title list | over_18 list | post_content stringlengths 0 9.37k ⌀ | C1 list | C2 list | C3 list |
|---|---|---|---|---|---|
[
"I added cold water to Everclear (95% Ethanol) and the bottle felt warm, why?"
] | [
false
] | About a 50:50 mix or 100ml:100ml. | [
"Here",
" you can find some values for the enthalpy of mixing water and ethanol at different ethanol concentrations. In all cases, the processes is exothermic. That is, the process produces heat and warms your solution.",
"Edit: why is this the case? It turns out that small chain alcohols are much better hydrog... | [
"If you wanna see something else that's pretty cool then mix X volume of water with X volume of alcohol and then notice that you get less than 2X total volume of mixture.",
"I.e, 200ml of water + 200 ml of alcohol does not equal 400ml of mixture"
] | [
"It'll depend on the proportions, a ",
"50/50 mix by initial volumes will give a total volume of about 96%."
] |
[
"Are blood samples a good measurement for chromosome errors throughout the whole body?"
] | [
false
] | If it is discovered through blood samples (which I beleive is the common way to measure this), that a certain chromosome error is present in say 50% of all cells. Would it then be safe to assume that this distribution holds true for the entire body: skin, brain, liver, everything. Or might there be different concentrations in different parts of the body? By chromosome errors, I'm thinking of cases were there are 1, 3 or more chromosomes in one "pair". Bonus question: How many cells are usually measured? tens, hundreds, thousands? (I posted this in "Biology", I'm not sure if it should be there or "Medicine".) | [
"As you probably already know, many people with genetic abnormalities (Downs syndrome for example) are mosaics. Some of the cells have one set of chromosomes and another has a slightly different set. This is caused by a division error early in embryo formation.",
"The distribution of the cell types is often very ... | [
"My understanding is that mosaic conditions will follow patterns in embryo development. Skin is derived from the ectoderm and bone marrow forms from the mesoderm.",
"If you need to know this for medical reasons then don't trust me (or Reddit) but I could almost guarantee you that it can be that sharp a divide or ... | [
"Thank you, this is a very good answer. So by \"very uneven\", does that mean that e.g skin could have <10% or >90% of abnormal cells even if the blood test measures about 60% abnormal cells?"
] |
[
"How do scavenger birds locate the carcasses they want to eat while flying?"
] | [
false
] | null | [
"Turkey vultures have an extremely sensitive olfactory system, and they can detect a single molecule of cadaverine or other compounds given off by dead animals. Then they cast back and forth the way a tracking hound does, until they detect a gradient and can follow the gradient \"upstream\" to find the source."
] | [
"In addition to the previous answers (smell, sight, etc) Another thing vultures do is that they glide at some distance from each other, but still close enough that they can see the closest one. So when one of them located a carcass and thus lands, the ones closest to it instantly follow, and on and on it goes. This... | [
"Another type that’s often seen with Turkey Vultures is the Black Vulture. The Black Vulture doesn’t have the sense of smell that the Turkey Vulture has. Instead they follow Turkey Vultures to the carrion"
] |
[
"Can a virtual photon be diffracted?"
] | [
false
] | Can a virtual photon be diffracted? If two plates are electrically charged creates a electrical field, this field can be diffracted by a small slit, since the quantum electrodynamics says that the electrical field is quantized as "virtual photons". Have these photons properties like frequency or momentum or something like that? I'm deeply thankful in advance for any answer to my question. Thank you. | [
"Virtual photons are not physical states. They are a label applied to some terms in integrals in an approximation framework called \"perturbation theory.\" A static electric field is not diffracted through a small slit. "
] | [
"http://profmattstrassler.com/articles-and-posts/particle-physics-basics/virtual-particles-what-are-they/"
] | [
"Indeed, it is what we expect the electric field to do. But despite the very fact that virtual photons are not physical states (and I would add that they are not particles at all), how do the electric field behaves if it are forced to pass a small slit? For example, if two plates electrically charged are separated ... |
[
"What does a medical study mean when they say \"increases risk of death?\""
] | [
false
] | The text that prompts this is: "There is currently a widespread belief that any degree of overweight or obesity , however our findings suggest this may not be the case." (from the Gizmodo article linked ). Isn't the risk of death 100%? How can it increase? | [
"In any given finite period, there is a chance that you will die. In the next 5 minutes, it is pretty small (unless you are making fun of a biker`s moustache or something) but over the course of a year, it is more likely and over decades, it is even more likely. ",
"Increases risk of death means that for some fin... | [
"Risk of death is assessed as a comparative measure between two populations. For example, let's say you have 1000 people taking a medicine vs 1000 people who are not taking the medicine. If, in the duration of the study (eg 10 years), you find that 500 of the people taking the medicine died vs 300 of the people n... | [
"The best way to think of this is in regards to an experiment.",
"Let's take a hypothetical experiment (which would never get ethics board approval), where ten unlucky \"volunteers\" (PhD students bribed with the promise of free Kraft Dinner and coffee) are randomly assigned to one of two groups. ",
"All ten of... |
[
"Can someone help me understand the connection between Poincare's Fuchsian Functions and the transformations of non-Euclidean geometry?"
] | [
false
] | I am studying problem solving and analogical thinking in psychology, and one frequently used example of analogical thinking is the example above. I am hoping to understand a little bit more about this relationship so I might obtain a little bit of understanding on the analogy itself. I was hoping for a relatively simple answer, though I understand that might not be possible. I have a little (college) mathematics background, if that helps. | [
"I don't know how in-depth I can be on the mathematical portion, but basically, Poincare comes us sometimes as a prominent example of analogical analogical, i.e applying an understanding of one concept to another to learn more about. An example sometimes brought up in science is the Wright brothers developing the a... | [
"Can you be more specific? The topic of Fuchsian groups is rather advanced and broad. Riemann surfaces, elliptic functions, fundamental polygon theorem, Mobius transforms, etc. It seems bizarre to me that fuchsian groups would be a commonly cited example of non-Euclidean geometry in a non-mathematical field like ps... | [
"Why try to use an analogy you don't yourselves understand? Isn't that the exact opposite of what analogies are about?"
] |
[
"If a curveball was thrown in an obstacle-free, zero-gravity environment, would it follow a spiral pattern or return to the pitcher? If it's a spiral - does it curve inwards or outwards?"
] | [
false
] | Alternatively, in the case that a curveball somehow requires gravity to function - if it was thrown from atop a high enough place, would it loop back to its origin point (disregarding altitude), or would it spiral? | [
"It can't curve if there is nothing there to curve the path. It at least requires air, that will slow down the spinning and motion of the ball and it will stop eventually."
] | [
"The curve of the ball is dependant on the resistance of the air to the spinning motion. All pitches take advantage of such resistance. A ball will even rise once it catches the air just right. A spinning ball in an space with air but without gravity would move in a curve until the air resistance stopped the spin. ... | [
"If the ball kept spinning at the same rate and flying at the same speed and stayed in clean air and probably a bunch of other assumptions it would fly in a circle.",
"The thing that makes the ball curve - air resistance - is also going to slow the ball down, and slow down the ball's spin, if you start accounting... |
[
"Do infalling photons contribute to a black hole's mass/momentum?"
] | [
false
] | [deleted] | [
"You've just stumbled upon one of the most interesting unsolved problems in physics, the black hole information problem. No, Hawking radiation has nothing to do with what went into the black hole. It's thermal, meaning it only depends on the black hole's temperature.",
"This is a problem because in physics you're... | [
"Yep! From the perspective of gravity, there's no functional difference between \"matter\" and \"energy\" - they all gravitate the same way. And a black hole is (as far as we know) nothing but pure gravity. From the outside, there's no way of knowing what went into it, so there's not a super well-defined sense in w... | [
"Isn't there Hawking radiation coming out of black holes that can tell us what fell into the black hole?"
] |
[
"Since in nuclear fission a very small amount of matter is converted to energy, is it Theoretically possible to create matter from energy and have we done this?"
] | [
false
] | null | [
"Yes, creating matter from energy is perfectly doable.",
"One example would be particle accelerators such as the LHC. In the LHC, proton beams are accelerated and thereby given a very high amount of kinetic energy. These highly energetic protons collide and produce various new particles. The combination of newly ... | [
"Uh, this is an ill-posed question. The LHC is a research instrument, so metrics like efficiency are not really defined. Furthermore, the Higgs boson is unstable and will decay very shortly after being created (potentially into two massless photons)."
] | [
"Not in a very useful sense, no. The energy that's stored in the chemical bonds is \"matter\", in the sense that it has mass and you could theoretically weigh it on a scale (if you had a scale precise enough), but that's an even more minuscule fraction (by hundreds of thousands of times) than in a nuclear explosion... |
[
"Why aren't humans ever born with mirrored internal organs?"
] | [
false
] | Such as heart on the opposite side of the chest and all of the other innards flipped accordingly. | [
"But they are",
"."
] | [
"Your heart is larger on one side because one side of the heart is only pushing blood to your lungs while the left side must push it through your whole body. With things like lungs, your left lung I believe is smaller to accommodate your heart lean. Limbs tend to be mostly symmetric until used, ie a righthanded per... | [
"They actually can be. It is known at situs inversus. A total situs inversus patient has complete mirror of all internal organs. In most cases though there is only a partial mirroring, and can lead to major health problems. "
] |
[
"Does the sun pass on momentum to the earth through photons?"
] | [
false
] | Since photons have momentum wouldn't a collusion between a photon and the earth transfer some momentum to the earth. If that was the case wouldn't the sun gradually be pushing the earth away from it. | [
"Are you implying that light doesn't carry momentum?"
] | [
"There is a ",
"radiation pressure",
". Wikipedia gives the radiation pressure on the Earth due to the Sun as 9.15 N/km",
" ."
] | [
"Photons are actually a viable explanation of the discrete nature of light, just as with all particles."
] |
[
"Why do they seem to find a cure for every single fatal disease every week in the news and then I never hear of it again?"
] | [
false
] | Every time I come on reddit I see "bone marrow transplants cure cancer" or "gene therapy 100% affective at curing HIV" It seems like we have been curing every disease every week for the past 10 years and then forgetting about it | [
"It's overly sensationalized media attention and poor scientific journalism. Those media reports are fueled by people who read the research (or at least we hope they do) and then create headlines. As you've noticed, the headlines (and very often the popular media summaries of the research as well) are not very ac... | [
"No. Not at all. Curing one rich person makes ",
" less money than an entire population of people. Get it out of your head that only the rich have access to cures for incurable ailments.",
"Pharmaceutical companies are global entities. Yes, you were correct to guess that the motivator is money, but you gotth... | [
"It's a lot of distortion at many levels between researchers and the public. A lot of this work is being done in basic research labs. In these labs researchers use cell culture, animal models and all sorts of interesting doo-hickeys to discover new things about diseases. The problem is that it's all painfully speci... |
[
"How big is the chance that you drunk the same water molecule twice?"
] | [
false
] | null | [
"Credit to the last time this exact same question was posted ",
"u/verylittle",
" provided this response:",
" For any given water molecule, the odds are basically negligible. But the odds that you've drank at least one water molecule twice are pretty much 100%. ",
" Think in terms of the numbers of water mo... | [
"On the other hand water molecules you already drank from your breath and sweat will get in every drink that is poured in your vicinity."
] | [
"That assumes that all the water on Earth is \"well-mixed\" on the timescale of a lifetime. It isn't. So you're not picking water molecules at random each time.",
"For example, if all your drinking water comes from an aquifer where water takes hundreds of years to get to from the surface, you'll ",
" drink the ... |
[
"Apart from the oceans, are there any parts of the Earth which remain unexplored?"
