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lkmlbe
|
How do radio waves get "encrypted"?
|
If radio waves are just non-visible light waves that are picked up by a vibrating rod, how does a radio wave get "encrypted" so that it can't be picked up unless it's unencrypted? Edit: Everyone keeps commenting that the content of the message is what's encrypted, not the radio waves itself, but that's not what I mean. Someone answered that digital signals themselves can be modulated or disguised, which is what I meant when I asked
|
Technology
|
explainlikeimfive
|
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"The content that they're holding is encrypted. Let's take a basic Caesar shift. Every letter in a phrase is shifted along the alphabet by a predetermined amount. So if I start with the phrase \"explain like I'm five\", I'll get \"hasodlq olnh l'p ilyh\". I transmit that over the radio waves. The receiver on the other end knows to expect a Caesar shift, so they undo it and get the original phrase. In Networking we actually divide the entire end to end communication into seven distinct layers. Layer 1 is the physical transmission medium (i.e., radio waves in this case, ethernet cables in others, etc.). That layer is only responsible for the contents of it's own layer, and anything else beyond it can be swapped out for anything else without any changes. The encryption would be at a much higher layer that doesn't really care about the medium that carries it.",
"The medium is not encrypted; the *message* is encrypted. The simplest way to send an encrypted message via radio waves is a [numbers station]( URL_0 ) \\- using a radio to send a message which is meaningless gibberish to everyone except the intended recipient.",
"The radio wave isn't encrypted - anyone can receive it. The *information* encoded in the radio wave is encrypted just like any kind of digital information can be encrypted.",
"A lot of people here have answered this, but I also want to add another method of \"encryption\". Its called have-quick. Basically two radios sync up according to a gps time signal and hop frequencies while transmitting in a predetermined pattern. Unless you know the pattern and programmed the radio with it, the most you could receive is fractions of a second of the message.",
"The wave itself isn't encrypted, the data you're encoding in the waves is encrypted. Someone can still intercept the communication easily but without knowledge of how it was encrypted (the algorithm) and any keys used to encrypt it being in their possession, it's just random unusable garbage to them. Easiest example of this is encrypted wifi - it's still just broadcast out in the clear but unless someone has the network key, they can't do anything with the data they intercept."
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lkmwg9
|
why is cancer so hard to cure?
|
Why is it taking so long time find a cure, or even an effective treatment that doesn’t destroy your body it’s literally destroying my family person by person, this is half question and half venting.
|
Biology
|
explainlikeimfive
|
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"Cancer is uncontrolled cell growth. It's a thing that happens in your body due to damage to the mechanisms of cell growth. It's not the disease, it's the symptom. You need to prevent that cell damage that causes uncontrolled cell growth, since the grown cells continue to carry that defect.",
"Cancer is not a disease, it's a symptom - like fever. You can't \"cure fever\" because new diseases can always pop up that cause fever in a new way. There isn't going to be a \"cure for cancer\", because there could always be a new form of cancer pop up, perhaps triggered by a new environmental factor. Many diseases, like diabetes, also cannot be \"cured\". We can vaccinate to prevent them, and even some cancers can be prevented this way, but solutions have to be worked out on a disease-by-disease basis.",
"I’m so sorry you are struggling with this. It’s truly a terrible disease. The short answer to the question is because there are so many different types of cancer. It all comes down to what DNA mutation is causing the cancer cells to grow out of control. For example sometimes the cell’s ability to check itself for errors becomes compromised and other times normal cell growth genes get a mutation that makes them overactive. There are a lot of different causes and the most effective therapy would be to target the specific cause. So the question is how do you kill the cancer cells and not the person. A lot of therapy is just carpet bombing all highly active cells, though this often includes normally active cells and we get a lot of nasty side effects. If you know the cause there are more targeted therapies and there is a lot of research in these, but you would have to find one for each different type of cancer.",
"Treating cancer in theory isnt very hard, the issue is doing it while causing minimal damage to the patient. Removing tumors without causing fatal damage can be very difficult, on top of that radiation treatment can also cause lots of damage to healthy parts of your body",
"Cancers are defined by: 1- cell type 2- location 3- if metastasis or local invasion has occurred 4- other specifications that are beyond the scope of ELI5 So a diagnosis of cancer looks like: small cell carcinoma of the left lower lung with metastasis. And that's a completely different disease than, lets say, vestibular neuroma of the left VIII cranial nerve. They have about as much in common as AIDS does with coronavirus. Yes they are both viral diseases but with totally different risk factors, disease process and treatment. So the question isn't: what is the cure for cancer? It is, however: how do we prevent, diagnose and cure, for example, osteosarcoma? And the answer to that will be completely different for prostate cancer."
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lkn673
|
Do water dams have an impact on the earth’s rotation?
|
Seeing that more and more dams are being built since they are environmentally friendly (more or less), I was wondering if the weight mass of the water from these dams might have an impact on the rotation and angle of the earth? And if so, how would it affect the rotation and climate longterm?
|
Earth Science
|
explainlikeimfive
|
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"Of course. It’s a pretty famous fun fact that the biggest dam in the world, the Three Gorges Dam in China increased the length of a day across the world by 0.06 microseconds. The primary reason for this was that water that would usually end up being stored in the oceans was stored at a higher elevation, increasing the earth’s moment of inertia a little bit. 0.06 microseconds isn’t at all significant in all other respects though, no climate impact expected.",
"So the collection of mass does effect Earths rotation. However this effect is absolutely tiny, and completely inconsequential in the grand scheme of things, there are many factors that outweigh water dams",
"Not enough weight. A lot of images of the Earth and it's core are misleading because of the scale differences between the crust and the mantle and core. Think of a peach. The skin would be the crust of the Earth. All of the water and rock that supports life is in that super thin part. Also the magma and stuff that make up the mantle and cores is significantly denser and more heavy than water."
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lkn8wg
|
What is a ring in the context of abstract algebra?
|
Mathematics
|
explainlikeimfive
|
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"A ring is a set of things that you can add and multiply together, according to the following laws: for any `a`, `b`, and `c` in the ring, * `a+(b+c) = (a+b)+c = a+b+c` (associative addition) * `a + b = b + a` (commutative addition) * `a * (b + c) = a * b + a*c` (left-distributivity, right-distributivity is similar) * `a + 0 = 0 + a = a` (additive identity) * `a*(b*c) = (a*b)*c = a*b*c` (associative multiplication) * `a*1 = 1*a = a` (multiplicative identity) Note that multiplication is not assumed to be commutative. Some authors don't require that rings contain a multiplicative identity. Notable examples of rings are Z (the integers) and quotients of Z, namely Z/nZ, where the result of every operation is taken modulo n i.e. take the remainder after dividing by n."
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4
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|
lkniq8
|
Why can't neurons regenerate themselves like other cells?
|
Biology
|
explainlikeimfive
|
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"They are a permanent cell type. So are muscle cells. They are so specialized and they aren’t supposed to die, so we don’t have stem cells lying around ready to replace them. In contract there are labile cells which are constantly regenerating, like your skin cells, the cells in your gut, and your blood cells. Peripheral nerves can regenerate parts of themselves, though if the whole cell dies it cannot."
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|
lko68u
|
Why does static electricity sometimes make a sound at high elevations?
|
Earth Science
|
explainlikeimfive
|
{
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"Holy crap that's terrifying. That sound is lightning looking for somewhere to hit. Basically, there's a bunch of little currents / eddies of electricity, swirling around looking for a path from the cloud to the ground. As you move your hand, you're changing how big those circles are, which changes their pitch. Stick around and eventually they'll line up into a short circuit, and you'll get hit by lightning."
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3
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|
lko6aq
|
Why do we naturally favour one hand over the other?
|
Biology
|
explainlikeimfive
|
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"Because you usually don't alternate between the hands. You just use the one you are used to using. The one you use gets more practice, and it then becomes your dominant hand. Your dominant hand is better because it gets used more, because it's better, and so on.",
"These practice based answers are kind of right, but there's a biological aspect too. Each of your arms is controlled by the opposite half of your brain -left arm by the right brain and right arm by the left brain. While myths about dominant brain halves are rampant, the language center of the brain happens to be in the left side, which would explain why right-handed-dominant genes would spread and dominate with the Advent of written language.",
"Do you mean why do people have a dominant hand? People learn how to write etc from their parents, so whichever hand they use will likely be the one you use. It takes hundreds of times of doing an action to wire your brain to be able to master the action, but you can practice switching hands to get more equal skill for both hands. Most people just don't do this, probably because I imagine it takes longer to develop the skill. Growing up using just one hand for mastering those tasks creates neural pathways and doing the task repeatedly strengthens those pathways, so when you suddenly try to use the other hand for the same task, your brain doesn't have the same development of those specific neural pathways, causing one hand to be more dominant."
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lkpa75
|
what causes loss of vision after sudden heavy bloodloss?
|
Hello, so yesterday I suffered a headwound and it just gushed blood for 30 seconds or so until I could stop the bleeding and after I stopped it there were a few seconds where I couldn't see anything, just like dots of light and black darting all over and then it went away and I could see normally again. Similar to static on an old TV I suppose. What causes this?
|
Biology
|
explainlikeimfive
|
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"Your eyes grow out of the same set of cells that eventually form the brain. Like the brain, the eyes require a great deal of blood to function Changes in blood pressure can cause vision loss or misfires in the light sensitive cells, making you see stars until blood pressure is restored."
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lkpls1
|
Why is it bad when a game developer has lost the source code to game it wants to rerelease/remaster? Isn't all the data needed in the original retail copies?
|
Technology
|
explainlikeimfive
|
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"text": [
"The code distributed to users isn't the original source written by the authors, instead it's a compiled machine code that can be run by a computer. In an analogy, think of it as a cake. You can't figure out the recipe just by eating the cake.",
"Another analogy would be to music. You can have all of the notes written out and instruments picked out and singers can have all of their lyrics ready to perform, but once that music is all put together and recorded, the final 'mix' is just that - a final mix. Yes, with technology, you can digitally manipulate music once it has gone on to the final mix, but if you wanted to change some notes in one particular instrument or change a lyric, you would have to rerecord that part and make another final mix. If you were to lose the 'files' containing these instruments or notes (aka the game source code in this analogy) that would mean that you cannot go back and change one or two things simply without totally recreating every other piece of the code as well. Hopefully that made sense.",
"Games created from the mid 90s onwards will most often than not be written using a high level language. These languages are easily read by the developers but not by the computer/console, therefore it will need to be translated (compiled) into a computer readable form called machine code. The downside is that machine code is hard to understand compared to the original source code. This is due to the fact that many useful features from the source code are missing, like comments and named variables. When a game is released, only the compiled machine code plus any extra files that the game may require are present. The source code could potentially be used to aid piracy so it usually isn't included. Some games may contain files that can be decompiled back into the original source code, though finding these files can be quite rare. If a developer loses the source code and wants to rerelease or remaster the game, they only have the compiled machine code and any decompilable file they can find (which in most cases will be none). They will have to run the machine code through a disassembler which will turn it into assembly language (low level programming language), then work through it all and see what everything does. This process could take months or years depending on how big the game is, and is generally not a task worthwhile doing. So when a company loses the source code, their best option is to remake it from the ground up which will cost precious time and money that could have been saved had the original not been lost. As for my analogy, think of it like building a house. An architect will have a blueprint for a house which will be used to build said house (compiling). If the blueprint is lost then the architect still has the house as a reference point (machine code) but it will be easier to draw up a new blueprint (starting from scratch). TL;DR: People translate sentences into a foreign language, they lose the original words and the foreign version won't easily translate back exactly as it was, so they recreate the sentences from scratch.",
"Think of it like cooking a delicious meal. The final prepared meal is the game, and the recipe that lists the ingredients and cooking instructions is the source code. With the recipe (source code), it's easy and straightforward to recreate the meal whenever you want. Without the recipe, it would be almost impossible to do so. Sure, a great cook could probably guess many of the ingredients, but they would still require a lot of trial and error to find the right proportions of ingredients and cooking instructions."
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|
lkpmqu
|
How come we sometimes are too tired to sleep?
|
Biology
|
explainlikeimfive
|
{
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"text": [
"This is me right now. Most of the time I can feel my mind literally racing through the universe like a network of every conceivable genius. Then it just throws out a random time I got dumped super hard or something. Stupid brain."
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lkpo26
|
Does colder air make a fire less hot?
|
If a wood stove draws outside air, does the temperature of the fire inside the stove depend on the temperature of the outside air? I know that wood stoves have different designs and setups and the actual temperature depends on the kind of wood, but all else being equal, is a fire fed with 0-degree air 30 degrees cooler than a fire fed with 30 degree air?
|
Physics
|
explainlikeimfive
|
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"Yes and no. Absolutely all else being equal, yes. The energy produced by the fire heats the air by a certain amount, not necessarily to a certain temperature. But cold air is denser, so fire being 'fed' colder air actually gets more oxygen by mass, which means it burns faster and creates more energy. I'm not sure exactly what that means for the temperature of the products, since you have 2 factors with opposing effects.",
"Wood stoves don't draw \"outside\" air. They draw air from the home and exhaust to the outside. Consider that wood has to reach at least 400 something degrees for combustion in ideal circumstances, and can reach several thousand degrees. Thirty degrees one way or another is negligible at that point. Simple answer is no. Lower combustion air temperatures might make it slightly less efficient since the fire has to warm the air more, but won't really affect the temperature of the fire. Good natural draft and well seasoned wood plays a much larger role in the heat of the fire."
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lkpye0
|
Common joke says that heaters are 100% effient because all they make is heat. How much energy is actually lost?
|
Physics
|
explainlikeimfive
|
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"Typical heaters are in fact 100% efficient. But you can do better by being willing to cool it down a bit more outside, by making a heater that is effectively the opposite of an air conditioner. Rather than *creating* heat, it just *transports* heat, and you can move heat for less than the cost of making it. These heat pumps can reach effective efficiencies of 200-300%.",
"No energy is \"lost\" in a heater.. thats not a joke lol.. because the purpose of a heater is to heat, and any energy \"loss\" through components is turned into heat.. so its serving the original purpose anyway.",
"0. They are 100% efficient. Electronics lose energy as waste through electrical resistance. As electricity passes through wires and other components, a small amount of it is converted to heat and lost to the environment. In a heater, the whole point is to make heat. By definition, all the energy used by the heater is put towards its intended use.",
"The joke is equivocating the word efficiency as meaning both \"how good it is at doing something\" and \"work done vs heat rejected\". An electric heater is 0% efficient since it's converting everything to waste heat. Maybe if you wanted to stretch real hard you could say that any noise it makes is \"lost\" since hearing it outside the place it's heating would be energy that didn't go into heat. That would be like not listening to the radio while driving to save gas. Technically true, but absolutely not significant. A heater using fuel would have losses since combustion is never perfectly complete."
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lkqeq0
|
How do neurosurgeons get to the middle of someone’s brain without damaging other parts of the brain?
|
Biology
|
explainlikeimfive
|
{
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"In short, they don’t. Detailed imaging (pre-op MRI and intra-operative CT) are often used to create a robust surgical plan which includes trajectories, burr hole locations, and implant targets to minimize risk of bleeding, damage to important speech regions, etc. Unintended cognitive, personality, speech, and motor symptoms are not uncommon following major neurosurgery. These kinds of side effects are often temporary, but no guarantees. Source: neural engineer who studies deep brain stimulation.",
"Going inside the brain is a last case scenario. In those cases the alternative to surgery is death or a great worsening of the patients QoL. So, rewards outweigh the risks in those cases. Damage does happen, and it is sometimes severe, but it's all dependent on the result. If going inside your brain meant possible vision loss in your left eye but also meant the removal of a lethal tumor, you'd likely say yes. Of course, brain surgeons are highly trained in what areas of the brain do what and the ways to do the least damage possible.",
"Getting to 'the middle' is a last resort. Getting much beneath the surface is always risky, and the central part is neurologically the most complex. But the brain is composed of several different lobes, which have some natural anatomical separation. To some extent you can also follow the path of major blood vessels. Any brain surgery is risky to some degree. But the patient and/or doctor may decide that some brain damage is an acceptable risk (or even likelihood) for a decent chance at removing a greater threat. And depending on where the problem is, the effects of those risks can be approximately calculated, something like \"you may lose the ability to speak\", or \"vision in your right field of view will probably be affected\"."
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lkr5s5
|
How does lizard camouflage work?
|
How does camouflage work in lizards and how lizards control what colours they camouflage to? Can they do it whenever they like and can they choose which colour they want to camouflage to?
|
Biology
|
explainlikeimfive
|
{
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"text": [
"If I'm thinking correctly they don't... not really anyways. If you're thinking of chameleons, I belive they don't change to blend in they change to show the mood and to look for a potential mate. Other reptiles can't really change colors they are born with the colors that best represent their surroundings, or I don't know of any lizards that can change besides chameleons. Now cuddle fish and octopus are absolutley amazing with changing colors and even texture to blend in."
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3
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[
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[
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lkro8w
|
Why does tin foil makes so much noise when you touch it?
|
Physics
|
explainlikeimfive
|
{
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"text": [
"Tinfoil (really aluminium foil) is both hard and weak. It's a rigid material because aluminium is rigid. This makes it good for making sounds, as it can vibrate rather than flopping like fabric. However, because it's rolled very thin, it's easy for us to bend it when we move it. Each time you move it, it's like loads of tiny cymbals being hit.",
"Every time you use tin foil (or aluminum foil) it's like handling a miniature version of a sheet of regular metal. If you bend it, it creaks. If you fold it, it crunches. If you crush it, it crackles. If you shake it, it makes a fwubbuhwubbah sound. With aluminum foil, it's all the same thing, but all of that is happening so fast at a smaller level because of how thin the material is, so it happens at both a much higher rate and pitch."
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4
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lkrs3a
|
Does the helium in balloons go back into the atmosphere?
|
I’ve been told there is a shortage of helium and it’s a non-renewable resource. If this is accurate, why are we still using it like it is never running out and does the helium from the balloons go back into the air to be used again?
|
Earth Science
|
explainlikeimfive
|
{
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"text": [
"Helium, in balloons or not, is lighter than air. Sufficiently so that it will float to the top of the atmosphere, where it gets bombarded with solar radiation and blasted off into space never to be seen again.",
"Yes, and then out to space. We are basically wasting an extremely rare and non-renewable resource, necessary for things like MRIs and other low temperature applications like super conductors, on temporary amusement.",
"Helium doesn't naturally exist in any significant quantities in the atmosphere. It is a biproduct of natural gas mining, and is trapped with the natural gas and then processed out. Once supplies under the crust are freed, there isn't any more on earth, cause it will end up leaving the planet."
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lku5hy
|
Why do we need to lose consciousness in order to regenerate and "recharge"?
|
Biology
|
explainlikeimfive
|
{
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"text": [
"There's a lot of \"why\" we can only speculate on, until the answers are discovered. For now, we know that nearly all animals with a brain must enter a state of inhibited consciousness at some point in order to rejuvenate their brain and body. Our brain, far from being inactive during sleep, is actually extremely busy- it's just most of our sensory centers are deactivated. Memories are being consolidated, the cellular trash is being taken out, and energy reserves are being replenished, among numerous other functions inside and outside the brain. At best, our understanding of sleep tells us that some or all of its functions simply can't be done with the brain awake. Many animals have evolved functions to mitigate the risk to their survival posed by long periods of unconsciousness- such as alternating brain hemispheres, hiding in burrows or trees, or sleeping in bursts instead of stretches. However, the need for sleep in some way or form is still present in nearly all animals.",
"Most physical injuries require simple rest, as the cellular regeneration which is necessary to rebuild damaged tissue occurs naturally without active guidance. However, when injury occurs, we are advised not to strain the injured part, i.e. keep weight off a sprained ankle, wrapping a broken bone in a cast to prevent stress from movement. Sleep is essentially the cast for your brain. With mental \"regeneration,\" the processes that return us to a healthy state require our conscious thoughts to temporarily halt. Active thoughts cause synapses in the brain to fire, and firing results in very minor damage to the brain tissue causing \"debris\" like proteins and damaged genes to build up. Sleep slows the firing of these synapses to allow for a \"maintenance mode\" to clear out this debris and repair the damage. It's very similar to taking a machine offline for cleaning and maintenance. It would be a very bad idea to change your car's oil while the engine is running, but when the engine is off, the process is simple."
