title list | over_18 list | post_content stringlengths 0 9.37k ⌀ | C1 list | C2 list | C3 list |
|---|---|---|---|---|---|
[
"Why does a string with a knot on one end seem easier to swing in a circle than one without a knot?"
] | [
false
] | If I have a uniform piece of string, and try to hold it by one and and swing it around in a circle repeatedly, it seems quite difficult. But, if I tie a couple of knots on the end of the same string, it seems a lot easier to swing around. What's the major effect at play here? Is it not actually any "easier" and just my... | [
"You're not crazy! If more of the string's weight is on the end of that string, the force you apply to the string is translated there (because where mass is is where the force is). It's way easier to generate centripetal force (i.e. the reason the string spins) when the mass is concentrated in one place."
] | [
"Why is it easier to generate centripetal force when the mass is concentrated?"
] | [
"[Not a professional in mechanics]",
"I think there may be multiple related issues in play here. Two of them are rigidity and density relative to the air. Consider whether you would be having the same problem if you were spinning a thin metal rod, like a coat hanger that you straightened out and then bent at one ... |
[
"Why do we feel a pumping or throbbing sensation when we have an injury such as a cut?"
] | [
false
] | null | [
"In the immediate aftermath of the cut your body reacts with localized inflammation and swelling as an immune response and to lessen blood loss. This combined with an increase in blood flow to the area puts a great deal of pressure on your blood vessels. Because of this increased pressure, you can feel your pulse t... | [
"This is a great question, I've answered it briefly in some of my other posts. What you are experiencing when you have that \"throbbing\" sensation is actual part of the definition of inflammation. It was first described by Celsus (a Roman physician from the 1st C. AD) and later expanded upon by Galen. Inflammat... | [
"Hi there! It’s not actually due to blood flow into the area but is a common misconception. There have been a couple studies that debunked this. I left an overly detailed answer in this thread as well, if you’d like to read it! I hope if you have any questions or things to discuss you’ll reach out!"
] |
[
"Publications from North Korea..."
] | [
false
] | null | [
"It wouldn't really matter much for me, but I can't really recall seeing a North Korean paper in any context, really. I did once hear a second or third hand account about a North Korean guest researcher they had at my university back in the 80's, who was accompanied by an appointed chaperone (I'd suppose, to make s... | [
"When it comes to Lysenkoism in USSR, similar things were starting to happen in other fields as well. However, that was also the time when Soviet Union was developing their first nuclear weapons, and scientists working on those managed to persuade the government against supporting followers of Lysenko in other fiel... | [
"True. In chemistry their society of chemists denounced resonance theory as \"bourgeois science\" in a letter to Stalin. I'm doubtful how far that ever went in practice though, or their organic chemistry would've been in just as bad a situation as their biology. ",
"Things lightened up once Stalinism and Lysenkoi... |
[
"Does a full fridge cool more efficiently than an empty one?"
] | [
false
] | [deleted] | [
"The full one - it usually even states this in your manual. But, when you open the door, you let that cold air escape, and the overall temperature inside the fridge goes up. Hopefully your beers don't escape when you open the door, but assuming they stay put, you won't add as much heat in every time you open the do... | [
"No, just always have a supply on hand to replace them, right?"
] | [
"So if a guy wants to save on his electricity bills, the key is to not drink the beers. Oh life, why are you so full of difficult choices?"
] |
[
"How does a spiral galaxy STAY a spiral galaxy?"
] | [
false
] | Dark matter, no dark matter, MOND, giant space whale shenanigans, you name it, but orbital periods still increase as you go out from the galactic core, and they range in the hundreds of millions of years, yet spiral galaxies keep distinct spiral arms for of years. How do? | [
"The spiral arms of the galaxy aren't a 'winding' phenomenon. i.e. They didn't start as straight lines that have been wound around the center as the galaxy rotates. ",
"All of the stars/gas etc in a galaxy have elliptical orbits - just like all of the planets in the solar system. The Spiral arms are a result of t... | [
"For a visualization, take a look at ",
"this youtube video",
". The left side describes the spirals as you think about them, while the right side are how they actually behave. The video description has more details."
] | [
"Great video thank you for sharing :)"
] |
[
"If there was a body of water that was as deep as the Marianas Trench but perfectly clear and straight down, would you be able to see all the way to the bottom?"
] | [
false
] | null | [
"Even pure water absorbs and scatters light so you could not see the bottom of the \nMarianas Trench (10,994 m depth). The amount of sunlight in the ocean decreases exponentially from the surface. The ",
" varies with colors (wavelength) with the blues penetrating the deepest to a few hundred meters. So even if... | [
"Obviously we can see that far...I see the moon all the time and it's ",
" 7 miles away..maybe 8."
] | [
"But those reflect light. But then so does anything that you can see.\nI'm not sure what anyone is talking about."
] |
[
"What would happen if you just took a commercial plane and drive it straight up into the atmosphere trying to reach space?"
] | [
false
] | null | [
"If you actually tried to fly it straight up, it would stall.",
"If you tried to fly at the maximum rate of ascent, eventually the air would get too ",
" thin for the engines to work, or for the angle of attack on the wings to have much of an effect, so you'd be effectively limited to a certain altitude (what t... | [
"Well it wouldn't ever be able to ever reach outer space but say we just plopped a plane into orbit there would still be a problem. Designing a body to maintain it's internal pressure with the near vacuum of space requires a more robust design than modern commercial aircrafts employ."
] | [
"Disagree on what grounds? A commercial aircraft at 30000 feet experiences external pressure of 4.3 psi, while maintaining an internal pressure of about 8 to 11 psi - a difference of 4 to 7 psi that comports with articles I found indicating that commercial airframes can withstand a maximum pressure differential of ... |
[
"In a reaction between enzymes and substrates, does increasing the number of enzymes affect the rate of reaction whatsoever?"
] | [
false
] | I've been getting mixed answers here and there when I tried to look it up. Some say only acidity, temperature, and substrate concentration affects. Some say enzyme concentration also affects. Others say enzyme concentration only affects the maximum rate of reaction and nothing else. So what's the answer? | [
"Enzyme concentration affects reaction rate as long as there are more substrates than enzymes, which we typically assume for most cases. The typical representation of enzyme action looks like this:",
"rate=k[E][S]/K+[S] where k and K are reaction constants (meaning they don't change based on concentrations of spe... | [
"Yes increasing the amount of enzymes will affect the rate of the reaction. But temperature and pH will also affect the rate of the reaction as there are enzymes that work more efficiently in specific temperatures and pH. Several factors affect the rate of a reaction. "
] | [
"Let's say you have a reaction A --> B catalyzed by enzyme X. ",
"You accumulate product B at 1 mM / min",
"Now dilute your enzyme 10,000-fold and try again",
"You will not accumulate B as quickly. ",
"On the flip side, if all of your substrate is bound by enzyme, and you have free enzymes floating around, ... |
[
"How do my cat's hairs have multiple colors on a single strand?"
] | [
false
] | I have a grey/black male tabby, and his hairs have bands of grey, black, and blonde on individual hair strands. He's an indoor cat, so it's probably not just faded from the sun. How does the pigment change on a single strand, and how is this different than the way human hair is pigmented? | [
"Cells responsible for pigmentation",
" can change pigments, rapidly, mid-hair, in some species.",
"\nMy cat Max is a brown ",
"Mackerel Tabby",
" (mutt cat, just describing the color accurately) and he has an Agouti (changing colors through the shaft of one hair) coat. ",
"More information on animal hai... | [
"Human hair grows without changing pigments mid-hair",
"I regularly pull hairs from my chin/beard that are combinations of red/brown/black/blonde.",
"Sometimes the tip of the hair is black and the part closer to the skin is blonde, sometimes the other way around, but that's the most common one I see.",
"Were ... | [
"Thanks for the specific answer. ",
"Agouti",
" perfectly describes his hair. Coincidentally, he is also a tabby named Max. Are you me?"
] |
[
"When you burn yourself pretty bad, say on the hand, the pain seems to stay on the surface of your skin. When you subject your hand to extreme cold, it feels bone deep. Why?"