] | [
false
] | null | [
"Caves dude. All sorts of caves. I forget the statistic that BBC's Planet Earth gives, but there's a huge percentage of Earth's caves that as of now are totally unexplored, or only partially explored due to their depth and there's a an almost certain chance that we haven't even discovered a large portion of them i... | [
"Couldn't we use some sort of sonar or something to find the big bubbles of not-rock and then dig down to them?"
] | [
"I once personally mapped a previously undiscovered cave. It was a hellish little thing. A 500-foot-long underground stream. The cross section never exceeded 2 feet in either dimension, and it was generally around 1 foot high and a foot and a half wide, with around six inches of fifty degree running water. Wetsuit ... |
[
"How can we tell what the function of a certain part of a brain is?"
] | [
false
] | null | [
"A surprisingly large amount of research in this area involves cases where certain areas of the brain have become damaged in individuals due to trauma, stroke or some other event. Behavioural studies pick up patterns of abnormalities in the behaviour of these individuals and this provides evidence that a particula... | [
"Most of our I initial ideas have come from the effects of brain damage on people's knowledge, abilities, behaviour and memory. We have then built on our initial knowledge via experiments on people undergoing brain surgery for which patients are awake as there are no pain receptors in the brain. ",
"Finally and m... | [
"There's an awesome book called \"The man who mistook his wife for a hat\" or something close to that. With interesting stories about brain injuries and the resulting changes noted. ",
"Edit: Here it is on .pdf. ",
"\"The man who mistook his wife for a hat\""
] |
[
"The space between atoms, that electrons fly around in: what is it made of, and what do we know about it?"
] | [
true
] | [deleted] | [
"Nothing. There doesn't have to be \"something\" throughout the entire universe (and the vast majority of the universe is so-called empty space).",
"Though, of course, electrons aren't really classical particles, but more probability waves, so it doesn't make too much sense to talk about them having positions. Bu... | [
"Hadrons are particles like protons and neutrons that are made up of quarks. You're probably thinking of the Higgs Boson.",
"The Higgs field might exist throughout all space, but that's really just a mathematical construct. Just like the electromagnetic field and the gravitational field also exist throughout sp... | [
"I think the double slit experiment would make you cry."
] |
[
"Can Astronomers actually see other galaxies rotating, other stars moving, and other such events in \"real-time\" or does space appear to stand still?"
] | [
false
] | [deleted] | [
"These",
" are the remnants of the supernova that exploded in 1987. ",
"These",
" are the locations of stars around a very massive, invisible object in the center of our galaxy. ",
"Barnard's Star",
" is moving pretty fast, by star standards. In all of those you'll notice that things are changing over the... | [
"Other galaxies are too distant for us to see them change in any measurable fashion from how they looked when we discovered them. The angular velocity of the stars in the galaxy is just too small from this distance, and our resolution on our telescopes isn't high enough to resolve any position changes. ",
"Howeve... | [
"It's probably different because after the supernova went off people looked back to see if there were any recent images of that galaxy, and that's what was available."
] |
[
"What causes the relative sweetness of sugars?"
] | [
false
] | My question started when I saw listed as an ingredient in the Junior Mints I was eating. Apparently, invertase is added to table sugar— —to make : a which apparently is sweeter and less than sucrose. However when reading the Wikipedia page for , I found of the relative sweetness of different sugars. The problem is that it says inverted sugar is half as sweet as sucrose. This directly disagrees with the Wiki page on inverted sugar. Does anyone know which information is correct? Also what properties of these sugars cause them to be sweeter? Google searches for sugar receptors only yields confusing results. (: I'm sure this has to do with taste receptor proteins and their shape so pictures would be nice. :) | [
"Because in di-mers like sucrose, the sugar is in pairs (glucose and fructose) hence we split the two for them to be actual pure sugars. But Inverterd sugar syrup already splits the two and we taste the pure glucose/fructose.",
"On a bigger scale, starch consists of many sugars and we dont taste the sweetness sin... | [
"I understand that breaking sugars down into less complex forms makes them sweeter. That's a good point. (: I remember doing that same bread trick but with dry pasta in elementary school :) ",
"But, why is fructose sweeter than glucose? And where should invert sugar really be on this graph?"
] | [
"I wouldnt imagine fructose being sweeter but I am guessing since Fructose is more natural sugar and since we are designed to find sugars pleasant to taste so we will eat more of it in nature, fructose would be more pleasing. \nThat is just a guess."
] |
[
"sleeping elevation level"
] | [
false
] | is there any difference to the body sleeping with the mattress on the floor makes to keeping the mattress on a frame? | [
"Keeping it on a frame makes it harder for the spiders to get you. (australian here)"
] | [
"to expand on one of those, less mold if you live in a wet climate "
] | [
"Fewer ",
"miasmas",
" as well."
] |
[
"Does increasing muscle mass also affect the tensile strength of tendons?"
] | [
false
] | Let’s take a body builder, do their tendons have a higher tensile strength than an average person? | [
"short answer, technically yes.",
"long answer: while they do adapt, tendons take way way longer to become stronger. that's why many people in gyms injure their joints - muscle power increases way faster than it takes a tendon to strengthen, so their joints can't cope with the new forces involved in moving ever-i... | [
"In non-drug takers there is an upper limit on how much muscle a bone can hold once you account for bone density, height, etc, and those muscles will have a maximum tension threshold, so it would stand to reason that tendons would have a similar maximum tension threshold. For obvious reasons it would be incredibly ... | [
"Isn't there also an individual upper limit to how strong tendons can get?"
] |
[
"Question about quantum fields"
] | [
false
] | It is my understanding that every elementary particle exists as an excitation within a 'quantum field'. But some of the particles have nearly identical properties besides their masses (electron, muon, and tau, for example). Are these similar particles different levels of excitations in the same fields, or does each particle have its own field? And how many quantum fields are there anyway? What are they called? | [
"The similar particles with a different mass (like electron, muon, and tau) belong to different fields. Having multiple excitations of a single field corresponds to having multiple particles of that type.",
"As to how many quantum fields there are in the real world, that's sortof an arbitrary question which is ba... | [
"Because we don't have flavour changing neutral currents, really.",
"If the muon were just a higher energy level of the electron, it would suggest that there should be a muon -> electron + gamma decay. But that is not observed. There is some symmetry or quantum number that prevents it.",
"Now, these kinds of de... | [
"Why don't we consider the three charged leptons (electron, muon, and tau) to be different energy levels of the same particle? Same for up-type quarks, down-type quarks, and neutrinos?"
] |
[
"When Archaeologists discover remains preserved in ice, what types of biohazard precautions are utilized?"
] | [
false
] | My question is mostly aimed towards the possibility of the reintroduction of some unforseen, ancient diseases. | [
"Well, none, really, apart from the care made to preserve the specimen. By the time any frozen remains are thawed enough to be discovered, the cat's already out of the bag, so to speak. Ancient pathogens are a concern, especially as the permafrost continues to thaw. Here's an article about an ",
"anthrax outbreak... | [
"Yes, but indirectly. The most dangerous viruses are the ones that jump from animals to humans, because we don't have defenses against them. (HIV, ebola and SARS are three that have made the jump in 'recent' history.) The more people going into the jungle to exploit it, and the more animals coming into human towns ... | [
"Is it possible as well for new viruses to be hidden in jungles that could spread as cut More down"
] |
[
"Is there any medium that can change the wavelength of light that runs through it?"
] | [
false
] | Such that when the light exits the medium, it is a different wavelength from when it was entering? | [
"Yep. This is how fluorescent lamps work (or those energy saving ones).",
"The mercury vapour inside the tube emits UV light which is then absorbed by the (white) phosphor (",
" phosphorus) coating on the inside of the lamp. The phosphor then re-emits photons with a range of frequencies (and so wavelengths) in ... | [
"Yes. Check out ",
"Nonlinear Optics",
". ",
"Typically, whatever method you choose works only within a narrow band (for one very specific color) and is very weak, so you need a very strong source to begin with. ",
"You've probably encountered a device which uses this effect before. Almost all green laser p... | [
"There are such materials. They are materials that have a strong nonlinearity in their polarizability. ",
"Typically uses are optical frequency doubling (aka second harmonic generation) and frequency mixing (two signals in, sum and difference frequency signals out). Even with \"strongly\" nonlinear materials, th... |
[
"Why haven't we found a cure to Nodding Disease?"
] | [
false
] | I understand why there are so many afflictions that we can't fix, but after some preliminary research, it looks like the disease is caused by a pathogen, which to me suggests that we should be able to find a way to fix it. Is this is a social or political issue? In case it's not clear, I'm talking about the disease affecting young children in parts of africa | [
"Also, just because something is caused by a pathogen doesn't mean it's elementary to treat - like HIV, naegleria, necrotizing fasciitis, etc. Couple that with the fact that it affects a small number of people in countries that rich people don't care about and it's an uphill battle."
] | [
"The situation is being framed in a rather bad light, it's all about resource allocation. I mean would you honestly advocate moving a significant amount of resources from aids and cancers to little know diseases that affect a small number of people? The cost to develop cures for a disease is not dependent upon the... | [
"Never heard of it, so looked it up:",
"Nodding disease or nodding syndrome is a recent, little-known disease which emerged in Sudan in the 1960s. It is a fatal, mentally and physically disabling disease that only affects children, typically between the ages of 5 and 15. It is currently restricted to small region... |
[
"How does temperature relate to electromagnetic waves?"
] | [
false
] | How does temperature cause light essentially? Like when you heat up something redhot, it emits gradually from infrared and into the visible spectrum, but how does the movement of atoms lead to photons being emitted? | [
"Thermal Radiation",
"Thermal energy results in kinetic energy in the random movements of atoms and molecules in matter. All matter with a temperature by definition is composed of particles which have kinetic energy, and which interact with each other. ",
"These atoms and molecules are composed of charged parti... | [
"What DrIblis said is correct, but it's not the cause of thermal radiation.",
"Nickel62 gave a good explanation.",
"If it were the atomic energy levels releasing the radiation, we'd only see discrete colors that correspond to the energy levels. But we don't we see continuous colors. ",
"In order to explain th... | [
"I understand atomic levels and their emission spectrum, but I know that a heated material moves up the visible spectrum, regardless of its emission spectrum."
] |
[
"Do female to male sex reassignment patients choose their penis's size? If not what defines it?"
] | [
false
] | null | [
"There are two types of FTM bottom surgery that people get, but I think this question is probably more in reference to phalloplasty. In that case, it depends on multiple factors like graft area, blood flow, and whether the person chooses to have implants placed for erection. In general people can make size requests... | [
"The other type, for those wondering, is called Metoidioplasty. They're different both in surgical method, and results, though both typically involve scrotoplasty, and both require any implants to be inserted in a separate procedure after healing to lower the chances of rejection. ",
"Instead of using skin grafts... | [
"There’s two major kinds of implants, one is an inflatable tube that fills with saline from a reservoir placed in the pelvis (my friend has this kind and the pump in in one of his balls! It’s cool) and the other kind is a rod with a series of connections that make it flexible. There’s pros and cons to both. The rod... |
[
"How much energy do you lose when coupling gears with a clutch?"