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lkujtr
|
- Predicting recessions ?
|
Please delete if it breaches rules Given that we have data from the past for a time period (Just before, during and after an economic recession). Shouldn't alot of people who work/track this information would see one coming or know we are on the brink of one or due in general just by looking at the numbers. If we know, shouldn't we have corrective measures put in place to not let it happen ? Is it just the scale that we can't predict Tldr - Why can't economic downturn predictions/estimates get better since we have data from the past which helps understand things better ?
|
Economics
|
explainlikeimfive
|
{
"a_id": [
"gnlwpj3"
],
"text": [
"Short answer: chaos. Some things are very predictable. Other things are very unpredictable. One great example of this is the pendulum. If you have a single pendulum, it's really easy to predict exactly where it's going to be for a long time. But if you have what's called a double pendulum, where a second pendulum is hanging off the first one, tiny changes in the starting conditions can lead to huge changes further down the line. There's a great gif of this somewhere. I'll try and find it. Point is, economics it's more like this. Even if you had almost perfect knowledge of the market, a tiny change could lead to a hugely different outcome."
],
"score": [
6
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"text_urls": [
[]
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|
[
"url"
] |
[
"url"
] |
lkuw63
|
How do chocolate chips stay soft inside cookies?
|
After you bake chocolate chip cookies and they cool down, the chips still stay soft. How can they still feel melted and gooey after they cool down to the same temp they were when they were hard?
|
Other
|
explainlikeimfive
|
{
"a_id": [
"gnm5h97"
],
"text": [
"It has to do with what's called tempering. When chocolate cools it turns into Crystals. It can turn into a bunch of different types. If it's mostly a certain type they join together, look kinda shiny and give that signature snap. In order for that to happen the chocolate has to come to a certain temperature to melt all the other shapes but that one then cool down slowly so they are the most likely to form. Now we don't get that with our chocolate chip cookies because they get far hotter than the tempering temperature and then they cool down kinda randomly. So instead of one type of well ordered crystal structure you get a bunch of crystals stuck together randomly."
],
"score": [
10
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
lkv3xw
|
How does depression "suck out" your energy?
|
A person can do push ups multiple times, but a cripplingly depressed person can barely lift their arm. Why? Is it like like adrenaline but backwards?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gnlzmzw"
],
"text": [
"Depression is different for many people. For me it is extremely draining when I am severely depressed. I feel so tired and drained no matter how much rest I get i feel physically drained as if I just finished a marathon and then you add the mental self loathing to that and I'm lucky to get up and brush my teeth."
],
"score": [
7
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
lkvig6
|
Why are the roads in Texas so icy this week when the roads in New England are rarely like that?
|
Earth Science
|
explainlikeimfive
|
{
"a_id": [
"gnm1kfs",
"gnm1uwv",
"gnm1oi3",
"gnm2suj",
"gnm1p1p",
"gnm24fc"
],
"text": [
"CT chemically treats its roads before and after storms. We do it routinely because snow and ice are normal. Most of Texas does not have either the equipment or the supplies to do this.",
"CT’s snow removal/road treatment budget likely dwarfs TX’s. It wouldn’t make sense for TX to build up the infrastructure (purchasing snow plows, hiring drivers, purchasing and maintaining the salt and other chemicals to treat roads, etc.), just to use them once every decade or so.",
"They're not used to this and don't put a lot (or maybe any) funding into road treatment. A snow plow is probably a regular sight for you. It's a real rarity down there.",
"Can't speak for other parts of the state, but where I live we had a couple of days of temps in the mid-high 20's leading into the storm. Then when it hit, we had sleet/freezing rain coming down off and on almost all day Sunday. Since the ground was already good and cold, this ice began to build up without melting much (although on the roads it did melt some, but left them wet in sub-freezing temps). Once the sun went down and not as many people were on the roads keeping all that water from freezing, it bagan to freeze leaving a nice layer of ice for the continuing ice to stick to. Once it started actually snowing, it was a very dry, icey snow because of the extreme cold temps (we got down to 5 degrees last night with the windchill pushing it to minus 12). All that snow that came down (almost 8 inches here, where most years we get no snow at all) covered the ice. But once you start moving on it, you compress it into more ice on top of the ice below it. Nice and slippery. Add to all of that the fact that major parrs of Texas get no snow most years, and only an inch or so in the years we do get snow (exceptions are the Dallas area, the panhandle, and west Texas near El Paso where they can get significant snow most years). This means we lack the equipment to clear roads effectively and nobody knows how to walk or drive on snow. It's rscipe for disaster. And they are predicting up to 8 more inches where I live in east Texas within the next 2 days. That will make 3 times it's snowed here within the last 3 weeks.",
"Most likely a mix of not having snow plows or salt/sand/gravel, snow tires, the temperature flucuations that make ice much more frequent, and inexperienced drivers. Mix all those factors up and now you’ve got a slippery slope or lack thereof, I just wanted to make a pun.",
"It comes down to being unprepared. Teams lack experience in heavy snow or icy conditions and because it's usually not required every year, sometimes they also lack equipment and supplies to combat it. Combine that with residents being unfamiliar with conditions, you get slippery roads, accidents, and winter horror stories. Meanwhile, those from more northern areas grow up knowing how to get around in the same conditions because the world isn't going to shut down when winter lasts months and could have those conditions any time. DOT teams are well oiled machines, they know how to handle even different types of snow, like wet, heavy flakes or light, fluffy ones or ice, because each one is different."
],
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12,
11,
6,
3,
3
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[],
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|
[
"url"
] |
[
"url"
] |
|
lkvq1w
|
- How is there snow on the Himalayan mountains if the peak of the mountain goes above clouds?
|
Earth Science
|
explainlikeimfive
|
{
"a_id": [
"gnmaiu7"
],
"text": [
"The majority of clouds that produce your major rain/snow are much lower in the atmosphere yes. But clouds can go all the way up to 50 to 60 thousand feet, twice the height Everest, and all clouds are made of some sort of water/ice crystal. So even If you don’t get as major cloud systems depositing snow, there is still some. Tl/dr: Everest and the Himalayas don’t go above every cloud"
],
"score": [
3
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
lkvs04
|
Why Do We Feel Cold When We Have a Fever?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gnm4jhk",
"gnm4p69",
"gnm7u4k"
],
"text": [
"As a rule, we don't sense temperature *per se.* What we sense is the differential between our body and the environment. When we have a fever, our bodies are increasing our internal temperature in an attempt to burn out an infection. We register the *difference* between our (raised) internal temperature and the environment as \"cold.\"",
"This can be broken down into relatable interactions as follows. If you touch something that is colder than you, it feels cold. Also, your body is typically used to the local \"room temperature\" if you've been in it long enough to acclimate. Now your body is confused by how much colder the world feels.",
"It’s some what backwards, you get a fever because you’re feeling cold. The immune system works better at a higher temperature (thought the rest of the body works worse at that temperature). So when your body detects a bad illness, it tells a lot of things in your body that it’s currently too cold, so it does all the stuff to warm you up. Stuff like shivering, and feeling cold so you go seek out a warm blanket. Because you feel cold when you’re not actually cold, your body heats up, creating a fever, which helps your immune system work better to fight the illness."
],
"score": [
14,
4,
4
],
"text_urls": [
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
lkvz94
|
What is MMT (Modern Monetary Theory) and how does it work? Also what are the arguments for it and what are some major criticisms?
|
Economics
|
explainlikeimfive
|
{
"a_id": [
"gnm8ngx"
],
"text": [
"NPR's Planet Money did a podcast about it, only about 20 mins. They'll do a better job of explaining than I. [ URL_0 ]( URL_0 )"
],
"score": [
7
],
"text_urls": [
[
"https://www.npr.org/sections/money/2018/09/26/651948323/episode-866-modern-monetary-theory"
]
]
}
|
[
"url"
] |
[
"url"
] |
|
lkwd9v
|
How do animals like horses and cows not have more bone issues?
|
It seems like their legs are too thin for the amount of weight that they need to support to stand, let alone run or even jump. How are broken legs not a much more common issue for animals that size when humans that are too tall have to use canes in their 30s?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gnm6n1p"
],
"text": [
"Their bones are \\*very\\* strong. You rarely see beef leg bones in the meat section because there's not much meat there (relatively), but take a look at \"soup bones\" if you can find them...the bones are easily 5-10cm across with walls well over a cm thick. Compared to even the strongest human bone, they're \\*massive\\*. Bone damage due to aging isn't usually an issue for cows...they don't die of old age much. Horses, especially race horses, can and do break their legs and it's a very bad thing when they do. But they, just like cows, have extremely strong bones (and tendons and ligaments) relative to ours."
],
"score": [
5
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
lkwkmr
|
How do panic attacks work? Like hormones?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gnm7pkz",
"gnnt5iv"
],
"text": [
"Your body releaes adrenaline which amps you up as if your life was on the line. Adrenaline is what creates the flight or fight response which increases your heart rate and shuts down your digestive system. But the problem is that our bodies give that response in scenarios that aren't life threatening therefore we just call it a panic attack.",
"This is how my therapists have explained it over the years, plus my own research as a psychology student (I have panic disorder, social phobia and general anxiety). The basic idea of the fight/flight response is one factor, though in a panic attack you generally can't pinpoint the event that triggered the response. You can then start to develop anxiety or fear related to the *idea* that you're going to have a panic attack, which can then make panic attacks more likely. It was explained that the panic attacks get put in the same category as a tiger in your mind. Sometimes you can stop this or recategorize the panic attacks as less dangerous than a tiger, but the human mind is a strange and complicated thing, so this doesn't always work (speaking from personal experience). They're also hard to study. One of the favorite ways to study mental health issues is to put people in an fMRI to see what their brain is doing. But to do this you have to either get someone into the machine as soon as they start to panic (super impractical if they have their attack away from the hospital/clinic) or induce a panic attack in someone (which is both a flawed research design since the attacks aren't \"natural\" as well as super ethically dodgy). As far as alpha and beta blockers go, I'm more familiar with beta blockers since I've been taking one for about 5 years for both my anxiety and my hypertension. I also take an alpha blocker, but it's newer and I haven't done as much research into it. They do help with some of the symptoms of a panic attack (I don't feel like my heart is going to explode) but there are symptoms that they don't touch (trouble breathing, tense and shaking muscles, \"spiraling\" or racing thoughts, etc.), and they have side effects at higher doses. My alpha blocker, for example, makes me super drowsy so I take it right before bed. I've about maxed out the safe dose for my beta blockers, according to the docs. Beta blockers also take awhile to have full effects, up to an hour or two. Panic attacks are rarely that long when left alone or handled with other techniques (deep breathing, reminding yourself you're not going to die, someone else helping to coach you down, etc.), so using them in the moment isn't as helpful as taking them regularly or before you do something that might trigger a panic attack. Taking too much of either can drop your blood pressure too low and you can pass out. Though, I guess you wouldn't be panicking anymore lol. So, the TL;DR boils down to 3 things: 1. Panic attacks aren't only the fight/flight response, but brains are super complicated and weird so we aren't sure of all the factors or even really how to study them. 2. Most medications take longer to act than a panic attack lasts as well as only targeting some of the symptoms. 3. There are side effects to alpha and beta blockers at higher doses that some people would need to take, like fatigue/drowsiness, low blood pressure, or are addictive (like benzos), that aren't always worth the trade off."
],
"score": [
3,
3
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
lkxlt8
|
why does wind make a whistle sound I always thought it was only in movies until I heard it myself?
|
Physics
|
explainlikeimfive
|
{
"a_id": [
"gnmend2"
],
"text": [
"It's not really the wind that makes a whistling, it's wind past objects that makes a whistle. Wind blowing past ropes, twigs, other thin things that can vibrate. A good gust of wind traveling through trees will make more of a roaring noise, past the end of a fence or similar sharp pointed thing can make a higher pitched vibration like a whistle."
],
"score": [
9
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
lkzmqc
|
Why does Congo have a near monopoly in Cobalt extraction? Is all the Cobalt in the world really only in Congo? Or is it something else? Congo produces 80% of the global cobalt supply. Why only Congo? Is the entirety of cobalt located ONLY in Congo?
|
Earth Science
|
explainlikeimfive
|
{
"a_id": [
"gnmn2vo",
"gnnt3pd",
"gnnomh7",
"gnnlzki",
"gnnuotg",
"gno921y",
"gno2x23",
"gnnxybc",
"gnooug7",
"gno8unk",
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],
"text": [
"Cobalt is mostly a by-product of copper and nickel mining. There are massive copper and nickel deposits in the Congo. However, another major factor is the lack of much mining and environmental regulation in the Congo. They can mine a lot of cobalt, cheap, because they pay the workers low wages, to work in dangerous conditions, with little regard to the effects to the local environment. So, it's simply cheaper for companies to buy Cobalt from the Congo than from many other places. Thus, it's much like two farms in your town growing apples. If Farm A can sell its apples for much less than Farm B, then Farm A is going to sell far more apples, even if Farm B can produce just as many apples as Farm A.",
"Speaking as a geologist- cobalt is a product of nickel and copper mining. But not all copper deposits contain cobalt. They have to have formed a certain way. The Central African copper belt, in Zambia and the DRC is one of the largest copper provinces in the world that formed in the way to allow mineralization of cobalt too. Then add in the DRC’s lack of good regulations compared to Zambia and you get a country that exports cobalt. 14-40% of cobalt is artisanaly mined.",
"It’s like the rare earth metals coming from China. Rare earth metals are not actually rare but China is a cheap source of them so they dominate the market. Congo is the cheapest place to produce cobalt and can produce enough to meet demand. If another place could produce cobalt but it’s even a little bit more expensive it wouldn’t make money. It is much cheaper for an existing operation to ramp up to meet demand than for a new mine to start production. It’s different for something like copper or aluminum. We use so much of these and our consumption is based in part in price. So a new mine can still be profitable by increasing global supply. We don’t use nearly as much cobalt so the few operating mines can supply our needs. We could get it other places but it doesn’t make sense to make that investment just to be undercut but existing operations.",
"The copper belt of southern Congo has both a high concentration of cobalt and a lot of it. When you mine cobalt, you pull out cobalt with other rocks - copper and rocks you don't want. The percentage of cobalt in the rocks in southern Congo (and the percentage of copper) is among the highest in the world. Not only is there a lot of cobalt in the rock, there's a lot of it, these deposits are massive, spread out over hundreds of thousands of square kilometers. So you have some of the largest (if not the largest) deposits of cobalt in the world and they have some of the highest concentrations of cobalt in the world. That makes mining in Congo attractive even though it is one of the most challenging and expensive places for miners to operate.",
"There is cobalt mining and refining in Canada, but precisely because of the problems listed it is extremely limited. And yes, it is colocated with the nickel deposits and extraction of northern (Sudbury) Ontario.",
"Why did you ask the same question twice? Why did you ask the same question twice?",
"Congo has a lot of valuable minerals such as Cobalt and Coltan. These minerals are often sought for their useful properties. Minerals such as Coltan are useful for basically all electronics. Cobalt is used for electronics such as batteries. Some of these are called Blood Minerals because of how much those resources fuel ongoing conflicts. Think of it like how Wakanda sits on a giant supply of Vibranium because that's basically what ideas of Wakanda were based on. However, over the past few centuries, the entire world seems to agree to nothing else but finding ways to exploit the African continent for its wealth of resources while screwing over the local population. International powers in addition to local rivalries (sometimes encouraged by international powers) have sparked countless wars, enslavement, genocide, child labour, and other atrocities. Governments and industries there are often goaded into having less-than-safe work conditions for dangerous jobs at far lower wages than most of the developed world, even though those minerals exist elsewhere. This isn't recent and there's HUGE histories of Colonization that are also are a factor. In particular, I'd recommend reading what the King Leopold of Belgium did in Congo and asking yourself why we only learned about Hitler as a mass murderer in school and not this monster. All that history currently results in a very de-regulated mining market in Congo, which sits on a giant mound of valuable blood minerals that fuel wars and death, that international companies and powers can cheaply buy and exploit, especially electronics companies. As a result, they are all too happy to turn a blind eye to the human rights abuses and cruelty they fund for their newest products. We are not necessarily innocent in all this either. Chances are your computer, your phone, and any batteries and electronics you own has minerals in it that are a product of this exploitation. Not much we can do about it now of course, but it's important to at least realize the history as to WHY these things happen and that it's still happening; too much history for me to get into entirely on Reddit. Some countries have mines for cobalt and other blood minerals or are considering opening new mines for them, but they actually have standards and regulations, so they're mostly ignored in favor of the cheap, blood soaked kind. Tl;dr: Cobalt is available in many other places in the world, just not nearly as cheaply. The reason it's mainly supplied from Congo is a complex web of historic colonization and exploitation that still persists in different forms. Source: I learned about this several years ago through my work at a museum while researching Coltan and other metals and had to teach this to school children using Black Panther and Vibranium as a relatable reference.",
"I am part of a team developing a cobalt mine in Idaho. Just happens that the economics work now where in the past they haven't. In the congo labor and enviro regs add way less cost so the economics were more favorable for a long time, not much else to it",
"Lol what's with the way you asked the question? Repeating things and seemingly offended hahaha",
"Most of it is there. There is also some in Idaho and they actually promote the fact that mining cobalt in Idaho doesn't support a repressive government.",
"Was part of the Black Panther comic setting based on this? It would make sense seeing as Wakanda is a large (the largest?) producer of a rare metal in the MCU. I'm just curious because I love connections like that."
],
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|
[
"url"
] |
[
"url"
] |
|
ll26jw
|
What happens when we acclimate to different weather?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gnn024w"
],
"text": [
"Your body constantly works at keeping you going. Heart is pumping blood, kidneys filter it, lungs exchange co2 for o2 etc. many of those can be tuned to your environment. So when you change your environment, your body learns a new normal and adjusts those patterns accordingly. Otherwise everyone living outside the „optimal“ place would be under heavy strain to their organs constantly."
],
"score": [
6
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
ll2bb1
|
Why is anorexia so much deadlier than obesity?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gnmzq7j"
],
"text": [
"Obesity doesn't outright kill you but it does put a lot of normal processes in your body in a bad shape. It speeds up and promotes disease processes like metabolic syndrome and cardiovascular disease. These things won't kill you overnight, they take years to decades to build up and in the same way are a slow march to death. You can slow or stop progression but you're left with the damage you've accumulated but not reverse it. That's different in anorexia, or more often, starvation. Your body only has so many stores of particular components in your body. Electrolytes are particularly important because they have to be within very narrow levels, your blood has to be at a certain pH, you need to have particular essential vitamins and nutrients to make the building blocks that go in your body. Once you're into starvation, low levels of these things in your body quickly cause things to go wrong. The biggest killer is low potassium, which messes the rhythm in your heart. This means your heart can no longer function properly and goes into an electrical rhythm that's unstable, then later likely lethal. Refeeding syndrome is dangerous as well - when bringing these people back into normal function, feeding them can also cause disturbances in electrolytes which can quickly become lethal."
