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7w6tuc | How do people who are deafblind learn to communicate and learn about the world around them? | Repost | explainlikeimfive | {
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"It's not easy, and it can depend on the individual case. If one sense lasted longer than the other (ie: they went blind when they were a child, but lost their hearing due to a loud noise in their 30s) then they might retain the ability to talk and have some coping mechanisms through touch; similarly if they were deaf, they already know sign language, and just need to learn how to read finger-spelling through their hand (but could, in theory, sign normally in return). One of the most famous deaf and blind people in the world is Helen Keller, and her story was made into a movie called the Miracle Worker; she lost both sight and hearing very young, so she was basically taught sign language through touch; so she could have someone sign onto her hand and she could tell what the letters were."
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7wc01e | What exactly is a game engine? | Repost | explainlikeimfive | {
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"A game requires A LOT of code. Things need to be considered like how will the camera work, how will light be rendered (eg effects like bloom, shadows, as well as just how things will appear or be \"drawn\" in the world), how collisions will work (a foot against the ground, a bullet into a body etc), sound/audio, and heaps more. Lots of this code is reusable, so instead of rewriting all of this for each game, companies will instead design an engine (Source, UE, Unity) which contains all the basic, ubiquitous code found in all of their games and then build each of their games on that. A lot (but not all) of these engines are licensed or sold out to other companies",
"A lot of good technical explanations here, so I won't repeat what's already been said. In the spirit of ELI5, I thought I would try to give an analogy. The game engine is a lot like pancake mix. The advantages are clear: you don't have to start from scratch and the quality of each of the ingredients are well known. You are still going to have to at least a little work to make those pancakes. Of course, if you want your pancakes to *really* stand out, you might do quite a bit of work. You might alter the suggested recipe as well, perhaps to make them extra fluffy. Or you might use the mix in some recipe that looks nothing like pancakes, but the mix just saves you a lot of pointless busywork. This is the nature of a game engine. All the common elements come already mixed together, but you are going to have to do the last few steps yourself to make a game. And if you want your game to stand out, you are going to have to do quite a bit of work adding to the engine.",
"Pretend you're trying to build something, and you need various shapes. Now pretend you have a toolbox that hold everything you're going to be building with. That toolbox holds everything you're going to be using. Now what you've done, is build a whole bunch of preset items and put it in the toolbox. As you go along, you take the preset items and use it in your build. So basically you create something before hand, and you take the things you have created and put it into your current project so you don't have to keep repeating what you have done before. Its like having a database that you can keep pulling things out from Or maybe pretend that you're building a mario-like game. When you're building, you make various types of blocks that the characters can jump on. And you have it in a way that you can just drag the block into the level and use it while creating the level. It'll be like you being able to keep pulling the premade blocks and putting it in the level you're making",
"Computer programs can use “libraries”. A Library is a bunch of common code you can reuse, to save time. You have libraries for math, for making websites, for anything software related. A game engine is a library for making games. It can include common features such as rendering graphics, playing sounds, helping you implement multiplayer, and lots of other things.",
"Back in the days when consoles like the NES or SNES were the absolute pinnacle of gaming hardware, games didn't have engines. They were written from top to bottom in code in order to be able to get the most out of the weak hardware available. However, doing this meant that it was very difficult to make complex games, as each time you wanted to change anything about the game, you had to find the corresponding lines of code and change them. And that's where an engine comes in: Instead writing the game entirely in code, you first write a bunch of tools. These are responsible for basic things like the graphics, sound, physics, loading and saving games, ... All this combined is what's called the \"engine\". With an engine, you no longer need to code everything in a language like C++ in order to make the actual game. Instead, it can read out much simpler things like XML documents or LUA scripts, which have the advantage that they are much easier to read and write for humans. For example if you go to the settings menu in a PC game and change the resolution from 720p to 1080p, what usually happens is that it changes an entry in a file called something like \"config.ini\" from \"resolution = 1280×720\" to \"resolution = 1920x1080\". Now when you restart the game, the game engine reads that file and sets the resolution to whatever it says in there. This is a simple example, but it is how a lot of the things in a game are made: The levels, the quests, the monsters, the items... it's all in a bunch of files that can easily be read, understood and changed by humans."
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7wde4y | How does a hard disk drive read and write data differently than a solid state drive? | Repost | explainlikeimfive | {
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"A hard disc drive uses a magnetic metallic plate that spins around and a electromagnetic read/write head. That head can ready the magnetic properties within a very small area on the plate, or change the the magnetic property within said small area. This allows for 2 magnetic states (think of magnetic poles) which can be read and easily translated into the binary states for 0 and 1. Solid state drives instead use a way to essentially trap electrons, which are for the most part either floating-gate-transistors or charge trap flash. You can imagine it as a very tiny cell which traps an an electronic charge. To trap a charge you need much higher voltage than to read it, as you essentially have to force that charge into the cell. And said force is also required to push it out again, while lower voltages allows you to check if there is charged trapped or not. This is also the reason that flash memory degrades over time. Forcing the charge in and out of the cell slowly destroys the ability to hold the charge within the cell. Reading also slightly damages the cell, but not as much as writing to it. I don't think I can ELI5 how the trapping works as the effect used for this is called quantum tunnelling which as the name suggest is a quantum mechanical property.",
"SSDs use electrical charges to store data. This eliminates the bottleneck of a HDD head needing to physically move around to access data. I've been awake for 36 hours, so I can't give you a much more detailed explanation, but this is a really great answer to your question. Skip to 54s. URL_0"
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7wdkky | How can different liquors affect someone different, ex, “Whiskey makes him crazy”, are there any actual differences or is it BS? | Repost | explainlikeimfive | {
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"It's mostly based on one's personality and the culture around you. URL_0 URL_1 URL_2 URL_3 TLDR: It's all in your head. Alcohol is alcohol. You perception of what it is alters your behavior and reaction to it.",
"Different types may hit you faster or slower and thus you'd act differently drinking them but the actual inebriation is identical based on alcohol content. Someone can drink beer slowly all night and maintain a strong buzz and then decide to have a few shots of whiskey that puts them into really drunk territory and they act...well...really drunk."
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"http://www.peele.net/lib/sociocul.html",
"http://www.sirc.org/publik/drinking4.html"
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7wfqjz | Why we say the speed limit in universe is the light speed just because we couldn't observe anything faster than it? | Why this limit? Why _c_ ? It has been pretty logical to me until I thought why it's not just us can't detect or see or interact something faster than light? The universe is pretty big and expanding every second, there are massive amount of _things_ out there waiting us to observe them. How can we that sure about the speed limit in universe? | Repost | explainlikeimfive | {
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"The speed limit of the universe is only counter intuitive when you make certain \"obvious\" assumptions about the way the universe works. We see space as a rigid grid. I could take a meter stick anywhere and put it in any orientation and it will always be one meter long. If I have two meter sticks that are exactly the same length as one another then they will always be identical. Similarly we see time as something that marches ever forward at a constant rate. If you and I have synchronized clocks then there's nothing that either of us can do to get the clocks out of sync, short of tampering with then. That view of the universe is very nearly accurate and works for most physics and all day to day activities, but it is actually fundamentally wrong. If you and I both have meter sticks and I start to move then my meter stick will be shorter than yours. As I approach the speed of light the length of my meter stick becomes shorter and shorter, approaching zero. This is not a question of engineering a stronger meter stick or a question of having good enough observation. It is a fundamental property of the universe. It is the nature of space that things in motion are shorter along their direction of motion. Similarly if we both have clocks and I start moving around then my clock will run slow. The nature of movement is that everything in the universe has some amount of total movement (and I'm speaking in coarse language here; I'll abuse some terms for the sake of ELI5). When an object is at rest its movement is entirely through time. As it starts to move it trades some movement through time for some movement through space, but the total is still the same. What makes this foreign to you and me is that the conversion ratio is *enormous* (it is the speed of light, 300 million meters to one second). The analogy would be to Bill Gates buying a burrito at Chipotle. One may see a multi-billionaire with no burrito walk into the restaurant, then a multi-billionaire with a burrito walk out of the restaurant. Another day you see the same, but he walks out with a box of 100 burritos to throw a burrito party for a group of people. Someone watching Bill Gates may posit that there is no burrito limit of the universe. Gates was a multi billionaire before and after each transaction, even with differing numbers of burritos. Clearly there is a limit, though. There is some finite, albeit enormous, quantity of burritos that Gates can afford. When you find the conversion ratio between Dollars and burritos the burrito limit is trivial to compute. That is what we've done to determine that the speed of light is the speed limit of the universe. We discovered that motion through space \"costs\" motion through time, then we found what the conversion rate is.",
"\"Light speed\" is a bad name. It's actually the speed of causality, which means that it is the fastest possible speed at which anything can affect any other thing in another place in the universe. It just so happens that any massless particle (like photons of light, for instance) travel at that speed. But I haven't answered the question, really. Could there be things that go faster than light? There have been a number of hypotheses about these types of things, some of which are plausible at least to some extent. The problem is that these exotic types of particles would have very bizarre properties: imaginary mass, experiencing time the reverse of how we do, etc. They also would have to violate causality. That is to say, it would break our understanding of cause-and-effect. So not only would they be hard to find, but it throws some tricky wrenches into physics as we understand it. EDIT: Let me sum this up, I'm not happy with how I left it. The long and short of it is, yes there could be faster than light stuff out there. Judging by what we have found and how much physics we know, it seems that they are either unlikely to exist, or they don't interact with normal particles in any way of serious consequence.",
"> How can we that sure about the speed limit in universe? Because we have not seen anything that breaks that rule yet. If we do, science will incorporate that into the existing theories. This is a reason why the recent observation of gravitational waves was important. We knew that a cosmic event was going to happen (I don't remember, was it a supernova? Binary star collision?), and the gravitational effect occurred at the speed of light. We expected it to do that, and it did.",
"We make observations about the universe. We construct a theory, usually involving mathematical equations, that explain those observations. We make more observations and see how they fit with the theory. For light, we observe that the speed of light is the same regardless of your frame of reference (Maxwell's equations). From this we (as in Einstein) deduced the relativity of time and the fact that nothing can go faster than the speed of light. Our observations of the universe at a large scale are consistent with the mathematical equations whose consequence is that you cannot go faster than the speed of light. It's important to note that there is nothing special about light here. Rather anything that is massless *must* always be travelling as fast as it is possible to travel. Since light is massless, it travels at this maximum speed. We call it the \"speed of light\" simply because the photon is the most common massless particle that we deal with and it is our observations of light that led us to this discovery.",
"It's the only way of making sense of the universe as we observe it. It all began with an experiment to detect the presence of something called \"ether\". At the time people weren't sure what light actually was; one theory was that light is waves in this mysterious thing called ether, like waves in water. If that's true, then there should be a detectable \"drag\" slowing light down slightly as it travels through the ether. So some scientists set about trying to measure this drag. How do you do that? Simple: you measure the speed of sunlight in the morning, when the bit of earth you're standing on is rotating towards the sun; and again in the evening, when you are rotating away from it. You should be able to detect a difference in the measured speed of the sunlight. You then calculate how much of the difference is down to the earth's rotation: if that doesn't exactly account for the difference, then that means ether exists and is slowing down the light. The problem was that the results of the experiment made no sense: the measured speed of light was always *exactly the same*. Understanding the results took the genius of Einstein to look at these results and work done by other scientists, and finally figure it out: the speed *c* is the maximum speed any two objects can move relative to each other, and light (at least in a vacuum) always moves at *c* relative to everything else. This is hard to grasp because it goes against our intuitive understanding of how the universe works in our everyday experience, but there it is: if *c* is the universal speed limit, that would explain the weird results of that experiment. Einstein's theories made some predictions -- that light should be affected by gravity, and that accelerating to very high speeds results in something called \"time dilation\". Since then, scientists have done experiments and confirmed that light is affected by gravity, and that time dilation is a thing. Not only that, but your GPS is able to pinpoint your position exactly thanks to Einstein's equations, based on the idea that *c* is the universal speed limit. On balance, then, it seems that Einstein was right. As weird as it sounds, there is no such speed as \"faster than the speed of light\": all the evidence says that that speed simply does not exist."
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7wg6vq | why/how do we get more courage and self-confidence when we drink alcohol? | Repost | explainlikeimfive | {
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"Alcohol serves to dull our inhibitions, which would otherwise caution us in the form of fear."
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7wid08 | How do construction companies get cranes on top of sky scrapers that are hundreds of stories high? | Repost | explainlikeimfive | {
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"Idk if I'll get deleted for linking this but I shot a lil time lapse for when these questions get asked. Note the weight hanging in the front for balance as well as the hydraulic ram on the backside of the tower, where the workers are moving. What u see them roll out is 20 foot tower section. So the crane grows and shrinks 20 feet at a time. URL_0",
"Here's a good video that should answer your question: URL_0",
"The base of a tower crane is a concrete slab that is fixed to the ground (it can be attached to the sides of the buildings/structures as well). The base connects to the tower which is what gives the crane its height. At the top of the tower is a slewing unit which allows the crane to rotate using its gear and motor. Now you know the basics, the answer to the question is really surprisingly simple. The crane builds itself up, level by level, using its own hoisting power. Let me break it down a little more… To assemble to a tower crane initially, construction crew will use a (smaller) mobile crane to assemble the jib and machinery. The tower rises from the base, and grows itself one section at a time. A top climber or a climbing frame is used for this process. It fits between the top of the tower and the slewing unit. Explained simply: 1. A weight in hung from the jib to balance the counterweight 2. Slewing unit is detached from the top of the mast. 3. Hydraulic machine in top climber pushes the slewing unit up 4. Crane is lifted up (by the crane into) another mast section into the gap that has been opened up by the climbing frame. 5. Once lifted it is bolted into place and a whole tower section taller",
"It’s deconstructed, moved to the top by construction elevator/pulley system and reconstructed at the top"
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7wj3eh | Why did Korea split into North and South? | Repost | explainlikeimfive | {
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"At the end of ww2 Korea was occupied by the Japanese then spit by the victorious allies with the communist north and the US backed south.",
"Prior to WWII, Japan occupied Korea. Near the end of the war, the Soviet Union declared war on Japan, as per their agreement with the other allied nations. They attacked the Japanese in northern China and continued into Korea. When the Japanese surrendered, the parts of Korea invaded by the Soviet Union were administered by the Soviet Union, and the parts that remained under Japanese control when they surrendered to the USA was administered by the USA. The USA and the Soviet Union negotiated for a unified Korea, but they could not come to an agreement. In 1948, and without a resolution between them, South Korea and North Korea both officially became separate independent countries, although they both claimed to be in charge of all of Korea."
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7wmr8y | How do guitar amps amplify the sound? | Repost | explainlikeimfive | {
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"A transistor! To answer the follow-up question of \"okay and what the hell is a transistor\".... A transistor is a lil' electronics part made of silicon. Silicon has some funny properties: it's a semiconductor, and different stuff can influence how well it carries electricity. So a transistor has 3 connections on it: an in, an out, and a signal, positioned in-between the two. A strong current goes into the \"in\", but nothing comes out until any current (even a trickle) goes to the signal connection. So what they do is hook the \"out\" to the amp's speaker. Then when you strum the guitar string, that's connected to the \"signal\" and causes the signal current to wobble. This means the \"out\" juice starts to flow, and wobbles in the same way.... but much stronger, since the \"in\" was a strong current. This makes the speaker vibrate in the same pattern your guitar string did."