] | [
false
] | I'm not thinnking about a car specifically. Say you have a system where you want to lose as little energy as possible and you want to couple two gears with different speeds. When using a clutch, how muc energy is lost? | [
"Sorry for being vague.",
"Say I have a wheel on one end that is moving with a certain speed. I want to transfer as much of the wheel's energy as possible to another wheel, which starts out as sitting still. How much energy can I hope to actually transfer if I use a clutch? (I can't think of any other system to t... | [
"A clutch will only add rotational inertia if it is fully engaged. If it is not fully engaged, then some energy will be lost due to friction between the plates. Also, if the system is a propulsion system and is being propelled itself, the weight of the clutch will require energy to be propelled forward. Your questi... | [
"A clutch doesn't really transfer energy from one wheel to another. A clutch is a break in a shaft so that one side of the shaft can be disconnected from the other. So having a clutch that is engaged loses no energy as it is no different from just having a shaft."
] |
[
"If a calorie/Calorie is a measurement of energy, does hot food have more calories than a cold version of the same dish?"
] | [
false
] | null | [
"The scientific definition of calorie: The energy needed to raise the temperature of 1 gram of water through 1 °C (now usually defined as 4.1868 joules).",
"The 'food' definition of Calorie/kilo-calorie or 'food energy': the convention is to use the heat of the oxidation reaction, with the water substance produce... | [
"Yes, but it ends up not making a big difference. That didn't stop some people from turning it into a diet fad, though. I saw a website that was talking about how letting a tablespoon of snow melt in your mouth burns on the order of 100 calories, and how it was a perfect diet food. Well, not really. 100 calories is... | [
"So further to this, if you drink cold orange juice direct from the fridge in the morning your body a) has to digest it, and b) warm it up to core temperature of 37°C. To warm it up the body will use energy (the whole warm-blooded thingy)"
] |
[
"What things were predicted by math before their observation?"
] | [
false
] | Dirac predicted antimatter. Mendeleev predicted gallium. Higgs predicted a boson. What are other examples of things whose existence was suggested before their discovery? | [
"I think the ",
"discovery of planet Neptune",
" is a very famous example. The position of Neptune was predicted using the unexpected changes in the orbit of Uranus by Urbain Le Verrier, and was observed shortly after that. "
] | [
"Edmond Halley used Newton's math to predict the return of a comet in 1758",
". This was a verification of Newton's theories. The comet was named Halley's comet in honor of Halley."
] | [
"Rutherford predicted the neutron in 1920. He was wrong about its composition, but it was nonetheless discovered in 1932 (though first generated in 1931).",
"The neutrino was predicted by Pauli in 1930, coincidentally also called the neutron in the theoretical literature. The neutrino was detected in 1956.",
"G... |
[
"A spider at the door of my new rental has killed about 7 spiders and rolled them into a big ball which it now calls home. Why? Should I be afraid of this spider?"
] | [
false
] | null | [
"Biology"
] | [
"Biology"
] | [
"Thank you for your submission! Unfortunately, your submission has been removed for the following reason(s):",
"/r/AskScience",
"For more information regarding this and similar issues, please see our ",
"guidelines.",
"If you disagree with this decision, please send a ",
"message to the moderators."
] |
[
"Why don't warm and cool air masses in the atmosphere mix together?"
] | [
false
] | As anyone living in the American midwest recently knows, we've been having some really crazy weather that seems to switch between winter and summer on a daily basis. I believe this is due to warm air masses from the south and cold air from the north colliding and the edge between them constantly moving. Why do these air masses continue to stay separate instead of mixing together for a more stable temperature? | [
"This...isn't quite right, though. There's a big difference between viscous diffusion and thermal diffusion (defined as the Prandtl number).",
"The fact is that warm and cold masses of air ",
" mix - it's just that temperature differences are also steadily maintained by the vast difference in the amount of sunl... | [
"I'll add one point to the discussion, and I'll try to keep it simple (but hopefully not diminish the accuracy too much).",
"Along the boundary where warm and cold air masses collide (a front), they do mix. But air masses are so large that they can't mix through each other entirely. The front between these air ma... | [
"In addition to the different densities of hot and cold air, the air over land, sea and ice are heated differently (since energy is emitted and reflected by those surfaces differently). Also the earth is rotating, so air is being heated as it moves into the sunlight. So the system, earth, is dynamic and there is no... |
[
"If North America converted to 240v electrical systems like other parts of the world, would we see dramatic energy efficiency improvements?"
] | [
false
] | null | [
"No. In reality, power loss is actually because of the transmittance of power from the power plant to your house/local transformer. the power lost is defined by P=RI",
" where P is the power lost, I is the current going through the wire, and R is the resistance of the wire. Now there are a few more equations that... | [
"You would have to define \"dramatic\" but the increase would not be as much as you might think. That is because most of the energy which is lost is lost between the power plant and your house, not inside your house. And the wires between the power plant and our house are already running at 100's of thousands (or e... | [
"I believe you meant a 'transformer' as the device used to step up or down the voltage. With AC systems, this is done with a transformer and that equation you supplied.",
"Inverters are used to convert AC to DC and DC to AC."
] |
[
"Is it possible that there is another planet in our solar system that we can't see?"
] | [
false
] | [deleted] | [
"Yes! Theres an area just outside of Pluto's orbit (\"just outside being very relative\" called the Oort cloud that used to be considered empty! Turns out theres a dwarf plant a little smaller than Pluto recently discovered there, and patterns of light diffraction suggest there may be thousands of planets from the ... | [
"Behind the sun? No. ",
"That would only work when the planet was at the exact same distance of Earth and it would be noticed in the orbits of all the planets. Also that planet would only stay behind the sun relative to Earth for a couple of tens of years because Jupiter would pull it before or after the perfect ... | [
"To extend a little beyond the answers so far any planet existing the in inner part of the solar system would have been noticed long ago. Beyond detection by satellites a 'hidden' planet would have given itself away by the gravitational force it exerted on the other planet's orbits. This is how we originally discov... |
[
"How are scars permanent if our skin is constantly replacing itself?"
] | [
false
] | [deleted] | [
"There are many layers of skin cells, the bottom layer is called the Stratum Basal. This layer is Alive and constantly dividing, creating new skin cells which die and rise to the surface of your skin.",
"Scars can develop it the Stratum Basal is injured, for example in a deep wound. This prevents the cells there ... | [
"Do you know if the formation of scar tissue is a programmed response, or just haphazard tissue formation? That is, does a scar-forming wound induce any sort of pathway that is only active as part of a scar-formation response?"
] | [
"Yeah there's inflammatory and wound healing processes/pathways that try to repair damage to body tissue. "
] |
[
"is there a proof why nubers are dividable by 3 if sum of their digits is dividable by 3?"
] | [
false
] | so my question is this: i would like to see the proof how we know for certain that this rule works for every number. i dont know how to explain the rule. rule being that number 261 is dividable by 3 because 2+6+1=9 and number 9 is also dividable by 3. hope i explained it good enough. I am sorry for lacking english speaking/writing skills | [
"There is a proof.",
"It's important to note that something like \"261\" is really just shorthand for an actual mathematical expression: 2*10",
" + 6*10 +1. Almost anything that has to do with a digit representations of number (eg: why does multiplication algorithm we learn in 3rd grade work?) can be resolved u... | [
"thank you very much. ",
"i love how simple these proofs are if you think the right way about them. but in the same time, i couldnt come up with them in 100 years."
] | [
"That was an unexpectedly cool question and answer. I feel I tiny bit smarter",
"Thanks!"
] |
[
"If Violet and Red are on opposite sides of the wavelength spectrum for visible color, why are they so similar (i.e on a color wheel they merge into each other)?"
] | [
false
] | null | [
"Hi! This is a good question, and we've covered it several times before. You may like ",
"this thread",
" and ",
"this thread",
". Let us know if you have any follow up questions!"
] | [
"Ah! Thanks, sorry, I searched with the wrong keywords in the physics section and not in neuroscience or with different keywords in physics, thanks!"
] | [
"No need to apologize! Reddit search isn't the best, and honestly I'm not sure which field those questions should go in. I remembered a post from a couple weeks ago so I knew it'd pop up. :) Just let us know if you need anything else!"
] |
[
"Why are household electrical sparks blue? And why is lightning white? Aren't they the same thing?"
] | [
false
] | null | [
"Lighting bolts are actually a bit violet. A quick google image search can confirm this.This is due to their extreme temperature, in excess of 50,000 degrees. (I forget if it's C or F).",
"The color that a lighting bolt as you see it is determined primarily by two factors. One is visual saturation, the other is a... | [
"Very good explanation , thank you. Is it safe to say that electrons give off photons in the blue range?"
] | [
"Electrons give off photons of all frequencies, generally. The higher the energy of the photons, the bluer the light will appear. ",
"Air is non conductive, and you usually have to give electrons a lot of energy before they will conduct through it. (High Voltage). This means that the air and electrons will get ve... |
[
"Is there an empirical study that shows that diversity of culture, background, ideology, and preferences actually improve society?"
] | [
false
] | null | [
"Thank you for your submission! Unfortunately, your submission has been removed for the following reason(s):",
"/r/AskScience",
"For more information regarding this and similar issues, please see our ",
"guidelines",
"You can find the basic answer with a google / wiki search. Please start there and come bac... | [
"I didn't ask for any of that... I simply asked if a study had been done before. I would like to read it. Please reinstate."
] | [
"In offering peer review, it is included and implied that we won't do the necessary bibliographic review.",
"Thanks."
] |
[
"In psychology how do I know what I'm measuring is actually what I want to measure? What if eye contact has nothing to do with extraversion or introversion? But we defined it as such."
] | [
false
] | null | [
"In the behavioral sciences, this is an issue referred to as validity. In a general methods class, they generally teach about 5 types of validity:\nFace, Concurrent, Predictive, Convergent, and Divergent.\nThe conglomeration of these types of validity can help you determine whether or not you have a good measure of... | [
"The questions asked can not be defined any better than Koriania has just detailed. Bravo and ole for helping OP (most likely a second semester psychology student?) out."
] | [
"What if I say how open you are or how closed you are is defined as how often you make eye contact with someone among other variables, how do i know to include this in the measure of that particular personality trait."
] |
[
"what makes water reflective on a molecular level?"
] | [
false
] | Hi Reddit, I was just wondering what makes water reflective on a molecular level? | [
"Water reflection is due to the fact that it has a different electrical ",
"permittivity",
" than air does. This causes light going through water to move more slowly than light that goes through air. As it turns out, this difference in light velocity causes refraction and reflection when light moves from air i... | [
"/u/Cholly",
" already answered this question: The strong intrinsic electric dipole moment of the water molecule and the lack of this in air is what makes the interface between air and water reflective to light. What part didn't you understand?"
] | [
"I actually didn't understand that connection, so I felt like the question was unanswered. Would you mind explaining why this boundary causes a change in direction of photons?"
] |
[
"Blood iron level or the anemia test before blood donation"
] | [
false
] | null | [
"Every hospital I've worked in reports hemoglobin in g/dL, but if that was g/L it would be a normal value."
] | [
"Ahhh, I saw ",
"this",
" wikipedia page, but the units were dL, personally I have never seen dL before so I skimmed over, but it meaning I assume decilitre makes perfect sense. Thanks for clearing that up."
] | [
"Oh no confusion, just curiosity. They wouldn't have taken my blood if I was low."
] |
[
"If snow is just water, is it possible to have snow like effect with different elements/substances?"
] | [
false
] | null | [
"Yes. Many substances form crystals under the right conditions. Dry ice for example is CO2 in solid form, it can be crushed and looks just like snow - with finer crystals.",
"Fun example, as is often wondered at, it snows (or rains) diamonds on ",
"neptune"
] | [
"On earth no, but other solar system bodies have the potential to produce snow from other substances. ",
"Here",
" is a NASA article about Titan and methane ice clouds at its north pole."