],
"score": [
10
],
"text_urls": [
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}
|
[
"url"
] |
[
"url"
] |
|
ll2hxc
|
- how much stronger are men on average than women? What is the female potential for strength and muscle gain? How long would it take for a woman to become as strong as the average man?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gnn1zgg",
"gnn3rjx",
"gnn21l0",
"gnn1e8m",
"gnn4c04"
],
"text": [
"Well, one way to measure this is weightlifting. It's an Olympic sport, so the very best athletes have pretty detailed measurement histories. It's done by weight class, so you can compare men and women of the same mass if you desire. For men, the snatch+clean & jerk record is 484kg. For women the corresponding record is 332kg. For men in the same weight class as that women's record, 85-87kg (they changed the boundaries a couple years back), the record is 396kg. In no sense are these people \"average\", they are incredibly strong. So this at best represents the potential for strength as measured in lifting barbells. But this is actual fact as opposed to political opinion from some other setting, like transgender track.",
"The world record raw bench for women is 457 pounds at 198. Mens is 610 at 198. That’s a 28 percent difference. Women’s squat raw = 603 lbs at 185 Men’s = 804 at 181 28 percent difference on the same weight class Deadlift Womens= 600 at 198 Men’s = 881 at 198 That’s a 37 % difference You also have to take into consideration that this seems to be the weight that women cap out on. That’s why I’m comparing weight. Men can get waaaay bigger and stronger. But if you compare weight, your looking at an average of 31 percent difference in strength. And just to put things into a better perspective, here are men’s raw maxes for each lift all time Squat = 1,080 pounds 56 percent difference Bench = 770 pounds 51 percent difference Deadlift= 1,102 pounds 58 percent difference This means that if you compare a mans max capabilities and a woman’s, you get an average of 55 percent difference. So there you have it",
"This is almost impossible to measure for a few different reasons. There are many different ways to measure strength, people behave different to training for the exercizes beforehand, there are cultural differences as well as biological, etc. I have seen some test results from the end of army boot camps of drafted soldiers of both genders, which is probably as good a sample as you will get, that roughly a third of female soldiers perform better then a third of the male soldiers. But this still have issues with selection bias and the dificulty of comparing physical strengths. If you instead look at top athletes, where you get the best of the best of each gender, it is again very dificult to compare them as there is a lot of variance between different exercizes and even different conditions. But you often see womens competitions at roughly 70% of the male competitions. But again there are many variables here and it is very hard to come up with good numbers, people are constantly trying in order to get fair competitions between all the athletes but they never get it quite right. So it is possible for women to become stronger then most men. Since you gain more strength when you start to exercize and most people do not exercize at all it should not take long to become stronger then most men.",
"I don't have numbers for averages. As for potential for women squat and deadlift is about 70% of men while bench press is about 50%.",
"> How long would it take for a woman to become as strong as the average man? It really depends on your average man. There is bound to be some variation. I bring this up because i was reading up on the tragic Franklin expedition, lost in 1847. So far they have analysed the DNA of 24 individuals of the all male crew. Four were found to be European females. There is no definitive explanation for this disparity. But it is entirely possible that women were employed to do men's work. Men who grew up in the overcrowded cities would have been undernourished and sickly still in adulthood. Women who grew up in the countryside would have been well fed as children and then accustomed to farm work as adults."
],
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10,
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3
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|
[
"url"
] |
[
"url"
] |
|
ll3amo
|
How did Edwin Hubble prove that the universe is expanding in 1920?
|
Physics
|
explainlikeimfive
|
{
"a_id": [
"gnn5e82"
],
"text": [
"There's a property of objects when they move relative to each other called the Doppler Effect, where waves emitted from things moving towards each other are pitched up from neutral, and things moving away are pitched down. The same applies to light coming from Galaxies very far away. Except that when he looked, he saw that everything except the closest galaxies were always tinted red (light pitched down) indicating that *everything* was moving away from us. Not only that, but the amount of redshift was equivalent for all objects the same distance away. That could mean two different things 1. Everything just happens to be moving away from our part of the universe in perfect spherical symmetry (implausible). 2. The universe itself is expanding, and everything is moving away from everything else."
],
"score": [
23
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
ll48vt
|
How can the universe be speeding up in its expansion? Since gravity is the only force that controls wouldn't the universe ultimately always contract again over time because gravity would eventually win out over the initial acceleration caused by the big bang?
|
Physics
|
explainlikeimfive
|
{
"a_id": [
"gnnagaq",
"gnna7vn",
"gnnl3kr",
"gnnbtpw",
"gno4jib"
],
"text": [
"There is a thing called the cosmological constant, or energy density of space, or dark energy, which forces the universe to get progressively bigger. As is obvious from its name, we don’t really know what it is. This is an area of active research.",
"1. Gravity is not the only controlling force. 2. The universe is not just expanding, but the expansion is accelerating. Meaning, some thing is causing the expansion and that something is overpowering the gravity. Scientists call this dark energy and it's characteristics are unknown.",
"We don't know. We observed that the expansion of the universe is accelerating, but until we figure out the underlining mechanisms any explanation is a purely theoretical hypothesis.",
"Imagine a stretchy sheet with two rocks on it. The mass of the rocks will distort the sheet around them, and if they're close enough, they'll eventually both pull together into the same stretched-out area. That's gravity. Now imagine putting those two rocks on the stretchy sheet, and then pulling the ends of the sheet apart constantly. Each rock is still distorting the sheet around it, but the sheet itself is moving apart more quickly. Even if the rocks started off near each other, they'll end up in their own little stretched-out areas instead of together, because the sheet pulled them apart more quickly than they rolled together. That's the expansion of the universe.",
"The only correct answer right now is \"we are not sure\". Gravity is pulling everything together, yes. As far as we can tell, gravity will always keep local things together against the constant stretch of universe expansion (on the level of, say, our galaxy and a couple close galaxies nearby). Anything on the larger scale seems to be getting blown apart, though, on a trajectory that will in time take them speeding away from us faster than light, effectively cutting them off from us forever. The really weird thing here is that these objects being stretched apart aren't really traveling away from one another, per se. They're not all escaping form some center of an explosion. Everything is receding away from everything else simultaneously, in every direction. The only way we can think this to be possible is that the galaxies themselves aren't so much moving away from each other, as it is that space itself is somehow passively causing all distances between things to increase. This is what they mean by \"space is expanding\". The very concept of distance itself seems to be warping, as \"more space\" seems to be constantly creating itself out of nowhere, everywhere. The leading theory right now is \"dark energy\". To be very clear, dark energy is not actually \"a thing\", as far as we currently know. It's just a name for an imaginary phenomenon that scientists made up by pointing their telescopes at the sky, noting the fine details of the universe's expansion, and basically trying to invent something with all of the necessary properties that should be able to cause what they see. That's what makes it \"dark\", we are literally *in the dark* about it because *we don't actually know*. But that's not to say that it's a hoax. A \"made-up\" answer is always the first step to discovering new properties of the universe. By inventing a substance that creates the effects we see, we can extrapolate extra details about it that could make a prediction, like, \"if dark energy is real, and it behaves how we think it does, then we should be able to point our telescopes at < whatever > and see < certain effect > \". Then we can actually run that test to see if the prediction holds water. If it does, it adds compelling evidence that our imaginary substance as we understand it could actually be real after all, and we can build on that with more tests. If not, we have to go back to the drawing board and revise our theories so it jives with the new observation. Either way, the more experiments we can craft and successfully run, the closer we hone in on the actual cause of the effects we see. This is the current state of affairs with \"dark energy\" at the moment."
],
"score": [
14,
12,
3,
3,
3
],
"text_urls": [
[],
[],
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
ll4arn
|
Why should I care that Google and other tech giants have my data?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"gnnai8m",
"gnndnzh",
"gnnamtk",
"gnndgzi",
"gnnet0n"
],
"text": [
"Because you have almost no say in what Google does with it. Sure, it might might OK if they sell it to a company who uses it to show you ads for things you actually like or want. But what if Google were to sell your website browsing info to your health insurance company? Say you were looking up a place to go skydiving, and your insurance company saw that and decided you were a high-risk individual to justify raising your premiums? Or what if your mortgage company obtained data that showed you were looking for a new job, and similarly decided you were a risk and raised your rates? The controversy about data harvesting is that we *don't know* what's being done with our sensitive personal data- the process is immensely opaque- and the potential harm from having your personal data out there for the highest bidder can't really be estimated yet.",
"Its also about you as a thinking, feeling person, but as data points. Everyone is correct that the true trouble is that we don't know what they're doing but think about how much the tech giants know about your: -eating -sleeping -passions and prefetences -sex drive/interests -locations you frequent -political leaning and intensity of opinions -your inner social circle -and so, so much more The giants can build a better profile of you and everyone on earth than a thousand Private investigators ever could. This data has been used to fix and sway elections through triggering people's psychological reactions to real issues, with fake stimulus. I.e. \"vote for X because Y did THIS! CAN YOU BELIEVE IT?\" And our stupid lizard brains simply must engage at some level because the content is specifically built for and streamed to your internet and apps based on all the data aforementioned. The Great Hack (hulu) and The Social Dilemma (netflix) Have good takes on these issues. Sure, \"nothing to hide, nothing to fear\" seems good on the surface, but ask yourself: if privacy isnt a default expectation of humanity, why do you always close the bathroom door?",
"Companies might buy said data and use it to discriminate against you in selection process for jobs. LGBTQ+ people might get accidentally outed just based on their search history. And many more cases like that that can have negative impact on your life. The counter-argument usually is that people that have nothing to hide have nothing to fear but just think how many things you DON’T tell everyone out of fear. That’s why we need privacy.",
"Data is a commodity that can be traded for profit. Now, compare this to oil... if oil is found on land you own, it's yours. You might not be doing anything with it, but others (like companies or the government) may have a desire to mine and use it. But, from what I understand, you have a right to be paid appropriately for resources like that found on your land, even if others extract it. With data, you have no such rights (for now, anyway.) Companies can harvest this resource from you and turn a profit from it without you seeing a single cent... which seems wrong, at least to me. It's data generated by you being active on the net, you passively create it, so as far as I can tell you should be entitled to some if the value that comes from it.",
"It matters what Google knows about you, first of all because there’s an assumption that what we do in our home is writing the realm of privacy. Google invades your privacy to build a vast stockpile of knowledge about your tastes, interests, habits, and even what you know and don’t know. Then, they use what they know about you to manipulate your behavior, showing you specific information to guide your decision making processes, and steer your behavior to make you easier to manipulate. Finally, they exploit your weaknesses to take your money, and the better they get at this, the more people they sell access to manipulate you."
],
"score": [
124,
8,
7,
6,
3
],
"text_urls": [
[],
[],
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
ll5bsw
|
Why does it always feel like more effort to 'Pull' vs 'Push' a door open, given that the mass of the door and your physical strength stays the same.
|
Physics
|
explainlikeimfive
|
{
"a_id": [
"gnngafv"
],
"text": [
"When you push, you can literally lean on the door and and that's how it gets pushed. So no active involvement. When you pull, even if you lean back there is a tension on your arm or wrist depending on the posture. That's why it makes it feel harder or more effort. PS : Doors(fire and emergency exists) always open to outside. Say there are 50 people behind you and crowded then it's impossible toove everyone back and then make space to open the door inwards."
],
"score": [
21
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
ll5jja
|
Can someone explain how fiat money works? I’m very bad at economics and reading about it is making my brain hurt. Is money even real?
|
Economics
|
explainlikeimfive
|
{
"a_id": [
"gnnhqgx",
"gnodjz7"
],
"text": [
"Nothing in society is “real” besides that people as a group agree that it is real. The time on the clock isn’t “real”, those are just numbers we put on a machine we invented to help organize our day. The borders between countries aren’t “real” because chances are at some point that was just a line drawn on a map by some dude claiming to be in charge, even if there’s a nice line on the ground or wall there now. It probably wasn’t there 500 years ago. We put it there. But these things are still real, we use the time on the clock, and there are people in prison who will tell you that yeah the borders between countries are very much real and crossing them the wrong way can negatively impact you. Fiat money works the same way. Everyone agrees that the money has value and is worth something. Way back in the day, pretty much all money was based on previous metals. Gold, Silver, even copper. The United States dollar worked the same way, you used to be able to take your dollars and go and exchange them with the government for real, physical gold. In 1971, the US abandoned the gold standard (for many reasons, one main one being that having a physical commodity restricting how much money you can print into circulation can put a damper on the economy). Instead now the US dollar is just backed by trust. It isn’t back by any physical commodity you can do exchange it for. Instead it is backed by the fact that we all, me, you, banks, the government, agree that it has value, and use it. Which really, isn’t that different that using gold backed money, tell me, is gold to a normal person really worth anything? Sure you can make some shiny looking stuff, but if you were starving or freezing you couldn’t eat it or warm yourself with it unless you could get someone else to also agree that the gold has value and trade with you for it. But if that person didn’t like shiny metals, then you just might be out of luck.",
"Fiat money is the natural endpoint of an economic system. /first we had bartering, which was incredibly inconvenient because carrying your goods to market just to trade them for other goods was unnecessarily difficult. So then we moved to representative money, the bills represented something with an agreed upon value. So a bill would say be worth 1 bar of silver, and one could go to the bank and exchange the bill for a bar of silver or vice versa. Fiat money has value because it is believed that is has value, and people believe in that value. The value is also determined by how much money is in circulation, If there's very few bills in circulation, the value is generally high, if there's way too many bills in circulation, the value will plummet, So a central bank (In the case of the US the federal reserve) watches the amount in circulation and prints money accordingly, most economists consider a slow steady inflation rate is ideal. This is the reason why governments can't just \"print more money\" to pay debts, if they do their currency will enter a state called \"hyperinflation\" that is the currency becomes essentially worthless. An example is Zimbabwe, wherein the Zimbabwean dollar was reduced to so little value that a 100,000,000,000 note was worth about a third of a cent in USD."
],
"score": [
14,
3
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
ll5wz6
|
Why are MRI’s so loud?
|
Just had an MRI. Why are they so loud? Additionally. I could decipher about 12 different “tones/noises.” What does that translate to ?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"gnnk2q9"
],
"text": [
"The machine generates an enormous pulsing magnetic field. Almost everything in the machine is as non-magnetic as possible, but that's not completely non-magnetic. Copper atoms, for example, react to strong magnetic fields. While the machine is quite sturdy, any possible flex will cause motion. Moving innards makes sound. The forces are large enough that you can hear the sound."
],
"score": [
11
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
ll6m7o
|
Why are telecommunications cables not all underground?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"gnnrrn6",
"gnnspvv",
"gnno8nt",
"gnnnqjh"
],
"text": [
"Everything boils down to money. Switching from poles to underground sounds easy and logical on the surface. In reality it's very different. You have a utility pole in your back yard, utility company has an easement and right of way to it. That's long since established in your property deed. Switching that to underground means the utility needs to get a permit from the city, work with all the other lines on that same pole, like power/phone/cable. And some times even radio antennas for local citywide WiFi, emergency agency radios, mobile radios. Then the utility company shows up at your house, wants to tear up your fence and back yard to dig up the pole and bury new lines. Who pays go restore the fence, garden and maybe even that pool they had to dig through?",
"All F/O cables are underground, and the vast majority of residential and commercial internet is buried. They typically follow the sewer lines as cities tend to install 'conduit' when they dig and bury city utility since they know this is inevitable. This assumes a bunch of things, like you live in a city-like area and not in the boonies. Source - this is my job.",
"Because telephone poles came around first and when you already have the infrastructure in place, it's difficult to convince people to spend the enormous amount of money required to dig up the city/country to lay cables.",
"Putting cables underground means they're safe from the weather, for sure...but it also means they're a lot more expensive to install (since you have to rip up the ground and then fix it all when you're done) and maintain (because anytime there's a problem you need to rip up the ground, all over again, then fix it all, all over again) and upgrade (more digging, more fixing)."
],
"score": [
7,
5,
4,
3
],
"text_urls": [
[],
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
ll6t04
|
How do we know how many calories are in something?
|
Chemistry
|
explainlikeimfive
|
{
"a_id": [
"gnnp1vc"
],
"text": [
"It can be put into a machine, set on fire, then the amount of energy released from the food can be calculated, then converted to calories. Fun fact, when we talk about calories we usually mean ‘kilocalories’, which is why labels usually write ‘kcal’. So that 150kcal bag of crisps actually means 150,000 calories. We just ignore the kilo part usually."
],
"score": [
7
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
ll73yl
|
why are power companies doing planned outages of residential neighborhoods instead of non-essential commercial areas?
|
Other
|
explainlikeimfive
|
{
"a_id": [
"gnnqowg",
"gnnyw84",
"gnns330"
],
"text": [
"People aren’t home most of the day in the middle of a Tuesday. It’s more of a hassle to turn off power to industrial areas, shutting down and starting up equipment can be a considerable process. Any production procedures that take multiple hours to complete can’t be run at all if you expect to lose power at some point that day. It’s a nightmare. Residential blackouts are just a nuisance.",
"I don’t know where you’re getting your information, but it is false. I work for a major manufacturer (3rd largest electricity consumer in the state) and we’ve been ordered to shut down operations to conserve energy for residential customers.",
"Industrial and commercial sites are already tied in with the power company and provide [Demand Response]( URL_0 ) where the power company can either email/call them to ask to reduce their load or send a signal and the control equipment on site turns off/dims lights, reduces HVAC settings, and may even turn off some equipment The big boys already have the equipment in place and generally use it during the hottest days of the summer when Air Conditioning loads get high. Having all the office buildings in a region automatically trim their HVAC back by a few degrees and dim their lights saves you more power than rolling blackouts through specific regions of them and doesn't inconvenience them nearly as much."
],
"score": [
10,
9,
6
],
"text_urls": [
[],
[],
[
"https://en.wikipedia.org/wiki/Demand_response#Industrial_customers"
]
]
}
|
[
"url"
] |
[
"url"
] |
|
ll7vqn
|
Why does orange juice taste awful after brushing your teeth?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gnnv7cr"
],
"text": [
"My best guess from my scientific background is the acidic orange juice having a neutralisation reaction with the alkali toothpaste. You can reduce the sensation by swilling your mouth with warm water after brushing (but isn’t great for your teeth as it can take off the fluoride layer which you’ve just put on when brushing)."
],
"score": [
4
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
ll8lf2
|
Is there a specific psychological reason people don't like hearing their voice?
|
Other
|
explainlikeimfive
|
{
"a_id": [
"gno18sl"
],
"text": [
"(I’m not 100% sure this is the correct answer) It’s not that we don’t like to hear our own voice, but rather, we don’t like to hear recordings of our own voice. Every time we speak, we hear our voice. But we also hear it through the vibration of our skull, which makes it sound deeper than it really is. But in our mind, this is how our voice really sounds. When we hear a recording, we hear our real voice. To everyone else, it sounds normal. But to us, it sounds really high pitched. This is because we are used to hearing ourself with a much deeper voice than we really have. Something similar happens with mirrors. We are used to seeing ourself with a mirror, which flips left and right. Now, I should point out, nobody has a completely symmetrical face. But for most people, you don’t really notice the asymmetry. So, we are really used to seeing our own reflection. This means that any small change to our face would be really obvious to us. It also means that when we see our face how it really looks - and not flipped, like in a mirror - we immediately notice all the asymmetries and think we don’t look good in the photo. This is why many phones use a flipped image for the selfie camera"
],
"score": [
20
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
ll96q4
|
Why do companies ask you to forward phishing emails to them as an attachment?
|
When you get a phishing email, sometimes a company will have a specific division that deals with that concern. So they'll ask you to forward any emails of that nature to a specific email address. But sometimes they ask you to do so as an attachment. Why?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"gno36p0",
"gno86xj"
],
"text": [
"Because if there's any malicious code in the e-mail itself, having it separate as an attachment helps mitigate that. The IT department can open it on their own terms as opposed to opening your forwarded email that could then infect their systems.",
"This also retains the message exactly as it came in, since forwarding it normally could lose a lot of metadata especially if they want to inspect it closely."