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7wnpo2 | Why do some many animals immediately know how to walk after birth, yet it takes human babies months just to learn how to crawl? | Repost | explainlikeimfive | {
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"Humans have large heads to control our large brains. Unfortunately, human female pelvis's are basically too small to pass fully developed large heads. So basically all humans are born premature (by animal standards) in order to let our mothers fit our massive heads through their pelvis. Then we continue to develop after being born and can't walk for months."
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7wnpqa | How does the temperature gauge that reads the outside temperate that is displayed inside your car not get thrown off by wind/other elements when you’re traveling fast down a highway? | Repost | explainlikeimfive | {
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"Wind doesn't actually change the temperature. Wind feels colder to you because your body is 98.6 degrees, so on a cool day with no wind, there is a layer of warm air (warmed by your body) surrounding you... but on a windy day, that warm air gets blown away, so you feel cooler. A thermometer doesn't have a layer of warm air around it, so it just feels the temperature, regardless of wind.",
"The wind doesn't make a thermometer any cooler. It makes warm-blooded mammals like us cooler because, unlike a thermometer, we're not at equilibrium with our surrounding environment. Instead, we heat the air around us, and wind blows that pocket of warmer air away, causing us to lose heat faster. And since we feel heat loss/gain, and not actual temperature, blowing away that warm air makes us feel cooler.",
"ELI5 version: Your car's gauges lie to you all the time. They are made to be close enough to be useful without wiggling all about and being distracting or annoying. Cracked has a decent articles about it: URL_0"
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7wqxc7 | What causes your limbs to "fall asleep" | Repost | explainlikeimfive | {
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"The idea that it's circulation is actually a myth; when limbs lose blood flow, they don't \"fall asleep\", they die. A limb falling asleep is caused by pinching the major nerve leading to that limb. Signals can't travel up the nerve very well, so feeling becomes limited. When the limb \"wakes up\", you feel pins and needles because there's a huge backlog of signals in the nerve being cleared and your brain is trying to make sense of it all.",
"When your limbs \"fall asleep\" it's called paresthesia. It's caused by either accidently pinching/putting pressure on a nerve or by decreased blood flow to the area. It doesn't typically cause nerve damage due to the short duration that it happens, usually. It also usually goes away if you adjust or move the limb around. When the sensation persists or happens frequently it can cause complications, and is usually associated with another medical issue. That would be the time to consult a doctor."
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7wuzv2 | What actually happens when your legs fall asleep and why does it hurt so much to walk when they do? | Repost | explainlikeimfive | {
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"You've put pressure on a nerve, most likely. This interrupts the normal ability of that nerve to send signals to be interpreted by your brain. So in a sense your brain is 'blind' to this area. Once you remove the pressure, the nerve can begin to send signals again, but the pressure and the stoppage have resulted in abnormal signaling. It's this abnormal signaling that takes a little bit to clear, and which results in the weird sensations like pins and needles.",
"Brain (mom) stops getting messages from nerves (you). You finally come home and Mom hasn't heard from you and it's midnight, so she grabs her switch and starts chasing after you around the dinner table and then whoops your butt."
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7wv0kn | How does moving water freeze? | Repost | explainlikeimfive | {
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"Moving water freezes just like non-moving water does. First, imagine floating in a still pond that's beginning to freeze. Bits of water around you will start turning into small pieces of floating ice. The ice will grow and grow until it covers the surface of the pond. Now imagine floating in a moving stream. Bits of water around you will start turning into small pieces of floating ice, just the same as before. From your perspective as someone floating along with them, it looks identical to ice forming on a still pond. The only difference is that the whole process is moving downstream as it happens.",
"Okay...Rivers never actually freeze solid. Not that I can find an example of... Ice is a good insulator and poor conductor of heat, so the exposed part of the rivers will freeze over, but it slows down exponentially the thicker it gets as the ice actually acts as an insulator to the cold outside... So the kinetic energy of the moving water flowing and rubbing against each other plus the nice cozy layer of insulating ice above it kinda warms the water at the bottom of rivers enough to keep it from freezing throughout. I'm sure the pressure makes a difference as the weight of the ice pushes down on it, and pressure changes the freezing point even lower... but i'm not too sure so... Also fun fact: the fact that ice floats on top of water instead of sinking is actually really weird... chemically speaking. If it sank to the bottom, THEN rivers would freeze solid. And in a world where ice sank there would be no life, at least not complex life. since the oceans would have frozen solid during the worst of the ice-ages as it slowly froze from the bottom to the top, nothing but microbes could live is solid ice. [in theory. i'm no expert] I'm open to anyone correcting me and improving the explanation. It's my first ELI5 comment. sorry"
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7wv2cv | Hypnosis/being hypnotized | Repost | explainlikeimfive | {
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"text": [
"Hypnosis is a very controversial subject. Please take any answers/articles/links with a grain of salt, and beware of the pseudo science/superstitions going around on the internet."
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7x0oqt | How do pain relievers relieve pain? | I’m currently sick and just took some ibuprofen and wondered how it helps. | Repost | explainlikeimfive | {
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"Ibprofen isn't a pain reliever per say, it is an anti-inflammatory. What is does is reduce swelling, so it may be reducing the swelling in your throat or nose so you may feel less pain. Other medications that are pain relievers block pain receptors like the user above explained."
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7x1ddm | Why does light always travel at c (in a vacuum), no matter what the speed is relative to? | Repost | explainlikeimfive | {
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"There isn't a satisfying answer to this. It simply *is*. We observe that this is the case, so the \"why\" is that it does. All of our theories about the universe and how it works (and why things do things the way they do things) all *rely* on the fact that light travels at the same speed to all observers."
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7x87di | If our own average core temperature is 37°c, then why do feel hot in same outside temperature? | Repost | explainlikeimfive | {
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"What you feel is not temperature, but the exchange of thermal energy. Consider the following: a paper book and a piece of metal are lying in a cool room. After some time, you go in and touch them both. Even though both have the same temperature (since they have been in the same room for some time), the metal object will *feel* cooler than the paper book. The reason for this is, that metal is a better thermal conductor than paper. Since your fingers are hotter than both the book and the piece of metal, both will transport energy away from your fingers upon contact. The piece of metal, however, will do this much more efficiently and faster than the paper. Thus, you are losing way more energy to the metal than to the book, which is why it feels colder. Being aware of this, we can answer your question: Our bodies are used to losing a certain amount of thermal energy to our surroundings. We feel comfortable losing a rate of thermal energy that corresponds to being in a ~20-25°C environment. If our surrounding environment is the same as our body temperature, we will not be able to lose thermal energy to the air. Thus, the flow of thermal energy from our bodies to the environment will be smaller than our bodies are comfortable with, thus making us feel hot."
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7xgoun | Why A Glass Of Water Left Overnight Develops Bubbles? | Repost | explainlikeimfive | {
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"text": [
"Gases can dissolve into liquids. The amount of gas that can dissolve into a liquid is dependent upon the temperature of the liquid, and the pressure of the gas at the interface (the boundary between the liquid and the gas). In this case, the pressure is the atmospheric pressure in your locality. When you fill a glass with water from the tap, there will be an amount of gases dissolved in it (mainly nitrogen and oxygen, as these are the most abundant in our atmosphere). Typically the temperature of the water from the tap will be considerably lower than the room temperature. As the water temperature increases to the room temperature, the amount of gases that can remain dissolved decreases. Microbubbles of gases will begin to form. They will collect on imperfections in the surface of the glass. (The glass looks and feels smooth to us, but at the microscopic scale it is not.) As they collect on the imperfections they will coalesce (fancy word for them joining together to make bigger bubbles). Eventually they will get big enough to be visible. This effect is similar to bubbles coming out of a fizzy drink, but in the case of a fizzy drink it is a sudden reduction in pressure (taking the cap off the bottle) that causes the dissolved gas (carbon dioxide) to come out of the liquid."
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7xim6x | – what are the causes of sudden nose bleed? | Repost | explainlikeimfive | {
"a_id": [
"du8icis"
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"text": [
"The main culprit is usually dry air. Dry air causes your nasal membranes to crust up pretty much in the same way skin gets dry too. The nasal membranes can crack when they're dry through some movement in the nose or even randomly, which causes the bleeding."
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7xizaf | Game theory. And what are some real life examples of putting it to use ? | Repost | explainlikeimfive | {
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"du8lu88"
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"text": [
"Any time you've held off on buying something because you know it's on sale elsewhere (or that it will be on sale next week), that's game theory right there. Just as one example."
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7xoob0 | Bandwidth for internet vs. tv | Thanks in advance for the ELI5! ISP's always say you need faster speeds for downloading, gaming, etc. What confuses me is that I can watch TV on as many TV's as I want (which is delivered via the same cable to the house) and not have it degrade service at all. But, somehow that same configuration with streaming will slow down the service (for example, streaming a movie, playing a game, etc.) if I do it on multiple devices. Since the service is piped through the same wire, how is it that speed matters for one service but not another. Isn't the TV service, technically, streaming? I am guessing not, but didn't understand why it would matter. Thanks! | Repost | explainlikeimfive | {
"a_id": [
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"text": [
"The difference is cable is a broadcast. It's just the same information down the same wires at the same time, you're just reading it in multiple locations, you're not streaming. Streaming is an on-demand service, which is different. Each device you use for streaming requests its own lump of data to be sent. Even if you and six other people in your house go to Youtube and hit Play on the same video at the same time, it's still sending that information down the wires six separate times. So with streaming the more you ask of it, the more bandwidth it uses.",
"While others have stated that TV is broadcast to every TV using the same signal, and the Internet is sent to each device individually. I thought I can expand a bit on how it works. Your cable wire is basically just the same thing as radio waves, but they are all stuck in the cable instead of going through the air. and just like the with the radio where you can have stations broadcasting on 101.3FM and 105.7FM and they do not interfere with each other, there can be more than one station (which in the Cable TV world is a channel) working at a time. Cable TV (In North America) channels are all divided into blocks of 6MHz each. So channel 40 is centered at 321MHz, and Channel 41 is centered at 327MHz. We call these EIA channels (For the Electronic Industry Association, which wrote the standard) and are different from what most people today think of as a TV channel. Your cable box may have a 'TV Channel' 312 that then has a map inside of it that says if I want to look at channel 312, it can be found on EIA channel 29, program 3 and then displays that. Each one of these 6MHz block can contain one of a few things. * 1 single Analog SD TV channel, with stereo audio * A group of Digital TV channels (Usually 2-5HD stations, or as many as 15SD) * A Internet channel (DOCSIS) which can run 38Mbps of Internet. There is a limit to how many of these channels will 'fit' on the cable. Most modern cable systems can fit 116 (750MHz) or 158 (1GHz). Every house on a cable node gets the exact same signal sent to it. With TV, as it has been pointed out, every TV gets the same copy of a station so it does not take extra bandwidth to add more TV's. But with Internet, every device (not just in your house, but in every house on the node which can be up to 100 or so) gets its own copy of the data. But since every house gets the exact same signal, every house is getting a copy of everyone's data, and those DOCSIS channels quickly can fill up. Just as a point, in modern cable systems, internet data is encrypted between the Cable company and a modem, and only your modem can decrypt the data that is intended for you. So while every house on your node gets a copy of your data, only your modem can actually do anything with it.",
"I believe when you get a cable package, all the cable channels that you have are always sent to you. So when you use the TV, you get the same channels and \"streams\" as everyone else, always; the TV is just choosing which of the streams that you're sent to look at. You can hook up as many TVs to this cable as you want, and it won't affect the speed you get the data at at all, because the data has already been sent; you aren't asking for anything new. When you're streaming, you are asking for an individual stream, which requires bandwidth. You don't get all of Netflix by default; you have to pick out an individual show, and then download that show from Netflix's servers somewhere. In turn, downloading multiple shows takes a longer time because you're receiving twice as much data. Basically, it's a lot easier and faster to send everyone the same thing than it is to send a bunch of people a bunch of different things. I am not sure this is accurate at all, though, so I'd appreciate someone to verify."
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7xpf01 | How do EMPs actually work? I know WHAT they do, I just don’t know HOW they do it. | Repost | explainlikeimfive | {
"a_id": [
"dua3iio",
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"Electromagnetism. Electricity moving through a wire can create a magnetic field, and a moving magnetic field can create electricity in metal objects. When a big EMP happens it creates big electric flows in electronics - bigger than they are designed to take. This can damage all the delicate things inside your phones and things.",
"Electromagnetic pulse. Basically, you know the basic principle of radio transmission. Voice goes in one end, it's converted to radio frequency and that signal is pumped into an antenna. That then travels as radio waves, and is picked up by an antenna at your end, and is turned via electronics back into sound. In the most basic electrical sense, an electrical signal in a wire is creating an electromagnetic signal which causes an electrical signal to be induced in a wire (or antenna) at your end. EMP is just that principle, just stepped up to crazy power levels, so the resulting electromagnetic signal is powerful enough that the electrical signal it induces is enough to burn out various electronic systems, because every wire will act as an antenna to some degree. EMP takes advantage of that to cause intentional damage."
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7xq07l | Meteors and debris burn up in our atmosphere upon entry, why are rockets not affected in the same way when leaving the planet? | Repost | explainlikeimfive | {
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"They don't move fast enough in the athmosphere to burn. They do accelerate to a significant speed but are already pretty much in space when they finally do go that fast.",
"Rockets start slow and go fast once they leave the atmosphere and all that wind resistance. Meteors start really fast and then get slowed down by the atmosphere with all it's wind resistance. That wind resistance causes heat that burns them up.",
"The heating is caused by compression of gas. You probably know that if you compress gas it heats up. Objects entering our atmosphere from space tend to do so at tremendous velocities, so they hit the air hard, and squash a lot of it in front of them. This air gets very hot and in turn heats up the object. Even stuff in orbit tends to be moving *very* fast (otherwise it would crash into the ground), and this means when it hits the air, it smashes a lot of air into a small space, and that air becomes very hot and heats the object. A space ship is designed, as others have noted, aerodynamically, so that less air gets squashed in front of it. Additionally, they generally take the shortest route possible through the majority of the atmosphere, so there is less time spent with a significant volume of air in front of them to squash, and during that time they are coming from a stop, so their speed is lower than a reentering body. Once a ship is in orbit it doesn't come to a stop with respect to the atmosphere, but in fact must accelerate to a significant velocity in order to \"stay up.\" Otherwise it would simply fall back to the ground. Next time it hits the atmosphere, it will be with a significant portion of that tremendous speed.",
"The atmosphere is thickest towards the bottom. Meteors get faster as they fall, whereas rockets speed up as they climb. So the meteor is fastest when the atmosphere is thickest, but rockets are fastest when the atmosphere is thinnest.",
"A number of factors: Speed of leaving the atmosphere is much lower than a meteor which can reach speeds of almost 300,000 kph, compare that to a rocket, around 30,000 kph, so the forces tearing at the spaceship are much lower. Space shuttles have material very resistant to heat damage on different parts of the space craft, like silica tiles (basically a quartz composite). Some crafts even have a plastic coating that melts away pulling the heat energy away from the craft. There is also a layer of insulation under the outer layer to protect the inside. Upon reentry, things get a little more complicated. Shuttles have to come in at the perfect angle (around 40˚) too flat and they can bounce off the atmosphere back into space, too sharp and they risk burning up."