] | [
"Yes, in the Earths interior there may be ",
"iron snow",
" and may be important for the geodynamo on Earth and other planets/moons (",
"Davies and Pommier 2018",
", ",
"Wong and Aubert 2020",
", ",
"Soderlund and Schubert 2014",
"). ",
"You can also get helium rain which is also thought to be imp... |
[
"Is time a result of the expansion of the universe?"
] | [
false
] | I have been thinking a lot about time and how it . Does traveling at the speed of light stop time for the traveler? I understand that anything with mass cannot travel at c, as it would require an infinite amount of energy. In this case, lets consider a photon. As a photon travels, it does not experience time, right? So, does that mean time is an emergent property of other factors? related: I often see people asking why we cannot travel faster than the speed of light. Is this because the universe expands at the speed of light? Picture a guy running down a walkway that is materializing under is feet. He cannot run beyond the walkway, so his speed is limited. In this example, the materializing walkway is the expansion of the universe, and the guy is a photon. If time does not exist from the photon's perspective, then isn't time a function of other factors? Is this a bunch of nonsense? Is my donkey on the wrong trail? | [
"The universe doesn't \"expand at the speed of light.\" First, it's exceedingly likely that the universe is now and always has been infinite in size. Not at all that sphere of explosion that's so often portrayed in popular media. When we say that it expands, we mean specifically that the distance between regions of... | [
"oh sorry, I was trying to be encouraging not insulting. Merely saying that without years of training in the field, you can get ideas that seem right or interesting. If you don't feel compelled to gather those years of training that's completely okay too, so long as you come here and ask us and are okay with seeing... | [
"no it's worth while to always ask questions and think about science. Before I had a proper science education I was full of crazy-ass ideas much like this one. So really, don't feel bad.",
"Does the photon change states at different points in space? It takes time for it to travel the space between two things. 8 m... |
[
"How does the language in which we think change?"
] | [
false
] | So at one time the language my brain uses to express thought changed from one language into another and I can’t understand the process behind that. (At that time I lived in another country for some time and was not confronted a lot with my first language.) How does that happen? My brain made all these associations throughout my life doesn’t it have to “reboot” all the information? Isn’t it difficult to translate everything I remember? Why does my conscious mind do that, even though I understand my first language better? As you can tell, I have a VERY rudimentary understanding of neuroscience. Do these questions make sense? Language is so fundamental to how we think. I am just confused about how this drastic change happens. | [
"Languages have evolved and/or be designed to be very flexible in their ability to relate to the world and our thoughts. Our brains have evolved to be good at associating different inputs/concepts with one another.",
"When you learn your first language as a child you’re learning, for the first time, to relate spo... | [
"Language is definitely not fundamental to how we think. It's fundamental to how we ",
". We think all the time without having a word for things, indeed we often don't have words to express an idea or feeling. I'm sure you've had an idea of some sort in your head and couldn't find the right word for it. Sometimes... | [
"Gonna have to massively disagree with you here… while we can conceptualise something and struggle to find words to put to it, that doesn’t mean language isn’t fundamental to cognition.\nThere’s a bunch of work done on the effects of ‘Language Deprivation’, something that (sadly) often occurs in deaf children who, ... |
[
"Would the new hydrophobic material weve been seeing online have negative impacts on water treatment plants and the environment?"
] | [
false
] | The stuff as seen seems amazing, but could it potentially be a dangerous pollutant when being washed away into treatment plants, rivers, general environment etc? | [
"Generally if it's really hydrophobic it will either sink to bottom or float to the top of the pool of water it's in, making it relatively easy to clean in a treatment plant. Think cooking oil for example. Let it aggregate on top, then scrap it off, easy-peasy.",
"If it gets out into the world that's another stor... | [
"If it's hydrophobic, it won't mix with water. If it doesn't mix, it's either more or less dense than water and will therefore sink or float. What about that is controversial to you?"
] | [
"You say oil isn't that bad of a pollutant because it is easily biodegradable (which it isn't in relation to most substances commonly described as such) yet you have no information on this substance to support the comparison against this product.",
"While oil is not toxic itself, it still interacts with the oil t... |
[
"AskScience AMA Series: We are Drs. Emily Landon and Allison Barlett, infectious disease experts from UChicago Medicine, here to answer your questions about life after your COVID-19 vaccine. Ask us anything!"
] | [
false
] | Hello ! We are infectious disease experts from the University of Chicago Medicine. Emily Landon, MD, specializes in infectious diseases and leads the academic health system's infection control and prevention efforts. As the medical specialist for the High-Consequence Pathogen Preparedness Program, Dr. Landon has helped steer UChicago Medicine, the University of Chicago, and its affiliates through the COVID-19 pandemic. She also regularly advises businesses, industries and government officials on how to best respond to the global crisis. Allison Bartlett, MD, MS, is a pediatric infectious disease expert who specializes in the medical management of acute and chronic infectious diseases in children and the associate medical director of the pediatric infection control program, and has spoken on the unique challenges and medical issues facing kids during the COVID-19 crisis. As multiple COVID-19 vaccines are rolling out around the world, infectious disease experts and government health agencies are beginning to issue new guidance on all aspects of life, from social distancing to mask wearing. But in this nebulous state where some are vaccinated and some are not, what does that mean for day-to-day life? What can (or should) you be doing differently, or the same, once you've been vaccinated? What can you expect after getting the vaccine? We'll be on at 4:30 PM ET (20:30 UT), ask us anything! Links: Username: | [
"How likely is it for people who are vaccinated to still be carriers for COVID that could potentially get non-vaccinated people sick?"
] | [
"There is conflicting media about just how effective/ineffective the new virus variants are at usurping the current vaccines. What's the real story?",
"What is your opinion on the Astra-Zeneca rumored side effects?",
"Is it likely we will be carrying around \"vaccine-passports\" for a while to participate in no... | [
"How soon before those who are vaccinated will need to be given a booster to protect against variants? Or will the variants become a moot point once we reach herd immunity?"
] |
[
"If a regular Nuclear reactor produces energy by heating water into steam, how is a cold fusion reactor supposed to produce energy?"
] | [
false
] | null | [
"'Cold' in this case just means not having to raise the material temperature so high that kinetic energy alone is sufficient to initiate fusion. The result is still fusion and the energy output should still be in large part heat."
] | [
"Lets add a number: 15 million degrees K.",
"This is the core temperature of the sun where fusion happens. Is a few hundred degrees K of the steam generated in power plants cold? Yes."
] | [
"Question: How does a cold fusion reactor work?",
"Answer: It doesn't.",
"http://en.wikipedia.org/wiki/Cold_fusion",
"Cold fusion is now generally called LENR (Low Energy Nuclear Reaction)",
"No-one has it working yet. There is most likely some kind of effect taking place associated with it, but there's no ... |
[
"Does the blood-brain barrier exist for all animals with brains?"
] | [
false
] | [deleted] | [
"As you move from simple animals to more complex ones, you end up seeing something like a 'brain' even before you see a circulatory system. For example, nematodes have a nerve cluster that functions as a kind of brain, but have neither heart nor blood vessels nor any separate circulating fluid we would consider ana... | [
"Although you are correct that CSF plays a role in circulating some nutrients and removing waste products, the blood brain barrier and the meninges are ",
" the same thing. Blood vessels do go through all layers of the meninges to supply the brain. Oxygen is supplied by blood.",
"The BBB consists of specialized... | [
"I thought CSF only interacted with the exterior surface of the brain and the brain tissue adjacent to ventricles (diffusion through the pia mater) and was actually a weak point in the blood/brain barrier to microbes? Isn't it the glial astrocytes wrapping around blood vessels and controlling passage from blood to ... |
[
"Re: Subreddit of the year -- Let's brainstorm on how to increase/maintain the *quality* here. Also, what additional sciences would you like to see recognized by their own category?"
] | [
false
] | [deleted] | [
"it seems the majority of people want to have the FAQ act as a firewall or filter. ",
"This post",
" made a great suggestion that would work the way the reddit admins have set up their messaging system.",
"If we could develop the FAQ to be general and thorough and have good reference material and links come u... | [
"It doesn't matter whether it's for subreddit of the year or not. We should have an interest in keeping this board as high quality as possible. ",
"In this regard let me provide my observations into the discussion:",
"The strength of this board is in its civility. Ultimately everything boils down to having civi... | [
"Should we 'reward'/recognize top contributors in some way?",
"I don't think that's a good idea. Sometimes people message me and tell me they like my shit, and that's a more meaningful reward than a Best Redditor Ever medal."
] |
[
"Is it possible that bacterial spores act as \"life pollen\" throughout the universe? Is there any compelling evidence for panspermia?"
] | [
false
] | null | [
"It is possible. There is no evidence though other than the general fact that life exists so it must have begun/arrived somehow, and perhaps fallaciously that there is no well supported theory of abiogensis on Earth as of yet."
] | [
"How do posts like this get downvoted in askscience? Who does that?"
] | [
"It's absolutely relevant. Trolls. "
] |
[
"Could the casimir effect explain gravity?"
] | [
false
] | null | [
"No, they're completely unrelated."
] | [
"Could you further explain"
] | [
"The Casimir effect is due to the electromagnetic force."
] |
[
"The Heisenberg Uncertainty Principle."
] | [
false
] | I've been reading a lot of physics books recently out of curiosity and interest in physics (I'm a compsci major). I was wondering if anyone could explain to me the Heisenberg Uncertainty Principle. I get what it's saying about how if one property is measured to high precision the others can't be. I'm confused as to why this is true. | [
"There are multiple ways to approach this. ",
"The most intuitive approach is you ask how you would simultaneously measure both for some quantum system (where this principle becomes important). E.g., if you want to measure an electron's position, how do you do it? You bounce photons off of it and measure the p... | [
"First, note that it doesn't mean if any one property is measured precisely than no other property can. Certain properties cannot be measured simultaneously, like x position and x momentum. In QM, properties like position and momentum are not determined to be a specific value, but by a probability function that a... | [
"I think a lot of confusion in understanding the Uncertainty Principle comes from descriptions that start off by using measurement example (high energy photons give better position, but impart momentum). This implies that the problem lies in the measurement and if there was a way of measuring without imparting ener... |
[
"What is the mechanism for smell? Where can I find images of the main organic molecules we detect with our noses?"
] | [
false
] | I understand that the tongue tastes only salt, sour, sweet, bitter and umami, and that the nose detects several thousand different chemicals and therefore (along with mouthfeel), the nose has a great impact on the sense of taste. But what is the mechanism for an olfactory bulb cell to detect a specific organic molecule? And what do they all look like? There's a few , and I know that the chemicals in peppers and mint (capsaicin and menthol respectively) are responsible for their apparent hot and cold. But is there a more comprehensive source of images of all such chemicals humans can sense? Edit: has some information but does not fully answer my questions. | [
"You should note that receptor-ligand interactions are never limited to ",
" ligand per receptor, so it's not like there are only 5 molecules taste receptors respond to. Likewise, it's not like there are several thousand different receptors, each for the unique chemical your nose is sensitive to.",
"What part o... | [
"You should note that receptor-ligand interactions are never limited to one ligand per receptor, so it's not like there are only 5 molecules taste receptors respond to. Likewise, it's not like there are several thousand different receptors, each for the unique chemical your nose is sensitive to.",
"Exactly. A sin... | [
"is there a more comprehensive source of images of all such chemicals humans can sense?\nis akin to asking if there is a comprehensive list of images of all chemicals humans can see",
"Yes, but the sense of taste can be represented by five basic chemicals - salt (NaCl), sugar (glucose and other sugars), sour (H+ ... |
[
"Will Mount Everest always be the tallest mountain?"