],
"score": [
4,
3
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
ll9b6a
|
What is a truncation problem?
|
Hey, I'm learning Python and the book is talking about truncation problems when i creat float Numbers out of fractions or decimals. I know what it looks like but I don't really understand what it means. Please help.
|
Mathematics
|
explainlikeimfive
|
{
"a_id": [
"gno5ws1",
"gno64b0"
],
"text": [
"In computing, truncated means \"cut short\". In the scenario your describe, changing from one data type to another could mean the number is truncated, I e. 3.24575432456 becomes 3.25.",
"The problem is that numbers are given a fixed amount of space in a computer. But sometimes the numbers do not fit. Floating point numbers do this clever trick where they store two numbers in the same space where one represent where the decimal point is, hence the name. This is very similar to scientific notation. However if you do some math that results in a number that requires more precision then is available then you have to truncate it to fit the space, but then you lose some precision. For example (10/3)\\*3 = (3.33333)\\*3 = 9.99999 which is a bit off the real answer. Similarly (1+BIG\\_NUM)-(2+BIG\\_NUM) = 0 because of the rounding issues. Obviously floating point numbers deals with binary numbers and not decimal numbers so these issues can appear even though they are not obvious when you do the math in the decimal system. But it is something you need to be aware of and it does often help to program defensively for example by avoiding to compare floating point numbers by their exact values."
],
"score": [
5,
4
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
ll9i88
|
How do we know how many calories are burned in any given exercise?
|
I know that heart rate has something to do with it, but if my heart rate is 120 from nervously speaking publicly while sitting still, I'm surely not burning the same calories as I would while swimming or walking up stairs, am I?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gno5nla",
"gnonztq"
],
"text": [
"We never know exactly unless we put some balloon on your mouth and nose and measure how much CO² you breathe out. Everything else is basically an educated guess based on previous measurements compared to your current situation.",
"A lot of things with calorie readouts are just an estimation. The gps unit I use to track my bike rides knows how much I weigh. It can then estimate how much energy i need to burn to move the bike at a given speed."
],
"score": [
11,
3
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
lla4e7
|
Can humans digest coal?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gnobtlw",
"gnocbvi"
],
"text": [
"Pure carbon, no, it’ll go right through you. But coal isn’t usually pure carbon; there are impurities that your body might (probably will) absorb which won’t do you any favors.",
"We can not digest coal. However unless there is any toxic materials in the coal we can eat it. However it does not do much within our intestines and exits the body in more or less the same form as it entered. So in general eating coal does not require you to seek medical attention unless your are presenting with symptoms. But it is not advisable to test this out. There is even one medical use for coal. If you have eaten a toxin then you might follow it up by eating some clean activated charcoal which will hopefully bind up some of the toxins and let them pass harmlessly through your digestion system without getting digested."
],
"score": [
6,
3
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
llahs0
|
How does reverse image searching work?
|
Other
|
explainlikeimfive
|
{
"a_id": [
"gnpdyvn",
"gnog0c5"
],
"text": [
"A “perceptual image hash” of your sample image is calculated. Depending on the scheme, this is a number between 8 and a few hundred bytes in length. It contains information about the image in a condensed form. Two images that are similar would have similar, but probably not identical, hashes. In simplest terms, they compare the hash of your image against the hashes of every image in their database. Other images whose hashes differ only by a few bits are very likely to look similar. There are algorithms to find matches much faster than brute force. A super simple \"perceptual image hash” is to convert the image to gray-scale, then scale the image WAY down to an 8x9 pixel image of 256 grayscale levels. Then scan each row. If the pixel to the right is brighter than the one before, write a ‘1’. If the next pixel is the same or darker, write a ‘0’, scan the entire row and then the other rows. This will result in an 8 byte ‘hash’ of the image. Other images that that look similar might have fairly similar patterns of brighter/dimmer pixels when scaled down so tiny. If you XOR your image hash against the other image hash, the only bits left will be the differences. If the number of difference bits are few, the images are probably similar. Two totally unrelated images would tend to differ by about 32 bits. But images that differed by 6 bits probably look similar,. There are FAR better perceptual hashes than the one I described.",
"The search engine indexes loads of photos and keeps a note of the relative location of some (or all?) of the pixels. When you search with an image, the search engine looks at the relative location of the pixels in your image and compares that to its database of images and presents pictures that match."
],
"score": [
9,
7
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
llakxf
|
Most insects don’t have pupils. So how do they see if it’s too bright or too dark outside?
|
Are they just rendered blind for the majority of the day and night and have other senses make up for it? Do their compound eyes have a different light filtration mechanism? I tried googling and only found really complex and long research papers.
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gnqpfkp"
],
"text": [
"There are actually different kinds of compound eyes, so there isn't a catch all answer. Some limit the amount of light that reaches the photo receptors with special lenses, or have pigment layers that absorb light like the human iris, so they in a sense *do* have pupils. Or, well... \"pupils\", but the pigment moves to constrict the entrance of light photons. At any rate, like us, there are mechanisms that can react to reduce or limit excessive amounts of light from reaching their retina. Can't tell you how effectively they can."
],
"score": [
3
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
llasxz
|
Why do medical tests happen on rats before they happen on humans? What biological link do we have to rats?
|
Question is in the title
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gnodar7",
"gnodr1l"
],
"text": [
"We are mammals , just like rats, and by and large have very similar physiology and anatomy. Rats however are fast breeders, easy to raise, mostly diurnal, not dangerous to handle etc so that makes them good lab candidats.",
"It's not exactly a \"biological link\" rather rodents are an animal that breeds quickly and is easy/cheap to feed. So they make excellent initial test subjects. As mammals they share most of the organs that humans have so it can be a decent way to test things. Using primates like chimps would provide us with a closer comparison, but chimps are an expensive animal to keep. Especially if the thing you're testing may or may not kill the subject. All that is ignoring the simple revulsion people have to animal testing on primates moreso than rodents."
],
"score": [
10,
4
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
llb02o
|
Why are mosquitoes and other small insects seemingly unaffected by wind currents from things such as fans etc.?
|
I'm being bled dry, I need to know
|
Other
|
explainlikeimfive
|
{
"a_id": [
"gnoid8b",
"gnolk6t",
"gnotmnx"
],
"text": [
"They very much are. But compared to the average speed of airstreams we normally encounter, like ceiling fans or heating vents, they can fly quite a bit faster than that so they just do their own thing, albeit a little slower in one direction than another. If they get right into the core of a fast airstream, like a desk fan or hair dryer, they'll get blown around, but those high speed air jets dissipate pretty quickly. If you get them outside in the wind, they're screwed. They have to seek calm air...that usually means behind things or close to the ground.",
"They are effected by fans, infact in high mosquitoe areas alot of people will just put oscillating fans on their porches to blow them all back until they give up.",
"As other posters pointed out, small, airborne insects are impacted by breezes, fans, etc. However, people can’t really identify the patterns of the insects trying to compensate for counter-drafts . (This is as five-year old without going into physics and insect biology/physiology"
],
"score": [
60,
19,
3
],
"text_urls": [
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
llc57b
|
How do researchers test survey particpants for their awareness on a certain subject?
|
If researchers try to do this, wouldn't they always get skewed data because they change the level of awareness of their participants as soon as they start the survey? Is this just an accepted fact when trying to test for awareness or is there some method where they can get unbiased responses?
|
Other
|
explainlikeimfive
|
{
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"text": [
"By making the survey questions open ended without mentioning the thing you actually want the data on. So if I wanted, say, to know the awareness level of a given product, I would ask a question related to like products and then see if the product I want data on is mentioned by the respondent. This helps me gauge the level of awareness the test group has on the subject I'm testing without letting them know it is this subject I want data on."
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7
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[
"url"
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[
"url"
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llck48
|
Why are medical bills in the US so high?
|
Other
|
explainlikeimfive
|
{
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"gnoomga"
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"text": [
"There is still a pretty large gap between \"can afford the cost of health insurance and a few thousand in unexpected expenses\" and \"makes enough that government subsidies for health insurance can make it barely affordable even if not used\"",
"there are a lot of factors. medicare doesn't pay the full bill, people without insurance not paying their bills, malpractice insurance is extremely expensive, the degree to become a doctor is expensive, medicine prices, etc. yes, obamacare was SUPPOSED to lower the cost, but it had the opposite effect. when a law states that citizens must purchase a product, the price of that product always goes up. regardless of what it is. don't even get into what was actually in that bill.",
"Even with insurance, they can deny payment because you went to the wrong hospital. Or because they don't think you *needed* the procedure. Or because they don't generally cover the procedure. Or they'll make you pay the difference if the doctor charges $500 but they only think it should be $250. Or they can stop paying if your bills for a calendar year are too high. Edit: insurance here is so dumb that my medical insurer has an insurance policy to bail them out if my claims go over $250k in a year."
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4,
3
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|
[
"url"
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[
"url"
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|
llct6f
|
How does binary trigger current in hardware?
|
I’m not very technical so apologies if I use terms interchangeably that don’t make sense but I will try to explain. What I understand and put very basic is: we write code, it then gets “converted” so that the computer understands it. This is represented by 1’s and 0’s that trigger current in the hardware that gets stored in memory, lights a LED, etc. through (I think it’s called) logic gates. That’s my ELI5 way of understanding it. What I don’t understand is how the current is triggered? What causes that interaction? For example, when I click save in a document. How does that trigger it to be saved in the hardware. Is it that, when I physically click on my mouse. That physical interaction of clicking sends a current and the computer recognises that the proportion of the pixels on the screen represents saving the document, which then triggers it to send that current to the logic gates? Edit: Thank you for all your answers.
|
Technology
|
explainlikeimfive
|
{
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"text": [
"Is it your hand which grasps, or is it your fingers doing all the work? Is is software which puts those icons on your screen, or is it currents? The thing to understand about the computer is that it's *all* just electrical currents. All the logical, visual stuff you see represented on the screen and in the computer's abstractions ilke \"icon\" and \"desktop\", all of those things are just different arrangements of currents flowing through that big array of logic gates. So to ask how clicking the icon 'triggers' a current, well, it's just currents triggering other currents. That's really what a logic gate is, is a voltage trigger. There are various logic gates such as \"and\" gates and \"or\" gates, and their job is to trigger in a certain if-then scenario. It performs a rule like \"If input voltage A is high *or* input voltage B is high, *then* set output voltage C to high.\" The job of a CPU maker, is to wire these gates up to each other in ways so that physical if-then scenarios concerning the voltages on the wires between them, will map cleanly onto *logical* if-then scenarios that are useful for computation, such as the 'carry rule' for binary addition: \"if both addends have a 1, then carry a 1 over to the next digit.\" The software in the computer can be looked at in two different ways. Looked at in one way, the meaning of a particular software instruction could be: Store the value \"hello\" in a string starting at memory location 15. But looked at in another way, the meaning of that instruction is: \"Set the following voltages on the RAM data bus: high low low high high [...] high high\". It's kind of like the difference between saying \"write 'hello' on this piece of paper\" and \"deposit ink on the paper in the following shapes.\" The same physical thing is going on, but you're describing it at a different level of meaning. That's the difference between \"saving a file\" and \"triggering currents.\""
],
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6
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|
[
"url"
] |
[
"url"
] |
lldyam
|
Why do small animals like squirrels not lose appendages to frostbite when temperatures reach below freezing, and they walk around on ice and snow all day?
|
Biology
|
explainlikeimfive
|
{
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"I think most people's answers here are wrong. The main reason four-legged creatures can walk without shoes in freezing temperatures, in general, is that they have different vasculature in their feet than we do. Their feet get more blood flow to stay warm, and their fur keeps their blood warm enough to keep their feet warm. They also have thicker skin on their feet which protects the deeper \"alive\" layers of skin from frostbite. Someone else would have to tell me the answer to this, but I would bet that people that don't wear shoes have at least somewhat better resistance to frostbite than those who don't due to skin thickness and the increased vasculature in their feet from using them more. I know there are some people of Scandinavian descent that have a gene variant that allows them more resistance to coldness in their hands due to increased vasculature, which causes your hands to cripple when exposed for too long in you and me. It's a survival adaptation.",
"Bird legs work like the kidney’s Loop of **Henle** Basically, warm blood going down into the foot is right next to the blood going up. The body stays warm but the foot is nearly frozen. The heat goes from one side to the other. Near the top of the loop, warm blood from the body loses heat to colder blood coming back from the foot. Here are a couple of pictures. URL_1 URL_0 (Kidney: loop of Henle) Edited: thanks to folks below who corrected my spelling and apologies to Mr. Friedrich Gustav Jakob Henle It’s HENLE not HENLEY.",
"Essentially, it’s because they have fur that we do not. In the case of a fox, they have a thick layer of fur that grows in to trap their body heat. Other animals such as whales or walruses, have a thick layer of fat to keep them insulated. To add, frostbite does not directly affect the skin, it affects the internal body temperature. Frostbite is caused when a layer of the body reaches a temperature low enough to freeze a deeper layer of skin. Because humans do not have a thick fur, our skin is exposed much more to the cold and is more likely to freeze. However by insulating the body, fur can keep the body heat trapped, preventing freezing.",
"Studied vertebrate physiology for a year in college, the basics boiled down to this. Small furred animals have enough insulation with their fur, fat built up ready to hibernate as well as just store energy and protect them in the winter time, and better circulation due to their small size. A squirrels heart beats 300 times per minute in the winter, that’s roughly triple a normal persons. Rodents such as squirrels, rabbits, raccoons, etc. eat extra food and build up fat during the winter, whether you can visually tell or not is irrelevant. You try to tell people’s body shapes from how and what they were outside right now and you’d probably be wrong. TLDR: Faster heart beats for smaller animals mean more heat is pushed around the body keeping them warm. They also have fur that thickens in the winter usually and eat extra food to have some fat that helps insulate.",
"Good explanations here as to why most animals don't lose their feet to frostbite but I should point out one thing that anyone living in a rural area will know: They can and they do. Doesn't happen as often as it could for reasons others have stated here but animals absolutely can suffer miserably in cold conditions.",
"Evolution. We are adapted to living in the hot grasslands of Africa. That's why we suck at living in the cold. If you grabbed another animal from that same area and made it wander around Alaska in December it would soon die. First, animals in cold areas have fur adaptations, both long guard hairs and small 'fluffy' hairs You can find these between the toes of may animals that have developed their winter coats. Second - animals have different levels of bloodflow in their furthest extremities. Birds have very little bloodflow through their feet, meaning when exposed to cold they aren't as impacted as other animals (although they will still stand on one foot holding the other close to their bodies to conserve heat...and cold weather birds have feathers on their feet for warmth). Just like low bloodflow, some animals address it with high levels of bloodflow. Third, there are other adaptions like 'pads' on paws. Think about a dog's foot. Those pads are composed of keratin (the same substance that makes up hair ,fingernails, and horns) collagen, and a special fat. Think about the thickest most calloused hands you've ever seen. Do you think that they could a hot plate a second longer than normal before the heat soaked through? The pads on a dog's feet are much thicker than that, plus with fat and collegen mixed in. This works good for cold surfaces, hot surfaces, rough surfaces, etc. Fourth, when it gets REALLY cold, animals seek shelter, frequently curling up in a ball to protect those extremities.",
"Countercurrent heat exchange ***does not*** prevent frostbite. If anything it reduces peripheral limb temperature as well as promote vasoconstriction. It does however preserve core body heat, reducing the risk of hypothermia. PS it's the same stuff that keeps yer balls cool. [ URL_0 ]( URL_1 )",
"Because of the metabolic ability, like the bird's bare feet on ice, to thermoregulate their blood flows (think different ratio than us of volume/size of the arteries carrying blood into the legs) and heat exchange vascular system (think counter current heat exchange system) to achieve homeostasis (the condition of optimal functioning of the body). In short, this heat exchange system allows for the tissues in the feet to receive just enough heat to prevent cell death, and can greatly reduce heat loss, up to 90% depending of the species. It really is a marvel of adaptation.",
"I'm curious as to their gait on ice. I know squirrels have claws, and since they are light enough, they could confirmably walk on them, like horses, who basically walk on their big toes, with nails providing the actual contact with the ground, without direct blood flow to the area contacting the Ice. If that were the case, then everything else everyone is saying ( increased metabolism, subcutaneous fat insulation of critical systems, etc) would make sense, but without some actual physical minimization of cold surface contact, it would be laughable to say that these method alone are successful. For example, I have personally seen birds feet get frozen to their perch, but they do not die from these inquiries alone, rather from infections or deficiencies arising from this condition. A bird I rescued from this situation had this outcome exactly. So my guess is that there were non vascular evolutionary responses to this situation that create some, even minimal, space between the frozen surface and a vascularized dermal contact. Eli5: nature creates ways for creatures to not physically directly touch surfaces that would be harmful to them.",
"Artic foxes have a pair of vessels (a vein and an artery) that don't branch at all until they get to the foot bads. This allows for counter current heat exchange warming blood coming up and cooling blood going down. This allows their paw pads to stay at 1-3° above the tissue freezing point for hours walking around on ice."
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"https://en.m.wikipedia.org/wiki/Countercurrent_exchange"
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[],
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"https://en.wikipedia.org/wiki/Countercurrent\\_exchange#Countercurrent\\_exchange\\_of\\_heat\\_in\\_organisms",
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|
[
"url"
] |
[
"url"
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|
lle9x4
|
In scuba, why does the diver's air get more compressed with depth? Does the tank not protect the air from outside forces?
|
Physics
|
explainlikeimfive
|
{
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"text": [
"The air in the tank doesn't get more compressed, it's unaffected unless maybe your corpse falls down the Marian's trench. The regulator drops the air pressure from that in the tank to match ambient for you to breathe. If you're above water, it lets out normal atmosphere pressure air. If you're 10m under water where water pressure is two atmospheres, it lets out air at two atmospheres to breathe. Why does it do this? So you're lungs and chest don't collapse. If you were still breathing in surface one atmosphere pressure air but had two atmosphere pressure water on the outside of your chest, it would be like trying to breathe with someone sitting on your chest.",
"The air in the tank is already pressurized (compressed). The diver breathes through a regulator that lowers the tank air to the same pressure as the \"outside forces\". That is why a tank of air will get used up faster the deeper the diver goes.",
"The pressure inside a SCUBA tank is much greater than the outside water pressure - even when a couple hundred feet deep. The air coming from the SCUBA tank is always moving from high pressure to lower pressure, it does not \"get more compressed\" with depth. It just does not drop in pressure as much as it would if you were breathing at the surface. The air inside the tank can be over 3,000 psi. The first stage of the regulator (the part that clamps onto the tank) reduces the tank pressure to about 150 psi. That is 150 psi above ambient pressure. The deeper you go the higher the absolute pressure, but the first stage always provides 150 psi above whatever pressure you are in. \\*150 psi is an example from memory, the exact values may be different. That means that there is always 150 psi of air in the hose that connects to the second stage (the part that goes in your mouth). When you are at depth the ambient pressure is greater. When you breathe in air from the 2nd stage regulator at 33 feet depth, the air in your lungs is almost 30 psi (absolute pressure) or about 15 psi greater than when at the surface. For every 33 feet of depth the pressure increases by about 15 psi. At some point, when the tank is nearly out of air, the first stage will no longer supply the 150 psi of pressure - because the tank itself is less than 150 psi. You might find that you have to \"suck\" the air out of the regulator. Of course if you are doing this then you have failed to be a good diver. Source: I'm a PADI Divemaster and I used to service and repair SCUBA equipment.",
"The tanks do not get compressed when you dive If you look at [Diving\\_cylinder]( URL_0 ) a bar approximately an atmosphere and the pressure increase by 1 bar per 10 meters of depth. So the low-pressure take will have higher pressure on the inside down to 1650meters depth. The tanks will not be compressed to any significant degree for the depth you dive at * low pressure (2400 to 2640 psi — 165 to 182 bar) * standard (3000 psi — 207 bar) * high pressure (3300 to 3500 psi — 227 to 241 bar). You breathe in the air at higher pressure at lower depth because you like to have the pressure in the lungs the same as the pressure of the water so there is not net compression on your lungs and ribcage. It would be had/impossible to breathe anything in if the pressure is a lot slower than the water pressure because you need to push against the water to expand the lungs and get air in."