] | [
false
] | This is from my experience. Does a severe burn also feel bone deep? I thought of this question today at where I work, it's a frozen yogurt place and I was holding some in my hand. After a while, my bone started to hurt, as it always does, all the way up to my elbow. I have never experienced a burn that felt bone deep. ... | [
"Because a burn ",
" damage to the surface of your skin. If your hand was burned all the way through, your nerves would be dead from the heat. The low temperatures you're referring to don't actually do damage to your hand, which is why you can feel them so acutely.",
"If you put your hand in really hot water ... | [
"Painful stimuli travels to the brain via two different pathways. One, the Neospinothalamic tract, transmits pain much faster and is associated with more acute stinging type pain which is generally more localized (i.e., to a burn on the surface of your skin). ",
"The other, the Paleospinothalamic tract transmit... | [
"Thank you!"
] |
[
"Ask Anything Wednesday - Biology, Chemistry, Neuroscience, Medicine, Psychology"
] | [
false
] | Welcome to our weekly feature, Ask Anything Wednesday - this week we are focusing on Do you have a question within these topics you weren't sure was worth submitting? Is something a bit too speculative for a typical post? No question is too big or small for AAW. In this thread you can ask any science-related question! ... | [
"[Psychology] Posting here because my post didn't show up on the \"new\" page after hours. ",
"Some years ago I have watched a youtube video about persuasion techniques used in the media to indoctrinate people. The video spoke about a technique whereby media will show many photos of something to give you the impr... | [
"The technique (or really phenomenon) that you’re describing is called the “availability heuristic.” There are a million articles on it, but kahneman and tversky are highly cited co-authors who have written extensively on the topic (as well as other common heuristics that humans rely on) if you want a more in depth... | [
"[Biology, taxonomy] If there were aliens and they were examined, where would they be classified in the current systems of classification? would they be put in one of the existing Domain/Kingdom, or have a completely new one if they were:",
"1) Not based on carbon;",
"2) completely different to any form of life... |
[
"during the annealing stage in PCR, why don't the recently split complimentary DNA strands attach back to each other instead of the primer?"
] | [
false
] | is it because they are so much bigger? or do they attach to each other like 1/2 the time, and the other 1/2 the time the primer attaches first? | [
"Yes to your first supposition; it is because the primers are much shorter, and there is a much higher concentration of primers than template. This is also why annealing is not at body temperature. During initialization and denaturing, the strands not only break their hydrogen bonds but also mix around the tube and... | [
"They can, but it is unlikely. ",
"At the beginning of the reaction you probably have 10",
" more primers than target. Even by the end of the reaction, you will have about 100 times more primers than target. "
] | [
"ah crap. now i feel retarded. i wasn't even thinking about the concentrations. thanks guys."
] |
[
"Can an element's properties be predicted from the structure of its atom?"
] | [
false
] | I.e., imagine there was no gold on Earth and humans had never encountered the stuff before. Would we be able to guess that "Unknown Element 79" would be yellow in color, very dense, and melt at 1947.52 °F based on the fact that it had 79 electrons, 79 protons, etc? | [
"To my knowledge color is beyond our ability to predict right now, but phase, density, and melting/boiling points are things that are calculated, although to nowhere near that level of precision. You can see that today with synthetic elements, like ",
"Copernicium",
", which is predicted to be (possibly) the on... | [
"Actually, the chemical properties of a substance are much more dependent on the electron structure than the nuclear structure. For example, the way we would know about the metallic nature of any atom is by looking at its valence electrons and seeing if it is holding on to them very strongly. Generally, metals tend... | [
"Nuclear structure affects electronic structure way too much to divorce the two concepts like that.",
"Not really. The Z of the nucleus determines the number of electrons in an atom. Then there's things like isotopic shift and hyperfine structure, which are very small effects."
] |
[
"Do we have any systems in which other planets rotate around a giant planet instead of a star?"
] | [
false
] | Like something with star-level mass but not out of material that can react in a fusion reaction under that much gravity. If no, then why not? | [
"Well, I think anything with high enough mass would become a star. I guess if you would collect heavier elements than helium in a large enough quantity, that wouldn't start fusion and won't be a star. But given that 98% of material is hydrogen or helium, that just doesn't happen naturally."
] | [
"Hydrogen and helium are by far the most common element in the universe. It's just not plausible to form an object of stellar mass that isn't a hydrogen-helium composition.",
"There are planets orbiting white dwarfs and neutron stars, but those used to be stars."
] | [
"The Planetary Solar System Model dictates that in order to be classified as a Solar System you would not find a planet at the center only a Star. We do have systems and that would be classified as a planet with moons. It is part of the classification verbiage. So the answer is yes but it is not an actual Solar Sys... |
[
"How do we measure the caloric content of food?"
] | [
false
] | How, for instance, do we know that there are 100 calories in a serving of whatever (oreos, for instance)? | [
"Realistically, you just determine the protein, carbohydrate and fat content (or know that content for all the ingredients and calculate from there) and, from the known energy contents of each of those, calculate the total energy content.",
"As for how those values are initially obtained, you literally do that by... | [
"I remember using a calorimeter to measure kilocalories in a chemistry lab in school. Burn a sample and measure the generated heat. I don't think that is how calories are calculated for food labels. The following link that describes the Atwater system. The components (protein, carbs, and fat) are measured and c... | [
"Awesome, thanks!"
] |
[
"What would happen if you remove the electrons from a sand grain and put them inside a second sand grain and release them at some distance from each other?"
] | [
false
] | null | [
"The charge must be considerably more than 1.3 x 10",
" C, as even one electron is 1.6 x 10",
" C. The molecular mass of silicon dioxide is 60g/mol, so here we have 8.3 x 10",
" moles, which is still 5.0x10",
" molecules.",
"I think the charge should then be 5.0x10",
" x 1.6x10",
" C = 8.0x10",
" C.... | [
"Ah I see what happened if you type \"electron charge per mole\" into google it gives you nonsense.",
"This will give you the correct charge: \n",
"https://www.google.com/search?q=electron+charge&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-beta#hl=en&client=firefox-beta&tbo=d&rls=org.mo... | [
"For amusement I throw in the gravity between those two grains of sand and it's 1.7 × 10",
" newtons"
] |
[
"Did NASA really just say they performed an apparently successful test of a reactionless drive?"
] | [
false
] | and its comments suggest that NASA engineers tested some kind of reactionless thrust device with positive results. From the comments I was led to , but I can't penetrate the jargon well enough to get a clear idea of what it's saying, nor find the full paper. Commenters and I found say that the NASA device is kind of ... | [
"Effectively, yes. Everyone is still relatively skeptical, as is natural, but basically, three independent agencies, one of which is NASA, have tested one of two variants on this drive. The one China and Argentina (I believe) is the EmDrive, and NASA tested a version called the Cannae Drive. The one NASA tested see... | [
"You're right they were careful, but the control they used suggests some kind of mistake is reasonably likely. They used a disabled version of the drive to ensure that they would measure 0 thrust, but they actually still got thrust. Generally speaking, if your control experiment gives the same result as your test e... | [
"You could not be more wrong. The lack of propellant used is such a vast advantage, such an incredible prospect that it would utterly revolutionise the space industry.",
"You totally underestimate the limits placed on spacecraft by having to carry fuel. "
] |
[
"[Physics][Astronomy] Is there any property of space which enables it to \"remember\" its previous configuration?"
] | [
false
] | This is my thinking process: Consider a room. It has objects; tables, chairs and so. Since these objects have mass, they cause a very small dent in space-time. Now, if these objects are removed from the room, the space-time will come back to its original state; that is, it will no longer be curved/distroted. Does this ... | [
"Gravity moves at the speed of light, so space-time will restore itself pretty much instantly. Gravitational radiation ",
"http://en.m.wikipedia.org/wiki/Gravitational_wave",
" might allow us to capture the potential impact that an object had on space-time though. "
] | [
"Gravity propogates at the speed of light. When we refer to the speed of gravity, we are essentially talking about gravity waves that travel at the speed of light.",
"Source"
] | [
"C isn't technically the \"speed of light\", it's actually the speed of massless particles.",
"\"Thus, the speed of \"light\" is also the speed of gravitational waves and any other massless particle.\" ",
"http://en.wikipedia.org/wiki/Speed_of_gravity"
] |
[
"Can polar and nonpolar molecules ever mix?"