] | [
false
] | null | [
"No, eventually enough physical weathering will take place that it has worn down and plate tectonics will create newer mountain ranges that are higher given enough time. We are talking about long long periods of time here of course. Possibly millions of years. "
] | [
"It's actually relatively simple to have an approximation of the size of the biggest mountain using force balance at the surface of the earth. If I remember correctly from my Geophysics classes, it should be around 10 000 m high, so Mt Everest is actually quite close."
] | [
"Technically there must be an upper limit of how big (in matters of base area and height) a mountain can get, because it has to support it's own weight. Also considering that the earth crust has a certain thickness and the mantle isn't quite solid underneath, a mountain will sink back in eventually, making mt. Ever... |
[
"Need Translation from Medical-ese to plain English"
] | [
false
] | Can anybody explain simply how the drug Vidaza works? Description from Wikipedia: Azacitidine (5-azacytidine) is a chemical analogue of the cytosine nucleoside used in DNA and RNA. Azacitidine is thought to induce antineoplastic activity via two mechanisms; inhibition of DNA methyltransferase at low doses, causing hypomethylation of DNA, and direct cytotoxicity in abnormal hematopoietic cells in the bone marrow through its incorporation into DNA and RNA at high doses, resulting in cell death. As azacitidine is a ribonucleoside, it incoporates into RNA to a larger extent than into DNA. The incorporation into RNA leads to the dissembly of polyribosomes, defective methylation and acceptor function of transfer RNA, and inhibition of the production of protein. Its incorporation into DNA leads to a covalent binding with DNA methyltransferases, which prevents DNA synthesis and subsequent cytotoxicity. | [
"So your DNA is like a necklace, made up of a string of beads which carry your genetic information. There are four 'beads' which we give the abbreviations A, T, C, and G (these are just carbon-ring molecules called nucleotides). ",
"Azacitidine, or Vidaza, looks a whole lot like bead C (cytosine), and can get p... | [
"The side effects of Vidaza mostly come from its potential to colaterally kill off other dividing cells that are important and vulnerable, like the cells of our epidermal skin, our hair, the lining of our stomach and intestines, and our red blood cell producers."
] | [
"Thanks!"
] |
[
"As a US resident I always hear about all of the invasive species we have here from other continents. Do other continents have invasive species from North America?"
] | [
false
] | Stink bugs, spotted lantern flies, kudzu plant, asian carp, lion fish, etc, etc. Seems like we are being taken over here in the US with all of the invasive species from other continents. What I am curious about is where other continents have to deal with any invasive species from North America? The only one I remember reading about is raccoons in Germany, but I hardly see trash pandas as invasive and displacing/threatening native species. | [
"Absolutely yes. For another example to add to this thread, the slider turtle (",
") is a pond turtle endemic (native) to the southern United States, where it is commonly seen basking on logs and banks of ponds and slow-moving rivers and streams in large, dense groups. Common varieties include the yellow-bellie... | [
"Certainly for the U.K. is the Eastern grey squirrel native to NA, and has massively replaced our [beautiful] native red squirrels. They can transmit a virus to the red squirrels, or just generally outperform them in a survival-of-the-fittest manner. We now have active efforts to protect the remaining areas where r... | [
"The American Bullfrog, native to Eastern and Midwestern regions of the US, is an invasive species in Canada, Mexico, Central and South America, Western Europe, and Southeast Asia. (",
")",
"The Tecoma stans flowering shrub which is native to the Americas (primarily from southern US and Mexico) is invasive in t... |
[
"Is it possible to have type 1 and type 2 diabetes at once?"
] | [
false
] | Has anyone experienced these two conditions simultaneously? Edit: Thanks for the answer! | [
"Not really, and there is a lot of overlap, as there are significant genetic factors that influence metabolism, fat storage, food drives, etc. It's one of the things I've talked with a few endocrinologists and internists about as far as my own treatment courses go. ",
"There is a project at the University of Kent... | [
"Yes, the two diseases have different causes and affect different parts of the body. Type 1 is the lack of insulin production in the pancreas. Type 2 is insulin resistance in muscles, fat and liver. Untreated, they have the common symptom of high blood sugar."
] | [
"Yes. ",
"Type 1 is typically autoimmune. The body destroys the insulin-producing cells of the pancreas, sees them as foreign. Someone who has type 1, I would not expect that they would be diagnosed with type 2 later on. Because there are no insulin producing cells to speak of. ",
"Type 2 is the more interes... |
[
"What is at the bottom of deep fresh water lakes like the Great Lakes?"
] | [
false
] | null | [
"That depends on the lake.",
"Usually, the very bottom is bedrock, like granite or limestone or so. However, over years, this gets smoothed down by currents to form sand, which is mixed with materials that have sunk, like leaves, wood, dead animals, and human garbage, as well as various soils and sands that have ... | [
"In the larger lakes, it varies a lot from place to place, based on currents and silt coming in from shore. For example, here's a high-level map of bottom sediments in Lake Michigan:",
"https://databasin.org/datasets/31fe67a2eef3486b9d978daf6b35323f",
"Take note that the areas marked as \"sandy\" have boulders ... | [
"For some reason that description freaks me out. I just picture it all dark down there..."
] |
[
"What happens when an oil \"deposit\" runs dry??"
] | [
false
] | So with the various oil related issues, from the deep water well breach to the tankers spilling oil.. I thought of a question.. if these wells are tapping into large underground deposits of oil.. Are these deposits like underground lakes of oil? Are they like underground caves filled with oil? When we drain them... Are they then big open caverns? I know enough that in order to take something out of a sealed environment.. Something else has to replace it... Typically air? Water? Like the big oil deposit under the gulf of Mexico... We drain it dry... What fills the space the oil occupied? Water? If so... Couldnt something bad happen like the gulf of mexico draining into it causing a big vortex?? | [
"Oil is usually trapped in a porous rock. The rock structure is also under an enormous amount of pressure (thousands of feet of rock sitting on top of it), so if you just dug an air-filled hole down to the reservoir, the oil would come gushing up like a geyser. It can't get out normally because there's layers of im... | [
"Just to clarify from this answer: there are no big lakes or caves filled with oil that we drill into. We extract it from the tiny ",
"pore spaces",
" in between grains of a reservoir rock."
] | [
"Laymen here. Just putting it out there that the we won't extract the oil to extinction. We will extract it only to a point where the cost of extracting it far outweighs its benefit."
] |
[
"Would it be correct (albeit a bit sloppy) to state that the observable universe is only 1/infinity-th of the total universe?"
] | [
false
] | And if it is, I think my head might just explode. | [
"Since the question's been answered adequately, let me rant for a minute.",
"And if it is, I think my head might just explode.",
" don't do this. This kind of \"woah wow man\" thinking is a ",
" among younger people these days, and it needs to stop. Have some self-respect. Stop underestimating your ability to... | [
"After being chastised for not standing up for your own intelligence it seems you decided celebrity worship was the right way to go. Please try again."
] | [
"\"Imagination ... is more important than knowledge. Knowledge is limited. Imagination encircles the world.\" ",
"A rather important physicist said these words. A sense of awe and wonder at the world around us is not something to be denigrated."
] |
[
"What would happen if a person stayed underwater continuously without drying off? Like.. for a day, a week, a year, whatever."
] | [
false
] | Would their skin dissolve? How would salinity of the water affect this? Edit: Words. | [
"Well, David Blaine was in a tank of water for a week. From Wikipedia:",
"On May 17, 2006, Blaine was submerged in an 8 feet (2.4 m) diameter, water-filled sphere (isotonic saline, 0.9% salt) in front of the Lincoln Center in New York City for a planned seven days and seven nights, using tubes for air and nutrit... | [
"It is a similar effect as weightlessness on astronauts. Circulation problems occur and the liver cannot function properly. Gastrointestinal problems and other symptoms are experienced by long-term underwater divers as well."
] | [
"Any idea what caused the liver failure? That seems to be an odd condition from being submerged."
] |
[
"Why can't we transplant organs (like kidneys) from primates or other mammals into humans?"
] | [
false
] | null | [
"Short answer is we can, their are folks walking around with pig heart valve.",
"Longer answer is that we have a hard enough time overcoming rejection on human transplants. Using organs from other species would only compound it. Here is a tragic example. ",
"http://en.m.wikipedia.org/wiki/Baby_Fae"
] | [
"Perhaps unfortunately, humans are not machines in which you can just replace a defective part with another equivalent or similar part.",
"The human body (or, really, any animal) has evolved a very successful immune system, which actively seeks out anything in your body that is not a part of you, and exterminates... | [
"Basically because our body can differentiate from \"self\" and \"Non-self\" and your immune system attacks everything that is non self. ",
"But, some people may be able to survive with animal parts if they consume immunosuppressant. "
] |
[
"What is the optimal running speed for an average human being in terms of energy?"
] | [
false
] | [deleted] | [
"8mph is not walking speed. "
] | [
"This",
" study by Karen L. Steudel-Numbersa and Cara M. Wall-Scheffler in 2009 found that \"optimal runningspeeds averaged 2.9 ms",
" in females and 3.7 ms",
" in males\"."
] | [
"Lets look at the marathon shall we? Quite a feat to run 26.2 miles. I know I can't do it. Hell, I know a lot of people that can't do it. In 2005, the average time for all male finishers in the US was 4 hours 32 minutes. That's a pace of 5.78mph, or 2.58m/s. ",
"source",
"Unfortunately, the standard deviation i... |
[
"How many sustained G’s can the human body take, as in how many could the human body take for days or weeks continuously?(eg on a spacecraft under constant burn)"
] | [
false
] | null | [
"Not much more than 1g. Probably 2g is already too much.",
"NASA has conducted several studies for human acceleration tolerance. Key findings are:",
"Most of this research was focused on designing launch and reentry vehicles that can provide a comfortable acceleration for humans. It also provided guidelines to ... | [
"Just to add a fun bit to this, forward acceleration is sometimes referred to as \"eyes in\" and backwards acceleration as \"eyes out\". You might imagine why."
] | [
"i can't answer for days or weeks, for moments the rocket sled experiments gave huge numbers.\nI can't find my note but i think they maxed at 70 GS (based on the effect on the test subject whatever the high test was is probably past the limit you want to expose someone supposed to be functional to)"
] |
[
"Nuclear Reactor Design"
] | [
false
] | I'm not a nuclear engineer, but I have a fair bit of knowledge in this regard. Lately, I've been reading a lot about Hyman Rickover* and the development of nuclear power, and one question keeps bothering me, gas cooling. A lot of coolant/moderation combinations were considered in the early days of nuclear engineering. I can see why liquid metal coolant/moderation was pursued, and rejected. I can understand many of the advantages of the various types of water/graphite. What I don't understand is why no one has ever seemed very interested in gas cooled reactors, at least until . Helium can't be irradiated, which means it can drive a turbine directly without a heat exchanger. As a gas, it won't interfere with passive safety features like a melting valves. Can anyone explain why there hasn't been more interest in this kind of reactor? Edit: Decided to put up a about . | [
"i am a nuclear engineer (although still young so I'll try my best).",
"I think there are a few reasons why gas cooled reactors havent had too much put into them. \nFor one, the US NRC is very stringent and i think the rest of the world would need to be running gas reactors for 20 years before they would let a pe... | [
"A BWR runs at about 550 F and 1020 pounds pressure, and I believe a PWR is something like 620 and 2000? (i dont know the temp. i work at a BWR, but i am pretty close on the pressure).\nThe secondary loop in a PWR runs around 1000 pounds pressure as well I believe and that is the part which goes through the turbine... | [
"Good question. I'm sure somebody will have a detailed answer, but I think it has to do with the amount of potential energy stored in a phase transition. The transition from liquid water to steam for instance. This is related to why refrigeration and heat pumps use not just a compressible gas, but a liquefiable ga... |
[
"What is the actual risk of cardiac arrest during exercise?"