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|
[
"url"
] |
[
"url"
] |
|
llfjl2
|
Why do unhealthy foods taste so much better than healthy foods?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gnp6nzn"
],
"text": [
"Unhealthy foods are typically calorie-dense. Millions of years of evolution have developed organisms that are used to having a high risk of dying from lack of access to sufficient food. Traits that encourage organisms to eat as much calorie-dense food as they can when they have access to it have been beneficial for survival. One of those traits are feel-good chemicals in your brain that encourage you to keep doing the thing you're doing. Now, most humans in first world countries have access to way more food than they need and a wide assortment of food. Maybe it was beneficial to your ancestors to stuff their faces full of fatty/sugary foods, however now that we have access to a ton of that food it's become more of a problem than a help."
],
"score": [
9
],
"text_urls": [
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|
[
"url"
] |
[
"url"
] |
|
llflqw
|
Why do lips get thinner as we age?
|
I can understand why skin sags and gets wrinkles but eli5 why/how do people’s lips get thinner and thinner as they get older?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gnp79z6"
],
"text": [
"Lips are mostly collagen and estalin. Our body produces less of these as we age (which leads to sagging skin in general), so our lips start to appear thinner. There isn't much you can do about it, it's just one of those things that happen as we age. Edit: I should say that collagen and estalin are what make our lips appear plump and full."
],
"score": [
10
],
"text_urls": [
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|
[
"url"
] |
[
"url"
] |
llfnd6
|
What is delta 8
|
What is delta8? What is the is the difference between delta8 and delta9? Is it safe? and what makes delta8 legal and delta9 cannabis illegal?
|
Chemistry
|
explainlikeimfive
|
{
"a_id": [
"gnpbeea"
],
"text": [
"The 2018 Farm Bill defined marijuana as \"cannabis that contains more than .3% of THC-9\" and hemp as cannabis that contained less than that. At the time that the Farm Bill was passed it was believed that THC was one compound (THC-9). As it turns out it is scientifically possible to characterize two different forms of THC. Those are THC-8 and THC-9. THC-8 and THC-9 are essentially identical to one another, both chemically and in function. For all practical purposes they are the same chemical. At the time that the Farm Bill was written nobody knew about THC-8 so they just used the formal, scientific name for THC, which at the time was THC-9. However, because the Farm Bill defined marijuana on the basis of THC-9 content, some people have been making an argument that cannabis that contains high levels of THC-8 and < .3% of THC-9 wouldn't be considered marijuana and so would be considered hemp at the Federal level. This is a fairly academic argument because: 1) There isn't a strain of cannabis that would be legal under this definition and it would take some time to produce one that would be. 2) Even if there was a strain of cannabis that met this definition, both CBD and THC-8 are still illegal to sell in consumer products. 3) The Farm Bill didn't affect anything in the Federal Analogue Act and so THC-8 is likely still illegal as a THC-9 analogue anyway. That doesn't mean people aren't selling it as a \"legal alternative\" to marijuana. But people do that with a large number of other substances that are illegal under the Analogue Act as well. The Federal government doesn't *generally* prosecute marijuana related crimes in states where it is legal, and marijuana prosecutions in states where it is not legal are also quite rare. That's why people are \"allowed\" to sell it - its not legal there just isn't much enforcement on it. As to how THC-8 is being produced from hemp - its possible to convert CBD to THC-8, which is also clearly illegal to do at the Federal level."
],
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13
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|
[
"url"
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[
"url"
] |
llfsxj
|
What has actually happened to the power grid in Texas and how does green vs. fossil-fuel energy factor in?
|
Technology
|
explainlikeimfive
|
{
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],
"text": [
"Mainly they have had to shut down power production because the facilities weren't designed to handle the cold weather. They use water to produce power in most places, and the water froze. And fossil vs green didn't factor in. 23% of their power comes from wind normally, and it all froze up because it also wasn't prepared for cold weather. All in all about half of their power production is off line. And since their grid is isolated from the rest of the country, nobody can help them.",
"A lot of things have actually happened to the Texas grid, going from how buildings are made to how power is transmitted and generated there. In Texas, the time of year when the most power needs to be generated at any given time is the summer. It's when it gets VERY hot and folks have to run their air conditioning for extended periods. So, because of the climate in Texas, most buildings aren't really shielded from the cold weather. This means that even though people may have heat in their homes, they might also be \"leaking\" a lot of that energy. Think of drafty windows, lightweight materials, etc.Second, because the winter is \"slow season\" for power generation over there, power plants may have been under routine maintenance or not have enough fuel stocked/purchased ahead of time. Finally, because this cold snap is so rare (and extreme), a lot of the power infrastructure has not been shielded from that kind of weather. Think of pipes bursting because the liquid inside is freezing, and even ice on power lines. Green vs fossil fuel power is not a super important factor, really. In fact, of the power generation that's \"out\", about a third is wind, and the rest is coal and gas. Meaning that most of the power generation that's current;y disrupted is not wind. More importantly, the issue is that temperatures are much colder than expected, and the operators of the electric grid did not prepare sufficiently. & #x200B; This article from USA Today is pretty good and cites local scientists: [ URL_0 ]( URL_0 )"
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]
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|
[
"url"
] |
[
"url"
] |
|
llfv3z
|
What does the code that makes up programming languages look like?
|
Take a language like Java. How was it originally created? I can’t wrap my head around how someone invented a computer language to run without having some “prior” language that it allows the first lines to function. Is it just Java all the way down, like someone wrote a single line of Java and then every other line was built on that? What about the first computer language? What was the basis that that functioned on? Thanks for any help, I hope that was phrased in a mildly intelligible way. Edit; I’m trying to think of it like human language: at some point there was a first “word” spoken by someone and understood by another and from there the structure started to be born. What were the first “words” on a computer that led to where we are now?
|
Technology
|
explainlikeimfive
|
{
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"text": [
"There are many different \"levels,\" to programming. (Warning, lots of words, but pretty simple) The lowest level of programming is transistors. We can build up simple logic gates such as AND and OR directly in the circuitry, and by turning certain switches on and off, we can get out certain behavior such as switching between different components, storing information, or doing simple math. These on and off switches can be represented as 1s and 0s or \"binary.\" **01010101 01001111 01101011** \\- > Would give the instruction \"store number 79 in memory slot 107.\" The first block (or \"byte\") would be the \"store,\" instruction, followed by the binary number for \"79,\" and finally the binary number for \"107.\" (the actual binary would differ depending on CPU architecture, so this is just pretend). Writing complex programs in nothing but 1s and 0s would be a nightmare, so instead we wrote just enough 1s and 0s to build a program that translates a more readable language called \"assembly,\" directly into the 1s and 0s we need. So instead of binary, we now write: **mov 79, 107**\\- > When run through our new assembler program, gets directly translated to the binary 1s and 0s from the first example. It basically just looks up what \"mov,\" translates to in a large dictionary and swaps it out for the needed binary. Basically just simple cut and paste. An assembler is a *very* simple program, but allows us to start thinking closer to human language, and thus allows us to develop more complex software. From there we can write a \"compiler,\" which is a program that can read over a text file in whatever language we want to come up with and translate that into the binary we need. **int myVariable = 79;** \\- > This gets read over by our compiler and translated into binary to be executed. This is how languages like C, C++ work. From there it's a self contained loop. A compiled language can be used to write new/better compilers, which in turn can be used to write new/better compilers, etc. Languages like Java and C# are one level above this. They aren't compiled into binary, but instead into \"bytecode,\" which is like binary but instead of being run by the CPU, it's run using either the Java Virtual Machine or .NET framework which are programs on the users machine designed to read this special bytecode. This allows the individual software developer (like you or I) to write a Java/C# program once, and it will work on any computer system someone has programmed a virtual machine for (most likely programmed in C or C++) which is designed to read these instructions. Finally we have \"Interpreted,\" languages like Python and Javascript which are the highest level. With these languages the actual text the programmer typed is what is sent to the end user, and the actual conversion to binary happens as each line is run on the users machine. This is why you can press \"F12,\" right now and see all of Reddit's code, since HTML5/Javascript is interpreted.",
"Java is actually run by a \"virtual machine\" entirely written in C++. So it's a pretty bad example. But C++ is being compiled by compilers entirely written in C++. How do you compile such compiler? Well, with an older C++ compiler! But, but, what about the first compiler? It was written in assembly, a long time ago. Although people like to bootstrap C++ from time to time, aka. start from scratch with a smaller language, easier to compile. But that's just for the kicks of it. By the way, did you know we need a mill to make a mill? Lots of stuff in the world is built on previously built stuff, it's kind of a fun chicken and egg problem. Almost all of them, originally started from painstaking manual work. Edit: It's even more fun when you realize C++ compilers have bugs, yet produce newer C++ compilers with less (hopefully) bugs.",
"The very first \"words\" on a computer were some poor, patient soul litterally plucking in every 1 and 0 by hand. They'd do this by baking it straight into the circuitry rather than programming it with a keyboard, because, well, how would a keyboard even work if programming doesn't exist? People still do this all the time, by the way. A common tool that lets you experiment rapidly is called a \"breadboard\", which lets you plug and unplug wires and simple chips to create complex circuits. After the first literal hard-coded computers were in place, they were extended to be more modular and accept arbitrary input from users via input peripherals, that could then be run as new code. Everything snowballed from there.",
"Many prior languages existed and some were similar to Java or c++. I am a retired mainframe assembly language developer, I did that in the 80-90s. Assembly was the first mainframe language, it's a step above the machine code executed by the chip. Assembly language is what many mainframe languages compiler generates as it's native to the chipset. Assembly is crude and rude, you better know WTF you're doing or bad things happen. Sometimes you can have to read and understand the machine code to debug your code. Principles of Operation is the reference manual for the language. ETA: One of our programs for class was to be written in machine code to demonstrate our knowledge of the language.",
"It's easy to build up a small sand castle with just a single small bucket, and this is like binary. If you want to build something amazing, though, you'll need to have more tools to make the job doable. You can technically use binary to create whatever you like, although it is much easier to program simple programs which encompass basic tasks like adding or subtracting. Then, using this new program as a 'frame' for a new program, you can layer on complexity (or remove complexity, depends how you look at it) for accomplishing more complex tasks. This is the difference between coding \"bare metal\" and using a high-level language like Java. There was a first word, but instead of thinking of it as a baby learning English, think of it as how humanity learned to communicate - we're talking ancient runic text instead of \"mom\" or \"dad\". Compared to programming, English itself is like a high-level language.",
"Don't think of it as a language, think of it as the evolution of a tool and its uses. Digging, for example. Originally, to dig one would use sharp objects. Eventually, the spade was invented, along with various sizes to accommodate different tasks. Larger tools for digging were invented until machinery allowed for even larger digging equipment and thus more tasks could be accomplished with this greater digging power. In the same way, programming started as soldering circuit boards, eventually moved to punch-cards and and tape reels. Then, with the advent of monitors and keyboards, people could do things like data entry and complex calculations and it just kept going from there.",
"ELI5 answer: It look very, very simple. The code that makes up programming languages itself is very simple. The language can then be quite complexe. Java is one of the worst example you could pick, because it is an interpreted language (this means than it relies on another programm, the interpreter, to run). But the codes that build it is simple. It starts with basic instructions: I want to add data. Instruction: add I want to store my result: store You might want to creat type: a byte might be an integer, or a character. Then, you need to repeat the same instructions in your language. You start to put a label at the start of your instruction: label my_little_routine Then you say that you want to go to your label again: goto my_little routine Then you say that this set of instruction should be used everywhere, so you create a function. This is a mechanism where you store your current data somwhere, then go to your label, then extract your data back from storage once you finish. You can use a compiler of compiler to create an advanced programming language out ofthese basic operations: [YACC]( URL_1 ) is one of them Modern languages implement natively many high level mechanism called design pattern, which is why you are confused: templates in C++, interfaces in java, iterators in python... These design pattern are common solution to frequent problems. So we grow programming language, from simple, obvious instruction, to a complexe toolbox. [Bonus track]( URL_0 )",
"The first general purpose computers were one-off machines. Their language were the lowest level opcodes, the binary bits that were used to drive what circuit paths the data inputs were going to undergo. There's an opcode to add two values, to multiply, to load from a location, to store to a location, etc... With that, programs were very simple and it was easy to think of programs in terms of CPU instructions alone. These programs were written in terms of punch cards or punch tape. The devices to do this had already existed due to the telegraph system. Indeed, Linux is directly compatible with telegraph teletype machines from the 1910s, you can see some guys on YouTube login to a Linux terminal on one. Of course, that doesn't scale. Eventually, especially by the later 1950s, computers already got large and powerful enough, not that programs HAD to get more sophisticated, but that they COULD. Then it became more valuable to manage the complexity by raising the level of abstraction from raw machine instructions to the first programming languages. They existed in private before 1955, but that was the year the first commercial languages debuted. I can't remember which came first, Lisp or FORTRAN. Both are still used today, and both represent nearly polar opposites of how to approach computation. FORTRAN is an abstraction of hardware, and Lisp is an abstraction of *a* calculus notation that can express computation, called Lambda Calculus. The first compilers and interpreters were written on punch cards or punch tape in machine instructions. Once the compiler was loaded, source code in that language was text encoded in punch cards. Again, this sort of thing already existed in the telegraph industry. ASCII encoding was developed for telegraph, and so ASCII and even unicode are both backward compatible with late telegraph development, hence why those early telegraph devices still work with modern computers. If you had a nice punch card key, it would even type, as a typewriter, the corresponding character on the card in ribbon ink. Each card would be a line of code, and you would try to cram as much code into a single card as possible. Verbosity was your friend when you had to keep thousands of cards in order. So instead of nice variables today, like \"velocity\", you would just use \"v\". It's a habit we haven't needed to have since the 80s and we've been trying to shed it as an industry since. Well, you get yourself a shiny new mainframe, and when you turn the hulk on, New York dims. Ok, how do you write programs for the damn thing? Well, you already have that other mainframe over there, with compilers and programs... Use IT to \"transcode\", to \"cross-compile\" a program for that new machine. Programs are just a form of data, and compilers merely interpret source code into *a* machine code, it doesn't have to be for the machine the compiler is currently running on, it just means the program that's output won't run on *this* machine. Ok, so then take your paper tape from that machine, bring it over to the new one, and feed it in. Bingo bango, you just compiled your compiler from source code to machine instructions for the new architecture. Now you can reuse all your source code from the other computers. Oh, you have a new magnetic storage device? Cool, skip the punch cards and store your data on that. Now you can just copy floppies and sell them. This whole process was repeated from scratch many times, because often enough it was easy enough to do in the early days. When the micro-computer was invented and people had their first Commodore 64s and ZX Spectrums, they even had interpreter firmware built into them. You could just boot them up with nothing and go straight into writing code, typically a form of BASIC or Forth. --- Java is a language that is compiled into a universal byte code. These are machine level instructions, but for no machine that actually exists. The machine is virtual, a fiction that exists as a spec document. Java compilers conform to that spec. When you run a Java program, the instructions are first interpreted, so the program can start running all the sooner. Meanwhile, the byte code gets compiled again (Just In Time(tm), aka JIT) into the actual hardware native instructions. The next time that code is executed, it switches over to the machine native form. The first Java byte code compiler and interpreter, because it didn't start out with a JIT, was itself written in Lisp.",
"The CPU only talks in numbers. Every number is an instruction. You have to know the \"codebook\" of what number, in what order, does what. Instruction 43 might be \"multiply these two numbers\", for instance. So 43 2 3 gives an answer 6. That number is literally represented in binary on the CPU's input pins when you want it to do something. You set those pins, they correspond to the binary for 43, and the CPU knows what to do next. But that codebook is a pain to program in. Ask the Apollo astronauts who had to calculate their trajectories, etc. by setting \"Verb 23, Noun 15\" on their computer system to get it to do, say, a basic multiplication instruction. That's all they had to communicate. Numbers. That's \"machine code\". But those numbers were assigned those tasks by the human CPU designer. So somewhere there's a codebook that tells you that 43 is multiply, for instance. So... why not let the human just use a shorthand. Say, \"MUL\". And computers are designed to do all the boring legwork, that's their entire purpose, so why not get the computer to take the text \"MUL\" and output \"43\"? Congratulations, you just made an assembler. A program that takes the text instructions and converts them to machine code. The first one would have been written in \"machine code\" by someone. Tricky, but you only had to write the assembler and then everything got easier. You obviously don't sit and write all your programs in machine code once you have a working assembler. But even \"assembly language\" (the codebook language that has \"MUL\") is a bit tricky to program in. So you make the computer do the work again. Using assembly language, you make a program that takes more complex text, and converts it into assembly language for you. So it might take something like \"A = B \\* C\". And it works out that it has to get B and C from memory, run the MUL instruction on them, and put the result into some part of memory called A. That program that does that might be called a compiler. There is a programming language called C. Generally this is the first compiler that anyone writes for a new type of computer, because it's relatively easy to write a C compiler in assembly language, and relatively easy for a human to write a program in C. That C compiler takes your C code (which looks a lot like Java) and converts it to simply assembler or machine code. Now that you have a C compiler you find that you can compile most things! Parts of Java itself are written in C. So when you have an entirely new type of machine, someone (who knows the \"codebook\" well) writes an assembler for it. The next (or even the same!) person then finds or makes a C compiler that itself can be written in assembler (there are lots of them already, but sometimes we have to make new ones!). Then the person after that? They have a C compiler and a whole raft of operating systems, kernels, programming languages applications, etc. that are already written in C. Notice, though, that all it took was two programs - some way to get assembly language into the computer, and then some way to convert C code down to assembler. Those are probably the most difficult types of programs to write, and sometimes you have to write parts of them from scratch (e.g. if a chip has never been seen before and is different to everything that existed before), but the assembler you can literally write by hand, and the C compiler is just a case of tweaking an existing C compiler. And only those two programs are needed (a slight exaggeration, but once you have them, everything else can be compiled from C!) to get everything else working. Computers in the old days (e.g. Apollo missions, and home computers right into the 80's) used machine code only and often had machine code tutorials in their \"starter manuals\". One of the programs they often got you to write was an assembler! And then C and other languages came later. Nowadays nobody bothers because it's all done for you, but still someone, somewhere, sometimes has to write an assembler (or modify an existing one to work on a new chip) or a compiler. It's like having to learn the alphabet, then learning how to form that into words, then words into sentences, then sentences into paragraphs, then paragraphs into chapters, and so on. It all starts at the bottom. And I could probably teach someone who knew nothing about computers how to write a very basic program in machine code, and a basic assembler to help them, in a few days. It would take far longer to write a C compiler but you probably wouldn't need to. Even today, when starting on a new chip, the people at the chip manufacturers will do that part for you - and they often start with the machine code to write an assembler, then using that assembler to compile a \"miniature\" C compiler (e.g. tcc), then that mini-C compiler to compile a full compiler (e.g. gcc), and then give that to you in a download so that nobody ever has to do that part again and we can all just take C code and compile straight to the new chip without having to have anything to do with machine code or assembler."
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[
"url"
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[
"url"
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llgu0b
|
When food is fermented how is it ensured that the right type of fermentation occurs so that you don't make pickles when you want alcohol and vice versa?
|
Biology
|
explainlikeimfive
|
{
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"There are three different kinds of fermentation. Lactic acid fermentation is one kind, which is when sugars and starches ferment into lactic acid. This can make pickles and saurkraut and kimchi. Ethanol fermentation creates alcohols by breaking down sugars into glucose, using a process called glycolysis. Acetic fermentation creates stuff like vinegar and kombucha. This works with starchy grains and fruits. The different kinds of fermentation are caused by different kinds of yeasts, bacteria, or chemical fermenting agents. You combine those different fermenting chemicals with different kinds of organic materials to get the process you want."