] | [
false
] | What if polar and nonpolar fluids had the exact same specific densities? Is there anything keeping them from mixing? | [
"When two liquid phases, A and B, are in equilibrium (even if they are immiscible) there will some A in the B phase and some B in the A phase. A common measure of this phenomenon is the partition coefficient ",
"http://en.wikipedia.org/wiki/Partition_coefficient"
] | [
"There is one product which you may have seen if you've ever looked at the ingredients in Mountain Dew. Brominated vegetable oil is used to tune the density of citrus flavors so they are the same density as the water. They form an emulsion and prevent an oily layer from forming.",
"http://en.wikipedia.org/wiki/... | [
"Yes, but for all purposes the non-polar tails of soaps don't interact with the water. The soap molecules form micelles (an aggregate of soap molecules forming a spherical shell) with the tails facing into the shell and the polar heads forming the surface of the shell and interacting with the polar water. ",
"Tha... |
[
"Would the sun's core be pitch black as it is too hot for the visible spectrum?"
] | [
false
] | null | [
"No. The distribution of the radiation wavelengths will vary according to temperature (with all wavelengths increasing in intensity as a black body becomes hotter), and any part of the sun undergoing fusion would emit radiation in the visible spectrum. ",
"http://en.wikipedia.org/wiki/Black-body_radiation#Spectru... | [
"Absolutely. Nuclear weapons achieve, for the briefest of instants, an exponentially tiny fraction of what is going on and has been going on every second since the Sun began nuclear fusion. The Sun transforms 600 million tons of hydrogen into 596 million tons of helium every second. The remaining 4 million tons ... | [
"An even stronger statement can be made: A blackbody will emit ",
" light at every wavelength than a cooler blackbody.",
"The center of the sun would be much much ",
" in visible light than the surface."
] |
[
"How is energy harnessed from a fusion reactor? Is it the same principle as fission reactors or is it something entirely different, given the vast difference in temperature involved?"
] | [
false
] | null | [
"When you think about it, aside from wind, solar and hydro, most of our electric power plants are basically steam engines. The only thing that varies is what makes the heat to boil water."
] | [
"When you think about it, aside from wind, solar and hydro, most of our electric power plants are basically steam engines. The only thing that varies is what makes the heat to boil water."
] | [
"having steam turbines is in fact very beneficial for running a grid because they give builtin stabilisation measures allowing you to react fast enough when the frequency of the power grid drifts, the inertia of the rotating masses softens sudden frequency drops. photovoltaics for instance don't have these mechanis... |
[
"Is there a cryptographic system that does not depend on a specific problem being hard to solve?"
] | [
false
] | [deleted] | [
"Yes. The one-time pad. It is a substitution cipher that hashes a message with a specific key, previously distributed between both parties, and as the name implies, that key is discarded after use. That key can be as simple or as elaborate as needed, derived from a purely mathematical arrangement or a book or anyth... | [
"It's very simple and completely unbreakable (excepting things like rubber hose cryptanalysis), but you have to distribute the keys between the communicating parties without them being intercepted, and each key can only be used once."
] | [
"It's very simple and completely unbreakable (excepting things like rubber hose cryptanalysis), but you have to distribute the keys between the communicating parties without them being intercepted, and each key can only be used once."
] |
[
"Biologists: Is there an animal \"Y\" that can breed with \"X\" and \"Z\" but \"X\" and \"Z\" can not interbreed?"
] | [
false
] | This would be in relation to Evolution and Speciation. I am curious how common the blurring of the line is. I know some dogs can not interbreed because the birth is normally fatal for the mother (if the mother is the smaller breed). But is the function common on a genetic level? Like, if "Fox" could breed with "dog".... | [
"Ring species",
" is what you're looking for."
] | [
"Ring species, as bperki8 says. \nBut interbreeding is more complex: ",
"Absolutely can't interbreed (no mating, no viable offspring)",
"Won't interbreed: Don't ever get to meet, nocturnal vs diurnal, don't approve of each other's mating behaviour.",
"Can hardly interbreed (hardly ever fertile offspring (donk... | [
"Richard Dawkins observes that ring species \"are only showing us in the spatial dimension something that must always happen in the time dimension.\"",
"That's a pleasing way to think of it."
] |
[
"Are EM waves a ripple in a universal field, or do EM waves propagate into areas where there is no EM field?"
] | [
false
] | Sorry if this is a dumb question, but I was reading another thread in which someone asked about whether radio waves are considered light, and one of the responses mentioned something related to the question I've asked. I'm wondering if there's an EM field that's everywhere, sort of like a "gel" that's at rest, so to sp... | [
"This question is by no means dumb, in fact our conceptual understanding of this problem lies at the root of modern quantum field theory. The best analogy I have heard for describing fields is to visualize a field as a giant mattress with springs throughout, like ",
"this",
". In the simplest case, let us imagi... | [
"Just to tack on to this, A. Zee's ",
" does an amazing job tackling the mattress/spring analogy in an understandable way for those who are interested. Very easy to find on Google, and the underpinnings of field theory are outlined very neatly in the first chapter."
] | [
"Firstly, \"particle physics\" is a field which suffers from one of the worst cases of poor naming in science. Particle Physics (i.e. the standard model) is not a theory about particles, it's a theory about fields. We talk about electron particles and photon particles but the mathematical language is actually tha... |
[
"When the James Webb telescope is complete what are we expecting to see?"
] | [
false
] | I know we'll be able to see farther but will we be able to see closer things with more detail? Like the surfaces of planets we think might have life. | [
"The main limit on resolution (the ability to differentiate two objects separated by a certain distance) is the size of the primary mirror; diffraction becomes a problem if you go too small. The James Webb telescope will have a 6.5 meter mirror compared with Hubble's 2.4 m, so ",
"this figure",
" shows that the... | [
"Assuming an earth-radius planet at a distance of 10 parsecs, about 30 kilometers. Not to fear, we can synthesize a telescope with an aperture of 30 kilometers using interferometry - in fact that's sort of what the TPF was supposed to do... before it got cancelled."
] | [
"Nope. You can thank the politicians (and NASA's tiny budget - they can barely afford JWST!) for that one."
] |
[
"On Apollo 13, it mattered what order they turned systems on in - why?"
] | [
false
] | On Apollo 13, some time was given to making sure that spacecraft systems were turned on in the correct order. Specifically, I was reading which discusses how if systems had been turned on in the wrong order, there would have been insufficient power. Can somebody explain this to me? Why does the power drawn depend on ... | [
"Check out ",
"this article",
", part of the series of articles cited in the Wikipedia article you provided above.",
"But even with fully charged batteries, the Odyssey risked running out of electricity before it splashed down. Batteries are rated using a term called ampere-hours. If you start with a 40 amp-h... | [
"Sorry I realize this might not be your area of expertise but do you know why \"once a system had been turned on in the Odyssey, it had to stay on\" ? Why not turn it on for a quick minute then off until you need it again?"
] | [
"It Was Now over three days since the explosion in oxygen tank two. It was time to get ready for re-entry. The first step was to recharge the batteries in the command module, which had been significantly depleted before the lunar module came on line.",
"Remember how, while figuring out lunar module lifeboat proce... |
[
"Does Quantum Mechanics really say there's a universe where Elvis didn't die?"