] | [
false
] | For example; Patrice Muamba's heart attack during an EPL match. | [
"Some estimates are :\nUS high-school and college athletes (age 12-24) - 0.5 per 100,000 per year.\nIn Italian competitive athletes (age 14-35) 3.6 per 100,000 per year. The rate is estimated as five times higher for men than women, and twice as high in college athletes than in their high school counterparts.",
... | [
"What is the actual risk of cardiac arrest during exercise?",
"It depends...",
"Statistics can tell you how many have heart attacks during physical exercise, and from that we can make various estimates. But that is all general information with absolutely no relevance to the individual. ",
"A wide array of fac... | [
"And does anyone know if a heart rate monitor would help you know if you're pushing yourself too much increasing the risk of having one?"
] |
[
"Will anti-matter every be an economically viable energy source?"
] | [
false
] | I understand that antimatter is currently produced in particle accelerators, requiring a huge amount of energy attempts even to produce a very small amount. But will this always be the case? Do the laws of thermodynamics prevent us from creating anti-matter with less energy than what we'd get back from it's annihilation with regular matter? If we can find a simple way of "flipping a bit" in a proton to make it an anti-proton then it seems all of our energy problems will be solved? This, of course, is ignoring the insane difficulty of actually containing antimatter. | [
"I am no astrophysics, but this is what I have been told:",
"It is true that you would be able to create a perfectly working galaxy with anti-matter. However, since we know that we are made from matter, there would be a boundary between matter and antimatter. This boundary would shine in gamma rays. Even at the l... | [
"I am no astrophysics, but this is what I have been told:",
"It is true that you would be able to create a perfectly working galaxy with anti-matter. However, since we know that we are made from matter, there would be a boundary between matter and antimatter. This boundary would shine in gamma rays. Even at the l... | [
"As others have pointed out, antimatter is not an energy ",
" because it's not naturally occurring.",
"But ",
" are not naturally occurring, and we get energy out of them, so there must be something else applicable here. That something else is the idea of using antimatter to ",
" energy. You stuff energy in... |
[
"How do we know that there is an unobservable universe beyond the observable universe if we can’t see it?"
] | [
false
] | null | [
"Direct electromagnetic radiation from something is not the only way to learn about its existence. The matter that emitted the cosmic microwave background we see today was in contact with matter a bit farther away. There is no light from that matter that reached us directly, but it influenced things which we can se... | [
"Based on our current understanding of spacetime there are two possibilities: either the universe is infinite or it loops back on it’s self such that going in one direction for long enough would bring you back to where you started. If the universe did loop back on it’s self like that it would be finite and could b... | [
"That's the answer, basically. One should add that it is based on the assumed validity of Einstein's field equations."
] |
[
"Large-Scale \"Finger Over the End of the Straw\" Trick?"
] | [
false
] | I'm sure everybody here knows when you put a straw in water, put your finger over the end, and pull it out, the water stays in the straw. What would happen if someone were to try and recreate that on a much larger scale? Would you be able to, say, swim around in the water in the tube? What if you swam to the bottom of the tube and stuck your hand out of the water? | [
"It wouldn't work, because of the ",
"Rayleigh-Taylor instability",
". Consider the liquid surface at the bottom of the straw. If it bends a down little bit (bulging out in a particular place), even on the few-mm scale, then the water pressure becomes slightly higher at that bulge (there is a taller column of... | [
"just take a drinking glass, submerge it open-end up into a full sink so it fills with water.",
"Then turn it upside down and pull it out. As soon as the rim of the glass leaves the water, all the water falls out."
] | [
"Also a quick test with a bottle or jug would show this isn't feasible when stepping up to larger diameters."
] |
[
"If you put a giant copper coil around the Earth, would you induct a current strong enough to harness energy from?"
] | [
false
] | null | [
"I assume you are talking about induced current as a result of the earths magnetic field. This only happens when there is a ",
" (a change in magnetic field). This can be calculated by the relation:\n",
", where Φ is the magnetic flux and t is time. \nFlux is equivalent to the magnetic field strength times the ... | [
"I dont know the magnitude of the earth's magnetic field, but either way you would need to move the coil relative to the magnetic field. The voltage is proportional to the speed that you move the coil at, perpendicular to the magnetic field. So if the coil is just sitting out there, stationary relative to the earth... | [
"Thank you for the in depth reply! "
] |
[
"Biologists of Reddit, what is it in virtue of that photoperiodism causes thicker fur during winter in animals?"
] | [
false
] | Disclaimer: Apologies if this is poorly worded or inaccurate in any sense. I do not study science. This question arose from an argument (based on speculation) that I had with someone last night. Our argument regarded the cause of seasonal changes in animals. I argued that the sun is central to biological processes and blah blah. I confess I am rather ignorant about biology, I could not offer a more technical explanation, and now my interest is piqued. What process exactly does the sun set into motion that amounts to thicker fur? | [
"You're talking about photoperiodism, there's a little bit at this wiki article",
"http://en.wikipedia.org/wiki/Photoperiodism#In_animals",
"Essentially changes in the the dark-light balance during the year change the hormonal regulation of the animal's body. Some of these hormonal changes will have effects on ... | [
"There's a theory as to the certain timing of physiological processes that is governed by what's called a \"",
"circannual rhythm",
"\". It's similar to a circadian rhythm but takes place on an annual scale.",
"Essentially there's an internal clock that takes into account photoperiods, weather conditions, an... | [
"Thank you so much. It definitely seems I overlooked the complexity of conditions involved - namely the role of internal mechanisms. And at first after reading your response I wanted to ask whether internal mechanisms are only useful insofar as they are stimulated by external cues. Then I realized this can be ap... |
[
"How do colorblind people perceive lasers at the wavelengths they cannot see?"
] | [
false
] | null | [
"the common forms of colorblindness (",
" and ",
") don't really reduce the range of visible wavelengths (at least, not significantly), they just reduce the discriminability of wavelength patterns. the 'missing' cone pigments (so-called Long and Medium pigments for protanopia/deuteranopia, respectively) are so ... | [
"The question shows a misunderstanding of what colour blindness is. It's not that there are colours the person cannot see: it's that there are colours they can't distinguish. A colourblind person can perceive the same range of wavelengths of light as someone with full colour vision."
] | [
"More specifically, colorblind folks (at least the common red-green type) still have functioning rods, so they would be able to see the laser. And they have functioning blue and red cones, which will still fire slightly even in response to a green laser. So the laser will still be present perceptually, but it might... |
[
"Why do I sometimes hear electronic/mechanical noises in my head?"
] | [
false
] | null | [
"We cannot advise you about your own personal human body experiences."
] | [
"Hi EKUSUCALIBA thank you for submitting to ",
"/r/Askscience",
".",
" Please add flair to your post. ",
"Your post will be removed permanently if flair is not added within one hour. You can flair this post by replying to this message with your flair choice. It must be an exact match to one of the fol... | [
"Thank you for your submission! Unfortunately, your submission has been removed for the following reason(s):",
"We do not offer ",
"medical advice",
" on ",
"/r/AskScience",
". Please see our ",
"guidelines.",
" If you have concerns about your health, you need to speak to a medical professional.",
"... |
[
"Can an object become a black hole by moving fast enough?"
] | [
false
] | this week in school we have been learning about special relativity and we learnt that an objects mass increases as its speed approaches c. Does this mean there would be a point where its mass is large enough that it could become a black hole? | [
"No. The easiest way to see why the answer is no is to remember the laws of physics have to work the same in every inertial frame of reference (per special relativity). If the object won't act as a black whole in its stationary frame of reference, the same must be true for any other frame of reference where its spe... | [
"Here is my (well-deserved) rant against relativistic mass. (Your answer is buried in there somewhere. The answer is \"no\".)",
"I honestly do not know why many intro texts, courses, and teachers insist on telling students that an object's mass increases as its speed increases. This concept is so incredibly misle... | [
"The mass of the object doesn't actually change as it speeds up. The modern definition of mass is Lorentz-invariant, so it doesn't change with speed.",
"I really adore this sub. Until just now i was holding on to the arcane explanation that anything with mass cannot reach the speed of light because its mass would... |
[
"How does getting knocked on the head knock you out?"
] | [
false
] | I mean, you can get knocked out from a punch to the jaw, from a blow to the back of the head, maybe other ways. What's the physical mechanism of losing consciousness? | [
"I've answered this question before, but I can't find it. So I'll try to give a brief answer.",
"A great answer is, we don't really know.",
"However, a very likely guess comes from the act that neurons don't like to be \"jiggled\". I've seen first hand how most neurons will start to behave very abnormally if yo... | [
"would that be similar to the mechanism by which people are choked out or (if this is even real, I don't know) something like a karate chop to the neck? or is that a different process?"
] | [
"Choked out is caused by a loss of blood pressure to the brain. This then causes neurons to behave strangely, though whether this is due to loss of oxygen partial pressure, or due to the loss of physical support of the brain, or even some other mechanism is unclear.",
"Chop to the neck, no idea. Is that a real th... |
[
"How detailed is our knowledge of our own solar system? Is there any possibility of there being a physical body large enough to be classified as a planet that we have not discovered yet?"
] | [
false
] | null | [
"First let me tell you the story of how Neptune was discovered. ",
"All planets prior to Neptune were discovered by astronomers looking at the sky. As some scientists were looking at the data for the positions of Uranus in the sky, they noticed that Uranus was not behaving quite as predicted by Newton's gravity... | [
"Here's a chart",
" showing how large a planet could be at a given distance from the Sun without WISE detecting it. Looks like a planet the size of Neptune would need to be at least 3000 AU away (100 times Neptune's distance from the Sun), one the size of Saturn more than 10,000 AU away, and one the size of Jupit... | [
"There is a space telescope called WISE (Wide-field Infrared Survey Explorer) that scans the sky looking for things like this, and it has not found anything. It has been scanning the sky long enough that if there was something like that out there, WISE probably would have found it by now."
] |
[
"Directional sound: how do we distinguish front from back?"
] | [
false
] | I understand how the brain determines the left-right direction of incoming sounds based upon a time lag between the sound reaching one ear compared with the sound reaching the other ear (and also the volume drop between your ears). However, how does your brain determine front from back? If a sound is coming from 45 degrees (front-left), the time lag and volume drop would be the same as sound coming from 135 degrees (back-left). Is it a result of the shape of our ears affecting the shape of the incoming waves? | [
"It's mainly due to the shape of your ear--the quality of the pitch changes slightly due to the shape of your ear being non-symmetrical with respect to front and back.",
"I don't know exactly ",
" these changes manifest themselves (i.e. what the front/back filters do), but I know this is the general principle."... | [
"I studied this exact question for my undergraduate thesis, and again in graduate school. Let me first point out that the problem is inherently 3D, not just front-back. This is part of a complex process called auditory scene analysis, which is the general problem of figuring out what things in the environment are... | [
"Yes, the shape of the ear acts as a directionally sensitive filter.",
"http://en.wikipedia.org/wiki/Sound_localization"
] |
[
"how much potential energy is accrued the further a body moves away from the earth?"
