover in one place for 12 hours and end up on the other side of the world?
|
Physics
|
explainlikeimfive
|
{
"a_id": [
"gmvcq0v",
"gmvd5xm"
],
"text": [
"They can. But \"hover in one place\", as you mean it, would effectively mean \"fly to the west at hundreds of miles per hour\". The problem is that the atmosphere is rotating along with the Earth's surface. And so is the helicopter, initially. All three are moving eastward at the same speed, which depends on latitude but is very fast at any latitude where most people live. What looks like \"hovering\" to you is in fact moving along with the flow of the atmosphere moving rapidly to the east. If Earth had no atmosphere, you could take off (still moving with the Earth's rotation), accelerate westward for a while (until you're stationary with respect to an observer that isn't rotating with the Earth), and then hover and watch the Earth turn below you.",
"For the same reason why you won't fly across the room in a westward direction at 1,000 miles per hour when you jump up. You are moving with the earth as it rotates, you don't all of the sudden come to a stop relative to the earth when you jump up and neither do helicopters."
],
"score": [
5,
3
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
lh5wzt
|
Why do babies love rocking nonstop? I mean, sure, who doesn't like ride, but really, NONSTOP for HOURS?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gmve6l5",
"gmvfhaz"
],
"text": [
"When babies are in the womb they are accustomed to the feeling of motion as mom moves around. Rocking is not only similar to that, but the repetitive motion of rocking is also soothing. It’s also the reason why they like to be carried a lot in the first few months.",
"They associate it with being safe and not alone. Being left somewhere alone was pretty much deadly for most of human history."
],
"score": [
11,
6
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
lh6ecw
|
Legendary sword that was 1 atom thick (Hanjo Masamune)
|
Other
|
explainlikeimfive
|
{
"a_id": [
"gmvheqp",
"gmvhmof",
"gmvj7ma",
"gmvjrb1",
"gmvhtti"
],
"text": [
"It’s not possible to have a functional steel sword one atom thick because 1) steel is an alloy of iron and carbon (two different kinds of atoms) and 2) it would not hold its shape in Earth gravity Edit: If we’re just talking about sharpness of the edge, you still can’t have just a single row of steel an atom thick because of 1)",
"It's a myth. Materials of roughly that thickness, like carbon nanotubes, have been created, but nothing like that would have been possible forging steel, even the high-carbon steel that was popular with Japanese blades. Conveniently, the particular sword you're talking about was handed over to the US military and seemingly lost when Japan surrendered in WWII. Thus nobody ever really had a chance to measure it with technology that could say whether the sword was as thin as reputed.",
"It is a legend, and due to the loss of the Honjo Masamune sword, this legend cannot be conclusively disproven to those that want to believe in its magical qualities, granted for some, not even the blade would be enough. Steel is a compound of iron and carbon, for the edge to be 1 atom thick, would mean it would either be iron, which is hard, but brittle, or carbon, which is also brittle, but of varying hardnesses. Short of being made of diamond, a blade with a sharp edge one atom across, would lose said edge with even the simple act of sheathing. That said, Masamune would not have been able to see if his blade was that sharp without an electron microscope. Furthermore there are limits to how much you can maintain an edge on sharpened steel. Even the best steel scalpels have a rough edge no matter how polished, which is why some have moved to obsidian and other silicate blades which can have a consistent curved edge. At the atomic level, it’s all rough though.",
"There's literally no way possible to do that at the presumed tech level. I don't even think that's possible with today's technology. I don't think that's possible at any tech level.",
"It’s seems like it’s an exaggeration or legend of sort. Steel can’t even be one atom thick because there is no such thing as a steel atom, steel is an alloy made of different elements. I’m also fairly certain that it wouldn’t even be theoretically possible for a blade to be one atom thick, because most blades are made out of multiple layers, and you couldn’t have multiple layers that equal one atom in thickness"
],
"score": [
13,
8,
4,
3,
3
],
"text_urls": [
[],
[],
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
lh6x35
|
If increasing your heart rate during an exercise helps your cardiovascular system, how come drugs (Weed, Alcohol, etc...) that typically increase the heart rate hurt your system?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gmvkhvy"
],
"text": [
"Basically your question is backwards. Your heart rate increases when exercising because of load on your muscles which is good for your cardiovascular health, increased heart rate is just a byproduct of this process. So increasing heart rate through drugs is not increasing load on your muscles which is the part that improves your cardiovascular health. Not to mention drug and alcohol also have a myriad of other risks to general health, but that's outside the scope of this question."
],
"score": [
3
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
lh7okc
|
How does night vision work on animals and how does it compare to night vision googles?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gmvo7ck",
"gmvskvu"
],
"text": [
"Many animals that can see well at night do so by simply having eyes that are better at capturing the same light we use to see during the day. They have more and better receptors and lenses that focus more diffuse light. Night vision goggles, by contrast, work by seeing light that has a lower frequency than the light we use to see during the day. Light at this frequency is given off by basically all living things as they transfer the heat they generate to their surroundings. Even if the sun isn't around, plenty of this light gets emitted by anything decently warm in the area which night vision goggles pick up. Some animals can see this light, too, though.",
"Some night vision technology is a simple function of having an IR “flashlight” combined with a camera that can see the IR light. Human eyes can’t see it at all. So the “invisible” flashlight shines on everything in the area and the camera reveals it to a human observer. As for animal adaptations, there are many. First of all, eyes use cones and rods as light receptors. Cones are more specialized for color and acuity, whereas rods are better at low-light and peripheral vision. So many nocturnal animals have more rods than cones. It makes their vision slightly worse overall, but much better in low light. Another adaptation is the tapetum lucidum, the additional layer that some animals have that causes their eyes to glow at night. (Cats are the perfect example of this.) Light goes into the eye, bounces off the retina, then bounces back off of the tapetum lucidum, effectively increasing the brightness of what the eye is seeing. It’s like a built-in light amplifier."