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[
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[
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|
llhcg3
|
How come all vegetables didn't develop the same defense onions have (burning your eyes when you cut them)?
|
Biology
|
explainlikeimfive
|
{
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"text": [
"Evolution is a random process, so while it might be advantageous it is unlikely to randomly occur in many items.",
"In short, there was just no need. If a plant is big, being eaten isn't that much of a problem. There are also other defensive mechanisms than the chemicals that onions produce. Some plants even profit from their fruit being eaten to spread seeds with the poop of animals. Evolution is a big \"if it ain't broke, don't fix it\" game. New mutations only spread quickly if they bring a major benefit, which isn't the case for many plants. And in case a plant doesn't need it, producing something with the sole purpose of repelling enemies is just wasting energy and nutrients."
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[
"url"
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[
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|
llhjnx
|
How are electromagnetic waves and sound waves related and unique from each other?
|
Physics
|
explainlikeimfive
|
{
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"text": [
"This sounds like a homework question. Can you elaborate what made you ask?",
"A wave is just a periodic form of energy propagating out from a source. There's a bunch of different kinds of waves. Sound waves like you say, are energy moving through the air. Ocean waves are the energy moving through water, etc. Electromagnetic waves are different from most other kinds of waves in that they do not move through a \"medium\". Mediums are the things that hold the waves energy, like the air for sound waves. So to say how they are the same- they're both waves that move energy from one spot to another. And to say how they are different- electromagnetic waves have no medium, while sound has the medium of air."
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4
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[
"url"
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[
"url"
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|
llhmqw
|
How do trees survive temperatures well below freezing that would cause frostbite/cell death in animals?
|
I was curious given this week's extremely low temperatures, and how yearly, trees seem to avoid death of their cells and structures in what would be otherwise destructive temperatures. How do they do this?
|
Biology
|
explainlikeimfive
|
{
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"They cycle out water in the fall and replace it with pitch and antifreeze. This happens at a cellular level, not just in the trunk and branches. Since there’s no water in the cells that can crystallize, the cells are safe until much lower temperatures.",
"The sugars and other chemicals in the sap lowers the freezing point so they can survive. If the sap were to freeze, ice crystals would probably destroy the cell walls like they do for some vegetables in a freezer. Trees don't grow above a certain altitude where the temperature would drop too low in that location, called the \"tree line\".",
"So, a couple of things, plant cells are not like animal cells. Our cells are soft and squishy, essentially like a thin-walled water balloon. Plant cells are more firm walled, more like a juicebox. That helps to make them more resistant to freeze damage right off as the membrane is tougher. Plants can tolerate a greater range of internal conditions than we do, as well as being able to survive and recover from serious physical damage better than animals, so even when they do get freezing damage it may only kill a part of them, not the entire tree. They have some specific tricks they use, which are actually pretty much the same tricks many animal species that have 'antifreeze' use. Below is a summary of them copied from the article *[How do Trees Survive Winter Cold?]( URL_0 )* > Schaberg’s work suggests three basic ways in which living tree cells prevent freezing. One is to change their membranes during cold acclimation so that the membranes become more pliable; this allows water to migrate out of the cells and into the spaces between the cells. The relocated water exerts pressure against the cell walls, but this pressure is offset as cells shrink and occupy less space. > The second way a tree staves off freezing is to sweeten the fluids within the living cells. Come autumn, a tree converts starch to sugars, which act as something of an antifreeze. The cellular fluid within the living cells becomes concentrated with these natural sugars, which lowers the freezing point inside the cells, while the sugar-free water between the cells is allowed to freeze. Because the cell membranes are more pliable in winter, they’re squeezed but not punctured by the expanding ice crystals. > The third coping mechanism is altogether different. It involves what Schaberg describes as a “glass phase,” where the liquid cell contents become so viscous that they appear to be solid, a kind of “molecular suspended animation” that mimics the way silica remains liquid as it is supercooled into glass. This third mechanism is triggered by the progressive cellular dehydration that results from the first two mechanisms and allows the supercooled contents of the tree’s cells to avoid crystallizing. Here's [another longer multi-part article that goes into more detail]( URL_1 ).",
"As tree grows older it generates new cells from inside out from the layer we call Cambium ( thanks for clarifying u/crinnaursa ). Outer layer of cells then becomes it's bark. The nutrients (sap)flow through the walls (or layers). And each year through the seasons it forms a new layer, new padding behind the bark. Over a period of time the outer bark stops receiving the nutrients. It dies and forms the basis for a woody structure. It has dried fiber and miniscule air dots. Many such layers protects the inside of a tree. However, depending upon the size of the tree and bark thickness, a tree can get freeze and die too. In tropical landscapes, such things happen to even older trees because the fiber of the bark is not strong enough to withstand cold. Edit: updated with inputs from u/crinnaursa"
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"https://www.canr.msu.edu/news/trees_avoid_damage_from_freezing_temperatures_part_1"
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[
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[
"url"
] |
llhyvg
|
How do digital to analog conversions work?
|
Analog signals are waves, meaning they should have a near infinite amount of possible states, compared to a digital signal which can ONLY be a 1 or 0. I understand that some logic is required to properly perform a DAC, and conversely an ADC, but how does a 1 or 0 represent a real world position of a wave? A wave doesn't necessarily have to be constrained to a certain boundary, for a simple example a wave of water can go as high as the amount of water in the ocean will allow. A digital signal however can only ever be a 1 or a 0, and that 1 or 0 is delivered at a different time than the next 1 or 0. I understand that perhaps the wave is formed by a collection of say 8 bits, a 1 being say a step up, and a 0 being nothing, but wouldn't that make audio choppy and discontinuous? As the computer has to wait for the full 8 bits to arrive before outputting the analog signal? If I'm completely wrong about this please feel free to educate me my mind is confused.
|
Technology
|
explainlikeimfive
|
{
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"Let's start by analog to digital conversion. Let's imagine a speaker, that moves back and forward, and we want to digitally capture what's happening. There are two things that need to be decided beforehand: - How often will we measure the position of the speaker (we call this *sampling rate*) - How precise will the measure of the position will be (we call this *bit depth*) For CDs, the standard is 44,100 measures per second (sampling rate of 44,100 Hz), and 65,536 possible positions (a bit depth of 16, e.g. 2^16 values). Why a value as high as 44,100 measures per second? The [Nyquist-Shannon sampling theorem]( URL_0 ) says that reconstructing a _perfect_ wave is possible, with no discontinuities nor chopping, as long as the captured frequencies are half the sampling rate; in the CD case, that means sounds up to 22,050 Hz can be perfectly reconstructed (humans can't hear above 20,000 Hz, so we even have some wiggle room). The sole trade-off of analog-digital transformation is addition of some noise, caused by the non-infinite bit depth. At 16-bits, though, the level of noise is low enough to be a non-concern. So, we start recording. We store the first 16-bit value; could be `0110110010110101`, then the second, `1001011010001010`, then the next; we do this 44,100 times per second. On playback, the DAC reads 16 bits at a time, that gives position of speaker at time Tₒ; reads another 16 bits, gets position of speaker at time T₁, and so on. The DAC keeps a set of values, then applies the Nyquist-Shannon sampling theorem to recreate the analog sound wave. Without choppiness; without discontinuities. A recorded sine wave will not “look like” a staircase once digitized then converted to analog, it'll be smooth as baby skin. (Why no staircase? As the sampling rate is 44,100 Hz, the DAC _knows_ that the maximum frequency is 22,050 Hz; a “staircase-like” waveform is impossible when only using frequencies below 22,050 Hz) So your hunch is right, the DAC needs to wait for a bunch of bits before it starts outputting analog signal, but that process is *very* fast for hardware.",
"> I understand that perhaps the wave is formed by a collection of say 8 bits 8 bits can represent 256 different numbers. If we have a wave maximum and a wave minimum, we can have 256 different levels. 8 bits per \"sample,\" we can make a rough wave. [The result is something that looks like this.]( URL_0 ) We can use some other electronics to smoothen out its bumpiness but essentially that's it. > wouldn't that make audio choppy and discontinuous? As the computer has to wait for the full 8 bits to arrive before outputting the analog signal? The computer can send bits far faster than it needs to create the audio level.",
"> but wouldn't that make audio choppy and discontinuous? Nope, if you use enough bits per second of audio you can make clear audio. Think of it like the resolution of your monitor, but for audio waves, it used to be that you had pixelated (choppy) and low color range (low dynamic range for audio), but now that we can use more digital storage for both, new can have clear and near perfect audio and picture saved digitally."
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[
"url"
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[
"url"
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llj2rx
|
Why isn't it a standard practice to use metal detectors and smaller magnets on a patient before putting them in an MRI machine?
|
Especially if a patient is not lucid, wouldn't it make sense to, firstly, check with a metal detector if there is anything metal inside, then use a small magnet to see if that something would cause problems, and only then put the patient inside the MRI machine? I guess there must be a good reason not to do that routinely, right?
|
Physics
|
explainlikeimfive
|
{
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"text": [
"Almost all MRIs are of patients with known medical records. Those records should include implanted metal. Metal detectors aren't that accurate, to find a small screw or pin.",
"You'd have way better luck finding small pieces of metal by just throwing the person in a full body xray/take multiple xrays, metal shines on xrays, i should know, I have enough in me."
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3
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[
"url"
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[
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lljj9b
|
How is light considered "electromagnetic" radiation, What does it have to do with electromagnetism?
|
Physics
|
explainlikeimfive
|
{
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"text": [
"Before we knew what light was, James Clerk Maxwell was studying electricity and magnetism. He developed a series of equations describing how the two forces related, and realized that these equations could describe an oscillation in space that could travel on its own without a nearby source. It only works if you quickly change the electric field, though, and a constant field won't do this. He did the math, and discovered that all such waves would travel at a specific speed. Around this time, the speed of light was measured by someone else, and they turned out to be the same the speed. Further experimentation revealed that these waves behaves differently at different frequencies of oscillation. Higher frequencies became more like visible light, and higher still like x-rays and gamma rays.",
"light is considered EM radiation because it just simply is. EM Radiation describes any radiation with electric and magnetic fields that vary simultaneously. (heres a gif of that [ URL_0 ]( URL_0 ), its a bit easier to wrap your head around seeing it that way). Basically light waves have two components, an electric component E, and a magnetic component B. All light, both visible and invisible (like microwaves, radiowaves, UV rays, Xrays, and Gamma Rays) are made up with those same EM fields/waves, just with different Wavelengths/Frequencies.",
"Light is made out of wiggles in the electric and magnetic fields. These are the same fields that electrically and magnetically charged things interact through. An obvious example is through one of the ways we commonly create a certain kind of light: radio waves. If you have a metal antenna and you send electrons back and forth through it, the electrons are making an electric field that wiggles back and forth. Since they are moving, they also create a magnetic field that wiggles back and forth. This wiggling creates radio waves (a form of light), which are wiggles in the electric and magnetic fields.",
"It just is. We use the word “electromagnetism” to describe the phenomena of which light is a subset. Visible light, gamma radiation, radio waves...is all radiative energy transfer that causes simultaneous electric and magnetic field changes in a repeating manner."
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[
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[
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|
lljmzm
|
where does the carbonation in carbonated drinks go after we drink them?
|
Some may be burped up. But carbonated drinks don't usually cause a ton of gas. If we're not burping or farting out the carbon dioxide, where does it go? Do we absorb it?
|
Biology
|
explainlikeimfive
|
{
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"text": [
"any carbonation that makes it to your stomach is going to be burped or farted out. just like all the other gasses that your digestive tract creates on its own. it doesn't get absorbed. You have to consider that unless youre chugging a brand new opened can/bottle, not much of the carbonation is going to make it to your stomach, hell all the fizzing you feel in your mouth is air escaping right there."
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11
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[
"url"
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[
"url"
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llk99z
|
How is something “grounded” (electricity) even though it might not be touching the ground?
|
I’m thinking the connections in Bluetooth speakers for example or pickups on a guitar. In particular I know audio ports typically have a left/right and a ground wire but if this is in a portable Bluetooth speaker that you’re holding how does the ground work in this case?
|
Physics
|
explainlikeimfive
|
{
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"text": [
"Grounded simply means connected to a large enough pool of neutral atoms. Earth ground is obvious very good since there's a lot of contiguous matter to act as a pool, but in order for something to be grounded it only needs to be connected to some object that can successfully drain off excess charge buildup.",
"the ground wire will typically tie into the greater structure of the item. Even if something isnt touching the ground, the structure of it itself has a pretty decent ability at absorbing and dispersing, to an extent, electrical charge. For example, when you're jump starting a car. you attach the two positive terminals on the batteries together, and you attach the negative terminal to the \"ground\", or any bare piece of metal in the car. This is to help prevents sparks because the metal of the car itself can soak up a fair amount of electrons if it needed to."
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[
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[
"url"
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lll2l7
|
according to the EPA the average car produces 4.6 metric tons of carbon dioxide every year. How is that even possible?
|
Chemistry
|
explainlikeimfive
|
{
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],
"text": [
"Carbon dioxide is CO2 so carbon from the fuel and oxygen from the air. Carbon has a mass of 12 u and oxygen 16u so carbon dioxide is only 12/(12+2\\*16)= 27% carbon by mass. So 73% of the mass of carbon dioxide is from oxygen in the air. Gasline is made of carbon and hydrogen. Hydrogen has a mass of 1u Let's use Octane C8H18 so 8\\*12/(8\\*12+18) =84% carbon by mass. So from 1 kg of fuel, you get 1\\*0.84/0.27 3.1 kg of CO2. So 4.6 tonnes require 4600/3.1=1483 kg of gasoline. gasoline has a density of 0.8km/l so 1483/0.8= 1853 liters =489 US gallons. IF you look at US gasoline usage on [this page]( URL_0 ) the result is \"American drivers on average using 656 gallons per person.\" So the 489 gallons per car do not sound unreasonable.",
"Keep in mind the oxygen from the carbon dioxide comes from the air. I don't know if the EPA number is correct, but 4.6 metric tones (4600 kg) of carbon dioxide would only contain ~1254 kg of carbon, the rest would be the weight of the oxygen that mostly comes from the atmosphere not from the gasoline. Of course since gasoline has ethanol and other things it has a little oxygen, but still the vast majority comes from the air."
],
"score": [
14,
6
],
"text_urls": [
[
"https://www.fool.com/investing/2017/01/14/heres-how-much-gasoline-the-average-american-consu.aspx"
],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
lllnes
|
how hazel eye colour and heredity works
|
I only have a basic understanding of eye colour in the brown/blue recessive and dominant example from high school biology. My husband and I both have hazel eyes. Our daughters both have dark brown eyes much darker than either of us. How is this possible? I thought the dark brown would be dominant and so my husband or myself would need to have this dark brown gene? Meanwhile our son has blue eyes. My own parents have blue eyes and hazel. My husband's parents have blue and green eyes. Where is the dark brown coming from? Thanks!
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gnqoaif"
],
"text": [
"There are 2 eye pigments—yellow and brown. And the lack of pigment is blue. If you only have yellow pigment, then your eyes will be green as the combination of yellow and blue makes green. If you have yellow and a limited amount of brown, that makes hazel. Brown pigment or brown and yellow make brown eyes. Several different genes control eye color so you have multiple signals for brown and yellow and no color. So if you and your husband both have hazel eyes. That means you both have some combination of yellow, brown, and no pigment. These genes are transmitted separately to your baby, and the baby only gets half of them. So one baby happened to get more of the genes for brown and less or none of the genes for no color. And your other baby didn’t get any of the genes for brown or yellow eye pigment, so has blue eyes."
],
"score": [
7
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
lllsrb
|
I know what the idiom "hand to mouth" means but what does it LITERALLY mean? How did it originate?
|
Other
|
explainlikeimfive
|
{
"a_id": [
"gnq9vfg",
"gnq9yyq"
],
"text": [
"This idiom is quite old and dates all the way back to the 1500s. To understand this expression, it can be helpful to imagine the following scene. There is a very poor man who doesn’t have any money, or even any food, saved at all. He has only enough food for his immediate hunger. Every time that he needs to eat, he must go find food. This man is living a hand-to-mouth existence. Some sources say that this idiom comes from a period of famine in Britain. At that time, there was so little food that whenever people found some form of sustenance, it went straight from their hands to their mouths. They didn’t dare save it for later.",
"Like most long-standing idioms, the origin isn't definite, but it is most likely a reference to a period of famine in which people were so desperate for food that as soon as some was placed in their hand, it would be in their mouth."
],
"score": [
12,
4
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
llluvi
|
How come, when your fingers are “frozen” from being outside in the extreme cold, running hot water over them hurts like hell, while running cold water over them warms them up?
|
Chemistry
|
explainlikeimfive
|
{
"a_id": [
"gnqaibe"
],
"text": [
"Because the sensory nerves in your body do not measure temperate in absolute values. They measure them in relative values. So a nerve in you hand doesn’t go “hey this thing is exactly 20 degrees (Fahrenheit, but the concept applies for whatever measurement you want)” it can’t know that. All it can know is “hey this thing is much hotter or much colder than me”. So to your nerves. A hand that is 40 degrees being covered in 120 degree water (typical water heater temps) feels the 80 degree difference. And 80 degrees is a huge difference. That would be like putting your normal hand, ~80-90 degrees into 170 degree water. To the nerves in your hand, which react to differences in temperature. Those both feel the same and feel extremely hot and painful. Take that same 40 degree hand and put it in “cool” 60 degree water and it just feels a bit warm, like running your 80 degree normal hand under kinda hot 100 degree water. Tl:dr your nerves react to temperature differences, not necessarily the true absolute value of those temperatures."
],
"score": [
18
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
llmiwo
|
why are there cables at different speeds if they are all made of copper?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"gnqeu05",
"gnqfzf2"
],
"text": [
"When signals travel through copper they create a magnetic field that in turn and induce signals on other copper wires. The solution for this is to have the cables twist around so that both of the wires recieved the same amount of noise, this is a balanced cable. I a cat 5 cable the there is 4 pairs of wires, and they all have a different number of twists per meter, allowing fewer places where the twists will line up perfectly parallel to eachother. In cat 6 the ratios are better, and also there is a plastic seperator to stop the wires from sitting so close together. You could technically try to put higher speeds through cat 5, but cross talk would just cause the data to corrupt.",
"The “speed” of a copper cable on a short run (less than 50ft) isn’t particularly related to the speed of a signal that passes through. It’s more related to how many signals can be passed through per second without loss. If you add more individual lines in the cable or increase how many signals you send per second, then you increase the speed. But if there’s interference between the lines or if the receiving device can’t read the signals as fast as they’re being sent, then the signal you’ll receive will be garbled. In a physical example: if you’re trying to get 2000 cars from one side of a city to the other, increasing the top speed of the cars won’t help. Increasing the number of avenues and reducing the number of crashes (interferences) is the best way to do so."
],
"score": [
14,
12
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
llmvqn
|
How does exercise extend a life instead of killing it quicker?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gnqp592",
"gnqgjau"
],
"text": [
"Exercise, when taken to the extreme, would kill you. What happens when you exercise is that your body has to work extra hard to keep you alive- you breathe faster to get more oxygen into your body, your heart beats faster to get your blood where it needs to be, so basically your body is stressed trying to do what your brain is telling it while also trying to keep your brain alive and your organs working properly. But once you stop exercising, your body reacts to the additional stress by trying to get nutrients to where they need to be in order to be better prepared for that stress to occur again, because your body assumes that what happens once will likely happen again. So when you rest (and eat), your body uses the extra nutrients (and down time) to rebuild back stronger, with bigger/faster muscles (including your heart), and fixing up any scrapes/bruises (like building up calluses on your hands/feet so they're tougher the next time you grab the barbell or go for a run). Basically, exercise starts to kill you, but then you rest and your body gets itself better prepared for the next time the exercise tries to murder your body again :)",
"Among other things it can result in a lower resting heart rate. A lower resting heart rate is shown to be directly correlated to longer lifespan and better cardiovascular health."