] | [
false
] | obligatory excuse my ignorance. if an object at rest on earth is lifted to a higher altitude then the kinetic energy required to do so is converted to potential energy? so is there a limit to this? If an object is lifted higher and higher until it is only negligibly affected by the earth's gravitational field, does the amount of potential energy it gain keep increasing too? Would the voyager probe or some equivalent far off former piece of earth have enormous potential energy? | [
"Neatly this is how escape velocity is found. The kinetic energy of an object at escape velocity at sea level (or any other altitude you define escape velocity from) is equal to the amount of GPE it needs to gain to get out of the Earth's gravity well, basically to reach infinite distance at zero velocity.",
"Not... | [
"To lift an object at a steady speed (and therefore to not add or lose any ",
" energy between start and end of the lift) requires exactly balancing the force of gravity.",
"F = GMm / r",
"The gravitational potential energy gained is equal to the work done by the lifting force, which is force times distance m... | [
"It does go up as you move away from the Earth, potential energy is a negative number, therefore the closer it is to 0 the bigger it is"
] |
[
"What are these weird white hairs that grow really fast on my body?"
] | [
false
] | I've noticed them on other people too. They are very fine and thin white hairs that seem to sprout overnight. I get one under my chin and I also get one in my eyelashes on my left eye. My husband has one that grows out of his eyebrow and one on the top of his ear, and my friend has one that sprouts right out of the middle of her forehead. They aren't there and then in a matter of days they are, and are at least half an inch to an inch long. Does this phenomenon have a name? What causes this to happen? | [
"I would remind those responding that this isnt ",
"/r/DAE",
"Guidelines regarding commenter etiquette ask us to focus on answering the question.",
"Of 31 comments I see one reasonable response ( theswedishshaft )"
] | [
"thin white hair sounds like ",
"vellus hair",
", though you seem to describe isolated single hairs. Anyway, vellus can be influenced by hormone fluctuations in both males and females.",
"Disclaimer: I am not a scientist (not in the exact sciences anyway)."
] | [
"Some people just bloom late."
] |
[
"If boiling (or heating to 100ºC) kills all germs, what is the component in \"gone bad\" meat that can make you sick even after it is cooked."
] | [
false
] | If I had to guess it would be that maybe a chemical reaction creates some sort of toxin that obviously doesn't 'die' but I'm an art student and really have no idea.. | [
"Bacteria produce toxins, ",
"endotoxin",
", which is part of the bacterium, and released when the cell dies, and ",
"exotoxin",
", which is secreted by the cell when it is alive. Both of these can survive the boiling process. "
] | [
"Endotoxins would be my guess as well, but I want to point out that 100°C doesn't necessarily kill all bacteria. Length of exposure and pressure affect survival rates, and some bacteria can survive in extreme environments just fine. Example: strain 121 can survive autoclaving treatment (121°C at 15 psi for 20 minut... | [
"A good way to tell if it is the endotoxins that caused the sickness or the actual bacterium is the onset of symptoms after consuming the food. If it is rapid, immediate to an hour or so, then it is probably the chemicals in the food. If you wake up sick then the bacterium were probably not all dead, they were also... |
[
"If a skydiver's parachute never opened, would their body splatter upon impact, or would they make a small crater in the ground?"
] | [
false
] | [deleted] | [
"We are mostly water. Water is pretty good at absorbing energy. People stay pretty well intact when they hit the ground fast. The gorey stuff is usually the result of other situations. Like being dragged or sliding on concrete after an MVA."
] | [
"They would hit the ground moving at terminal velocity which is around 122 mph or 195 km/h which is fast enough to severely injure and probably kill them but not really fast enough to make a crater or a \"splatter\""
] | [
"Humans rarely fall into pieces from a fall. They would likely just bounce a bit. I've read about parachuters bouncing into trees after a fall. There is footage of people jumping from the WTC on 9/11, they just thud."
] |
[
"How significant is the effect of spicy food on metabolism?"
] | [
false
] | I've been going through a lot of Sriracha sauce lately and it got me thinking. I have always read that spicy food helps with weight loss as it speeds up your metabolism. Is this caused by irritating the gastrointestinal tract, causing food to pass more quickly, giving a similar result as not eating as much? Does it mean if one is to eat a fattening dish, covering it in hot sauce negates some of the unhealthiness? Is there an upper limit to the beneficial effects of capsaicin? I found a similar question asked , thought it doesn't really answer my question. Thanks! | [
"Most studies i've seen on it suggest that metabolic rate may be raised by about 10% for a rather short duration. ",
"See this abstract",
" for one example. RMR was only elevated for about 30 minutes. Sorry for the only-the-abstract link.",
"There are several studies out there researching other possible benef... | [
"I have been told that capsaicin consumption will make my sense of smell weaker.",
"Is there any truth about this?"
] | [
"I'm not a nutritional or biochemist of any kind, but I think it has to do with the compound ",
"capsaicin",
". Hopefully someone else with formal training can expand on this? "
] |
[
"Does therapy work?"
] | [
false
] | [deleted] | [
"The APA sure seems to think so. ",
"Here's their official statement regarding the effectiveness of psychotherapy",
".",
"Here's most relevant passage.",
"Research on Effectiveness",
"WHEREAS: the effects of psychotherapy are noted in the research as follows: The general or average effects of psychotherap... | [
"Reminder: ",
"/r/askscience",
" is not the place for personal anecdotes. Please provide sources for your posts. "
] | [
"As others have noted, there's plenty of evidence to suggest that psychotherapy is effective in the treatment of disorder. However, there's lots of variability in clinical practice and theory. It's a bit to broad to say that \"psychotherapy\" works. There's lots of practical differences between say Cognitive-Behavi... |
[
"if atoms and particles have \"rest mass\" or \"rest mass energy\" when they're moving is their mass different? how does the higgs field relate to rest mass?"
] | [
false
] | [deleted] | [
"People used to define masses which change based on how the object is moving, but they are ugly and generally an unnecessary concept. These days \"mass\" and \"rest mass\" mean the exact same thing. Rest energy is just rest mass times c",
".",
"The Higgs mechanism gives certain particles some of their (rest) ma... | [
"If you define mass to be the energy of an object in its own rest frame, that's an invariant quantity. That means that no matter what frame I'm in, your mass is always defined to be the quantity that ",
" measure in your own rest frame. All observers agree on that."
] | [
"In this instance, how is energy conserved?",
"Energy is conserved in each individual reference frame, but it's not invariant under change of reference frames."
] |
[
"Can't understand torque transfer in a LSD differential - i have a little example of locked differential, maybe someone would help to explain what would happen if we replaced locked with LSD diff?"
] | [
false
] | So i watched a video from youtube channel EngineeringExplained about - here's the picture of the So he explains that in that situation we have about 9000 N on the back of the wheels. Because one wheel is on the snow, the maximum force that you can apply to the wheel without spinning it would be 4500*0.3 (friction coefficient) = 1350 N of the force. When we exceed 1350 N, the wheel will "want" to spin, but because it's locked differential, it won't spin and the torque will transfer to the second wheel. So lets say we have a wheel radius of 0.4 m. To spin both wheels we'll need to exceed: 0.4*(4500+1350) = 2340 Nm. Is that right? Plus, in that situation the wheel on the snow gets 540 Nm, and the other on the pavement 1800 Nm(thus the 77/23 torque distribution that he mentions). Lets say we have the same situation but the differential is an LSD type and it has torque of an 180 Nm(i can't understand what does this number means too). Plus, the differential is not fully locking. What will happen if we send the same amount of the torque to the wheels(if we have an LSD differential with an 180 Nm torque split(?) )? How will the torque that needed to spin both wheels(2340 Nm) will be distributed? If it is not fully locking, then we don't have to "wait" to exceed the 2340 Nm point, is that right? But if the distribution is not,for example, like in locked - 77/23,and lets say it is 60/40, then it is not "enough" 2340 Nm to spin the second wheel(60/40 split means 1404/936), and we'll need more torque from engine to be able to spin that wheel.. I am completely lost.. Maybe can someone explain me a little bit? | [
"180Nm is what it takes for one wheel to spin differently than the other. So the the wheel in the snow gets 1350 ",
" , the other gets (1350-180). ",
"Limited slip differentials aren't designed for this."
] | [
"Sorry, that should have been (1350+180). Also the 180Nm could be either constant, initial, or maximum torque difference between the wheels. Constant being independent of torque applied, initial being with no power applied through the drive train, and maximum being max power applied with max traction.",
"Limited ... | [
"So this torque is constant? Like always there will just this difference(-180Nm) of torque? And what do you mean by that that they aren't designed for this? You can't calculate precisely how torque will be distributed in a different conditions?"
] |
[
"Why, if we get a new set of skin every 80 days or so, does skin ever become wrinkled and old?"
] | [
false
] | Cells replace each other, so why does skin age if they are new cells? | [
"Collagen and elastase degradation in the skin matrix. These proteins give skin its flexible nature. Over time the protein is no longer secreted as readily by fibroblasts and the existing matrix begin to degrade, resulting in looser skin."
] | [
"As much as I'm flattered that so many people have remembered senescence and telomerase after cell biology class, there's a lot of misinformation in this thread due to the assumption that the skin is made entirely of cells. The collagen/elastase that ",
"/u/CarlJungBlood",
" correctly refers to are actually fou... | [
" ",
"Look, I also remember being a biochemistry major and learning about telomerase for the first time and thinking, \"WOW, if only we had a perfect version of telomerase and were invincible to DNA damage/errors, we could live forever!\" But that's not the way it works.",
"Telomeres are not there to make you... |
[
"why do most celestial bodies rotate?"
] | [
false
] | null | [
"It's pretty much just conservation of angular momentum. Most astronomical objects form from some large diffuse cloud and gravitationally shrink. To conserve the angular momentum, any net rotation in the large initial object (even if initially just random and very small) can end up having a large effect.",
"For e... | [
"You're right and this is nitpicky but what you're really explaining is why things rotate faster as they condense, not necessarily why they rotate in the first place. You're close with the mention of the rotation being seeded \"",
"\" net rotation, but that net rotation need not be influenced by neighboring syst... | [
"So a body rotates faster the more it shrinks in size. The rate of rotation depends on the conservation of angular momentum while the shrinking depends on the gravity of the body. Is that right?",
"So my question is, when a black hole forms, can we calculate how quickly it would end up rotating at a given mass an... |
[
"I'm confused between the calories I learnt in high school Physics and the calories associated with nutrition."
] | [
false
] | What is the relationship? If a piece of food has 100 calories on the backside label, what does that mean? Does it mean that it will take my body a 100 calories (418J) to burn it off? Does it mean my body has to generate that 100 calories? | [
"It'll take 418 ",
"joules. The food Calorie is actually a kilocalorie."
] | [
"1 calorie is the amount of energy to raise 1g of water 1°C, in food the Calorie you see i actually a kilocalorie (hence the capital C)"
] | [
"To add to that, this link explains somewhat well the concept of this calorie thing ",
"http://recipes.howstuffworks.com/question670.htm"
] |
[
"What exactly does it mean when something has a \"negative\" charge or a \"positive\" charge? Why do like charges repel and unlike charges attract?"