],
"score": [
8,
4
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
lh7ytl
|
why ulcers form on feet in diabetic neuropathy?
|
I always hear the same thing "reduced sensation on the pressure points", but that doesn't make sense to me... people can have sensory denervation for all sorts of injuries and palsies, but they don't spontaneously form ulcers on whatever dermatomes are denervated & #x200B; Thanks!
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gmvra12",
"gmvqmm2"
],
"text": [
"So what happens in diabetes is that the high levels of glucose directly cause damage to the nerves (through some alternate processes in nerve cell metabolism). This leads to the condition known as Diabetic Neuropathy. As a result of this damage, there is decreased ability to feel any sensation in the foot, pain or regular touch. Additionally, these prolonged periods of high glucose in the blood cause blood pressure to be high which will destroy capillaries and decrease circulation in the feet. These two features tie in like this. Ulcer's don't just show up. A diabetic person accidentally hurts their foot in some way but doesn't realize it because their foot is numb. Generally, this is just a small and almost un-noticeable cut. This injury is very, very easily infected during the process because the poor blood circulation makes it harder for immune cells to reach the site of injury to fight off the infection. As the infection worsens, the ulcer forms and gets bigger. There is also another type of ulcer that can form in diabetes from this very poor circulation (peripheral vascular disease) without injury, but what you were asking seemed like the more common infection pathway. & #x200B; TLDR; Diabetic neuropathy numbs foot. Person injures foot. Infection starts. Diabetes causes poor access to site of injury for immune cells. Ulcer forms as infection worsens",
"Reduced sensation means that positions that would normally be very uncomfortable (and thus get you to move) aren't. So you'll leave your foot in a position that puts enough pressure to do damage to it, rather than moving it as you usually would."
],
"score": [
10,
3
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
lh80o5
|
What is ray tracing in video games?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"gmvq4sj"
],
"text": [
"Even though it looks like they do, games don't usually simulate light actually starting from a light source and bouncing around a scene. Instead, they use a number of visual tricks (like normal maps, which give surfaces 'texture', or ambient occlusion, which makes distant objects look more faded) to simulate the rough appearance of a real scene. Ray tracing is *actually* following the light rays from light sources as they bounce off different objects. This is very computationally-expensive and requires good hardware to achieve a decent framerate, but it's also much more realistic looking."
],
"score": [
12
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
lh9mig
|
How does sleep help us to stay alive?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gmw0ase"
],
"text": [
"We don’t really know yet. Sleep is one of the things about the brain that we haven’t completely figured out yet. What we do know is that is absolutely necessary, it is possible to die from lack of sleep, (though very hard to do so, because eventually your brain just starts turning itself off even while standing, google Randy Gardner, who served the record for longest time without sleep going 11 days, by the end of the experiment (which was observed by medical experts) he started experiencing some pretty strange stuff like hallucinations and completely losing feelings of time). Some theories as to why we need sleep revolve around letting the brain rest/recover. When you are working out all day, your muscles get tired and need a break. Well your brain is working all day too, and somehow sleep is your brains version of resting and recovering. Possibly the brain is repairing itself, possibly the consciousness is organizing it thoughts/memories, we aren’t exactly sure, but our brains seem to need a break."
],
"score": [
16
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
lhan80
|
Why does a hammer deform the material you strike with it, but a mallet does not?
|
Physics
|
explainlikeimfive
|
{
"a_id": [
"gmw6s5o",
"gmw7497",
"gmw640a",
"gmw74ir"
],
"text": [
"Either can deform the material. Imagine hitting play doh with a mallet. However, in general, a hammer will be made of a hard material and a mallet a softer material. When a mallet strikes something, the energy of the impact is absorbed by the material of the mallet. In a hammer, the material is inflexible and does not do this.",
"Because the mallet is made of a softer material, and its head is wider. The wider head means that the force of the impact is spread out over a wider area— it's five times harder to make a 2.5\" round dent than it is to make a 1\" one— and the softer material means that it's the hammer that gives, and not the work piece. The mallet usually bounces back and isn't permanently damaged, but they're not meant to last forever.",
"Well hello, here’s another timmy! With a hammer the head is much smaller and you need to focus more precisely the hit. With a mallet the head is usually bigger and the force radiates through more evenly. That is part of the answer.",
"A mallet is made out softer material than a hammer (plastic, rubber, wood or leather as opposed to tool-steel). A mallet also has a larger striking surface than a hammer - at least 4 or 4 square inches as opposed to 1 square inch. These two factors spread out the impact force over a longer period of time and over a larger area of material, meaning that you'll push the material rather than deforming it."
],
"score": [
11,
5,
3,
3
],
"text_urls": [
[],
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
lhaxyc
|
why is it that when you are sick/ have a fever, you tend tend to feel worse during the night than during daytime?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gmwbj1j"
],
"text": [
"Cortisol levels are lower at night to help you sleep (thanks to circadian rhythm). Cortisol is also an anti-inflammatory and contains the immune response during the day!"
],
"score": [
6
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
lhb81f
|
How does allowing water to drip from your faucet prevent damage to the pipes during winter?
|
Physics
|
explainlikeimfive
|
{
"a_id": [
"gmw9kpy"
],
"text": [
"The water fills the pipes to maintain pressure. That's why when you turn the faucet on the water comes out right away. If you leave stagnant water, the cold will freeze it. By having the water moving a little, it will take more cold to freeze it since the moving water is harder to catch (you did say eli5) The science: cold slows down atoms until they freeze (solid). By moving, it needs more energy to slow them down"
],
"score": [
7
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
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