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7xqcj0 | Soaps and conditioner | Repost | explainlikeimfive | {
"a_id": [
"dua9l5k",
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"text": [
"Basic soap is a fatty acid and an alkali mixed together, like animal fat and lye. The fat and the lye bond together. The fat hates water but loves just about everything else. The lye loves water and will attach to it. So, the dirt/grease on your skin or clothes sticks to the fat and the lye attaches to the water so that it all floats away. Dunno about conditioner, other than it's fat-rich and intended to put back some of the healthy hair oils that the soap stripped away.",
"In terms of germs since you mentioned you are a germaphobe: soap works to disrupt and destroy the cell membrane, or the walls of the cell . As mentioned earlier, since it is both fat and water-liking, it can work it’s way into the cell membrane and mess it all up. Another fun fact: When they recommend washing your hands with hot water, it’s not because the hot temperature“kills” the bacteria. It is because the hot water tells the bacteria it is “safe” so they can start reproducing. The cell membrane is the weakest and thinnest during replication since it stretches, so the soap works even better. TL:DR Soap damages bacteria membranes and hot water helps the soap work better."
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7xs9ct | Why do most car wheels have five spokes? | There are 360 degrees in a circle, which is the shape a wheel is in. 360 can be divided equally by every number (except seven) from one to ten. Obviously a one or two spoke wheel doesn’t make much sense, but four through ten seems to be viable options. Why do the vast majority of car wheels have five spokes? | Repost | explainlikeimfive | {
"a_id": [
"duatsgd",
"duau3ig"
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"text": [
"Four is not nearly as strong as 5 because the separation is too even. 5 is the least number that can be very-very strong.",
"I think it's a combination of minimal material and stability. With 5, if you lose one you still have at least one other leg supporting in the same half. Also, no spoke is directly across from another."
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7xsqh3 | Why can spoiled food still make us sick even after its been thoroughly cooked? | Typing this while I'm home sick with food poisoning.. If spoiled food is cooked long and hot enough to kill bacteria, why can it still make us sick? Can dead bacteria still cause issues? Or is it something else? (If anyone is curious, I ate week-old chicken curry that had been in fridge, and I boiled it for a solid 15 minutes to kill any bacteria. Still got sick. How?) Edit: I didn't intend for this to be a repost, but apparently it is! Thanks for answering anyway, both informative and terrifying. | Repost | explainlikeimfive | {
"a_id": [
"duatkyo",
"duauv4i",
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"In this case it's not the bacteria that make you sick, at least not as much as if the food hadn't already been cooked. It's the toxic substances produced ~~after the bacteria died~~ by the bacteria. Boiling will kill pretty much any bug that gets you sick, but it won't get rid of nasty stuff that happens after that.",
"There are many possibilities depending on what a person is infected by. The first and probably most common would be toxins released by an organism during it's life cycle. One classic example would be botulism toxin (BTX), which is produced by the bacteria Clostridium botulinum. BTX inhibits the release of the nurotransmiter acetylcholine which is a key part of muscle contractions. Because BTX is only a biproduct of the bacterium and not the actual organism, just killing the bacteria won't get rid of the toxin they have already produced. Another possibility for infection is by parasites. While cooking food will kill most parasites there are many that are capable of encystating and forming an incredibly resilient protective barrier until they receive signals from their environment that tells them that reproduction or growth is favorable.",
"The last time I saw this come up in ELI5 someone said, think of it like an old west town, Bandits poisoned the water hole. If you lock the bandits up, the water hole is still poisoned."
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7xuou0 | How does a road just have a big missing chunk? How does a pothole even happen? | Repost | explainlikeimfive | {
"a_id": [
"dubakwx"
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"text": [
"It can start with a crack and move it's way up from there. Most roads are either concrete or asphalt, so multiple things can cause damage. Constant wear and tear of multi-ton vehicles driving over it. Variable temperatures causing expansion of a limited space. The big one would be water, which can cause erosion, or worse, freezing in various cracks. Because water expands when it freezes, it can make small cracks bigger, break off pieces of the road until you get a pothole."
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7xvi1p | Film restoration: How is it possible that old lo-res films can be "restored" to HD or even 4k resolution? | Repost | explainlikeimfive | {
"a_id": [
"dubhlg7",
"dubi1xg"
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"text": [
"If the film is actual film then it doesn’t really have a resolution except what you scan it at. So you scan it at a higher resolution to digitize it. Then you fix any bad parts and/or run some filters to make it more modern.",
"Films are a series of pictures on a reel of film. That film has far higher resolution that we can actually scan. Each tiny cluster of chemical colorant molecules, the smallest unit in film, can store image data for a very long time. As long as film is not damaged, we can go back and scan it any time new scanning technology becomes available. As computer software gets better we can even correct for damage to the film and the colors that didn't record very well on film. Sometimes film needs to be fixed. If it was scratched, torn or cut some special mending needs to happen. A lot of that can be done by spicing in other pictures of the same thing, or redrawing the flawed parts of the image. Most of this is done on computers too."
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7xybb9 | Can someone please explain what stops glue from sticking inside the tub or tube? | Repost | explainlikeimfive | {
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"duc34nu",
"duc6hny"
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"text": [
"Most glues work on that they need oxygen to become sticky/harden. Inside the tube there is no air and thus the glue doesn’t harden. Some other specialized kind of glues mix 2 components with the use of 2 nozzles/tubes (epoxy etc) thus making them react into the sticky glue substance.",
"Most adhesives need some other components to activate. This can be air, heat, pressure, water, or another specially-made compound. For example: Super-glue (often cyanoacrylate) requires water to harden, which is usually absorbed from the air."
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7xyc20 | Why can so many medical things be done in labs and on mice but we never hear of it ever again? | Repost | explainlikeimfive | {
"a_id": [
"duc3cf5"
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"text": [
"Let me tell you a secret, passed down from generations of scientists, and now I bestow this sacred knowledge onto you: **People. Are. Not. Mice.** While we do share a fair amount of genes with mice, we are too different to reliably predict the outcome of a medicine on humans by observing what happens to the mice. Monkeys and pigs would be far better test subjects, unfortunately they're much more expensive than mice, and testing on them is ethically less correct. So mice serve mostly as a first barrier for medicines: if it doesn't work on them, don't bother trying it on humans."
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7xysiu | How does Netflix make money? | Repost | explainlikeimfive | {
"a_id": [
"duc6yd9",
"duc6sv3"
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"text": [
"> How does Netflix make money? They charge people for their service. > It can't be just from subscriptions can it? Yes it can. > Aren't they in debt? No. They pulled in over $11B in revenue last quarter.",
"They have over 100 million subscribers. At approximately $10 per subscribers, they bring a revenue of over $1 billion *per month*. I'd say that's more than enough to make a profit."
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7xythm | The Monty Hall Problem | Repost | explainlikeimfive | {
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"duc7aau"
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"text": [
"You have three doors. Behind one - randomly - is a car. Behind the other two are goats. You only have a 1 in 3 chance of picking the car. So, whatever door you pick, it has a 1 in 3 chance of being a car and a 2 in 3 chance of being a goat. Odds are, you picked incorrectly and the car is behind one of the other two doors. It's in your best interest to pick a different door, but you don't have any information to make a better choice than a random pick meaning you can't - without additional information - increase your odds better than 1 in 3. Monty gives you that information. He removes a bad door from the remaining set. Remember, when you originally picked your door, there was a 2 in 3 chance you were wrong and it would be better for you to pick a different door but you had no way of picking a better door because you didn't know anything about the other two doors and would just have to pick randomly. With the information Monty gives you, you don't pick randomly anymore. He removes a known bad door allowing you to switch off the (likely) bad door you picked initially. This is simple enough to map out. In each case you have picked the first door. Scenario A: [Goat][Goat][Car] Scenario B: [Goat][Car][Goat] Scenario C: [Car][Goat][Goat] Only in scenario C do you want to stay with your original pick (the first door). But there is only a 1 in 3 chance you are in that scenario. If you are in scenario A or B, you want to swap doors because you are guaranteed to get the car in that case (Your original door was a goat and Monty removed the remaining goat)."
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7y1cba | how nielsen tv ratings work | Repost | explainlikeimfive | {
"a_id": [
"ductbcx"
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"text": [
"They used to give viewers/households a \"diary\", in which they'd describe their viewing habits and submit after some period of time. Now, they have electronic meters, little boxes that actually monitor what you watch, when you change the channel, etc., and sends that data off each night. The first of these used a phone line to send the data back... I'm really not sure if they just connect to the internet nowadays."
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7y1fxm | How do “they” determine how many calories are in something? | Repost | explainlikeimfive | {
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"text": [
"The old-school way was to actually burn it and see how much heat it produced: a calorie is an actual measure of energy. Nowadays, the food would be blended up and analyzed for the amounts of fat, protein, carbohydrate and alcohol (the stuff you can get energy/calories from), and knowing the amount of calories in each of those by weight, they just calculate how many calories it should have. The advantage here is that they can differentiate between calories your body will use, and calories it won't (like that in fiber: it'll burn, but our bodies don't digest it).",
"There are also tools available that measure calories. That's not necessarily how \"they\" determine how many calories are in a packaged or menu item, but it's one way they can get a value on how many calories some foods have. URL_0",
"To add to the comments about methods: A calorie and a Calorie (food) are not the same. 1 calorie is the amount of energy it takes to raise 1 gram of water by 1 degree celsius at 1 atmosphere of pressure (isn't metric great??). 1 Calorie (big C) is the measurement used in food, and is actually 1000 calories, or 1 kilocalorie, or 1 kcal. Not directly relevant to your question, but still useful to know.",
"It's easily estimated by measuring the carbohydrate, protein, and fat contents. Each gram of carbohydrates and protein contains approximately 4 Calories (kilocalories). Each gram of fat contains approximately 9 Calories. You can check the math since the nutrition facts should also include the contents of each of these.",
"Woah I have the real question here. If they determine calories by setting food on fire and measuring the heat it produces, can you apply that to anything you could set on fire? Like could you find out the calories of a chair?",
"In chemistry, you take a certain amount of the material and burn it inside of a cup that is inside of a larger cup of water. Then you measure how much hotter the water became after you burned it. But for humans it is much more complicated. Variables include - how digestible it is and how it effects your desire to eat more in the future",
"I don't know if this is what they still do, but originally you would set it on fire and see how much heat was released by the fire. If you had a thermometer in a glass of water, you could estimate how much energy was produced by the fire by calculating how much water there was and how much the water changed temperature.",
"I have to know: does hot food have more calories than cold food? I asked this to a dietician and she got triggered AF."
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7y1pym | How does Earth's atmosphere not get sucked into the vacuum of space? | Repost | explainlikeimfive | {
"a_id": [
"ducw825",
"ducwr5r"
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"text": [
"Because gravity. I mean, that's really the whole answer. Gravity holds the atmosphere to the Earth.",
"Two reasons: First, space doesn't 'suck' anything. The vacuum of space does not exert *any* force on the atmosphere at all. While we may refer to a vacuum as 'sucking' that's a misnomer. As you said, areas of high pressure move to areas of low pressure, so as to equalize the pressure. However, all of that force is coming from the area of high pressure. An area of low pressure is not 'pulling' anything to it, so much as an area of high pressure is pushing into it. Basically speaking, whenever you have a grouping of gas/liquid, it tries to spread out as much as it can. So, when there's an available path to a lower pressure region, it will expand to have a lower overall pressure itself. Since we now know that space isn't 'sucking' at the atmosphere, but rather the atmosphere is 'pushing' into space, what does that mean? Well, first, as you ascend earth's atmosphere, it gets thinner, and thinner. Also that as you descend it gets thicker, and thicker. So why doesn't all that thick spread into that thin, to become an even density? Gravity. If you can imagine that gravity curves space around an object, you'll see that the most 'intense' curve is at the object itself. So when earth is making all this gravity everywhere, it's strongest around the densest parts, or the outer core. For our purposes, let's agree that gravity is strongest at the surface, and gets progressively weaker as you go farther out. So two things combine here: * Air pressure and is trying to push air up and out into space. * Gravity is trying to hold air to the planet. Eventually, the farther away the gases get, the gravity becomes weaker. However, because the atmosphere is much less dense up there, there's less air pressure to keep pushing itself up and away. End result? Thick atmosphere at the bottom, getting thinner, and thinner, until it stops being an atmosphere. The atmosphere we have now is the result of planetary evolution, and it's not stable. At one point, it's likely that a much denser atmosphere would have lost some of itself to space because earth's gravity couldn't contain *all* of it. What we're left with is all the atmosphere that earth *could* contain, and thus it's not escaping anymore because what's here can no longer overcome gravity to get far enough away to be stripped off by solar winds and the like. ***Edit*** A simpler thought experiment, in case anyone wants to explain it to an actual 5 year old, or they don't fully understand the idea's above: *Atmospheres are like lots of springs all over a planets surface. Gravity is pulling down on them, compressing them. Space doesn't uncoil the springs in any way, the springs are naturally trying to uncoil on their own, because space doesn't provide a wall or any pressure to keep them coiled. Gravity is the only thing keeping them compressed and coiled.* *When you're in a space-ship, the walls and other enclosing materials are pressing the springs into the density we require for functioning. When you poke a hole in the wall, the springs don't get dragged out, they simply decompress, or uncoil, and 'jump' out of the hole as fast as they can until they're not compressed anymore.*"
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7y1scf | Why do car manufacturers allow cars to go way faster than speed limits? | Repost | explainlikeimfive | {
"a_id": [
"ducx34d",
"ducx01f"
],
"text": [
"You are allowed to go faster in order to overtake. Different speed limits in different countries. Top speed limits change over time (in NZ we just changed ours to 110 km/hr). Marketing and bragging rights. The customer is always right.",
"Takes more power to get to 65 than it does to coast at 65. Need to horsepower to get to the speed. Saw this question a couple days ago and that was the answer I saw."
],
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7y6e0h | How do air-conditioners produce cold air when it's so hot outside? | Repost | explainlikeimfive | {
"a_id": [
"dudy2mk"
],
"text": [
"An air conditioner can work as long as the compressed gas in the outside part can condense into a liquid. Let's look at how an air conditioner works. The science behind it is that when you squash a gas, it gets hot, and when you allow a gas to expand, it gets cold. You can feel this when you pump up a bike tyre - the pump gets hot as the gas is squashed. You can feel the other way when you use deodorant - the compressed gas expands as you release it, and becomes cold. So, an air conditioner has an amount of gas inside it. The pump squashes that gas, and it gets hot. This hot gas goes to the coils outside. As long as the outside is not as hot as the gas - 65°C is typical - it cools down, giving up that heat to the air outside. Provided it can give up enough heat, the gas condenses to a hot liquid, because of the high pressure. Then this liquid then passes through a valve that drops the pressure. Some of it instantly evaporates, and making that liquid evaporate (or, boil) takes heat energy. Just like that deodorant, the temperature of it drops. Now it is cold, and it is passed through the coils on the inside. Here it pulls heat out of the air inside the room, and this heat is used to boil off the liquid, back into a gas. This gas then flows back to the pump, to be compresed again, which heats it up, and it gives up the heat pulled from the inside of the room (together with heat from the work done by the pump) in the outside coils again. So as long as it is not too hot for the high pressure, hot gas to condense to a liquid, the air conditioner will work fine."