] | [
false
] | This has bothered me for a long time. I thought that whole interpretation was about different states of atoms, not macroscopic events but I see people say a variation of that variation all of the time | [
" ",
"I'll try to give you a fair introduction to the Copenhagen interpretation and Many Worlds - others are free to disagree with me though. I'm sorry for how long this wall of text became.",
"The idea that this is hinting at is a thing called quantum immortality, which is a sort of modified Schrodinger's cat ... | [
"You can't confirm Copenhagen empirically either, as far as we know. That's why we call it and MWI \"interpretations\". "
] | [
"It just isn't true that \"timeline-splitting\" in MWI is an \"ad hoc\" method of solving the problem of measurement. That's kind of the whole point: MWI is just unitary QM. If you think the MWI posits that worlds magically start \"splitting\" in order to solve the measurement problem, then you don't understand the... |
[
"When I'm walking or running, how is it that what I see isn't all shaky like when I try the same thing with a video camera?"
] | [
false
] | I just bought a steadicam for my DSLR and it got me thinking. How is it that the body acts like a natural steadicam for my eyes? ELI5 if necessary. | [
"Would this effect be compromised in zero gravity?"
] | [
"Would this effect be compromised in zero gravity?"
] | [
"Cameras with \"",
"image stabilization",
"\" often do something that's analogous to this. (Compensating for movement via an accelerometer, not saccades.)"
] |
[
"Do train tracks build up an electrical charge when a train approaches?"
] | [
false
] | null | [
"You can achieve the same affect by putting a metal bar across both rails",
"Could you do the same thing with a simple insulated wire? It seems like that would leave every railroad crossing vulnerable to pranksters. It's a good thing I didn't hear about this when I was a teenager!"
] | [
"You can achieve the same affect by putting a metal bar across both rails",
"Could you do the same thing with a simple insulated wire? It seems like that would leave every railroad crossing vulnerable to pranksters. It's a good thing I didn't hear about this when I was a teenager!"
] | [
"If it is powered by overhead electric lines, there would be some voltage on the rails in between grounding points, but it wouldn't be between the rails. It would be from rails to ground. I don't know if that would be enough to shock you. "
] |
[
"For animals that live closely with humans, do we know of any specific adaptions they have undergone in response to eating human's food."
] | [
false
] | Also, can we infer probable changes in our own physiology by looking at the adaption of animals like rats who presumably would adapt faster owing to their quicker reproduction and shorter lives. | [
"Coincidentally, ",
"this research",
" article was just published last month about genetic variation between wolves and dogs. Dogs had many more copies of the gene for amylase (30 to a wolf's 2), which means they have adapted to a more starch-rich diet."
] | [
"Do you know of a primary source for this? I heard the buzz about it after it was presented at one of the big evolution conferences in 2011, but even now all I can find is buzz."
] | [
"Do you know of a primary source for this? I heard the buzz about it after it was presented at one of the big evolution conferences in 2011, but even now all I can find is buzz."
] |
[
"Does the pavement compound of a road depend on the climate of its area? e.g. Would there be a different compound in a Michigan road vs. one in Florida?"
] | [
false
] | Thanks! | [
"Hot mix Asphaltic concrete (HMAC) or asphalt consists of aggregate and a binder. Binders are petroleum based and sort of glue your rocks together much like cement in concrete. The grade of petroleum binder is determined in part by the climate. If you pick an asphalt binder that is too soft for a warm climate, you ... | [
"Yes. After working with Highway Engineers, as a non engineer (In CA) they practically wax poetic about 'road mix'. ",
"In CA you have to design for desert, mountain snow, real extremes in temp. So the mix of rock, oil, etc. varies by temperature. Some mixes are so temp sensitive, that they can only be 'laid' ... | [
"I don't suppose there's any type of asphalt that can withstand years of freezing and heat? I've wondered like OP and many folk in MI why they have only two driving seasons: winter and construction..."
] |
[
"What makes certain liquids flammable and some not?"
] | [
false
] | I know nothing about this question, honestly. | [
"Volatility is a part of it, but another is whether the vapour can combine with oxygen present in the air to form a more stable compound (such as carbon dioxide and water), releasing heat in the process. Low molecular-weight hydrocarbons (such as butane and propane) vaporize easily (have high ",
" at ambient temp... | [
"Even if the vapor pressure of water were equal of that to the atmosphere (think: boiling water), it would still not be flammable. You can't light steam on fire (with the exception of superheated steam, but even then its flammability is not due to its volatility).",
"If the substance is capable of undergoing ",
... | [
"Flames come about (from most fluids you would think of) because of [combustion](Wikipedia.org/wiki/ combustion).",
"More generally, flames can come about when energy is released by a reaction (that is: it is an exothermic reaction). Take cryogenic rocket fuels, for example. Liquid oxygen and liquid hydrogen are ... |
[
"Is gravitational bending of light wavelength-dependent?"
] | [
false
] | Obviously it is dependent on the mass of the object bending the straight path of light. But does the bending depend on the wavelength of the light? (Ie. is there something like chromatic aberration in optical lenses when looking at gravitational lensing?). Also, does gravitational lensing itself cause an additional red... | [
"No, because gravity is curvature of space time, and anything moving along the same trajectory at the same velocity will take the same path, as long as we can assume that the object's own contribution to curvature is negligible."
] | [
"Thank you for your answrr, howerver I consider this tautological, as your argument cones from a model (which is necessarily based on assumptions).",
"I rather asked about observational evidence.",
"Wrt my second question, I seem to have found the answer of Shapiro Delay, ergo a minuscule redshift.",
"However... | [
"It is a local statement, there is no difference between the two in vacuum.",
"In matter you get a phase velocity, a group velocity and a signal propagation velocity, in general they can all be different and the first two can even be faster than the speed of light in vacuum, only the last one is limited by the sp... |
[
"Do plants ever get \"full\" of sunlight/water? If not, how do they store their surplus sunlight/water?"
] | [
false
] | AFAIK most plants don't have fat reserves like animals, so how do they store excess energy? And as for excess water, do plants have some process analogous to urination? | [
"Plants store energy as sugars and starches."
] | [
"Plants constantly lose water through their leaves via transpiration (evaporation through pores). I believe they just don't absorb more water than they transpire, so they generally don't wind up with an excess. "
] | [
"I believe they just don't absorb more water than they transpire",
"I am not a biologist, but they should take in more water than they transpire. The naive reaction going on inside the leaves is",
"H2O + CO2 + Light -> CXH + O2",
"Some water should go in building the sugar/starch and the expelled O2",
"/edi... |
[
"How accurate is the due date of a child?"
] | [
false
] | [deleted] | [
"There are a few ways an OB/Gyn will estimate due date and date of conception. The first way is by dates. On an OB floor are things called ",
"pregnancy wheels",
". You ask the mother the first day of her last menstrual period and then line up the wheel, but the wheel follows ",
"Naegele's rule",
". This is... | [
"Nope, no real questions. This is my first child (the reason I was asking this question in the first place), so my curiosity has been nagging me and I haven't bothered to ask the OB/GYN any of this. "
] | [
"It's just a estimate.",
"http://transitiontoparenthood.com/ttp/parented/pregnancy/duedate.htm"
] |
[
"Could there be bacteria in landfills right now evolving to digest plastics?"
] | [
false
] | We've all heard the facts about plastic water bottles, that they take many thousands of years to degrade, etc. But given that the ability to metabolize ubiquitous plastic products would confer a distinct evolutionary advantage to any organism that could do so, is it possible that such a bacterium could evolve to do so ... | [
"There are already bacteria which can eat some plastics. A nylon eating bacteria was discovered in 1975 and is one of the best examples of evolution in action\nEdit: It actually digests one of the byproducts of nylon manufacture",
"https://en.wikipedia.org/wiki/Nylon-eating_bacteria",
"And there is good evidenc... | [
"But can it break down polymers in order to digest them? Oil would be in the form of long carbon chains, but probably not on the same scale of length as a polymerized plastic, right?"
] | [
"It has been a few years since my course, so the specifics of its functions have left me. Granted, synthesized plastic is much more complex than crude oil, but we discussed how the microbe could still break it down. I do remember that my prof stated that the reason landfills are the size that they are is because i... |
[
"When a photon is blocked by a filter, say, a polarized filter, what happens to those blocked? Are they reflected or?"