],
"score": [
9,
6
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
llmwvl
|
How Alan Turing’s machine, the Bombe, worked to decode the German enigma-encrypted messages
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"gnqkbk4"
],
"text": [
"The main components was a bunch of rotors that were wired like those in the enigma machines. The first one was powered by a motor, and each full rotation it would advance the next one by one position. That allowed them to check all possible rotor settings of the enigma in a relatively short time. The second component was some really clever wiring that could defeat the \"Steckerbrett\" (plug board) of the enigma. [It is by far]( URL_0 ) the most complicated part of the bombe, and explanations you'll find online are often incomplete or just way too math-y to be easy to understand. But the short version is: It uses 26-wire cables connected in a clever way to check all possible combinations (many millions) of the plug board at once. The bombe was set to stop when it found a combination that could turned a part of the encrypted message into what they guessed was the correct word. When they had a hit, they could check if the combination can translate the entire message using an actual replica of an enigma machine. So finding messages that could be harvested for this kind of guesswork was a really important part of the operation - they often used weather reports, which came in nice and early and always included the word \"Wetterbericht\" at the same location."
],
"score": [
6
],
"text_urls": [
[
"https://upload.wikimedia.org/wikipedia/commons/thumb/5/55/Bletchley_Park_Bombe8.jpg/800px-Bletchley_Park_Bombe8.jpg"
]
]
}
|
[
"url"
] |
[
"url"
] |
|
llnoko
|
Why do we have nightmares?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gnqmcgx",
"gnqlm03"
],
"text": [
"Dreams and nightmares are our brain's way of preparing you for possible issues in real life. If you're stressed you have stressful dreams. Your brain tries to play through scenarios to figure out how to respond to them.",
"Neural synapses firing during REM are sporadic and unpredictable. Nightmares are most likely the result of regions of the brain with memories of things that scare you firing during the phase of sleep that you remember most dreams from. Thus nightmares."
],
"score": [
9,
6
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
llnrta
|
Why TV static is black and white?
|
I know TV static is just radio noise the TV antenna picks up with multiple sources, but why only black and white static? Why no colours even with a colour TV? Wouldn't the TV pick some noise that would give it some colour? I tried googling, but couldn't get a satisfactory answer or one that wasn't too technical. I hope you can help me!
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"gnqmwfl",
"gnqm8r8"
],
"text": [
"Tv started out as black and white. Later, color signals were added but they were added in a way to make the overall signal still compatible with black and white TVs. The color portion of the signal is controlled by a 3.5795Mhz frequency burst and the TV has to lock to this to produce a color picture. Static is random and won’t have the color burst signal in it for the TV to lock to and produce color and thus no color in the static.",
"Think the signal as a snake. The head contains the color information, then there are other information, then the tail contains information about other stuff like self correction (if any) and sounds. The snakes are coming one after another via the cable. Your tv checks each snake, analyze it and shows the information it extracted. Now for static consider scattered meatballs are coming instead of snakes."
],
"score": [
11,
3
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
llnu0p
|
How do rib fractures heal on their own?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gnqmdkk"
],
"text": [
"The most important thing for bone healing is that the two sides are in close proximity. As long as there is not a piece sticking out that will stab your lungs or spleen, the bone will heal if left alone. It wont be perfect but the purpose of the ribs is to protect organs, not look pretty."
],
"score": [
8
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
llof5u
|
why do tissues get permanently damaged by frostbite but ‘amputated’ limbs can be kept in ice to preserve them for surgery to attach them later on?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gnrylc0",
"gnqrkiw",
"gns2843"
],
"text": [
"Frostbite=cells freezing. Ice expands so cell walls are ruptured by the ice, killing the cell. It’s a movie cliché that severed limbs are kept on ice. They should be kept cold to slow down metabolic processes until reattached. But they shouldn’t be kept on ice because frostbite will damage them.",
"Frostbite \"kills\" the cells and tissue having sheer amount of cold. Amputated limbs don't usually \"die\" instantly, so they are kept in ice which is not that cold and could be reattached later.",
"I'm reasonably sure they're not meant to be in \\*direct\\* contact with ice... I had to take first aid classes (obligatory for anyone trying to get a drivers license where I live) and I believe they said freezing would damage the cells? So you're meant to like.. put another layer of something between the amputated bit and the ice"
],
"score": [
5,
3,
3
],
"text_urls": [
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
llom6s
|
why do some lightbulbs flicker on and off for a second when you turn them on?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"gnqx9bo"
],
"text": [
"Are you referring to the initial flickering and clacking of fluorescent tubes? That is because the gas inside needs to be ionized before it can glow, and ionization requires quite a bit of energy. So they build up energy slowly, then release it in a spike which ionizes some of the gas, rinse, repeat. Each of those energy spikes will cause a brief glow of the ionized gas. Only after most of the gas is ionized, the tubes' glow can be sustained with the small amount of energy supplied to them."
],
"score": [
5
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
llopbc
|
Unified Endpoint Management?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"gnqtm4f"
],
"text": [
"Basically, companies have to figure out strategies and tactics for managing all of the devices that handle their corporate data. Everything has tradeoffs. There are two main tactics - MDM and MAM - which decide whether IT owns and controls your entire mobile device or if they let you bring whatever you want and they just control the bits that are important to them. To actually implement the control requires tools that can interface these devices. This is where UAM and EMM come into play. While MDM and MAM are the tactics, UAM and EMM are the strategic systems that implement the MDM and MAM policies. UAM is designed to support MDM across multiple platforms - no longer should you require a tool for the Android phones and a tool for the iPhones and a tool for Windows 10 laptops and a tool for Linux systems, but instead there's one tool that allows control over all of those platforms. Likewise, EMM is the strategic platform goal of MAM where a single EMM platform controls and manages all of your enterprise applications and maintains security from that direction."
],
"score": [
3
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
llqomw
|
Why does high temperature feel great when you’re in the shower, but that same temperature outside makes you miserably hot?
|
Other
|
explainlikeimfive
|
{
"a_id": [
"gnr08gm"
],
"text": [
"We feel hot when our body can't get rid of the heat it produces. Non-moving air is terrible at transporting heat, so even though it's colder than your body you still risk overheating because the heat isn't transported away fast enough. (Thats why clothes keep us warm, they trap air close to you) Water on the other hand is an excellent medium for heat transport. Even better when it's moving. And in the shower you aren't completely covered in water. Large parts of your body are exposed to colder air, and evaporating water is an even better coolant than flowing water (thats why we sweat to cool down)"
],
"score": [
11
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
llsq4x
|
Why are internet cookies called cookies?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"gnr8897",
"gnr7tmd",
"gnrbltg"
],
"text": [
"Cookie comes from Magic Cookie, which comes from Fortune Cookie. The idea of a cookie with a hidden message inside.",
"URL_0 > The term \"cookie\" was coined by web-browser programmer Lou Montulli. It was derived from the term \"magic cookie\", which is a packet of data a program receives and sends back unchanged, used by Unix programmers.[6][7]",
"Me thinking that it was supposed to be like cookie crumbs that fell off which leaves a mark that works as a footprint"
],
"score": [
50,
28,
14
],
"text_urls": [
[],
[
"https://en.wikipedia.org/wiki/HTTP_cookie#Origin_of_the_name"
],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
lludwg
|
How did people in the medieval ages collected bacteria to use in fermentation or similar processes? Could they be found on plants?
|
I read recently about some processes of making food and I noticed that in a lot of "cultures" were introduced in food to ferment them or whatever, how did people in the middle ages acquire these cultures?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gnrg22h",
"gnrpmet",
"gnri5ce"
],
"text": [
"So they would mash up some ingredients like grain and leave the vet open and just wait. Drafts of air would bring spores in and the process would start. Then just hope it doesn’t poison everyone.",
"Microorganism like bacteria and yeast were not really known in medieval times. There was some awareness that you needed to do things like mix in remains from your last batch in your next for best results, but the exact reasons why were not yet known. For example a famous Bavarian law from the 1500s codified what ingredients brewers could use to make bear. The list went: \"water, barley and hops\" with no mention of yeast. People at the time understood that yeast was a thing that was involved, but did not see it as an ingredient and more of a tool like any other used in the brewing process. Similar things happened in a sorts of food production that involved some form of fermentation. The microorganism responsible were either introduced accidentally as they naturally occurred in the environment or transferred from one batch to the next over the years and generations. People back then were not stupid and could tell which practices yielded the best results. They simply had no idea why and how. They stumbled into process that we now use deliberately and while knowing what we are doing through trial and error and got some very impressive results that we still use and build on today.",
"So the history of humans and fermentation is older than even the middle ages. There is documentation of fermentation being practiced as far back as the Egyptian civilization. Long and short of it is that the bacteria and yeast that cause fermentation are found on the plants themselves. Most processes were slight modifications of spontaneous fermentation until the microbes were isolated and cultivated."
],
"score": [
7,
5,
3
],
"text_urls": [
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
llutbr
|
Why does black fabric attract hairs seemingly more than other colors?
|
Why does black fabric attract hairs more than other colors? If you let a hair fall in between to a piece of black clothes and another color it’s goes towards the black like it’s magnetically attracted
|
Other
|
explainlikeimfive
|
{
"a_id": [
"gnriszx"
],
"text": [
"It’s just that hairs are more visible on black. If you are directly observing the behavior you are describing then I suggest that the particular black fabric you are using has more static charge, but it’s to do with the fabric itself, not with its color."
],
"score": [
14
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
llv338
|
How do we know that unsolved math problems have an answer?
|
I was watching Good Will Hunting the other night, and this popped into my head. How do people know that unsolved problems have an answer? Furthermore, the professors in the movie seemed to know pretty instantly that the problem had been solved. Is that realistic? Or does it take additional years to prove that the answer was right? Finally, are most of these problems a result of a lack of effort, like how we could technically count all the sand on a beach, or does it take a genius to solve?
|
Mathematics
|
explainlikeimfive
|
{
"a_id": [
"gnrjpgn",
"gnrkeyi",
"gnrk4w1",
"gnrv4on",
"gnrtshu"
],
"text": [
"For a math problem, there may be both constructive and non-constructive proofs. A constructive proof proves that there is an answer, **and** the answer is given by the proof. A non-constructive proof is not as good, perhaps, but it simply proves that there is no answer, or it proves that there is an answer but not what that answer actually is. For example, Euclid's Theorem has a non-constructive proof that there is no \"largest prime number\". The problem \"What's the largest prime number?\" is now proven to have no possible solution.",
"We don’t! Some of these problems may not have a solution, although if you can prove they don’t have a solution that’s still a form of a solution in itself and and represents progress. The unsolved problems tend not to be a “brute force” issue of just running the numbers, they’re trying to prove a mathematical concept not solve difficult arithmetic. Some of them we think are true based on the outcomes of brute force analysis - but simply a huge number of possible combinations doesn’t ensure you’ve not missed one weird outlier that breaks the rule, and doesn’t solve the “why”.",
"If you know maths well, like really really well, you can definitely tell that an unsolved problem has been solved in a short time studying the solution. More often than not it takes some clever out of the box thinking to solve a maths problem that has been unsolved for very long. Brute force computations using computers and such is rarely used. For instance take the Riemann hypothesis, which postulates that the Riemann function has zeros only at negative integers and complex numbers with real part 1/2. Millions if not billions of calculations seem to suggest this to be the case. But you can't prove something this way because you can't test it infinite times. So in this sense, mathematicians are pretty certain there is an answer here and calculations seem to suggest that the hypothesis can be proven.",
"Lots to unpack here. First, the actual math problem in Good Will Hunting was just kinda tricky, not unsolved. Impressive for a janitor with no training to solve it. Perfectly reasonable for a student in a graph theory course. If the movie presented it as being unsolved, that was a fiction. Second, it's useful at this point to draw a distinction between difficult applied problems and difficult theoretical problems. There's an infinite number of difficult applied problems. These are problems where we know there must be a solution, there's a finite number of possibilities, and we can check a candidate to see if it solves the problem. The problem is that finite number of possible solutions is huge - way more than even a very fast computer can check in a very long period of time - and we don't have any good way to narrow down the list of possibilities or guide the search. This is indeed a \"count the sand on a beach\" type of situation. However, if someone were simply handed the solution to one of these problem, it would be easy to verify that it was indeed the solution. There's a much smaller set of (interesting) theoretical problems. These are usually trying to prove (or disprove) some conjecture. This is a very different type of problem, one where it's not clear how to proceed or what the answer might be. Solving the problem could involve inventing a whole new branch of mathematics. This also means that the answer provided can take a long time to be checked or accepted by the mathematics community. If you're curious, read about Shinichi Mochizuki's work on the abc conjecture. His claimed proof invents so much new math that even people working on the exact same problem aren't yet sure that he's right and may never be convinced.",
"> How do people know that unsolved problems have an answer? We don't. Generally the results of proofs fall in to one of very broad categories of \"This is the answer\", \"If there is an answer it has to follow these criteria (like an upper bound)\", \"There is an answer (but we do not know what it is, just that it exists)\", or \"there is no answer or it is impossible to find it\". if you have a problem you want to \"solve\" what you're doing is essentially studying the problem and trying to find everything you can about it. Any scrap of useful information is a jumping point to further information, hopefully building to finding a final solution proving the question right, wrong, or that you can not tell. > . Is that realistic? Sometimes, depends on the problem. Generally people will go over your proof and try to find mistakes. If they find them you go back to the drawing board. If you can not find any mistakes for long enough or see that you did everything correctly eventually people accept your proof as correct. Sometimes a mistake doesn't surface until years later. > are most of these problems a result of a lack of effort Some of them, but most of them are just really, really hard. We're essentially at the point where the most interesting questions we're interested in require years of work or inventing entire new branches of mathematics to get an answer."
],
"score": [
52,
20,
8,
7,
5
],
"text_urls": [
[],
[],
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
llvrbp
|
How does banking works interest-free islamic economy? How does a bank earn if there is no interest?
|
Economics
|
explainlikeimfive
|
{
"a_id": [
"gnrnhi5",
"gnrp1vx"
],
"text": [
"If everyone is being honest about it, it's just a set of technicalities. - You don't buy the car for $20,000, we buy the car and you buy it from us for $24,000 in equal $500 monthly payments over the next 4 years. - We're not giving you a loan, we're buy a piece of your business that you will buy back from us over time. - We don't give you interest on your savings account, we use your deposits to buy asset and give you a profit share. In reality, these countries all deal in interest anyway. Islamic countries issue sovereign debt all the time, and those bonds pay interest.",
"Banks charge a “profit rate”. On the face of it it’s sounds like they’re charging interest the same way as regular western banks, and as long as you service the loan the result is very similar, the difference comes if you default. First: Western loans - In western finance a loan is amortized- the interest is accrued on the outstanding principal each month. To use the mortgage as an example - at the beginning of the loan you’re mostly paying back interest. Depending on interest rates maybe a quarter of your payment goes to the actual loan, the rest is to interest. Later on towards the end the loan your payments are almost all towards the principal. If you default the bank sells your house, deducts out the outstanding loan and you get whatever is left over. The bank DGAF about selling the house for more than the outstanding loan so you might get nothing, even if you’ve been paying off the mortgage for a few years, particularly if the house has not appreciated. Islamic finance varies by country, but the gist, hopefully not over simplified, is: You take out the loan. The bank does the interest calculation at the start using the same math as the mortgage calculation, and sets up monthly payments. So far everything looks the same as a western loan. The difference is you’re not paying down principal, you’re buying back chunks of the loan, and each payment buys back an equal chunk. Say you have 100 payments and have made 20 - you have paid off 20% of the loan, where in a western loan you might have only paid off 5-10% because you’re battling interest at the beginning. The practical difference comes when things go wrong. Say you default - you and the bank then sell the house. If you’ve paid 20/100 installments and default you’re entitled to 20% of the proceeds (minus fees involved), the bank gets 80%, regardless of whether the sale covers the outstanding balance. The bank has a vested interest in selling the property for as much as they can as they get a percentage. If the house sells for less than you paid they eat some of the loss and you still recoup some of the funds. The front loading of paying down the principal combined with the default process puts a bit more risk on the lender, this tends to result in shorter repayment periods than western mortgages, and higher interest rates."
],
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128,
39
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|
[
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[
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|
llvuia
|
How do wrestlers and fighters ‘put someone to sleep’ without actually suffocating them to death?
|
Biology
|
explainlikeimfive
|
{
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"text": [
"When you do that, you're not crushing their windpipe, you are constricting one of the major blood vessels in the neck. This deprives the brain of oxygen which induces unconsciousness. Then, after the KO, you stop doing that, which let's blood back in.",
"Bjj purple belt here. When applying a blood choke ( a choke that constricts the flow of blood) the moment between applying the choke and the person fading is almost immediate, with only about 2-3 seconds for complete lack of control to set it. That said, a properly assisted recovery is just as quick, with the person recovering fully within 30 seconds ( barring the 2-3 minutes organizing your thoughts/dealing with the realization that you got choked). The recovery is quick because the blood rushing in remains oxignated and most chokes aren't fully set in; just deep enough to cause the fade and allow your sparring partner to recognize the situation and tap out. Fully set it, with no blood flow, the brain can survive an estimated 4-6 minutes before brain damage occurs. There is a humongous difference in time to consider and that said that buffer should never be abused. Always have a 3rd party available who is cpr trained to ensure safety in sparring or play.",
"By cutting off the blood supply coming through the neck to the head/brain they effectively cause the person to blackout. At this point, most people would release the pressure, and the person being choked would come back to consciousness. Held for much longer can lead to serious physical damage up to and including death."
],
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13,
10,
3
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|
[
"url"
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[
"url"
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|
llw0uj
|
How do AC to USB wall warts work?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"gnrppge"
],
"text": [
"They take the 120VAC, run it through a rectifier to make it about 180VDC. Then take the DC and switch it on and off with some transistors through a flyback transformer to transform it from somewhere around 180VDV to 5V. Bam, USB power. More complicated ones may be able to change the output voltage to allow for fast charging. Usually there will be some other misc features like short circuit detection and current limiting and similar. They can made a lot smaller that the wall warts of old because the high switching frequency 100kHz or more let's you use smaller transformers than the old ones that just let a transformer run off 60Hz."
],
"score": [
11
],
"text_urls": [
[]
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}
|
[
"url"
] |
[
"url"
] |
|
llwhwt
|
Why is it so hard for dishwashers to clean fried egg remnants from spatulas?
|
Chemistry
|
explainlikeimfive
|
{
"a_id": [
"gnrs84z"
],
"text": [
"Dishwashers will generally clean in two different ways. First rinsing with cold or luke warm water which will help get the worst bits off and get any protein based substances like eggs to come off. Then it will use hot water and soap which will dissolve any harder to clean pieces like fat and also disinfect the content somewhat. It is important that you rinse with cold water first because if you rinse with hot water then proteins will coagulate, basically the egg will get hard as it gets cooked by the hot water. The problem with fried egg that have stuck to the spatula is that you have already messed up. You have allowed the protein of the egg to get into the scratches and other concave surfaces on your spatula and then heated it so the protein coagulates essentially gluing it to the spatula. No amount of rinsing with either cold or warm water or even soap will get it off. You need to scrub it off and the dishwasher does not have any way of doing this. I would recomend a smoother spatula as this makes it harder for the egg to attach to it."