] | [
false
] | null | [
"Charge is an intrinic property of particles. The determination of “positive” or “negative” is purely a convention. You could easily flip what you call positive and negative and get back the same Physics. (If you did this now there would be positively charged electrons and negatively charged protons) Macro-scaled o... | [
"Right, CPT is the full symmetry, but that is really beyond the scope of this question. ",
"Also, you could imagine that if we originally had chosen the electron to be positively charged we would have determined all the same physics happening and things we typically think as being one way get flipped by due to CP... | [
"Thank you!"
] |
[
"Was Pangaea the only land mass at the time and how do we know that?"
] | [
false
] | [deleted] | [
"Depends on how you define 'only landmass'. A ",
"reconstruction of paleogeography for the Permian",
" during kind of the middle of the the existence of Pangea highlights that while the bulk of landmasses are semi-continuous, i.e. ",
"Laurasia",
" and ",
"Gondwana",
" are joined, there are semi-isolated... | [
"Also, continental crust can’t sink! It’s much lighter/less dense than oceanic crust - continental crust is what geologists call “felsic” (for the mineral feldspar, which can contain sodium, potassium, or calcium depending on the subtype of feldspar, plus silicon!) while oceanic crust is “mafic” (contains a much hi... | [
"This is kind of the 'Geology 101' version of things, however in reality, there is a measurable (and in some sense significant) amount of continental crust recycling through the combined processes of subduction erosion, subduction of eroded sediment, and true continental subduction / foundering of crustal roots (wh... |
[
"Are the dorsal ridges on Human/Mammal vertebrae vestigial organs? [Biology]"
] | [
false
] | If so, what function did they serve in our common ancestors, and is there any evidence to show that they are either shrinking or growing? | [
"Nice question! I assume you are refferring to the ",
"spinous processes",
" of vertebrae? If so, they actually serve some important functions for muscle attachment! Some muscles that originate or insert there include: the erector spinae and interspinals. this muscles helps flex the back (arch your back! that's... | [
"Thanks for your answer!"
] | [
"for sure! no problem :)"
] |
[
"Can you help me wrap my head around the idea that if you rotate an electron 360 degrees it's different, but if you rotate it 720 degrees it's back to the same state?"
] | [
false
] | Imagine that I have a magical box. Inside the box I have a bunch of suspended non-interacting electrons. I also have a magical pouch, which also has a bunch of suspended non-interacting electrons. Now I dump the electrons from the pouch into the box such that they hit head-on, and I watch which ones interfere. Imagine that instead of just dumping the electrons in the box, I walked around the box once first. Am I supposed to believe that the opposite electrons will interfere if I've walked around the box once (i.e. I see the box electrons to be 'rotated 360 degrees' with respect to the pouch electrons)? This seems silly to me. | [
"Searched",
"Relevant ",
"discussion",
"Original question by ",
"darksoulshaman",
"I was just reading ",
"this",
" thread, which has a lot of science-related comments, and it reminded me of something interesting my high school chemistry teacher once said.",
"He said essentially if you took a (tiny) ... | [
"Thanks, search bot. I have indeed seen the Dirac cup trick (or Feynman plate trick, or whatever you want to call it), but unless the electron is attached to something by, say, an arm, it doesn't really make much sense to me. I'm still looking for an answer to my question above, which essentially boils down to 'can... | [
"When doing quantum mechanics you have to be careful to separate the concept of the wave function from the probability. You need to rotate the electron 720 degrees to get the wave function back to where it started. If you rotate the system 360 degrees then the wave function will be negative one times the original w... |
[
"Why do acidic foods dissolve copper pots?"
] | [
false
] | According to the Food and Drug Administration, acidic foods cause copper on unprotected cookware to dissolve into foods. If you use unprotected copper-lined pots and pans, research the acidity of certain foods. Excerpt out of the table of galvanic series: With more noble metals being higher up, shouldn't the H atoms of the acid be unable to oxidize copper atoms? Cu + 2H → H2 + Cu seems impossible without an external power source | [
"They're pretty close in the galvanic series, but it's possible to get local cathodic/anodic activity, possibly a concentration gradient at a nick in the copper.",
"Honestly, copper can corrode in plain water as well (pH 7). Edit: at elevated temperature ",
"Regarding the galvanic series, these are certainly a ... | [
"My electrochemistry knowledge is very rusty, but I think you're right as far as where you got started. You should actually use the Cu(2+)+2e(-)->Cu(s) potential = +0.337 I think. But you will still get the same result.",
"However, let's look at Cu+2H(+) -> Cu(2+)+H2, for the sake of more understanding, even thou... | [
"This is an interesting question!",
"The standard electrode potential for hydrogen is for 1 mol/L strong acid (pH = 0) against a platinum electrode with an atmosphere of H2 (1 Bar). This is an equilibrium system, where the activities of all species in the redox couple are equal. You notice the anion of the acid d... |
[
"What would I experience if I was trapped in an air bubble on a sinking battleship?"
] | [
false
] | After looking at this picture: And seeing this video of a man they did find in an air bubble on a sunken ship: If I was trapped in an air bubble on lets say the Bismark and the ship was sinking to the bottom of the ocean, what would I experience in the air bubble as the ship descending to its resting depth? | [
"If it were to sink deep enough, provided the air bubble were large enough to sustain life, eventually oxygen toxicity would kill you. See the ",
"MOD table here.",
"Oxygen toxicity",
" occurs at about ",
"1.4 atmospheres,",
" or about 187 feet of depth. Nitrogen narcosis is highly variable between indivi... | [
"The pressure inside a submarine is one atmosphere, while outside it's higher, so eventually it gets crushed. But in this scenario, the ship is not sealed, the pressure inside and outside is the same, but the air bubble gets smaller and smaller. So there is no force to crush it."
] | [
"Good answer, something to keep in mind is that every 33 feet of salt water is equal to one atmosphere of pressure. So while the human body would be able to handle upwards of 30 atmospheres of pressure temporarily a few things would happen at those depths: first, you would likely very quickly succumb to nitrogen na... |
[
"If shaking a carbonated beverage in a can increases the pressure, why does letting it sit for some time decrease the pressure back to normal? What happens to that pressure?"
] | [
false
] | null | [
"The key here is nucleation.",
"https://www.youtube.com/watch?v=l5xbgNTxApo",
" - this video explains it all. Basically, small bubbles stick to the sides of the can when you shake it. When the pressure is released/lowered, those bubbles expand. And that rapid expansion pushes the liquid out.",
"When a can \"s... | [
"CO2 is dissolved in liquid. When you agitate(shake) the can you are adding kinetic energy which drives the gas out of the liquid phase. All the molecules are moving around at an increased rate and the gas comes into contact with more gas molecules and the liquid with the liquid. Molecules of the same kind typicall... | [
"Shaking carbonated beverage increases pressure because it releases CO2 from beverage to air gap in the can. When you let it sit, CO2 slowly gets back in to the solution. That decreases the pressure back to normal. "
] |
[
"How could a topical application of medicine travel to the targeted muscle?"
] | [
false
] | I have had several friends recommend some kind of topical cream for my muscle cramps. They say you just massage it into the skin at the problem area. I think this must be baloney, mostly, because anything that gets through the skin would be more or less carried away by the blood and metabolized right? I see an added benefit of the massage being helpful in itself, but come on, medicine on the skin doesn't just sink in deeper and deeper through tissue and into muscle, or does it? | [
"Topical pain-relief solutions work by “jamming” the pain signals from the muscle/joint. Most of these ointments have menthol as the active ingredient which basically gives you a mild chemical burn over a large surface area of skin.",
"This overloads the nerves and sends the “mildly warm” signal to the brain ins... | [
"I had wondered about this, too. But it seems the data from meta-analyses consistently holds out on their efficacy beyond placebo.",
"https://sciencebasedmedicine.org/topical-nsaids/"
] | [
"Sure works for me - I have severe arthritis in my hands, and I use a cannabis infused topical cream. Without it, I’d be a walking crone with talons for hands. Feels pretty good on my old knee too. ",
"As for HOW it works, or WHY? Don’t know. Just know that it does. "
] |
[
"With two observers in two different frames of reference involving relativistic mechanics, is length dilated, or time, or both?"
] | [
false
] | I'm brushing up my Relativity knowledge (12+ years out of touch) but I understand the basics. In this case, say, observer1 is moving at a constant speed approaching c, and the other is stationary. Also, keeping gravitation out for this one - will get to General Relativity later. | [
"Both. I don't believe there's a way to get one without the other. Normally you formulate questions so you only have to consider one or the other but a full battery of questions about what each observer 'sees' and measures will definitely include both at some point."
] | [
"One or the other.",
"Consider muons rushing from space down through the atmosphere to the ground. From our point of view they take a certain amount of time which is far more than their half life. This is possible because we see them traverse the atmosphere with dilated time.",
"From their point of view, howeve... | [
"We would also see ",
" length contracted, and they would also see ",
" time dilated. So, it's not one or the other, it's both.",
"In your muon example, there are two reference frames. There is the \"Earth\" reference frame, and the \"muon\" reference frame. Either reference frame can be considered at rest. I... |
[
"What is the exact wind speed the average weight seagull needs passing over it's wings to 'hover'?"
] | [
false
] | Just walking up form the bus stop, and I saw a seagull 'hovering'. Now, presumably the wind speed was just enough to pass over it's wings to generate enough lift to offset the seagulls weight, and it got me thinking. What is the exact wind speed that the average weight seagull needs flowing over it's wings to offset it's weight? | [
"It's going to vary. Unlike an airplane, which can only slightly change the shape of their wings, birds have much greater control. Changing the wing shape will change the lift and drag on the wings. I don't know much about how birds flap, so I don't know if their wings are always the same shape when flapping or not... | [
"Purely horizontal wind won't do it as the seagull is not producing any thrust when hovering, and the drag would push it backwards. To truly hover there needs to be an updraft for the seagull to 'fall' through to keep up forward speed."
] | [
"You'll still need a force to counteract the drag of the high-speed wind."
] |
[
"Is it possible to travel backwards in time under the current laws of physics?"
] | [
false
] | I understand time dilation can create a discrepancy of perceived time from those within the moving object, but are there any hypothetical way to travel in the opposite direction against the flow of time? | [
"The problem with time travel to the past is that it violates conservation of energy/mass. Say you time travel back three days and appear in your room. In the local reference frame, you were not there one second and then you are there the next second. Mass/energy has therefore been created out of nothing, which is ... | [
"However, it has been shown (by Richard Feynman) that antiparticles are regular particles traveling backwards in time.",
"It was shown that you could think of them that way as they would still obey certain symmetries, but that isn't what they ",
". For instance, a box of antiparticles isn't going to disobey the... | [
"However, it has been shown (by Richard Feynman) that antiparticles are regular particles traveling backwards in time.",
"It was shown that you could think of them that way as they would still obey certain symmetries, but that isn't what they ",
". For instance, a box of antiparticles isn't going to disobey the... |
[
"Is there any difference between eating vitamins from say, a vegetable or eating vitamins from a pill?"
] | [
false
] | Everyone who's ever had an opinion on this says that natural is better. But then they just say, because it's natural. So I want to know, is there any science behind this or is it just the naturalistic fallacy at work? Thanks. | [
"Doctor Stephen Novella talked about this on the Skeptics Guide. If memory serves then eating a pill gives you a very narrow benefit, lots of one specific vitamin. However eating your veg gives you a far far wider range of vitamins that pills simply cannot match. I believe that if you relied on pills, you would ... | [
"Yes, they put actual iron filings in the cereal. Because our body needs actual iron to survive. Yes, we process iron in that form."
] | [
"Yes, they put actual iron filings in the cereal. Because our body needs actual iron to survive. Yes, we process iron in that form."
] |
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