] | [
false
] | Thought of this when thinking about the whole Bell's theorem thingy. | [
"Photons that don't pass through a filter are typically absorbed by the filter material. This causes the filter to heat up (slightly)."
] | [
"One exception is a dichroic filter. They pass some wavelengths and reflect others. They use thin film interference."
] | [
"If it's 'blocked', there are just 2 options: the photon is absorbed or the photon is scattered.",
"'Absorbed' means that the photon seizes to exist and its energy transferred to another particle.",
"'Scattered' means that it will be reflected to another direction and it might, or not, lose part of its energy t... |
[
"Where does matter sit on the energy spectrum?"
] | [
false
] | null | [
"Hi ComeWatchTVSummer 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 t... | [
"Thank you for your submission! Unfortunately, your submission has been removed for the following reason(s):",
"This question is based on fundamentally flawed premises. Please conduct some background research and revise your question if you wish to resubmit.",
"Matter is not the same thing as light. You can't p... | [
"thanks for nothing"
] |
[
"Is there any area of science that a committed amateur with a few hundreds worth of equipment might make a worthwhile contribution?"
] | [
false
] | null | [
"Over the years many amateur astronomers have discovered things which have remained unnoticed by \"professionals\"."
] | [
"In Computer Science, you can make discoveries/advancements for the cost of a used laptop/desktop and several years of study.",
"I might suggest the specific fields of computer vision or artificial intelligence.",
"Source: Undergraduate in Computer Science"
] | [
"Mathematics. You need a pencil and a piece of paper."
] |
[
"Why does muscular dystrophy only happen in certain muscle groups?"
] | [
true
] | [deleted] | [
"There are two actual reasons.",
"The first is that certain muscles need to be very bulky and strong for them to be useful. These tend to be things like your hip extensors. If you lost 50% of the strength in your hip extensors, you probably could not stand from a seated position. You would have to use your arm... | [
"It's that genes are variable expressed. Certain muscles may express dystrophin more than other muscles. This is likely influenced by signalling during early development and by strain placed on the muscles after birth. Sorry that I don't have any specifics."
] | [
"It's that genes are variable expressed. Certain muscles may express dystrophin more than other muscles. This is likely influenced by signalling during early development and by strain placed on the muscles after birth. Sorry that I don't have any specifics."
] |
[
"What is the explanation for this flat earther claim?"
] | [
false
] | [deleted] | [
"The airplane is spinning around with the Earth. The 500 mph is with respect to the air.",
"Consider what is happening from the perspective of an inertial observer. The plane is already rotating at 1000 mph when it's on the ground. Then when it takes off, it has that rotational momentum. So the inertial observer ... | [
"If there were absolutely no wind, then east-west and west-east flight times would be the same. That's because the speed of the airplane with respect to the air (which, with no wind, is also the speed with respect to the ground) is the same no matter what direction the airplane travels.",
"The difference in trave... | [
"Shouldn't flying west be more energy efficient? Or is it? "
] |
[
"On what day(s) of the year is the ray from the Sun to the Earth pointing in the same direction as the Sun's (instantaneous) velocity around the galactic center?"
] | [
false
] | I'm trying to get a better sense of our solar neighborhood, and finding out which "direction" the sun is moving in as it orbits the galactic center would be helpful. Perhaps the ecliptic is aligned so that the Earth is never directly ahead of the Sun as the Sun orbits the galactic center--if so, then what time of year... | [
"(Not remotely my area.)",
"I would guess the answer is probably \"it never is\", because there's an angle of ",
"about 60 degrees",
" between the plane of the ecliptic (in which the Earth orbits) and the galactic plane (in which the Sun orbits, approximately). Perhaps ",
"this picture",
" will help?"
] | [
"Thank you. I didn't realize the angle between the ecliptic and the galactic plane is so big--I guess the angle of the milky way in the sky should have tipped me off."
] | [
"I just did some googling and a couple of quick calculations, and here's what I found:",
"One of the points at which the ecliptic and the Galactic plane intersect is only 12 degrees (roughly) from the Galactic center. The other point is correspondingly about 12 degrees from the Galactic anti-center.\nAs was sugg... |
[
"If the solar system were to survive Andromeda–Milky Way collision and flung into deep space, what effect would it have on the solar system if it were not part of a galaxy?"
] | [
false
] | Assuming the Solar system is intact when the collision happens and comes out unscathed. Would the solar sytem existing out of a galaxy have any major changes? | [
"There would be no difference except for the sky at night, which would be dark."
] | [
"dark"
] | [
"This event has a high probability (from 12% to 50%) but it will have no impact on earth or the solar system.",
"Sources : ",
"http://www.newscientist.com/article/dn11852",
"http://www.universetoday.com/1604/when-our-galaxy-smashes-into-andromeda-what-happens-to-the-sun/",
"http://fr.arxiv.org/abs/0705.1170... |
[
"With chirality, why are the properties of R and S forms so different?"
] | [
false
] | I'm trying to wrap my head around the idea of chirality. I am getting there in terms of the understanding of identifying chirality through the whole left hand-right hand and mirror image explanations. But in terms of the R/S forms, why do they have such drastic difference in properties - such as taste and smell? Are th... | [
"Well you understand the left hand/right hand metaphor which will help. \nTry to put your right hand in a left-handed glove or vice versa and it’ll make sense. The gloves, like your hands, are chiral. The left hand won’t fit properly in a right-handed glove. \nI looked it up and taste buds are chiral. So if a chira... | [
"As others have pointed out, they are actually EXTREMELY similar chemically speaking. I'll shed a little more light on it as someone who studies asymmetric catalysis.",
"Take two enantiomers R and S. Their NMR spectra are exactly the same. Their IR spectra are exactly the same. Their UV-vis spectra are exactly th... | [
"Some simple analogies that are helping me understand more, thank you."
] |
[
"The closest star to earth is 4.3 light years away. Is this par for the course in the Milky Way?"
] | [
false
] | Basically, is our cosmic neighborhood crowded, isolated, or about average | [
"But this doesn't take into account the fact that most star systems are binary, and some are trinary or more. Does anyone know the average distance between systems, rather than the average distance between stars? I think that would be much more informative, and more in line with the intent of OP's question."
] | [
"But this doesn't take into account the fact that most star systems are binary, and some are trinary or more. Does anyone know the average distance between systems, rather than the average distance between stars? I think that would be much more informative, and more in line with the intent of OP's question."
] | [
"Because it's like someone saying \"the sky\" in response to the question \"what's up?\". Everyone knows full well what the intended question is, because conventional methods for asking that question are being used, but the person replying is intentionally breaking with convention and giving a \"more literal\" answ... |
[
"Is constant light exposure beneficial to plants, or do they also require periods of low light?"
] | [
false
] | null | [
"The concept you're referring to is ",
"Photoperiodism",
" ",
"Depends on the plant, and the phase of growth that plant is in. Some plants do just fine with 24/7 light and can benefit from no darkness. ",
"Other plants, particularly those that flower in the fall, are dependent on changing day/light period... | [
"Tomatoes need at least 4 hours of darkness. It has something to do with reallocation of sugars produced. I have seen the ill effects off too much light in our lit greenhouses - in spring especially it is not hard to go over the edge with artificial light + natural light (as the day length rapidly increases)."
] | [
"An additional point for clarification: many of you may remember hearing about the light and dark reactions of photosynthesis, but these are now commonly referred to as light dependent and light independent reactions. These two crucial sets of reactions can both operate during exposure to light, so at least in this... |
[
"Why do cows have four stomachs when others grass eating mammals don't require that many?"
] | [
false
] | null | [
"Actually, quite a few mammals have stomachs with multiple compartments. People tend to say four \"stomachs\" but it's technically one stomach with four compartments. These animals are called \"ruminants.\" Some examples other than cows are sheep, deer, camels, llamas, and goats. There are quite a few others, as we... | [
"Vertebrates need microbes in their guts to break down cellulose in plant matter. There are different ways to go about this, but it basically involves lengthening the digestive tract to give the microbes more time to do their thing.",
"Broadly speaking, there are foregut fermenters, like cows, and hindgut ferment... | [
"Similarly, some animals like horses don't have multiple stomach compartments and are hindgut fermenters, meaning instead of using their foregut for microbial fermentation of plant matter, they do it instead in an enlarged cecum in the hindgut.",
"Other animals, like kangaroos, have a single enlarged, curved stom... |
[
"Could someone describe what was occurring in the early Universe? From the time of the Big Bang to the creation of protons and neutrons, where/when/why did quarks pop up in this primordial soup?"