],
"score": [
9
],
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|
[
"url"
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[
"url"
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|
llwjl1
|
Why do we cringe?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gnru6nv"
],
"text": [
"The human mind is very worried about peoples perspective on them. So seeing someone do something that normal society wouldn’t except and would just make fun of puts a image in the mind of all the shame and embarrassment that particular person that’s being “cringey” is getting. So in closing, it’s basically feeling a big dose of that persons embarrassment in a short time period causing the body to get chills and tense up."
],
"score": [
15
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|
[
"url"
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[
"url"
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|
llwnty
|
Where do Hollywood movie studios get all those old classic cars that they use for movies set in the 40's and 50's?
|
Other
|
explainlikeimfive
|
{
"a_id": [
"gnrtxdp"
],
"text": [
"There are entire companies in Hollywood and abroad that maintain vast inventories of period-specific props and rent them out to production studios. Nearly everything from firearms to cars to silverware can be obtained this way. It's also not unusual for production studios to work with private collectors or enthusiast groups to borrow or use privately owned props for production that would be impractical to own outright, such as vintage aircraft that have high value and require specialized training to fly."
],
"score": [
9
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|
[
"url"
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[
"url"
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|
llwoi4
|
Converting repeating decimals into fractions
|
Mathematics
|
explainlikeimfive
|
{
"a_id": [
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"text": [
"Short answer: Put the repeating part in the numerator and the same number of 9’s in the denominator. .33333333.... = 3/9 = 1/3 .18181818... = 18/99 = 2/11 .142857142857142857... = 142857/999999 = 1/7",
"You sneak the repeating part out, by using 10s: * Let's say you're converting 3.7..., so start by saying **x = 3.7...** * If x = 3.7... then **10x = 37.7...**, right? Easy enough so far. * Now subtract: * 10x - x = 37.7... - 3.7... * 9x = 34 * Now solve for x: * x = 34/9 If there's more than 1 repeating digit, just use as many 0s in your 10x. So in the above, we used 3.7... which has a single digit (7) repeating, so we used a single 0 in our 10. If we were solving for 8.43(repeating), with two repeating digits (43), then we would use two zeroes and do 100x instead of 10x: * x = 8.43(repeating) * 100x = 843.43(repeating) * 100x - x = 843.43(repeating) - 8.43(repeating) * 99x = 835 * x = 835/99",
"I'll start with one way to convert non-repeating decimals, then we can extend that idea to deal with repeating decimals. Suppose we want to convert 0.123 to a fraction, we can start by writing x=0.123 now to get rid of the decimals, keep multiplying both sides by 10 until we get 1000x = 123 And we can see that x = 123/1000. Now let's try 0.123123123... No amount of multiplying by 10 will get rid of the decimals, but instead it can give us two equations with the same decimals: x = 0.123123123... 1000x = 123.123123123... Subtracting them now lets us get rid of the decimals: (1000x & minus; x) = 123.123123... & minus; 0.123123... 999x = 123 And we find that x = 123/999. If we have some decimals before the repeating part starts then we need to do a bit more work to get two equations with the same decimals. For example 0.12222222... x = 0.1222222... 10x = 1.222222... 100x = 12.222222... (100x & minus; 10x) = 12.222222... & minus; 1.222222... 90x = 11 so x = 11/90"
],
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50,
11,
4
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|
llwq5d
|
Why is it that your brain does such a good job of removing your nose from your field of vision normally, but once you think about your nose being there you somehow can’t not see it, that is until you forget to think about it being there again?
|
Biology
|
explainlikeimfive
|
{
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"Your brain does this all the time! you’re breathing subconsciously right now aren’t you? Well not right now anymore because I’ve brought it to your attention, but don’t worry you’ll forget again soon. And probably while you were thinking about your breathing you forgot your nose was there.",
"The brain is fucking crazy. You can wear a pair of glasses that flip your vision upside down and after a few days your brain will correct it to right side up. URL_0 \"After 10 days, he had grown so accustomed to the invariably upside-down world that, paradoxically and happily, everything seemed to him normal, rightside-up. Kohler could do everyday activities in public perfectly well: walk along a crowded sidewalk, even ride a bicycle. Passersby on the street did ogle the man, though, because his eyewear looked, from the outside, unfashionable.\"",
"Even more impressive is filling in the optic nerve holes with typical background so you don’t have two black holes in your field of view.",
"Our brains try to filter out uninportant information all the time. This is part of why if we use a product all the time, we can have no clue what we use. If you need something not normally important (for example, to track your breathing), you can focus on it and your brain will filter it in until it decides it's unimportant again. Your nose is not usually important to your concious mind, so your concious mind doesn't usually get it.",
"Your senses generate a TON of incoming information. More than your brain has the resources to process. Your brain is constantly receiving: * HD visual from both eyes. * audio from both ears * touch pressure info from every nerve ending over your whole body * temperature info from other nerve endings all over your bodu * smell info from thousands of scent receptors in your nose * taste info from thousands of tastebuds * Other information on the position of your limbs, hunger levels, etc You physically can't process all this information constantly. It's not worth it because at any given moment most of it is useless. But the portion that's important changes depending on what you're doing. So the brain has a filter, before the level of conscious awareness, where it decides what small slice of incoming info to send up the chain to be fully processed into awareness. The rest is discarded. The key is, your conscious mind can control this filter! If you decide you *want* to see your nose, the filter says \"OK here's the visual\". But the default setting is \"constant nose = unimportant = discard\". Other things processed in a similar way is the feeling of your own clothes on your body or the taste of your own mouth. Constant repeated stimuli are ignored. \"pants...pants...pants\" is a waste of resources.",
"This is one of my favorite things, because its completely fucking nuts. Basically the reason for your question is, your brain lies. All the time. The world is full of, well, everything. That's a lot of stuff to keep track of, so it turns out, we don't. We just pretend to. Your brain ignores stuff that doesn't seem important. Things that don't change aren't important. So fuck your nose, its boring. Now if you go out of your way to look at it, your brain will be like 'oh wait, what? Uhh yea, this thing!' and now that you're paying attention to it there it is. The thing is, its not just your nose. Your brain does this to all kinds of stuff. If its not worth paying attention to, it doesn't. And if it guesses wrong and suddenly you pay attention to something it was ignoring, instead of getting caught, it lies. IT WAS ALWAYS LIKE THAT! That's why if you look up at an old ticking clock after having been ignoring the time for a while that first second 'tick' seems to take so much longer. Your brain is lying about the state of the clock to cover for the fact it wasn't paying attention. And since your brain lies about things that it wasn't paying attention to, it also lies about changes that happened to things you aren't watching. It's called Change Blindness and its *wild*. Things you'd think you'd absolutely notice can happen right in front of you and you totally don't notice. Experiments in this basically amount to trolling people, and some of them are really crazy. We're talking like, lead a person to a desk where they ask for a form, person behind the counter bends down out of sight to retrieve form, different person stands back up to hand over the form. Less than half the people notice the switch out when questioned about it. And by different person I mean, you can swap a white dude for a black dude and people still don't notice, its *crazy*. If you want to see this in action at home, go look in the mirror. Look at each of your ears one after another. You'll never see your eyes move. In fact, you'll swear they never change positions at all. You can feel them moving in your head if you pay attention, but because your brain will lie about what you've seen, you'll never catch them moving.",
"Along with OCD, I have a mental disorder that has been called \"lack of acclimation.\" As some have noted below, the brain does a good job at turning off certain signals/stimulus so your conscious brain doesn't have to pay attention to them. For people with lack of acclimation, those signals don't turn off correctly. Thus I can always feel where my clothes are touching my body, and it is often uncomfortable. When I was 9-10 years old I refused to wear anything but sweatpants because I could feel the creases and seams in jeans and other pants bunched up underneath my butt and thighs. It was really, really annoying. Luckily, it comes and goes and manifests in different ways at different times. There was a period of three or four days once when I felt like I had to remember to swallow. So I kept on swallowing until my mouth was dry and had no more saliva, but still my brain would say \"You need to swallow!\" It as miserable. Be thankful (as I am) that our brains can turn that kind of noise off."
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"https://www.google.com/amp/s/amp.theguardian.com/education/2012/nov/12/improbable-research-seeing-upside-down"
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llz0jr
|
How come rotary phones came before phones with buttons? Isn't it much simpler to use buttons?
|
I don't really know how phones work(ed), nor how the dialing of a number "called" a different machine, but why did it make more sense to use rotary phones instead of buttons right away? What in the whole process, made it suitable for rotary phones?
|
Technology
|
explainlikeimfive
|
{
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"text": [
"That was all before my time, but we covered it in electronics class. If im remembering right. The simplest way to explain it is that buttons were digital, rotary was analog. Buttons on phones are called \"touch tone\" because they don't actually work by button press=1/no press=0, intead they communicate with operations entirely through the sonic tones created when pushing a button. That was the whole foundation for \"freaking\" AKA 70s/80s machine hacking done by whistling. Touch tone was more efficient as the amount of telephones per household increased. While rotary phones are all mechanical dealing with governors and gear systems that establish the connection more directly, which worked well in a time when not everyone had a phone.",
"At the time rotary phones were invented, electrical buttons (the kind used in todays TV remotes and handset phones) didn't exist. Those came around in the 1950s or so (from a quick Google), so back when the patent for rotary phones came out in the 1890s that *was* the simplest method. I don't know the full technical details, but it was based on the rotation of the dial....the further you rotated it, the more electrical pulses activated while it traveled back to its starting position. So activating the number 6, would send 6 pulses to the central office (switchboard)....this is how it knew you \"pressed\" 6. Do that enough times and you get a series of 1 to 9 pulses representing each number in the phone number you were trying to dial.",
"Telephones were analog and not digital. There were no electronics at all at the time. The way that a phone number was dialed was to send a \"clicks\" along the phone wire. The clicks had to be timed in a certain way - so a rotary dial actually makes sense. The phone was designed not necessarily for the \"ease of use\" of the user but around the limitations of the day. The timing of the rotation of the dial was a necessary feature."
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llz9ke
|
How do animals decide what to do next?
|
For example, what causes a bird to decide to fly off or land somewhere and why does it go in the direction it's going? How does a sheep decide to eat, go walk somewhere or lay down. Humans can tell others why they do things. Do we know why animals do things?
|
Biology
|
explainlikeimfive
|
{
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"text": [
"I do believe it's the simple laws of survivability. After waking: Eat. Full? Now time to rest. Should I rest where I ate or walk elsewhere, maybe somewhere close to my next meal. Walk to new place, rest. Get up to use bathroom. Walk away from waste location because that's gross. Eat again. Am I tired, or hungry? No, let's play a bit with another animal. Rest. If it's mating season, mate. Pretty simple lives.",
"Humans also operate, believe it or not, over 90% of our day using our subconscious. In other words, we are not even aware we're controlling ourselves, we're habitually doing things and are barely present. Being present takes attentive awareness all the time, although it becomes easier once you stop denying that you're habitual and put forth effort to catch your thoughts with the intention of analyzing them. And to quote Alan Watts (completely non-scientific btw) \"There is consciousness anywhere there is 'I'.\"",
"I believe it can be more sentient than we think. I use the example of the local Canadian Geese. They avoid the golf course during summer playing months. When the golf course is empty, they fly in groups to the course about five miles away. The groups seem to be related. In heavy wind, they will try to take off. If it's too much for everyone in the group, the rest will return and give it another try to see if the weak bird can take off. I'm not saying they have a plan for tomorrow or next week, but they seem to formulate a plan for the day.",
"Birds fly when they need to go somewhere. They land when they're tired, or need to look at something, or need to eat. They eat when they're hungry. You: \"But how do you know that when they can't talk?\" Same way we know how gravity works even though physical matters don't talk. We know a great deal of stuff about things that can't talk, including people. We can communicate with the deaf/speech impaired.",
"Some of their actions have a purpose, some are just to pass the time. The same goes for you. You go to the kitchen and eat food when you're hungry, a bird flies around and finds some seeds to eat when its hungry. If you have nothing to do, you may just wander around your home or pace between rooms or choose a hobby to do at random, a bird may fly around or peck at stuff without much direct purpose just to pass the time of its existence.",
"Animal brains have circuits that control movement, and many movements are routine and automatic. Any animal will have the capacity to trigger movements for a set of routines that are typical for its species. Animal perception is tuned to differences in the environment that are relevant to choosing one routine (from its set of routines) rather than another. Some movement routines are instinctive, they develop in the maturing animal independent of what they experience in the environment. After a toddler learns to walk, walking routines are automatic. The knee jerk reflex when a doctor's hammer taps a human knee is an automatic circuit that controls walking, and the circuit only goes as far as the spine, it doesn't depend on the brain or learning. Depending on the species of animal, the set of routines can be expanded through learning from experience. The brain circuitry will be modified by perception and feedback cycles of movement in relation to the drives and motives of the animal (such as feeding, fleeing, fighting and copulating).",
"For most birds it’s determined by immediate needs: hungry > eat; tired > rest; danger > avoid; mating > look for mate. If you are a crow or a magpie it’s slightly different; to above you add: shiny object?!) > investigate > take to nest to decorate > observe humans for little girls that feed birds > trade objects for food > learn girls voice > tell family to take care of the girl > shiny object > bring gifts > screech like legions of hell > bring girl’s camera shutter that fell off a bridge > return to girl > get food > pick out random bunny’s eyes > practice black magic.",
"A bit late to the discussion but my PhD is in a very adjacent subject and I ultimately asked how/why/ and when does a specific species move from one place to another and why would they behave in a certain way. Of course, this is on a spatial level and is with two different mammalian species but I believe the general rule applies in other animals (at least according to the literature). As one person noted, simple survivability. Animals (and people) have basic needs and as a result, are hardwired to perform said basic needs (eat, reproduce, sleep etc.)...but that doesn't really explain the how and where (and sometimes, the why). Where animals decide to perform these things basically depends on the availability and acquisition of resources/a specific need (such as mating) balanced with surviving (such as not running into predators). For example, an animal may realise that one area is plentiful in resources BUT is also dangerous. As a result, they may avoid it and choose another area with less resources but are not as dangerous. I found that there is another option, which is going to such dangerous areas while also exhibiting specific behaviours that allows them to eat (in this case, it was food) while also using a behavioural strategy that they may not use as much in safer areas (such as being hyper vigilant). Now, How do they know if an area is dangerous or not? Sometimes, it really comes down to instinct. If you can't see your surroundings, you are more likely to be predated on. Other times, it is through personal experiences (that is hard to study) and often times (especially in social species), other members of a group may provide such ques and relay that information on (kind of like, you are taught to act a certain way in certain places/circumstances). The latter two would count as spatial memory or spatial awareness. When it comes to food that may not always be located in the same area (prey items, fruit...which is seasonal) it may come down (at least in birds and mammals, who I am more familiar with) spatial memory. So, an animal may simply remember the location of a specific valuable resource and when that resource is available. I guess, overall what I am trying to say is that when push comes to shove, many animals do engage in decision making when it comes to their everyday lives as deciding to go to one place (instead of another) can directly or indirectly influence their survival and it seems some species (at least the two that I studied) are aware of that in one way or another.",
"Animal behaviour is actually a huge area of science. And how animals decide what to do next, as in physically, is just as closely studied as why animals do what they do next. But instead of that dry science, you mentioned a lot of mammals. Darwin proved to us that animals, especially mammals, tend to share emotional features of humans, even how they physically express it. There’s really few unique human features of emotion that aren’t found somewhere else in the animal kingdom. When a sheep is happy or flops down tired, you probably already know something about why they decided what to do next because you’ve felt much of it yourself. What an insect feels you may not have experiences so much, would seem alien to us, but it has a physical explanation and can all be understood completely, one day. Scientists are obsessed with the question you posed, all the cool biologists are anyway."
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lm0b8g
|
How can a weather forecast go from 100% chance of it happening to not happening at all?
|
Should the ‘100%’ imply that it will indeed happen? Seems like it liable to change up until the hour it’s for.
|
Mathematics
|
explainlikeimfive
|
{
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"text": [
"That just means the forecast was wrong. Regardless of the percentage, the forecast is still a prediction. A \"100% chance of rain\" just means \"I am absolutely, positively certain that it will rain, no doubt about it\". Then, it might just...not rain. Oops - looks like they shouldn't have been so sure about that prediction.",
"When conditions like this happened before, it always rained. 99.9% of the time when they saw these very similar conditions, it rained. There are no guarantees, predictions are never as 100% as we assume, but if they said, 99.6% - it would be rounded up. This time it didn't rain, and that data point will be added in. Big numbers will occasionally throw an outlier. And the numbers get better the closer to the event. So 100% three days out can drop to 20% a few hours before, which can evaporate to 2% a few minutes before."
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lm0b9c
|
What's capital?
|
This term is always being thrown around, and I guess I have some notion of what it is, but I'd like a good formal definition. I've heard "it's machines and stuff" and I've heard it be used as a synonim for money. Also, I know it's the name of Marx's main book. Is it all the same thing?
|
Economics
|
explainlikeimfive
|
{
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"text": [
"\"Capital\" generally refers to the money and/or equipment required to do a job, as opposed to the raw materials (\"resources\") and the physical work and skill (\"labor\") that is required. It's generalized to mean \"money\" because money usually lets you buy or make the things you need. For example, if you wanted to make a pizza, you would need a person who knows how to make it, the raw ingredients (flour, cheese, tomatoes, etc.), and an oven. The oven is the \"capital\". The money you needed to buy the oven was also your \"capital\". Marx is using the term \"capital\" to criticize capitalism, the economic system based on the private ownership of capital. Marx essentially argues that capitalists produce wealth by exploiting workers, and then use that wealth, or capital, to create new ways of exploiting workers.",
"Capital, simply put, is wealth that can make more wealth without being consumed in the process. A gold bar is not, by itself, capital. You could trade the gold bar for something, you could make something out of the gold bar, etc., but you can only do it once. Once you've used or traded the gold bar, it's gone and isn't creating more wealth. A goose that lays golden eggs, on the other hand, *is* capital. You can keep the goose and have it continually produce additional wealth. You could sell the goose to someone else, and it would produce more wealth for them. ---- The trick is that in the modern world, money can easily become a form of capital because you can invest it (and have it produce more money). This wasn't always true: investment in the modern sense is a relatively recent invention in finance, dating back only a few hundred years. It turns out to be a powerful enough one that *capitalism*, the system in which you can do that, is essentially named after that innovation.",
"Capital is anything that makes the thing you sell - as opposed to the thing you sell, itself. If milk is a product, then the cow is the capital. Buying more cows is making an investment in more capital, with the hope that the increase in production makes up for what you spent."
],
"score": [
17,
8,
3
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[
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lm0o12
|
Why do 'S' sounds seem more audible over background noise?
|
If the TV is on and someone is having a conversation in another room, I can't hear most of what they are saying over the sound of the TV, but any 'S' sounds seem to get through. Why is this?
|
Other
|
explainlikeimfive
|
{
"a_id": [
"gnsji0j"
],
"text": [
"Oh! Wow my first answer. So it all has to do with frequencies and overtones. When you speak you don't produce just one wave length per sound, your larynx, throat, mouth, sinuses, tongue, cheeks, and lips all alter the sound and amplify some frequencies over others, or even use the wind to create entirely new frequencies. The latter is the case for \"fricatives\" like TH or S or Z in english. Using your example of \"s\", the wind comes up from your throat and through a very constricted opening that you create in your mouth. The \"pressure\" speeds up the wind and creates a high pitched frequency. Now, if you hum the lowest note you can without opening your mouth, chances are a friend wouldn't hear it a few feet away from you in a loud room. This is because low frequency sounds quite literally have \"less energy\" (wavelength/frequency) than do high frequency sounds. Low frequencies decay/fall off at shorter distances. Average speech / conversation is a mixture of high middle and low frequency sounds, but the \"s\" sound is among the highest frequencies utterable by humans. So having more \"energy\" the s sound \"beats out/overcomes\" all the other lower energy sounds and is heard more easily across distances and crowds."
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