],
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|
7y90m3 | Why do chrome and mirrorlike objects have a distinct "silvery" color when they are just reflecting their surroundings? | Repost | explainlikeimfive | {
"a_id": [
"duekxje",
"duei7fs"
],
"text": [
"Yo ho ho! Yer not alone in askin', and kind strangers have explained: 1. [ELI5: Why do we recognize that mirrors are \"silver\" when they appear to be the exact same color as what they are reflecting? ]( URL_0 ) ^(_ > 1000 comments_) 1. [ELI5: Why is it that we think of mirrors as being silver colored, even though they reflect the exact colors of objects around them? ]( URL_3 ) ^(_ > 100 comments_) 1. [ELI5:Why do I perceive mirrors as silver even when they are reflecting other (non-silver) colors? ]( URL_2 ) ^(_22 comments_) 1. [Why are mirrors drawn as silver/grey when they reflect any colors from their surroundings? ]( URL_1 ) ^(_20 comments_) 1. [ELI5: how can mirrors reflect an image and still \"look silver\" if the image has no silver or grey in it? ]( URL_5 ) ^(_6 comments_) 1. [ELI5: Why do I perceive mirrors and other reflective surfaces as silver? Don't they really just have the color of whatever they're reflecting? ]( URL_4 ) ^(_10 comments_)",
"What you are seeing is the color silver. I know. This doesn't sound very interesting. Silver absorbs a little bit of the visible spectrum just like other colors do. Mirrors are just metal coated glass, or bare polished metal, just like chrome."
],
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"https://www.reddit.com/r/explainlikeimfive/comments/4fa2pp/eli5_why_do_we_recognize_that_mirrors_are_silver/",
"https://www.reddit.com/r/NoStupidQuestions/comments/4st7vf/why_are_mirrors_drawn_as_silvergrey_when_they/",
"https://www.reddit.com/r/explainlikeimfive/comments/1vt8xa/eli5why_do_i_perceive_mirrors_as_silver_even_when/",
"https://www.reddit.com/r/explainlikeimfive/comments/5lw1g0/eli5_why_is_it_that_we_think_of_mirrors_as_being/",
"https://www.reddit.com/r/explainlikeimfive/comments/1zt7sj/eli5_why_do_i_perceive_mirrors_and_other/",
"https://www.reddit.com/r/explainlikeimfive/comments/1s75g1/eli5_how_can_mirrors_reflect_an_image_and_still/"
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|
7ya5fh | Why is it when someone gets hurt their instinct is to yell ow? | Repost | explainlikeimfive | {
"a_id": [
"duer7ps"
],
"text": [
"It's not an instinct. It's learned behavior that varies based on your culture. You were raised from an infant to associate \"ow\" with pain, and it's *heavily* ingrained in you, but it's not an instinct. If you had been raised in Japan, you'd say \"ite\". If you had been raised speaking Arabic, you'd say \"Akh\". Different languages and cultures have different sounds for this. But all of them tend to be short and easy to say."
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7yb4bn | Why is it that when my friends tap the top of my beer with the bottom of their (bottles), the beer foams and overflows? | Repost | explainlikeimfive | {
"a_id": [
"duf2lbj"
],
"text": [
"If you do this a few times you'll find that the beer foams less each time and soon doesn't foam at all. This tells you it's coming from an ingredient in the beer that's used up by the tapping and foaming. After a beer stops foaming like this it tastes very \"flat\". The ingredient is carbonation, i.e., carbon dioxide gas that's mixed together with the beer in the fluid. The gas molecules are weakly bonded with the nearby beer molecules, very similar to a carbonated soda drink. Tapping the beer bottle sends a small shock wave through the fluid, and the shock breaks the bonds, releasing the gas molecules to rise to the top and generate foam. Normally only the molecules at the top surface of the fluid (the ones exposed to air) are released, so the process is slow and the beer doesn't foam up much. The shock wave releases the gas through the whole volume of the fluid in a much faster process, so the foam overflows the space at the top of the bottle and spews out."
],
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7ybpxa | Why is it that whenever we take a picture of the sun or moon it looks so much smaller in the picture than it does with our naked eye? | Repost | explainlikeimfive | {
"a_id": [
"duf443e"
],
"text": [
"Because the human brain is horrible at estimating the size of things like the moon in the sky and our brain actually lies to us about their size. When you take and look at a picture, you're removing it from the context that the brain can't cope with and putting into a context that's more familiar. Here's an article that goes into detail about it and shows examples of the effect: URL_0"
],
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"text_urls": [
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"http://www.skyandtelescope.com/observing/moon-illusion-confusion11252015/"
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|
7ydlcc | Why are Directors praised for a good story? I mean, for good cinematography, sure. But they don't write the story. | Repost | explainlikeimfive | {
"a_id": [
"dufla55"
],
"text": [
"The story that is presented to the viewers is ultimately delivered via the director's choices. The same story in the hands of a less talented director wouldn't be as engaging and enjoyable for the audience."
],
"score": [
6
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7ydvau | Is there any logical reason as to why toilet bowls have a column of water sitting at the bottom? | Repost | explainlikeimfive | {
"a_id": [
"dufoqmc",
"dufoynm",
"dufrvio"
],
"text": [
"Yes, the water acts as an air seal to prevent sewer gas rising up from the toilet into your room. Most people don't want to smell old poop water.",
"It is a built in water trap. It prevents waste smells and gasses from coming back up after flushing. Most drains have a similar set up. If you look at the side of the base of the back of a toilet you can see the way the drain is designed.",
"Which \"column of water\" are you referring to? The bowl has water in it so you don't deliver waste directly onto the porcelain. Not a big deal for urine, may be a big deal for excrement. The piping (first ceramic then metal or plastic) has an elbow in it (or a \"J\" then connected to an inverted \"J\") to create as others have said an air trap. This prevents the horrid smell of waste from your sewage line from entering your home. In addition, past that dual \"J\" air trap, there's another pipe that leads upwards from the sewer line to above the roof. This is a vent that allows gases created by bacteria to vent and not bubble up through the double \"J\" air trap. Sewage system plumbing has been around for a while and is quite well tested."
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7ygzh5 | How will an unprotected human body die in space? | Repost | explainlikeimfive | {
"a_id": [
"dugh92h"
],
"text": [
"Due to the low pressure, oxygen will move across your lungs from your blood into the vacuum. You will fall unconscious within a matter of seconds, and die due to the lack of oxygen, asphyxiation, within a few minutes."
],
"score": [
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7yi9qr | depression. | Repost | explainlikeimfive | {
"a_id": [
"dugqxn8",
"dugsl9m"
],
"text": [
"Depression is the lack of emotion it looks like sadness but inside of you it feels empty there is no emotion everything feels worthless you feel worthless and nothing has any meaning it feels like you wasted everything you got and ended up in the deepest most miserable hole ever and no one understands how you feel and that makes it worse. Being sad is lasts for a while and its gone and then you feel better while when you are depressed it doesn't go away and the longer it is you feel worse if you need me to clarify something i will just ask on Source:myself",
"Avast ye! Yer not alone in askin', and kind strangers have explained: 1. [ELI5: Is there a difference between clinical depression and depression triggered by a traumatic event? ]( URL_3 ) ^(_19 comments_) 1. [ELI5: What is depression? ]( URL_5 ) ^(_23 comments_) 1. [ELI5: Why do people who have depression sleep a lot? ]( URL_2 ) ^(_11 comments_) 1. [ELI5: Depression ]( URL_8 ) ^(_50 comments_) 1. [ELI5: When suffering with depression, what is the physical feeling you get in your chest? Sort of like an actual sinking feeling. ]( URL_6 ) ^(_73 comments_) 1. [ELI5: What is anxiety and depression? Are they related to eachother? ]( URL_1 ) ^(_6 comments_) 1. [ELI5: Depression. How can someone not be able to get up and do things? ]( URL_9 ) ^(_88 comments_) 1. [ELI5: Why is Depression considered a real illness when it is all in the person's mind? ]( URL_0 ) ^(_ > 100 comments_) 1. [ELI5: What is anxiety and depression? Are they related to eachother? ]( URL_1 ) ^(_6 comments_) 1. [ELI5: Depression ]( URL_8 ) ^(_50 comments_) 1. [ELI5: What is the difference between \"true\" depression and low self-esteem/feeling sad? ]( URL_7 ) ^(_8 comments_) 1. [ELI5: How to explain depression to my spouse who believes it's not a real disease and can be controlled by deciding to not be sad. ]( URL_4 ) ^(_ > 100 comments_)"
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"https://www.reddit.com/r/explainlikeimfive/comments/344vez/eli5_why_is_depression_considered_a_real_illness/",
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"https://www.reddit.com/r/explainlikeimfive/comments/6c7m43/eli5_why_do_people_who_have_depression_sleep_a_lot/",
"https://www.reddit.com/r/explainlikeimfive/comments/7ahdom/eli5_is_there_a_difference_between_clinical/",
"https://www.reddit.com/r/explainlikeimfive/comments/23xtul/eli5_how_to_explain_depression_to_my_spouse_who/",
"https://www.reddit.com/r/explainlikeimfive/comments/36kstt/eli5_what_is_depression/",
"https://www.reddit.com/r/explainlikeimfive/comments/6ru6xg/eli5_when_suffering_with_depression_what_is_the/",
"https://www.reddit.com/r/explainlikeimfive/comments/2y0orq/eli5_what_is_the_difference_between_true/",
"https://www.reddit.com/r/explainlikeimfive/comments/1l90le/eli5_depression/",
"https://www.reddit.com/r/explainlikeimfive/comments/2tsu9g/eli5_depression_how_can_someone_not_be_able_to/"
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7yit5l | Why do commercial flights take longer going to a destination then coming back when they fly the same distance and course? Why can planes fly faster at higher altitudes? | Repost | explainlikeimfive | {
"a_id": [
"dugvg57"
],
"text": [
"They take longer going west because they're heading against the general wind direction. Same route going east, the wind is helping so it's faster. Higher altitude: the air is thinner, less friction."
],
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7ykalx | How can snowboarders fall 5 stories and not break their legs ? | Repost | explainlikeimfive | {
"a_id": [
"duh7oux",
"duh834d",
"duh86e7"
],
"text": [
"A) Snow is softer than dirt B) Just like motorcycle riders, they try to land on sloped ground so you're *not* dealing with the entire impact as a blow to the legs",
"Landing on a steep slope (like in the Olympic events) allows the person to slowly slowly decrease their speed of the fall. If the landing was flat, they would all suffer broken bones.",
"When falling, It isn't the collected kinetic energy that kills your bones, It's the sudden stop. Or more importantly, the change in momentum as you go from falling really fast to stopping in an instant. When a snowboarder or ski jumper fall down great distances they tend to land on a slope that slows their downward momentum over a longer period of time then a flat landing would."
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|
7ylpsw | How does dry cleaning work? | I struggle to get my head round the magical concept of how one can clean things without any water, hoping someone can help me wrap my head around it? | Repost | explainlikeimfive | {
"a_id": [
"duhh5yl"
],
"text": [
"Yarr! Yer not alone in askin', and kind strangers have explained: 1. [ELI5: What exactly is dry cleaning? ]( URL_2 ) ^(_ > 100 comments_) 1. [ELI5: How exactly does dry cleaning work? (And are dry clean-only labels a scam?) ]( URL_0 ) ^(_36 comments_) 1. [ELI5: How does dry cleaning work? ]( URL_5 ) ^(_4 comments_) 1. [ELI5: How does the process of Dry cleaning work? ]( URL_6 ) ^(_1 comment_) 1. [ELI5: How does dry cleaning work? ]( URL_3 ) ^(_9 comments_) 1. [ELI5: how does dry cleaning work and why do certain clothes need it? ]( URL_4 ) ^(_4 comments_) 1. [ELI5 How does dry-cleaning work? ]( URL_1 ) ^(_ > 100 comments_)"
],
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"text_urls": [
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"https://www.reddit.com/r/explainlikeimfive/comments/61rs3f/eli5_how_exactly_does_dry_cleaning_work_and_are/",
"https://www.reddit.com/r/explainlikeimfive/comments/vexeu/eli5_how_does_drycleaning_work/",
"https://www.reddit.com/r/explainlikeimfive/comments/2i334z/eli5_what_exactly_is_dry_cleaning/",
"https://www.reddit.com/r/explainlikeimfive/comments/6fyv8s/eli5_how_does_dry_cleaning_work/",
"https://www.reddit.com/r/explainlikeimfive/comments/33714g/eli5_how_does_dry_cleaning_work_and_why_do/",
"https://www.reddit.com/r/explainlikeimfive/comments/7gxtlu/eli5_how_does_dry_cleaning_work/",
"https://www.reddit.com/r/explainlikeimfive/comments/6twi49/eli5_how_does_the_process_of_dry_cleaning_work/"
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7ym5fi | Why can a huge human whack a tiny fly mid air and its seemingly unhurt? | Repost | explainlikeimfive | {
"a_id": [
"duhks18",
"duhxzzf",
"duholhq"
],
"text": [
"[u/stefonion]( URL_1 ) > [ URL_0 ]( URL_0 ) > When you swat a... well, anything, your hand builds up a small layer of air in front of it. When you swat a small thing, for a brief moment, they accelerate as the air layer pushes them. By the time your hand reaches them, they are not hit as hard as you think they were hit. > Now, if you take something larger than your hand, say, a friend's face, then the air layer is not big enough to push them, and they will feel the full force of the blow. > I am just trying to re-create this from memory. This was posted many months ago. > EDIT: Yes, this is exactly why fly swatters have holes, to remove as much of the lairheh as possible. It also helps that Flies have an exoskeleton and are very durable. If you scaled a fly up to the size of a cow, it would be the equivalent of a cow inside an army tank.",
"As with pretty much any question about why small things behave differently than big things, it's the square-cube law. Let's say the fly is 1cm long, so roughly 180 times shorter than you. That means the cross-section of e.g. its legs and thus its toughness is 180^2 times smaller. However, it also means its mass is 180^3 smaller - and mass results in inertia, which is what would harm the fly when being swatted in the middle of the air. So effectively, the fly, *because* it is 180 times smaller than you, is actually 180 times tougher against being swatted. Note that this only applies to being swatted in the air - if you swat the fly against a solid surface, then your absolute strength acts upon it rather than inertia, and it will be squashed.",
"Also, their very low mass means they accelerate quickly when hit so do not absorb as much energy as deformation as a heavier object would."