] | [
false
] | null | [
"Well, the current hypothesis goes something along the lines of ",
"this",
":",
" after the Big Bang (about one Planck time unit) - \"Planck epoch\" - Basically we have no idea what happened because all of our models fail in the extreme conditions around this time. It is hypothesized that around this time th... | [
"http://en.wikipedia.org/wiki/Big_bang#Timeline_of_the_Big_Bang",
"Read this and specify what you want to know! ;)",
"Quark-gluon plasma appeared after the inflation period!"
] | [
"Thanks! I'll definitely take a look."
] |
[
"What would happen if a coronal mass ejection similar to the size of the one in 1859 happened today?"
] | [
false
] | [deleted] | [
"Nothing good. We're not ready to deal with it.",
"Mostly electric grids would experience a high voltage rise due to magnetic induction. This could burn the transformers that lower the voltage for domestic use. Other devices, such as solar panels, would be affected to a lesser extent due to the smaller loop area,... | [
"Cellular networks would likely go down quickly because satellites aren't as protected. Electrical grids would blow quickly. There are some good documentaries on this, I would google solar flare documentaries. I know I've seen a good one before but I'm blanking on the name unfortunately."
] | [
"Yes, the astronauts would be safe. This kind of events are usually preceded by a ",
"solar particle event",
" that can give a lethal dose of radiation to unprotected astronauts within a few hours. But the walls and equipment of the ISS offer an equivalent aluminium thickness of 20 g/cm",
", which is enough t... |
[
"Standing on the other side of the world, would I have felt the Chicxulub impact?"
] | [
false
] | I know that puts me in the Indian Ocean today and that the landmass was . I only mean hypothetically. If Chicxulub's 4.2×10 joule impact was too weak to feel, then how about the impacts? What other immediate effects might I notice on the other side of the world? To what extent did any of these alter the world's spin, a... | [
"I did a quick ",
"calculation",
" for the Chicxulub impact with the ",
"Earth Impact Effect Program",
": Energy and crater size match pretty well. On the other side of the planet, you would not feel much of the impact. Very slight shaking after an hour and bad weather after 16."
] | [
"The calculation is inaccurate. It simply models the effect as a function of distance from the impact site, without treating any point on the earth’s surface as “special”. But the antipode (the point on the earth’s surface exactly opposite the impact) is indeed a special point, because of the way the spherical eart... | [
"It certainly appears so from this article: ",
"http://www.geologyinmotion.com/2011/10/chicxulub-impact-what-happened-on.html",
"I'm not able to make out whether the 4 meter displacement is as huge as it sounds, as the discussion of earthquakes seems fairly mild."
] |
[
"Can I preemptively get lots of sleep to help stay awake for a long time?"
] | [
false
] | Basically, if I sleep ~6 hrs a night, can I sleep 10 hours tonight and have an easier time pulling an all-nighter tomorrow? Please do not lecture me on how all-nighters are a bad idea. | [
"If ALL you want to to do is decrease your sleep drive for one night, then technically the answer is yes it ",
", but it doesn't mean it ",
". The amount of benefit you'll get really depends on how well rested you were to begin with, and the quality of your sleep over the several weeks preceding the \"all-nigh... | [
"You're sleep deprived enough that you're seeing effects of sleep inertia once you do start to sleep.",
"Also, the \"the longer I'm up, the less tired I get\" is due to the circadian influence on sleepiness. It has a natural up-down that goes through the time of the day, and once you pass the lowest point of it, ... | [
"Awwww, I wanted to overclock my cells!"
] |
[
"If electrons repel each other due to their negative charge, how do any bonds form to make molecules?"
] | [
false
] | I thought I understood this but I hit me recently. How does anything exist? Electrons are negative so they should repel each other, yet it is somehow a lower energy state to share electrons and become one molecule. I probably don't understand it all or have all the information. Does it have something to do with quantum... | [
"The electrons in one atom are attracted to another atom's protons. The protons in one atom are attracted to another atom's electrons. This also works for ions - for ionic bonding. To form a stable molecular bond (covalent or ionic) the octet rule should be observed, since all molecular bonds work with valence elec... | [
"The electrons are not bound to other electrons, they are bound to the positively-charged nucleus (or nucl",
" for molecules)."
] | [
"The negative charge of multiple electrons is countered by the positive charge of the multiple protons in the nucleus. This applies to both atoms and molecules. The orbitals of the electrons in the molecule can be described by quantum mechanics."
] |
[
"Why do optical illusions make us hallucinate?"
] | [
false
] | null | [
"What's an example of this?"
] | [
"Generally if you stare at the center of a rotating vortex for a certain period of time and then look away you would see things moving around"
] | [
"This is called the motion aftereffect.",
"https://en.m.wikipedia.org/wiki/Motion_aftereffect",
"https://michaelbach.de/ot/mot-adapt/index.html"
] |
[
"What is it that I can get from fresh fruit and vegetables that I can't get from a multivitamin pill?"
] | [
false
] | null | [
"Quick preface: this is a vastly oversimplified response, but it hits the high notes. Links provided throughout as a quick springboard into related literature in the field. ",
"Nutrition isn't only about the intake of 'essential' nutrients, i/e/ the compounds that our bodies can't synthesize (or can't synthesize ... | [
"explain the like i'm 5?"
] | [
"Well, vitamin C is an anti-oxidant, and without it there's the risk of scurvy.",
"However, there are many other anti-oxidants, and there have been many different claims as to their wonderful abilities - as far as I know, none of those (anti-ageing, anti-wrinkle, better memory, etc, etc.) have been proven."
] |
[
"Are humans supposed to be monogamous?"
] | [
false
] | [deleted] | [
"There is a benefit to monogamy. It assists in the rearing of children by encouraging stable, well defended family group, especially important if the offspring require many years to grow and reach reproductive stage. They will need protection from both parents for much longer."
] | [
"Before the first societies, humans were known to not practice monogamy.",
"If males don't know who the father of a child is, they all have an interest in supporting it. Hence, each child has the support of many parents."
] | [
"does monogamy solely produce these conditions? Can't other groups like extended family or polygamous families provide safe environments for children? Surely it's worked in the previous societies that were not monogamous, else we may not be here today."
] |
[
"Why does pressing the sharp edges of two knives together not create such high pressure and temperature that it fuses the edges together?"
] | [
false
] | If I have two knives, and I put the sharp side together in an X shape and press the edges into each other with all of my strength, why does it not cause such a drastic increase in pressure, (very, very small area and conservatively moderate force) that almost reaches infinity, that the atoms at the edge get compressed ... | [
"Your large pressure goes into yielding the metal, which will cause dents in the sharp edge. Since you are not doing very much work with your muscles you should expect very little temperature increase in the knives as well."
] | [
"The maximum pressure that you can exert in a setup like this is the ultimate strength of the material (more realistically, for a person pressing things together, it is the considerably lower yield strength). This pressure is quite low in the cosmic scheme of things - only on the order of 1 GPa - and it doesn't act... | [
"Basically, yes. To fuse the knifes together, you have to add lot of energy, using friction by example (like we do in friction welding).",
"EDIT: There are some extreme cases where you can weld metals together using only a choc or high pressure, like space mechanism in vacuum (mostly seen on aluminium, due to the... |
[
"How can lack of power physically damage computer hardware components?"
] | [
false
] | I've heard of 'black outs' and 'brown outs' damaging computer hardware components (ie graphics cards) beyond trivial repair. I understand how a surge can fry stuff, but how can a sudden drop in power destroy anything? | [
"every hard disk built in the last 10 years uses a magnet to pull the head into parking position once power is cut. this is no longer an issue. (",
"http://en.wikipedia.org/wiki/Harddisk#Landing_zones_and_load.2Funload_technology",
")",
"also, the 5-second power button push is just an ACPI override signal tha... | [
"every hard disk built in the last 10 years uses a magnet to pull the head into parking position once power is cut. this is no longer an issue. (",
"http://en.wikipedia.org/wiki/Harddisk#Landing_zones_and_load.2Funload_technology",
")",
"also, the 5-second power button push is just an ACPI override signal tha... | [
"This man explains it better than I ever could.\n",
"Brownout explanation"
] |
[
"I know visible light can't escape a black hole but can more energetic electromagnetic waves (gamma rays) escape its gravity?"
] | [
false
] | Envisioning this in a differnt way: Say we have two super high powered flashlights fused together pointing towards a telescope in space. The telescope can detect vIsIble lIght and gamma rays. One flashlight emmits visible light and the other emmits gamma rays. If the fused flashlights enter a black hole will the telesc... | [
"All frequencies of electromagnetic radiation will be affected in the same way by a gravitational field: they will get redshifted by the same factor, and the paths their photons take will get curved to the same degree.",
"Now, if you drop two lights (a regular one and a gamma-ray one) into a black hole and you ob... | [
"A different way of thinking about the question in your title: no, nothing can escape a black hole, not even gamma rays. The reason is that there are literally ",
". It's kind of analogous to how there are no paths leading backward in time.",
"Of course, in the experiment with the dropped flashlights, you would... | [
"Great response! Thank you!!! "
] |
[
"Does Monk Fruit and other \"natural\" sugar alternatives have the same health risks as artificial sweeteners?"
] | [
false
] | There have long been concerns about the health risks from artificial sweeteners. For example, recent studies indicate that artificial sweeteners could elevate blood sugar levels and raise one's risk of heart disease or stroke. There have also been reports that they alter our gut biome in harmful ways. For example this... | [
"I would read better sources on the safety of common artificial sweeteners. ",
"According to the FDA, common artificial sweeteners like aspartame have been extensively tested in multiple studies and no risk has been found."
] | [
"Not to pile on too much, but the fact that artificial sweeteners alter the gut microbiome does NOT make them unhealthy. First off, to a certain extent everything we eat alters the gut microbiome. Different microbes in our gut consume different things, and much like any ecosystem, as you feed some things at differi... | [
"Perhaps people should know that about 99% of all this research that shows artificial sweeteners are bad, is paid for by the sugar industry. It's been less than honest and more about keeping people eating sugar, which we know causes serious illnesses. Making artificial sweeteners the bad guy is the problem. The rea... |
[
"If the so called \"periodical cicadas\" (the infamous 13 and 17-year cicadas) emerge and reproduce in 13 and 17 year cycles, does that mean that every 221 years there will be a year when both types of periodical cicada will emerge?"
] | [
false
] | I was just wondering if there would ever be a situation when both the 17 and 13 year cicadas emerged at the same time and caused the worst cicada swarm ever, or at least emerged at different times in the year and produce two separate swarms. If this is so, what sort of ecological impacts would this have had or has had... | [
"You need to note, periodical cicadas are all synchronized, but not across the whole species. It's not the global population emerging at the same time, but 'only' the population of one region. So first, you need both species in one region and then, you need to be lucky enough that the years (and even hatching times... | [
"To add on to the \"birds can't even keep up catching them\": One find the same principle e.g. in forest trees like oaks, which have so-called mast years: Inbetween mast years, a lower fruit yield can only sustain a certain number of foragers, like mice and squirrels. In a mast year, the trees produce much more fru... | [
"It can happen! Mostly they just get very very loud and all the birds lie around going \"Oh, I couldn't possibly have another.\"",
"http://stlouis.cbslocal.com/2015/05/07/two-groups-of-cicadas-ready-to-emerge-across-missouri/"
] |
[
"What is the furthest distance we could have a satellite orbiting earth whilst still remaining useful to us here?"
] | [
false
] | I'm thinking for purposes such as GPS, but am interested to hear about others. My satellite knowledge isn't the best! Related questions. Are current satellites we'be put into space a similar distance away? Or do they vary dramatically? And do they share similar orbits/behaviours? Also, I'm on a phone and unable to add ... | [
"Depends of what you take as useful. ",
"The Kepler Space Telescope",
" is in a heliocentric orbit. It orbits the sun but follows the earth closely. It is pretty far away. If you you are talking about within the earths orbit then it would be the ",
"Sphere of influence",
"."
] | [
"30 miles isn't even out of our atmoshphere."
] | [
"While 30 miles up would technically be low earth orbit, some aircraft can get pretty close to it. Orbits of less than 80 miles aren't really practical due to drag. You need to get above 120 miles before atmospheric drag inhibits long term orbiting. GPS satellites are at roughly 10,000 miles up. DirecTV, TV bro... |
[
"High Fructose Corn Syrup is about 55/45 fructose to glucose, and sucrose is 50/50 but a disaccharide. In a mildly acidic environment (the stomach), the disaccharide is cleaved. Is there any merit to hating HFCS?"
] | [
false
] | Inversion (cleaving the disaccharide): Glucose can be used anywhere in the body, but does fructose metabolism in the liver produce more dense storage molecules? | [
"The process by which our body turns sugar into energy is called glycolysis. It turns glucose into ATP which is energy we can use to do work. It essentially uses chemical gradients that are always trying to reach equilibrium (but never do because if they did we could no longer produce energy and we'd die). Anywa... | [
"But as the OP points out, stomach acid cleaves sucrose into what is basically HFCS (but with 50/50 fructose to glucose). When does your body read whether the sugar has already passed the commitment step, if the conversation takes place before your intestines (with your taste buds)? It is unclear whether you really... | [
"I learned this in my biochemistry class about a year ago which was built around this textbook: ",
"http://www.ncbi.nlm.nih.gov/books/NBK22395/",
". I remember this topic specifically because my professor was an angry Dutchman that brought it up often and included this very question on our final exam. ",
"... |
[
"What would be the effects of removing excessive amounts of heat from the earth through the harvesting of geothermal energy?"
] | [
false
] | I understand it's implausible, but theoretically, what would happen if human efforts caused the mantle/core of the earth to cool? I suppose that the heat is caused by gravitationally-induced pressure, but doesn't thermodynamics demand a reaction of some kind if we were able to influence the temperature enough? Forgive ... | [
"I studied this subject the past weekend.the heat in the center of the earth is created by the gravitationally-induced pressure,radio active elements and a great deal of it is left over heat from when the earth condensed.The earth radiates about 44terawatt of energy through it's surface mantel.this energy can be mi... | [
"This is absolutely correct (though it would take quite a long time for the core to melt again if all thermal energy were extracted), and should not be downvoted. There is a truly absurd amount of energy in the Earth's core, so \"excessive amounts of heat\" is rather more than the OP was probably thinking of.",
"... | [
"Check out faul_sname's answer. If you replace 15 TW with the 44 TW noted above by moominza, you get something like 10 billion years before the core completely cools naturally. Of course, the real question would be \"how cool would the Earth's innards have to be for things to really change on the surface\", and t... |
[
"Does it get significantly harder to heat water another degree as temps go up?"
] | [
false
] | So say I put a pot of water on the range. If it takes x amount of time to heat up from 50 to 60 will it also take x amount to go form 60 to 70? Or does it get harder to heat up as it goes up? | [
"To add to what ",
"/u/DCarrier",
" said, in practice it gets harder, because the hotter the pot of water gets, the more heat it ",
"radiates",
", and the stronger the convection currents around the pot (causing heat lost to the air). Furthermore, if you use an electric kettle, the resistivity of the resist... | [
"According to ",
"this",
" it stays pretty close to 4.2 J/kg K. Though once you get it to boiling, it will take a lot of energy to actually boil it. More than it takes to go from freezing to boiling."
] | [
"There will also be more evaporative cooling."
] |
[
"Why can't we see in colour in a dark room?"