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"https://www.reddit.com/user/stefonio"
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7yml5d | How is data/information stored on USB's, SSD's etc, able to be stored on these devices without power? | You plug in a USB, place a file inside, unplug and it will still be there wjen you next plug it in. How does it stay there? My current thought is that the information is etched/embedded somewhere inside but I cannot seem to get my head around the concept! | Repost | explainlikeimfive | {
"a_id": [
"duhmgir",
"duhn1dc"
],
"text": [
"Flash memory, the one used in USB drives and SSDs, is a form of EEPROM. They use floating gate transistors, in which electrons are effectively being trapped in a part of a component. Much like you do not need water running to keep a glass full, the trapped electrons will stay there until overwritten (or \"evaporated\", to keep the water analogy, but that takes quite a while), even if the power that put them there is no longer in place.",
"Electrical capacitors (the most basic ones are just two metal plates separated by a plastic insulator) can store electrical charges (electrons) on the plates. So flash memory is composed of [floating gate transistors]( URL_0 ), that (if you look at the pictures in that article) basically have a tiny capacitor built-in, enough to hold a small charge of electrons on plates that are insulated in plastic, even if you cut off power. So the presence of a charge (electrons) is treated as a 1, and the absence as a 0, and that's how you get your data stored in 1's and 0's."
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7ypc5q | Why must we put our phones on airplane mode when on an airplane? | Repost | explainlikeimfive | {
"a_id": [
"dui7bzd"
],
"text": [
"In theory, this shouldn't be necessary; FAA regulations where you see the little disclaimer like \"this device cannot put out any harmful interference, and must accept any interference it puts out\" is mostly for airline safety: so that no consumer electronics will mess with aircraft instruments, as aircraft instruments don't have that restriction and can reject interference and give off interference with impunity. But, on the off-chance that there's a defect in someone's phone that makes it send out harmful interference, this would prevent it. And when you're dealing with hundreds of people in a metal tube packed to the brim with highly flammable liquids and being made to go several hundred miles per hour while flying several thousand feet above the surface of the Earth, you have as many failsafes as you can possibly have. The chance of any given phone causing EM interference is almost 0. The chance of a phone that is off or in airplane mode causing EM interference is a much closer number to 0, though, and when you're talking about airplane safety, closer to 0 is always better."
],
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7yvczr | What is the god particle | Repost | explainlikeimfive | {
"a_id": [
"dujemwm",
"dujfsut"
],
"text": [
"\"The god particle\" is a nickname for the Higgs Boson. The nickname is from the title of a book, which was originally meant to be \"_The God**damn** Particle: If the Universe is the Answer, What is the Question?_\" (emphasis mine), but there was a certain amount of meddling from the publisher and the \"damn\" was dropped. Scientists tend not to like that name much, because the Higgs Boson has nothing more to do with any God than any other particle, and also finding it won't make us into gods; there is no actual sense in which it *is* a \"god particle\". The Higgs Boson is the particle associated with the Higgs field, which is a quite complex concept in particle physics which explains why some fundamental particles have mass even though you might expect them not to.",
"I just learned this neat trick from another redditor this week. Use ' URL_2 ' instead of ' URL_1 ' for a more basic and easy to understand explanation of a topic! URL_0"
],
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"en.wikipedia.org",
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|
7yxh4r | How men and women are born in almost equal ratio on this planet? | Repost | explainlikeimfive | {
"a_id": [
"dujv38n",
"dujtjjd"
],
"text": [
"1. Suppose male births are less common than female. 2. A newborn male then has better mating prospects than a newborn female, and therefore can expect to have more offspring. 3. Therefore parents genetically disposed to produce males tend to have more than average numbers of grandchildren born to them. 4. Therefore the genes for male-producing tendencies spread, and male births become more common. 5. As the 1:1 sex ratio is approached, the advantage associated with producing males dies away. 6. The same reasoning holds if females are substituted for males throughout. Therefore 1:1 is the equilibrium ratio. URL_0",
"> How men and women are born in almost equal ratio on this planet? Human females have two X chromosomes (XX), while men have an X and a Y (XY). The sperm are generated with half of the genetic material of the male which means that roughly 50% get an X and the other 50% get a Y. All the female eggs will be getting an X because that is all the female has. So when the sperm meet the egg if the sperm has an X it will be a female child and if it has a Y then it will be male."
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"https://en.wikipedia.org/wiki/Fisher%27s_principle"
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|
7zcp8m | Why do most screens and other color pickers use red, blue, green instead of red, blue, yellow? | Repost | explainlikeimfive | {
"a_id": [
"dun2mmz",
"dun1o5t"
],
"text": [
"Cyan, magenta and yellow are used in printing, and adding them up makes *black*. (Subtractive colours) A monitor however uses light where the three primary colours red, blue and green (say, LEDs) add up to white. (Additive colours)",
"> Why do most screens and other color pickers use red, blue, green instead of red, blue, yellow? Because red, blue, and green are the primary colors of light (additive color) and cyan, magenta, and yellow are the primary pigments (subtractive color). Some people didn't learn cyan and magenta properly because colors are hard, instead calling them red and blue."
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7zdah8 | How is 85% of the ocean unexplored? | Repost | explainlikeimfive | {
"a_id": [
"dun5u6r",
"dun6m64",
"dun6or8"
],
"text": [
"oceans cover 71% of the earths surface. and that's not accounting for depth. ships travel at 30 miles an hour at most. oceans are 139.7 million square miles. which means if you stack size of the ocean one mile wide by 139.7 million miles long. it would take 531 years to traverse it all by ship. and that's just the surface, and not any depth.",
"It’s very deep and we are only just really developing submarines that can withstand the pressures at the ocean floors, and even then it only for limited time, plus it’s pitch black so only the lighting the ship provides allows us to see anything.",
"The sentence is usually referring to the fact that over 70% of the earth's surface is ocean-floor, and we have not explored much of the ocean floor. It's quite hard to get down there, thus exploration is expensive. Now you might think that there isn't a lot to be seen down there, but that is not true: on many expeditions they find new species on ground an in the open water."
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7zk129 | Why do gas prices almost always include “9/10” of a cent, and how could we be expected to pay in portions of a penny anyway? | Repost | explainlikeimfive | {
"a_id": [
"duol70a"
],
"text": [
"Basically when the tenth of a cent thing was introduced gas prices and wages were cheap enough that it gave gas stations a better degree of price control. If your price is $.10 going up to $.11 is a huge 10% increase in cost, so allowing them to make smaller adjustments let them price gas better. Since then prices have climbed but the tenth of a cent spot in the price has stuck around. As for how it actually works it relies on the fact that generally you buy multiple gallons of gas at once. So they just track the price like normal, and then when you finish filling up they just round up to the nearest cent and that's what you pay (the consumer always takes the loss in cases where you might have fractional cents like buying gas or sales tax)."
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|
7zktts | How does GroupMe and other free services make money? | Repost | explainlikeimfive | {
"a_id": [
"duotczk"
],
"text": [
"There’s in old adage: if you receive something for free, you are the product They sell your info"
],
"score": [
3
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|
7zpo4u | When swiping a card, you would think if you swipe slowly the machine could get a better read and accept your card. Why is this not the case? Why do you have to swipe it fast? | Repost | explainlikeimfive | {
"a_id": [
"duprdm8",
"dupstqx",
"duptb28"
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"text": [
"A magnetic stripe readers operates by listening to a magnetic field for changes created by the passing card. A card moving faster creates what could be described as a \"louder\" \"message\". Ideally, a consistent, swift swipe produces the most clear \"message\" for the reader to pick up on, and it is also generally easier to maintain a more consistent card speed when the card is moving over the read head faster.",
"THe way a magnetic stripe generates a signal is by what's called induction. This is basically where a changing magnetic field creates electricity, and it's how an electric generator would work. Now, put like that, would you expect an electric generator to create a bigger signal if you spin it faster than if you spin it slowly? It's that same principle that makes a faster swipe more effective than a slow swipe.",
"A magnetic stripe contains particles of a material that can be magnetized in one direction or another. The reading of the card is enabled by *changes* in the direction of magnetism as you go along the stripe. As you move the card stripe along a reader (or vice versa), the changes in magnetism [induce a current pulse in a coil in the reader head]( URL_0 ). The faster you move the card, the larger the induced current pulses will be. But they will also be faster in time. At some point, there's an optimal trade-off for the reading circuitry that has to detect the pulses. Too slow and the current pulses will be too weak. Too fast and they may look like random noise and not be properly detected. **TL;DR** - It's kind of like Goldilocks and the three bears."
],
"score": [
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"https://dsp.stackexchange.com/questions/715/extracting-binary-magnetic-strip-card-data-from-raw-wav"
]
]
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|
7zq6oj | What exactly is a muscle "knot?" Is it a recognized medical phenomenon with a more technical definition? And is massage actually an effective treatment for them? | Repost | explainlikeimfive | {
"a_id": [
"dupw5dq"
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"text": [
"Yer not alone in askin', and kind strangers have explained: 1. [ELI5: what exactly are knotted muscles in your back and where do they go when massage therapists work them out? ]( URL_4 ) ^(_28 comments_) 1. [What exactly are muscle knots? I assume they form under stress, but why do they stay formed for long periods of time? ]( URL_6 ) ^(_ > 100 comments_) 1. [ELI5: What is a muscle knot and what does it look like under the skin? ]( URL_5 ) ^(_ > 100 comments_) 1. [Eli5 how a \"knot\" in a muscle is formed, and how massaging the area gets rid of it. ]( URL_2 ) ^(_ > 100 comments_) 1. [ELI5: What exactly happens to muscles when you massage them and why is it good for them? ]( URL_0 ) ^(_7 comments_) 1. [ELI5:What actually happens when you \"pull\" a muscle? ]( URL_3 ) ^(_44 comments_) 1. [ELI5 What happens when the muscles in your back get knots? ]( URL_1 ) ^(_2 comments_)"
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"https://www.reddit.com/r/explainlikeimfive/comments/3k27mi/eli5_what_exactly_happens_to_muscles_when_you/",
"https://www.reddit.com/r/explainlikeimfive/comments/6r11jc/eli5_what_happens_when_the_muscles_in_your_back/",
"https://www.reddit.com/r/explainlikeimfive/comments/37n01p/eli5_how_a_knot_in_a_muscle_is_formed_and_how/",
"https://www.reddit.com/r/explainlikeimfive/comments/1nmj8s/eli5what_actually_happens_when_you_pull_a_muscle/",
"https://www.reddit.com/r/explainlikeimfive/comments/6h2d1j/eli5_what_exactly_are_knotted_muscles_in_your/",
"https://www.reddit.com/r/explainlikeimfive/comments/26b84t/eli5_what_is_a_muscle_knot_and_what_does_it_look/",
"https://www.reddit.com/r/explainlikeimfive/comments/164944/what_exactly_are_muscle_knots_i_assume_they_form/"
]
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|
7zqubg | What causes the sneeze reaction you get when looking at a bright light? | Repost | explainlikeimfive | {
"a_id": [
"duq1sph"
],
"text": [
"There's a genetic component to it. It's referred to as the \"photic sneeze reflex\" or photoptarmosis. If you have the gene, you will sneeze as a result of looking directly at bright light. If you don't have the gene, you won't sneeze. I'm going to disagree with /u/mmont49 about it being caused by tears in the sinus ducts. I have this gene and the urge to sneeze is immediate and powerful, not enough time for tears to travel through sinus ducts. Plus I don't have the urge to sneeze on other occasions when tears travel through sinus ducts. It's an instinct directly triggered by the bright light."
],
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3
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|
7zr151 | How can the entire world be in debt? | Repost | explainlikeimfive | {
"a_id": [
"duq2uue",
"duq2vrm",
"duq37i6",
"duq33y7"
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"text": [
"All nations carry debt. But they aren't just borrowing from each other. They borrow from banks and from people. For example, a big chunk of the US national debt is in government bonds to private citizens. They do pay them, or at least they usually pay them, but they carry debt for the same reason people do; they value the things they get for the borrowed money so much they're willing to shoulder the additional interest payments.",
"Debt is not \"bad.\" Debt is a tool. Its use can be bad, or can be good. Governments need debt because they need the ability to borrow money in the event that they don't raise enough money (through taxes) to pay their expenditures. Most countries owe debt to themselves. In the US, the debt is primarily owned by US entities - US citizens, the US government, state governments, etc. This just helps the government to function.",
"Think of it in the same way as a person has debt: An average person in the US probably has several tens of thousands of dollars in debt. A mortgage, a car loan, student loans, credit card debt, etc. But that debt isn't a *bad* thing, because they get to use that house, that car, that education, and so on, while they pay those loans off. So as long as the payments are manageable and the person is able to slowly pay down those debts while still being able to live their life normally, that debt is a good thing, for the most part. And even though the total debt might be more money than a person makes in a year (or many years, especially if a mortgage is involved), that's nothing to worry about, as long as it's being used well. It's the same thing, in many ways, for a country. A country borrows money from lots of sources - from its citizens, in the form of bonds, from other countries who have lent money, even in the form of pensions or benefits owed to citizens. And as long as the country is able to pay back those people bit by bit, the country has made good use of that debt, and everyone's happy. So even a debt that seems to be a huge number isn't a bad thing until a government isn't able to pay its debts.",
"> why is don't they pay them? Generally speaking, they are paying them. However, they continue to accrue new debts, and they don't generally pay off a single debt in one go but rather by an agreed upon schedule of installments."
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|
7zs86q | How does insider trading work and what issues does it cause to make it so illegal? | Repost | explainlikeimfive | {
"a_id": [
"duqdfcz"
],
"text": [
"For a five year old: As a parent I get to go grocery shopping and choose what cereal we have. When I purchase Cinnamon Toast Crunch (CTC), our favorite, and don’t tell my children about it, I have an unfair advantage at breakfast the next day. When I ask my children what they want for breakfast, they say Frosted Flakes not knowing that there is CTC. When I pull out the CTC and pour myself a huge bowl that contains half the box, I reap the rewards from my unfair advantage and the kids fight it out for whatever is left. Just an example, not saying this has ever happened at my house....."
],
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|
7zsqpu | Black Lights | Repost | explainlikeimfive | {
"a_id": [
"duqh2zu"
],
"text": [
"because some materials absorb ultraviolet light which has a lot of energy. then to get rid of the energy, they emit light at lower energy, usually as visible light. think of it as a set of stairs. you throw a ball to the top of the stairs (which takes a lot of energy), then the ball bounces back down one, two or three steps at a time releasing the energy in smaller amounts."
],
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|
7zte18 | What happens to a digital file when it's deleted | Repost | explainlikeimfive | {
"a_id": [
"duqlyls"
],
"text": [
"Your computer keeps a registry of the location of the data for that file. On a traditional Hard Disk Drive, that means the coordinates on the actual, physical, rotating disk (think track number on a CD - or record if you're old enough). On a Solid State Drive, it's a little more complicated with virtual locations and whatnot, but the idea is the same. Your data is stored at a location, and the registry knows where that location is. It's kind of like how the post office knows where your house is without keeping your entire house in the post office. When you write data to your drive, that location is protected so it can't be overwritten, because the registry tells the drive that the location is being used. When you delete a file, the entry in the registry is deleted. That's it. The post office forgets your address. The data remains there until that location is used for new data, at which point it is overwritten and \"deleted\". On an HDD, that means the metal disk is remagnetized (or demagnetized) at that location, switching the old combination of 1s and 0s to the new data. On an SDD, that means the NAND gates, which hold 1 or 0, are reset and again, changed to the new data. On HDDs, the process of changing the magnetization of the disk is not perfect. Remnants of the old pattern can be pulled up, which is what law enforcement agencies do when they go through disks to pull up deleted files."
],
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|
7zwlr9 | Why is warm water recommended for cleaning if germs grow better in warm conditions? | Repost | explainlikeimfive | {
"a_id": [
"durbt9r"
],
"text": [
"To add onto what was already said, hot water has a better dissolution capability. So it will dissolve more dirt and other hindrance material before being saturated, while also dissolving them faster and easier."
],
"score": [
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|
7zwpei | I am a European. What is Mormonism? Is it a cult like Jehovas witnesses? | Repost | explainlikeimfive | {
"a_id": [
"dura817",
"dur9n3f"
],
"text": [
"Is it a cult? You could argue both ways. Here's a brief-ish history of mormonism and you can decide. Here's a brief history of Mormonism: In the 1820's, Joseph Smith was a known con artist in Illinois running a scam where he would look into \"seer stones\" (small rocks with holes bored into them) claiming that they had the magic ability to tell him where treasure was buried. People would pay him to find treasure for them on their property, which of course he never did. Eventually he started claiming that and Angel came to him and told him the location of some golden plates with scriptures from ancient Native Americans on them. He insisted that no one was allowed to see the plates except him. He then uses the same seer stones that he did his treasure hunting with to \"translate\" the plates which became the book of mormon. The Book of Mormon tells the story of a family of Jews that fled Jerusalem, came to the Americas, got cursed with dark skin by god for being unrighteous, and descended into modern Native Americans. From there on he went on making a bunch of wild claims up (much like Scientology) and for some reason people believed him. He convinced one of his followers to pay to publish the Book of Mormon. After he got caught cheating with another women, he claimed that god or jesus (his story changed a lot) told him he should have multiple wives. Eventually a local newspaper published an article that exposed him and so he burned the press down and was arrested for it. got arrested for it. He and his brother were then killed by an angry mob who broke into the prison. After a bunch of fighting between his potential successors over which one of them would take over, one of them, Brigham Young, took his followers out to what is now Utah so they could live in peace and they became the modern Mormon Church. Eventually they got rid of some of the crazier elements like polygamy (at least the mainstream mormon church did. Some fundamentalist sects still practice it.) Now they're a multi-billion dollar business/religion.",
"Yes, it was invented in the 1800’s and is constantly changing, polygamy, no polygamy, no blacks, then allowing them. A lot is taken from Masons an they are told if the research Mormonism it shows a lack of faith. They claim Jesus was not one with God but a man who became a god. All people can do this too they claim. Families are together forever as long as they are in good standing with the church and give money. Salvation is earned by good works, a total opposite of what the Bible states. Christians are saved by believing Christ died for us to pay for our sins. If good works were required then it would be as if Christ’s life was not enough. Ephesians2: 8,9 “for by grace we are saved by faith, and not by anything we do. It is a gift from God, so no man can boast. “"
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7zx3ci | Is there an absolute hot? | Repost | explainlikeimfive | {
"a_id": [
"durcjdc",
"durcqe2",
"durgirs",
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"text": [
"With our current knowledge, there is a theoretical limit, called the Planck temperature. A body emit light with a wavelength corresponding to its temperature, and a body at the Planck temperature emit light with a wavelength of the Planck length. The Planck length is kind of our distance limit of the comprehension of the universe without a quantum gravity theory. If you want, at the Planck temperature, the energy involved are so high, we don't yet have a model that works to describe the behavior of matter. EDIT: as /u/JoJosh-The-Barbarian mentioned, the Planck temperature is not a limit as the higher temperature possible, but as the limit of our understanding",
"We don't know. The wavelength of light emitted by an object is directly calculable from its temperature. As temperature increases (however momentarily), wavelength decreases. Plank theory suggests that the universe is quantised, meaning that there's a constant step between points in space, energy levels, etc... The Plank constant theorises that there's a minimum interval between any two energy levels of ~4.1 x 10^-15 electron volts. The plank length theorises that there's a minimum interval between any two points in space of ~1.6 x 10^-35 meters. Were the temperature of a particle to exceed ~1.4 x 10^32 degrees Kelvin, the wavelength of the emitted light would fall below the plank length. We have no idea what happens next, much less how the laws of physics behave at such extremes. The Plank length is so small and the Plank temperature so high that we've had a very hard time conducting meaningful scientific inquiry into them or assessing their meaningfulness.",
"There are two good answers to this. The first is the “Planck temperature”, which is about 1.42×10^32 kelvins. In a system with that temperature, particles have so much energy that gravitational forces overwhelm the other forces like electromagnetism. We use quantum theory to model the behavior of particles, but we know that quantum theory does not properly account for gravity, so we know that it doesn't say anything sensible about what would happen at that temperature. A “quantum theory of gravity”, which is a sort of holy grail for physicists, might work to describe such a system. The second answer is in some sense the true counterpart to absolute zero. To explain it, I need to briefly talk about *negative temperature*. In thermodynamics, temperature is defined as the reciprocal of a quantity called *thermodynamic beta*. A high beta means that adding energy to a system will increase the entropy by a lot, while a low beta means that adding energy will only increase entropy a little. Cold systems have a large beta, and hot systems have a small beta. Absolute zero temperature corresponds to infinite beta — intuitively, this is one way of understanding why absolute zero can never be reached, because it's really an infinity in disguise. What if beta is negative? That would mean that adding energy to a system would *decrease* its entropy. This is forbidden by classical thermodynamics, but it's possible in special cases in quantum theory. For example, it can happen in systems where most particles have as much energy as they possibly can, so adding energy to the system would mean bumping up some other particles from their own diverse states to the common maximum. If a system has negative beta, then it also has negative temperature (because temperature is just the reciprocal of beta). But high beta is cold, and low beta is hot, so negative temperatures are hotter than positive temperatures! To illustrate, consider [this graph]( URL_0 ). (The graph has the right shape, but the labels aren't relevant to us.) We can take the X axis to represent temperature and the Y axis to represent beta. We can see that a positive temperature means a positive beta, a negative temperature means a negative beta, a large (far from zero) temperature means a small (close to zero) beta, and a small temperature means a large beta. We can see that as temperature approaches positive or negative infinity, beta approaches zero, and as temperature approaches zero, beta approaches positive infinity from one direction and negative infinity from the other. The absolute zero we know — absolute cold — means infinite positive beta. When we only look at the right side of the graph (positive temperature), it makes sense to handwave that this means zero temperature. Informally, we're dividing by infinity and getting zero. This is not really valid math, but it's a reasonable way to think about it. Absolute hot, on the other hand, would mean infinite *negative* beta. When we translate that to temperature, we'd be dividing by negative infinity and getting… also zero. (Again, this is not real math. Infinity and negative infinity are not real numbers and you can't divide by them.) So if we really want to talk about temperature instead of beta, then both absolute cold and absolute hot can be found at zero kelvin.",
"VSauce did a great [video]( URL_0 ) on this back in 2012. Even though your question has been answered, I still highly suggest watching it if you have 15 minutes to spare!"
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800fbw | What is the double slit experiment? Why is it important? | Repost | explainlikeimfive | {
"a_id": [
"dus1zrv"
],
"text": [
"[The experiment look like this]( URL_0 ), you send electrons into a screen with two slit, and behind this you got a screen on which you can see where the electrons land. If you believe the electrons are particles, in the sense that they are like a very \"small ball\", you would have points on two spots on the second screen corresponding to direct trajectories from the electron canon to the screen. But this is not what you get when you do the experiment. If you send electron one at a time, you get a point on the screen for each electron. But as you get more and more electron on the screen, you can see that it form a [pattern]( URL_1 ). It's exactly the same pattern, called interference pattern, that you would get if you send a wave through the slits. It means that the description of electrons as \"small ball\" is wrong, and electrons have wave-like properties. This experiment is the start of quantum mechanics."
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"https://skullsinthestars.files.wordpress.com/2009/03/tonomuradoubleslit.jpg"
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803cl2 | how can the radius of the observable universe be 46 billion light years while the universe itself is only 13 billion years old? | Repost | explainlikeimfive | {
"a_id": [
"dusomg0"
],
"text": [
"The universe itself is expanding still and doing so faster than the speed of light. Where nothing inside the universe can move faster than the speed of light, the expansion of it can. (In my very limited understanding) Where something was observed at point A and now at point B they can tell that the expansion is X."
],
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|
8041sx | How do the image captcha work? | Repost | explainlikeimfive | {
"a_id": [
"dustfcy"
],
"text": [
"That's Google's [\"No CAPTCHA\"]( URL_5 ) you're seeing. Basically, Google use: - the data they know about you (Are you signed into Google? Have they seen your IP before?) - [how you behave when solving the CAPTCHA]( URL_2 ) (Do you move the mouse like a human does, or does your mouse instantly shoot to the checkbox like a robot might do? Did you take some time reading the rest of the page first?) - [how you loaded the page]( URL_0 ) (did you load all the scripts and CSS like a browser does, or just the HTML like some scrapers do?) If their algorithm decides that you're a human, you just get the checkbox. Otherwise, you'll receive a challenge (generally image recognition with No CAPTCHA). Image recognition is a [difficult job]( URL_4 ) for computers, and requires quite a lot of computing power (most approaches use [neural networks]( URL_1 ), but how this is done isn't too important)... but recognising images is pretty easy for humans! How you solve the CAPTCHA is a useful clue too for Google's algorithm; humans and bots generally behave differently here, so that behaviour can feed into deciding whether you're a human. If the algorithm is *really* unsure, you'll get more sets of images to verify. It'll keep doing that until it's confident one way or the other, so that's why you sometimes get lots of image sets to classify. As a side benefit, [the image categories get used to train Google's image recognition networks]( URL_3 ), so Google gets better at image recognition with the data collected from CAPTCHAs."
],
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[
"https://security.stackexchange.com/questions/124532/what-triggers-googles-recaptcha",
"https://en.wikipedia.org/wiki/Artificial_neural_network",
"https://www.wired.com/2014/12/google-one-click-recaptcha/",
"https://www.google.com/recaptcha/intro/",
"https://en.wikipedia.org/wiki/Computer_vision",
"https://security.googleblog.com/2014/12/are-you-robot-introducing-no-captcha.html"
]
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|
804vq9 | What's a Fourrier transform | Repost | explainlikeimfive | {
"a_id": [
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"You know how when we write a number like 23.1 that means 2 tens, 3 ones, and 1 tenth? Any series of digits we write (and maybe one decimal point and minus sign if it needs it) can represent a number. Any integer can be represented by a series of digits and any real number can be approximated by one. Fourier transforms are very similar to this but for functions instead of numbers. If you don't know what a function is just consider it a line on a graph which we draw from one side to the other while never going backwards. We can add together a bunch of sine functions (they look about like ~, either longer or shorter and repeating forever in both directions) to get some function and any function (which meets certain common conditions) can be approximated by adding a bunch of these sine functions. A Fourier transform refers either to the \"digits\" which multiply the sines or the process of finding them. We can also do Fourier transforms in more dimensions by adding together some special multidimensional functions. It's actually a bit more complicated (\"digits\" which are imaginary numbers, continuous functions instead of a discrete number of \"digits\", etc.), but I hope this lets you get the basic idea. Uses: Once we do a Fourier transform on some function we call that having the function in the frequency domain. You can easily do some things in the frequency domain that are hard in what is usually called the time domain and then use an inverse Fourier transform to get back a transformed signal. If you have the Fourier transform of a bare audio signal (just the Fourier transform of the displacement of the microphone membrane from the pickup) then you can treat this literally. If you cut off all of the \"digits\" above a threshold frequency (or apply a filter which decreases the amplitude of the function we call the Fourier transform above a certain frequency) you can remove that frequency from the signal. When you do an inverse Fourier transform on the filtered Fourier transform and send the result to a speaker sound above that frequency will be gone. You can do the same for low frequencies, or the frequencies of human speech. You can apply different filters and make equalizers. You can store samples of frequencies humans hear well with more bits and those they hear less well with fewer bits in an audio file. This gives you smaller files. You can perform a Fourier transform on the signal from an antenna and filter it to get only some frequencies (or perform some sort of partial transform and not bother filtering). This lets you transmit and receive data in frequency bands and send multiple things over the air at the same time. You can do this without actually using a Fourier transform with various electronic components but the engineers who design the radio system use Fourier transforms to model it for their design. This is used in things like cell phones. Using a 2D Fourier transform and the trick above in the audio paragraph about dropping things people don't observe well you can get lossy image compression like JPEG so that image files are much smaller. You can also extend the frequency data to blank spots to get something like the Photoshop autoheal tool (I think, I don't know the theory behind this very well). Like /u/RiskyDodge mentions in this thread sometimes you can collect frequency data and then use an inverse Fourier transform to get the signal like with an MRI. Quantum mechanics uses Fourier transforms to describe the state of particles. Fourier transforms (or in some cases related things I've lumped together like Fourier series, discrete cosine transforms, etc.) have all sorts of use in modeling and manipulating things which can be thought of as having frequencies. This is true even for things you might not immediately think of that way like images."
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805ufw | Why does our stomach hurt when we're excited or nervous? | Repost | explainlikeimfive | {
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"Your body is sending more blood to the organs you might need if you need to get shit done i.e. fight a bear - skeletal muscles, heart, lungs, brain. So your gut organs get less blood, and digestion takes a hit. Poor digestion causes nausea, upset stomach.",
"It may be a triggering of the fight-or-flight response. To ancient humans, it would have been easier to fight or run from a predator on an empty stomach (ever tried playing football right after a thanksgiving meal?). Your body may be preparing to dump your stomach contents (through entrance or exit) in case you gotta act."
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805vv4 | Why are graphics cards good for mining crypto? | Repost | explainlikeimfive | {
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"Graphic cards (GPU) and your normal processor (CPU) differ in the order they compute processes. A GPU uses parallel processing, meaning it can run several smaller calculations at the same time. A CPU uses series processing so it can more intensive calculations but only one at time. With crypto mining you are looking for the next hash of the block chain. Hashing algorithms aren't very intense and you want to try as many possible hashes quickly. This means the best method is parellel computing and therefore GPUs what you want to use.",
"A GPU has hundreds or thousands of weak and simple processors A CPU has 1 to 16 strong and complex processors Crypto currency \"mining\" is calculating the next hash in the blockchain. A CPU is strong so a CPU Core can give you a hash to try extremely quickly but it only has up to 16 cores spitting out hashes. A GPU is weaker and takes significantly longer than a CPU to return a result, but has so many more cores that it comes out ahead. If you've got a 16 core CPU and a GTX 1080 with 2560 Cuda cores, then as long as a CPU core isn't returning results 160x faster than a Cuda core then the GPU will return more results per second and be better.",
"Their processors are better suited to the particular math equations that crypto currency uses vs a CPU. CPUs are generalists that sacrifice raw speed to be able to do anything asked of them while Video cards are purpose designed to perform a specific and repetitive task very quickly. Specifically parallel processing of video. It just happens that the hashes used by crypto currency are similar to video processing so a video card can grind through them much more quickly and efficiently than a traditional CPU can. URL_0"
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8063pb | What’s the difference between copyright and trademark? | Repost | explainlikeimfive | {
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"They are very different. Copyright is a system by which the creator of a work (a book, a song, a reddit post) may prevent others from copying that work. This allows the creator to profit from their work and to maintain creative control over it. Copyright exists to encourage people to create works. Trademark is a system by which a person or business may claim a symbol (a name, a logo, even a distinctive color) to represent them in trade. No competitor may use the same symbol to represent their products. This is what prevents anyone from starting their own company named “Apple Technologies” and selling computers. Apple would object that this infringes their trademark. Trademark exists to prevent impersonation and consumer confusion. These two systems are frequently confused and conflated, particularly on the internet. They are often grouped together (along with patents, trade secrets, and other systems) under the umbrella of “intellectual property” despite the fact that the only thing they all have in common is that they aren't property. Example: Apple's logo is an apple with a bite out of it. It was (presumably) drawn by an artist at Apple. Apple holds a copyright to that image. If you copy that image and use it yourself, you may be infringing upon their copyright. But Apple doesn't have a copyright on the *idea* of an apple with a bite out of it. Absolutely nothing would stop you from creating your own image of an apple with a bite out of it as long as it isn't derived from Apple's. Apple also holds a *trademark* on their logo. If you use that logo to sell computers, you infringe their trademark. If you use your own drawing of an apple with a bite out of it to sell computers, you may still infringe upon their trademark even if there is no copyright issue. However, if you used that same drawing as a logo for a restaurant, you would not infringe upon Apple's trademark.",
"One keeps someone from pretending to be you (trademark). The other keeps people from copying the stuff you write, draw, or record (copyright)."
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80i0lh | How did English become a global language, and why English? | Repost | explainlikeimfive | {
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"Because English was the dominant language of the superpowers of the 19th (UK) and 20th (USA) centuries. Countries tend to not change their language, no matter how shitty it is, unless they have to."
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80j57k | Why are mirrors “flipped” left-to-right, and not top-to-bottom? | Repost | explainlikeimfive | {
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"They're actually flipped front to back, we just parse it as left to right because we are used to someone having to turn around to make their nose swap places with the back of their head.",
"Everything is exactly the same. Wear a shirt with with writing and look in the mirror. Look at a letter in the mirror. Now look down. It's on the same side. It just looks backwards, because it was designed to be seen by someone in front of you."
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80m5mj | Why does America drive with automatic transmission for the most part, while most of the world still drives manual transmissions? | Repost | explainlikeimfive | {
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"1) Current automatic transmissions are actually more efficient than manuals. 2) Very small diesel engines never caught on in the US. 3) US tends to have more powerful vehicles, so small efficiencies from manual are not needed. 4) Manual sucks in stop and go traffic. I like a stick, but I understand why a lot of people don't.",
"Real answer for ya: America developed around it's population, and it's population will always migrate to wherever the job market is. These job markets more often than not are in big cities with corporations, factories, etc. Well most families, if given a choice (and stable income), would prefer a nice family home with plenty of space for kids, pets, and visitors rather than a cramped apartment in a noisey, bustling city. Thus, American culture gravitated towards endless suburbs instead of highrise apartments in every city. Consequentially, this upped the working class's average commute time by a substantial amount. Now, not everyone is a driving enthusiast that gets rock hard switching through gears of a manual transmission day in and day out on a 50 mile, round trip commute from work to their home. GM and Ford knew this, and started mass producing automatics and marketing them towards families because the automatic trans basically sold itself to the consumer. This was not the case in smaller, European countries with more established cities that had already built themselves around pedestrianism (I think that's the word), public transportation, and if needed, a cheap little manual transmission car to get you from point A to point B. Automatics aren't easy to sell to people that don't really need or want them. Hope this answered your question.",
"Not sure if just America or everywhere. URL_0 Manual sales in Australia was already taking a dive in 2015",
"I have been almost always driving a manual in Europe, then moved to the US for some time and got an automatic. After coming back to Europe I decided to look for an automatic as well - it's easier in city traffic and more convenient if you want to drink a coffee while driving. At the time it was an Accord with a 4 speed transmission. I found it to be quite a hassle actually, since the car was often in a wrong gear and I had to manipulate the throttle and brake to get the right gear before certain maneuvers. I think it just has to do with the way European streets are roads are build (not as straight and wide as in the US, a lot of passing, tight parking). Driving is more difficult in Europe and the manual transmission often helps. That being said, I now drive a manual and miss the convenience of an automatic transmission. I also think the dual clutch auto transmission is probably better suited for European roads and I think that the technology has matured enough for me to consider it for my next car (VW group had some issues with both electronics and clutch wearing prematurely in their first transmissions).",
"While we're all here can someone ELI5: How on earth do 4 lanes of freeway traffic come to a stop, if there are no accidents? What the fuck is the deal?",
"One reason, is Americans tend to like bigger cars. Back in the day that could mean a very heavy clutch pedal if it was manual. Also, automatics have been pushed as the luxury option.",
"It's 2018. Automatics are superior. 20 years ago it was different but it's an attitude that lingers.",
"This is gonna get buried, but I've had a few people tell me this reason. In many European countries, there are two \"levels\" of driver's licences, one for manual and one for automatic transmissions. People who pass the manual transmission test are allowed to drive automatics too, but not the other way around. Many new licencees lean on a manual car to take the manual test, so they don't get stranded with a car they can't drive. Now, you have the majority of the population able to drive a manual transmission, and auto manufactures can build these for cheaper. Cheaper cars attract more buyers (because they're able to drive them) so more manual cars make it into circulation. This encourages more people to licence standard transmissions... You see the cycle. **TL:DR;** It's because it's cheaper and because the drivers know how.",
"I don’t really know but probably because General Motors purchased the innovation of the automatic transmission and it was quite novel at the time. Since, people just thought it was easier and less work to concentrate on the gearing. Now people just get into car accidents because they’re looking at their cell/mobile phones. I’ve heard of more people going back to manual just because it’s “vintage” and also easier to take care of. Plus zoom zoom.",
"Generally speaking, American's don't have left feet. As a result, the only way they could drive clutch is if they used a hand clutch. While most Americans make more than $600,000/yr, many hand-clutch vehicles are still out of our price range. To accommodate our lack of left feet, we use automatic shift vehicles and rapidly stomp between pedals with our right foot.",
"I’m not sure most of the world uses manual transmissions, but the main reason I would assume is mainly price and ease of maintenance. A manual transmission is cheaper, lighter, and easier to maintain than an automatic transmissions system. That’s about it. I assume performance between the two systems is basically the same about now, with all the advancements in car technology we’ve had.",
"Most of the people I know drive manual. I have driven both and currently have automatic. European roads are generally narrower, bendier and steeper than roads in the US so need more \"driving\". A manual gives more control on difficult corners and being able to select 2nd gear for complex maneuvers and tight parking is a definite boon. There is generally the feeling that you are more in control of the car and are \"driving\" it rather than \"being driven\". Add to that the fact that automatics are less fuel efficient - and fuel in Europe is expensive - and it is generally thought they are less reliable and more expensive to fix (this may no longer be true). Finally, there is the question of image. Automatics for a long time were seen as \"old ladies\" cars and for a lot of young men it would be extremely embarrassing to confess you drove an automatic - tantamount to saying you had a stairlift or wore adult diapers. However, this too is changing.",
"In Czech Republic most people drive manuals. The reason is very simple - people want cheap cars that are cheap to run and cheap to maintain. The general consensus is that cheap cars with automatics cost more to run and maintain than their manual counterparts. If you have the money to shell out for a good car with a good auto, and you like that kind of thing, then so be it. Nobody really cares here, at worst your parents (who, if you're old enough, may have had to deal with commie block cars) will call you lazy. You're taught to drive a manual, most people around you drive a manual, and your first car (usually an old Skoda) will probably be a manual. Almost noone complains about driving a manual in traffic because it's normal. I've heard way more complaints about autos acting stupid and sometimes outright dangerous while driving on twisty roads. (Crappy cheap automatic transmission bias? Definitely.) Also, while drivers here can be a bit aggressive, they generally know pretty damn well how to drive.",
"Manual transmission is cheaper. In the past it was more economical in terms of fuel efficiency. But now automatic and manual transmission aren't too different in terms of fuel economy, so there isn't much of a reason to drive manual now.",
"I like manuals but I now drive a car with a CVT (continuous variable transmission). It's more fuel efficient than a human ever could be, and I don't have to pay attention to shifting in traffic. In my commute it's either stop-and-go city driving or open highway so there's no real advantage to having gear control, and the fuel efficiency in the city is leagues above what I could ever achieve with a manual, usually within 10-20% (30 vs. 35 mpg) of my highway fuel efficiency. Also, there are like 4 options for different rpms if I really need it.",
"So we can eat our donuts and put on our makeup while we drive. It's called multi-tasking! Also, because teaching your kid to drive is already a terrifying affair... Much less trying to teach standard. Some would say it's laziness, but I prefer the word \"efficiency\". (We can afford the luxury, so why not)",
"Simple because of the amount of traffic in large cities makes driving a manual more impratical. And as a whole, Americans drive more than other countries.",
"A different point, I think the fact that most people in America basically have to own cars and aren't just reducing the number to those who enjoy the car. So like as a higher percentage of people who drive cars Europeans are bigger into cars.",
"Ever see someone who has never driven an automatic drive one? Total confusion .",
"How else am I gonna eat my cheeseburger and drive man? I believe like pre late 2000s manuals made more sense for miles/kilometer per gallon as manuals used less. In the US gas is cheaper than in the EU, hence why European cars tend to have 2.0 liter engines and Americans can get away with large V8's without breaking the bank. Nowadays manuals are outdated, they're no longer better for racing as automatic transmission have made huge leaps and bounds in terms of shifting speed and gas usage. Autos now get better gas mileage. Manuals are still cheaper, and easier to work on but it's really not that big of a deal. I am like 85% sure the above is correct lol. Manuals are fun tho, I miss my old one...think my next car will be one. Manuals made me a better driver too I think, since it forced me to be focused on that car and the road.",
"Unless you're racing or hauling why wouldn't you want an auto?",
"Historically, Americans have had a lot of disposable income and culturally seem willing pay a great deal of money for convenience. Automatics are expensive, but very convenient.",
"I think the real question is what America’s obsession with column shift gearboxes is! I don’t know if it’s just a movie thing, but column shift is essentially obsolete in most other places in the developed world.",
"The overwhelming majority of electric vehicles use single-speed gearboxes, so the whole manual vs. automatic thing will eventually become moot",
"American here! I just purchased a brand new car that is a manual. The salesman looked suprised he asked if I was comfortable with driving a manual. Also, I was taught how to drive in a manual vehicle.",
"I live in the US (upstate NY) and drive a manual. I hope that I never have to return to automatic. I hate them! They lag when you step on the gas, I feel as if I have less control over my vehicle, and manuals are so much more fun to drive! I don't even mind it in city traffic. I honestly get bored and thus more distracted while driving an automatic because I don't have to pay as much attention to my driving.",
"The majority of Americans cannot operate a manual transmission because they were never taught because their parents didn't know how to either. Source: am American who knows how to use a clutch",
"Money. We don't get taxed on small things considered luxuries or unnecessary. Taxi driver in Ireland told me that air conditioning was an extra grand, auto transmission was same, power windows, door locks, etc. So a 20k car had and Additional 10k in on just taxes because those were luxury add ons. He bought used high millage cars from England because after shipping and even the constant repairs it was still cheaper to get a fully loaded car. Many others said the same and mind you I wa3a in Ireland for 2 weeks."
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80majp | How are psychiatric medications developed, if their mechanisms of action is often unknown? | Repost | explainlikeimfive | {
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"A lot of the time they are discovered by accident. In other words they don’t usually intend to create psychiatric medicine, but find that certain other drugs just so happen to have beneficial effects for mental health.",
"Tbh we don't really understand how Lithium works but it really does work. We know a lot though. We don't know enough not by a long way however. As a psychiatry trainee I do wish we had better insight into the neurology of mental illness. This is what should hopefully better inform which drugs treat specific illnesses. But our knowledge is definitely progressing very rapidly.",
"I have ADHD, so this is anecdotal, but I've heard that the way that stimulants were found helpful in ADHD is that \"disturbed\" boys were given a stimulant just to see what happened. I don't think that it was in a malicious way, though. They saw that these children were functional after taking a stimulant. *takes Vyvanse*",
"Initially, as you know, it started with coincidences. People who had psychiatric problems were given drugs that calmed them down, and eventually it was found that these drugs were also treating their psychiatric problems. Since then, discovery has led by finding molecules with similar structure, but recently we have been using something called high throughput processing. What this entails is having thousands of micro wells in a plate, each one of which has a few cells in it. We add chemicals to these cells that we know their effects (ex. Cause decrease in anxiett) and monitor how they work at the molecular level. We then look for similar molecular events when we add a random chemical to a micro well. This is kind of abstract so I'll give you an example. Imagine if an anxiety drug worked by increasing glucose intake into a cell. If we wanted to find a drug with similar properties, we would monitor the glucose uptake of cells in the wells we have. This is really a neat process, because you can test thousands of random drug candidates a day through this approach, all you have to do is add the drug to a micro well."
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80qzhd | Why does changing the speed of audio affect the pitch too? | Repost | explainlikeimfive | {
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"Pitch is a function of a soundwave's frequency as measured in hertz. Hertz is a measurement of cycles per second. If you take a soundwave of someone talking for 10 seconds and they are Ben Stein and talk in a monotone 150 hertz (I don't know if this is the frequency of Ben Stein's voice, but go with it) you have a soundwave that oscillates 1,500 times. (that is, 1500 peaks and valleys if you visualize the sound wave like you would in Audacity or some sound-editing program). If you play that back at 2x the speed, that 1500 oscillations is now happening in 5 seconds, so you end up at 300 hertz for your frequency, and now Ben Stein goes from sounding like an adult male to a very fast-talking child, what is commonly referred to as the \"chipmunk\" effect. All this is a really fancy way of saying that a sound's pitch is entirely a function of how fast it is, with higher pitches being faster. Therefore when you speed up the playback, you also raise the pitch."
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80vgaa | The Fed | Who are they? What do they do? And how do they do it? I know that they have the power to "raise interest rates" and are involved in "making sure inflation is in check" but I would have thought that that would be handled by market forces. Also, and I know that this could enter dangerous territory, but can someone please explain the controversy over the Fed. By that I mean that I know that some groups don't seem to like the Fed. Is that simply because of the lack of a gold standard (or some other equivalent) or is there something more to it? Or does me even asking that question just show that I really have no idea what is going on? Thanks in advance. | Repost | explainlikeimfive | {
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"The Federal Reserve is in charge of monetary policy in the United States. One of the most important aspects is setting the base interest rate. When inflation gets too high, the Fed will raise the interest rate. That's how they keep inflation in check. People don't like the Fed because of it's role in quantitative easing, which took place after the last banking crisis. Basically, this consisted of the Fed buying lots of lots of debt from the bond market, thereby helping to stabilise the economy. These are the same types of people who think we should be on the gold standard and who don't understand that the economy has moved on since the 1930's."
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80wbfj | why (most of the time) girls have a better calligraphy than boys | Repost | explainlikeimfive | {
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"A few comments are mentioning that it's more valued among young girls. That's true, but there's another factor. Young girls have more developed fine motor skills than boys of the same age.",
"Stereotypically speaking... Females tend to appreciate the cleanness and beauty of something. Males tend for speed and perceived efficiency. It’s also part of the archaic system of women taking the notes while men spoke."
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80xau7 | What was the "Dot-Com Bubble?" | Repost | explainlikeimfive | {
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"Back in the late 90s the Internet really took off commercially. There were lots of companies founded then (mostly Silicon Valley). Most of the big internet names you know (Google, Amazon, Ebay, etc) got their start then but there were many other companies that didn't make it (eToys, URL_0 ,etc) Investors were throwing money at these companies and running up their stock price. People became millionaires via stock options. Think bitcoin and crypto these days. Then it all came crashing down when the stock market started tanking in mid-2000. Suddenly a lot of those dotcom options were worthless again."
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810l2m | what does cancer do to your body that eventually kills you? | Repost | explainlikeimfive | {
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"Cancer is jackass cells running around screwing with normal cells trying to do their job. Stops them from working. \"What's the big deal with some cells not working?\" you might ask. Well... It's a problem when an organ stops working.",
"In same way as someone who will live in your flat, eat your food and use your computer). Plus - everyday he grows bigger, take more place and require more food. And every day clones of this person appear in other condo flats. First on same floor, then on others. In the end normal people will flee and move to other building. Unfortunately our cells don't have this luxery ...",
"Cancer cells are simply cells that have certain mutations that allow them to reproduce themselves indefinitely and leave their location of origin in the body. When a cancer begins, the mutated cells constantly reproduce, making a tumor. The cells in the tumor need nutrients, water, oxygen, and space, which they steal from the non-cancerous cells around them. This interferes with the normal functioning of that tissue. Once the tumor metastasizes (move to a new location), new tumors form in different tissues that rob nutrients, etc. from that tissue, interfering with its normal functioning. Eventually, the cancer cells invade enough tissues that the body can no longer function properly and the person dies.",
"Just to give you some personal examples; My mother has lung cancer. Her tumors will grow, pushing against her heart until it can no longer function properly. My grandmother has oral cancer. This has taken the form of a facial tumour that too will grow eventually making it impossible to breathe. I'm sure other forms of cancer have their own ways in which they kill. these are just the ones I know of."
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812k93 | Is the velocity of light not relative like other velocities? | My understanding is that velocity has no meaning if it has nothing to be relative to. If you are going near the speed of light in a void with nothing else around to compare to it is the same as not moving. But how then is there a maximum speed in the universe? The speed of light could be slower or faster depending on what it is relative to. | Repost | explainlikeimfive | {
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"That's what makes relativity so complicated. **Because** light always moves at the same speed, it turns out that distance and time can't be constant.",
"There are basically two principles of special relativity: 1. The laws of physics work the same in all reference frames. Among other things, this implies that position and velocity only make sense to talk about with respect to a chosen reference frame; they are \"relative\". 2. The speed of light is the same in all reference frames. So if you see something traveling past you at the speed of light, everyone else will see it traveling past them at the speed of light as well - no matter what their own speed is relative to you. This is why the speed of light is a maximum speed: you can't overtake the beam of light since it will appear to be traveling 299792458 m/s away from you regardless of how much energy you put into accelerating.",
"That's the weird thing about the speed of light - unlike other speeds, it isn't relative. If you and I were both measuring the speed of the same light beam, and I'm sitting on earth while you're zooming through space at a very high speed, we'll both measure the same value for the speed of light. This is essentially Einstein's special theory of relativity."
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819cm5 | What is past the borders of space? | Repost | explainlikeimfive | {
"a_id": [
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"text": [
"> I know space is expanding in all directions but whats past that? We don't know of any 'past' that. When we say space is expanding, we mean the space between any two distant objects is growing larger. However, there is no distance we are aware of at which there are no longer objects. So you have objects, in every direction, getting further apart, for infinity. If there is an 'edge' we lack evidence about it. > Also, whats between galaxies, why can't we travel between them? Much of the matter of the universe, but that's just because there's *so much* space between galaxies. Per square meter, it is extremely, extremely, super, super, duper, empty space. The main obstacle to traveling between galaxies is not the terrain itself, it's that it is *really, really, really* far away, and way way way farther than that to get anywhere. A roadtrip of x billion years doesn't have a lot of attraction, and it's hard to pack for. > Also, whats dark matter? Good question, although so far it appears to be \"something with mass\" which does not interact strongly with anything else outside of gravity. I.e. it doesn't block light, it doesn't bump into stuff, it goes right through objects, but it has a gravitational attraction.",
"> I know space is expanding in all directions but whats past that? That isn't a meaningful question. Space appears to be infinite in extent and simply becoming larger. > Also, whats between galaxies, why can't we travel between them? Nothing. They are a huge distance apart and moving away from each other very rapidly. > Also, whats dark matter? Don't know. It seems to make gravity and nothing else."
],
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|
81e7tr | How is the ratio between men and women in the world almost exactly 50% to 50%? What makes it not 58% to 42%? What causes this almost perfect mathematical relationship in something that is supposed to be completely random? | Repost | explainlikeimfive | {
"a_id": [
"dv2i9ri",
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"text": [
"Sample size matters. Flip a coin 10,000 times and you get very very close to 50/50 split but flip it twice and it's less likely you'll get one of each.",
"It's probably the vast amount of people that brings the ratio so close to even. If you flip a coin 10 times, you might get seven heads and three tails, but if you flip that coin 7 billion times, then the actual percentages will come closer to the theoretical probability."
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|
81em9m | Why is English the most universally accepted language in the world if it's the THIRD most spoken one? | Repost | explainlikeimfive | {
"a_id": [
"dv2lftm",
"dv2li2d"
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"text": [
"Because the British Empire was the most powerful force in the world for many years. It became the standard language for trade because the biggest navy, most powerful army & largest trading fleets used them. Then, America became the doming social, political, economic & military force in the world due to the World Wars. A language becomes popular because the people you want to speak to use it, not because of how many people speak it.",
"\"Accepted language\" has to do with economic incentives, historical priority (\"lock in\" effects), and power centers, not total number of speakers. Similar reason to how European scholarship was dominated by Latin long after the language ceased to be used in day to day conversation."
],
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|
81gs8m | How are people with bionic limbs able to control them? | Repost | explainlikeimfive | {
"a_id": [
"dv33xe7"
],
"text": [
"Hi, I am a rehab doc with several years experience treating amputees. There are two primary ways in which a prosthetic arm is controlled. The first is body-powered. What this means is that you use the energy from one movement to create the force necessary to cause the prosthetic device to move. An example would be bringing your shoulder forward (flexing) causes a pulley to tighten, which in turn opens a prosthetic hand. The second is myoelectric. What happens here is sensors are connected to intact muscles. By flexing that muscle, the computer within the device knows to make an action occur. This takes some practice, as activating individual muscles to cause an unfamiliar movement can be challenging. An example would be that flexing your anterior deltoid sends a signal which causes the device to open a prosthetic hand. Here's a systematic review that goes more in detail. URL_0"
],
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"https://www.rehab.research.va.gov/jour/2015/523/JRRD-2014-08-0192.html"
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} | [
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"url"
] |
|
81hppm | why do pigeons and some other birds bob their head as they walk about? | Repost | explainlikeimfive | {
"a_id": [
"dv38tpk"
],
"text": [
"Accord [to this website]( URL_0 ) it's also to stabilise vision. Pigeons and some birds don't track movement like we do so moving their head quickly from place to another helps them build snapshots of the world around them. Maybe a bit like a ballerina twirling - if they spun their head around at the same speed as their bodies are spinning the world would look like a blur to them, but ballerinas keep their heads still and kinda snap them around to minimise the blurring (and of course this lessens there dizziness!)."
],
"score": [
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[
"http://www.loc.gov/rr/scitech/mysteries/pigeon.html"
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} | [
"url"
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"url"
] |
|
81m4ce | What makes cling film / plastic wrap stick? | Repost | explainlikeimfive | {
"a_id": [
"dv3w0ax"
],
"text": [
"The plastic when pulled from the roll produces an electrostatic charge. Ever rub a balloon on your hair and stick it to the wall? It’s like that. That is why when you try to use plastic wrap on a metal bowl it doesn’t work as well. The metal disperses the charge."
],
"score": [
5
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"text_urls": [
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} | [
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|
81q6i3 | Datamining in Videogames | Repost | explainlikeimfive | {
"a_id": [
"dv4bc8l",
"dv4bdec",
"dv4ew4i"
],
"text": [
"Sometimes it’s content that’s not finished prior to release. Other times it’s finished and put on the disc for instance but then before the release they realise they can charge more for it so they just leave it inactive until it’s needed. With recent games, especially those with large assets it can save time later having the user download them.",
"They are there because in software development, you try and limit the amount of branches you have. If we have a base game, and I'm off adding in one hero, you're adding in another, and Joe is doing bug fixes, we are probably all going to be modifying the same files for this. The answer to having to modify the same files is version control software, such as GitHub. This way, we can each start a branch for our own work to keep it separate. However, as we continue to work on stuff, the more we touch before committing back into the Master branch (the one you publish from), the more likely we are to run into conflicts when we try and merge. To prevent potential chaos down the line, stuff will be merged into the code base early and often (basically at stages where we may not have everything fully implemented and polished, but not breaking anything), but just have options on it to not be accessible yet. This does mean that the raw files will have some data in them that someone can mine, but it really simplifies the development process.",
"\"Datamining\" is just looking through the game's data files to see what's there. Often times, there are plenty of things in the game's data that are either not accessible through normal means, or not accessible yet. Like when a new patch comes out for an online game, people will look through all the new data files and list all of the new things / changes made."
],
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|
81qefu | Why is ADD / ADHD treated with stimulants instead of depressants? | Repost | explainlikeimfive | {
"a_id": [
"dv4dcdd"
],
"text": [
"You're right, it's counter intuitive. To understand it you have to think of it not as hyperactivity but the inability to focus or concentrate on a task, a bit like being fatigued. It's the attention deficit part of ADHD. The stimulants act to enable the person to concentrate on a task and not be distracted. It rebalances the attention deficit."
],
"score": [
3
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"text_urls": [
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} | [
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"url"
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|
81r5z5 | Why does salt melt ice? | Repost | explainlikeimfive | {
"a_id": [
"dv4ii95"
],
"text": [
"I don't think it melts ice, it the raises the freezing temperature of water... or thereabouts."
],
"score": [
3
],
"text_urls": [
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]
} | [
"url"
] | [
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|
81uw0u | Why does food taste different warm than it does cold? | Repost | explainlikeimfive | {
"a_id": [
"dv5coxo"
],
"text": [
"Most flavors you taste are detected with your nose. You can taste 5 flavors with your tongue, but smell about 1 trillion odors/chemicals. When you heat up your food the odiferous chemicals in the food gain energy and evaporate, allowing you to be able to smell them easier. Thus making the food taste different."
],
"score": [
4
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"text_urls": [
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|
81ywlf | Machine Learning | Repost | explainlikeimfive | {
"a_id": [
"dv66v0v",
"dv68twa"
],
"text": [
"Machine learning is simply using data in a computer to teach the machine learning model how everything works. In a ML model, you pass in data known as training data. It’s the data that you want to work on, say to classify or predict the values. The model contains values called weights which are used by equations to do the task. Now either it can be right or wrong. So slowly over time using different optimisation methods, the model is made to change its weights which changes its decisions. So eventually, the predictions start becoming increasingly correct. Now this model which was trained is used to predict the results that you need. Some different models have their own ‘quirks’ that are handy at different applications.",
"Instead of telling the computer what to do to win a game, you tell it the rules and what the winning conditions are. Then you let the computer run thousands of games, each time it learns something from the games and starts working out the best way to win. Say for a first person shooter game you might tell current standard AI to find cover if it's being shot and shoot back. Machine learning you would tell the AI that the win condition is to kill the player. The rules are that it can move, shoot and use cover. The first few thousand runs it will probably just run out and get shot, that's a loss so it will start trying other things within the rules. A few more thousand runs and it's shooting back with great accuracy but still not winning 100% of the time, so time to try new things within the rules. Eventually after thousands more runs the Machine Learning AI will learn to take cover, learned to hide from the player for an ambush, maybe even learned to flank the player."
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} | [
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|
825z5i | why are some URL's, like Wikipedia, specific and others just a string of letters and numbers? | Repost | explainlikeimfive | {
"a_id": [
"dv7mivu"
],
"text": [
"as boring as the answer I'm about to give is, it most often just comes down to \"Because that's how the specific website handles things\". Url's are man designed for a specific purpose. Wikipedia has most of its urls descriptive of the content of the page, because they don't need a lot of information being passed around. other have a lot of data that needs to be passed into the url and while they could have it in plain text it is often more efficient to encode it to shorten the string a bit. The url might also be dynamically created (say, YouTube video identifiers) in which case base 64 encoding is better for compactness sake than a long base 10 number or some human-readable string. When you're designing a website you can design the url to be nearly whatever best fits your purpose."
],
"score": [
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} | [
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|
82787k | Where do absurdly wealthy people (as in $1bn+ net worth) keep their money? | Repost | explainlikeimfive | {
"a_id": [
"dv7vsni"
],
"text": [
"Usually these people are incredibly illiquid, so their wealth is an estimation based on the value of the assets they own (real estate, shares in their companies, and other assets). They’re not keeping money in the bank - certainly not billions."
],
"score": [
4
],
"text_urls": [
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} | [
"url"
] | [
"url"
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|
828g1k | How does a medicine 'know where to go'? | Repost | explainlikeimfive | {
"a_id": [
"dv85pxk"
],
"text": [
"> When I ingest the antibiotic how does it know to go to my hand and clear the bacterial infection? It doesn't. It goes everywhere and acts like it does in all those places, meaning it might clear up the bacteria in your hand but also in your foot. And screw with your gut bacteria, and your mouth flora, etc. That is where side effects come from."
],
"score": [
7
],
"text_urls": [
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]
} | [
"url"
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"url"
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|
82aeoj | How/When/Why are Hockey players allowed to fight? | Repost | explainlikeimfive | {
"a_id": [
"dv8lcr7",
"dv8mfd3"
],
"text": [
"They are not. It's against the rules, and players can recover penalties for fighting. But it happens anyway.",
"There's a whole series of unwritten rules about when players fight. It's often triggered by a player delivering a hit that's perceived as a cheap shot, regardless of whether that hit was technically legal. Other common triggers include hard hits on a star player or making too much contact with a goalie. The fights are seen as a way for players to police themselves. For example, if the best player on the opposing team has the puck, I may think twice before leveling him since I know that doing so will likely result in me being challenged to a fight by a bigger player on his team, which could be painful. There's a code of conduct surrounding the fights. Both players are expected to agree to the fight by \"dropping the gauntlet\" (i.e. throwing their gloves away) and the linesmen stop it once the combatants look tired or one of them falls down. Sucker punches and a variety of other dangerous tactics are not permitted and would be expected to result in a suspension. In the NHL, pushing and shoving will result in 2-minute minor penalties, and a fistfight will result in a 5-minute major penalty. There can be additional penalties or ejections for a variety of dirty tactics related to fights. At the college level, real fights are rare, in part because fighting is an automatic 5-minute major penalty, game misconduct, and suspension. In the NHL, fights are becoming decreasingly common and it's unusual for a team to have multiple enforcers/goons (fighting specialists)."
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