] | [
false
] | Looking around your bedroom at night when it's almost pitch-black you can still make out shapes, but everything seems to be monochrome. Why is this? | [
"Your retina has two types of cells: rods and cones. Cones see in colour, but their number is much smaller and they aren't very sensitive. Rods are much more numerous and sensitive, but they don't see colour.",
"Therefore, when you're in the dark you only see with your rods: you can make out shapes that your cone... | [
"It's probably worth noting too: the reason cones can differentiate colors is because there are three types of them which each have ",
"different sensitivities to different wavelengths of light",
". This means cones can relay ",
"three dimensions of color",
" to the brain, while the one type of rod would on... | [
"interesting how the sensitive frequencies for the green and red cones are so close, could be why red/green colourblindness is so common."
] |
[
"Why is the sum of angles in a triangle more or less than 180 degrees in elliptical or hyperbolic geometry?"
] | [
false
] | null | [
"In mathematics, any \"fact\" that is \"proved\" actually depends on a base set of assumptions called ",
", which are usually taken for granted. However, if you are interested in alternative forms of mathematics, you can change what these axioms are, and you'll often get different (and often surprising) \"facts\"... | [
"You got one thing backwards. Triangles in hyperbolic geometry ",
" have straight lines (by definition), but their projection onto a plane results in bended curves."
] | [
"When you refer to a triangle in hyperbolic geometry, it is important to remember you are not referring to a triangle in the classical aspect. That is, the sides of the triangle are not straight lines and define a single plane, but a projection of a triangle on a surface. ",
"In hyperbolic geometry it is always... |
[
"Is there a fundamental difference between tornadoes and dust devils, or is it *just* a matter of size?"
] | [
false
] | Are they formed by similar (yet differently scaled) causes, or are they, at their root, different beasts that merely each other? Does there exist a smooth spectrum (continuum) of possible sizes, or is there a clear jump from dust devils to tornadoes, with nothing in between? | [
"Tornadoes begin a rapid rotation of extremely powerful super cells. The rapid rotation concentrates and accelerates, and wind shear causes it to descend to ground level. Dust devils are small low pressure vortices caused by rising thermals and the backfill of air along the ground. Fairly benign, but in theory c... | [
"They are quite different.",
"Tornadoes must be attached to clouds; dust devils are not attached to clouds. Tornadoes require storms; dust devils form independently of storms. Tornadoes ",
" from the sky due to colliding air masses; dust devils ",
" from the ground due to heated updrafts."
] | [
"At their root, they are different beasts that merely resemble each other.",
"Dust devils are driven by surface convection; warm air rising from the ground leaves low pressure behind it, and pulls in surrounding air to make up the difference. If there's even a tiny random rotation to that mass of surrounding air,... |
[
"How does electric current flow through human body?"
] | [
false
] | For simplicity let's say that I touch two cables from electric grid. How these electrons moving in cables translate to, I guess, motion of ions in my body? Do these ions flow across cells, or in fluid surrounding? | [
"Ions wouldn't flow through the body, I'm not sure what you're getting at there.",
"Firstly, voltage is just potential energy to move electrons from one point to another. If you have a lot of voltage, the electrons have enough energy to flow through you, and that the high resistance of your tissue and flesh would... | [
"But how do you imagine electrons passing through the body? Skipping from one molecule to another? Over so much distance? That's highly improbable. "
] | [
"But the ions don't just move, they are a medium for the electrons if you like. They gain an electron at one side of the cable, and lose one at the other.",
"The salt content also makes you pretty conductive because under high voltage, they can generate a lot of current - as you might have expected, tissue and fl... |
[
"Does listening to music while studying makes studying less effective?"
] | [
false
] | I heard both recommendations of abstaining from listening to music while studying, and finding a song you know by heart and listen to it on loop while studying. Can someone give an answer for sure? | [
"So I actually did a research project on this in undergrad so I'll give a quick summary, but I'll have to dig through some old folders to find research to link.",
"So the main reason why listening to music can be bad is you encode (putting into memory) the sounds you're listening to while you're also encoding the... | [
"I've been listening to music to help me study for years. ",
"The best way I can explain it is that I need to have something that distracts me enough that I can ignore other things, but not so interesting that I need to think about what I'm hearing. This means music that I know really well, or instrumental music... | [
"This next part will contradcit my first post a little, but it'll clarify which type of music is better to listen to. So my experiment in undergrad compared the effects of classical music, modern music (pop, rock, etc.), and no music. Due do a design flaw our results didn't turn out perfectly, but basically they sh... |
[
"How can we tell if a person is related to another by comparing their DNA?"
] | [
false
] | Hi there, I'm currently working on a programming project that compares two sets of DNA and determines their relationship(if any). Problem is I don't know exactly what I'm looking for to determine that relationship. Any help is greatly appreciated. | [
"Hi, I'm sorry no one has responded yet, but if you're still stuck, I hope the following is helpful:",
"From your data set, it looks like the columns from left to right are the specific genes, the chromosomes the genes are located in, the position of the gene in the chromosome, and the individual SNPs (single nuc... | [
"Were you given this task in university and nobody explained to you what to do?"
] | [
"Sort of. My professor has a tendency to be vague in his project descriptions. "
] |
[
"Would someone who is exposed to germs more often have a noticeably better immune system over someone who is very hygienic?"
] | [
false
] | For example, someone who works outdoors all day versus someone who works in an office building. Or, someone who doesn't wash their hands and still eats food that is dropped on the ground versus someone who washes their hands frequently and never touches anything that might be dirty. | [
"This is in essence, the idea behind the Hygiene Hypothesis. It's the idea that the \"cleaner\" we've become, the less \"used\" our immune system is, and hence it becomes \"bored\". Of course, this is incredibly simplified.",
"Here are a few things I've seen in papers over the years that I can remember off the ... | [
"almost completely absent in the 3rd world.",
"I think we should be cautious about saying this. Low diagnosis rates may be more due to a lack of medical care than actually low incidence rates. "
] | [
"Does the \"more exposure leads to a better immune system\" idea only apply to children? Or are our immune systems dynamic enough to become stronger once we've grown into adults?"
] |
[
"Is there a maximum possible magnetic flux density?"
] | [
false
] | null | [
"There is the ",
"Schwinger limit",
": Above 4 billion T things get strange.",
"And then there is the Planck magnetic inductance, 2*10",
" T. That's at least the maximum where our known laws of physics have a chance to work."
] | [
"Photon+photon -> lepton pairs are routine interactions in particle accelerators, more recently light-by-light scattering has been observed, too.",
"https://cds.cern.ch/record/2220773",
"https://arxiv.org/abs/1810.04602"
] | [
"Photon+photon -> lepton pairs are routine interactions in particle accelerators, more recently light-by-light scattering has been observed, too.",
"https://cds.cern.ch/record/2220773",
"https://arxiv.org/abs/1810.04602"
] |
[
"What gives Polyester it's useful properties?"
] | [
false
] | I know that when Polyester is made into fabrics, the stretching forces the molecules into parallel patterns, giving the material more tensile strength, etc. What I want to know specifically: Why is it shatterproof? Why is it hydrophobic? | [
"\"Polyester\" is a broad class of materials. You're probably referring to polyethylene terephthalate (PET or PETE) which is the polyester used for soft drink bottles and most fabrics.",
"It is hydrophobic because its chemical structure is largely hydrocarbon based, with only weakly polar carbon-oxygen bonds at s... | [
"I would agree with you until the last paragraph. Depending on which source you use then PET is about only 20-40% stronger than semicrystalline PP or PE. It is much easier aligned (by say drawing) so its effective stiffness and barrier properties can be much better though. Cross-linked amorphous PE is quite weak - ... | [
"Thank you for the clarification."
] |
[
"Please explain this Hytadid cyst in the brain"
] | [
false
] | It was submitted here: There's very little background or text. The doctor claims he was going to publish this in the journal. There are really dozens of questions about this, but if someone could explain this or has seen the journal article and could sum it up, that would be great as that would answer most, if not all ... | [
"You're being awfully vague on what you would like to know about this. It's a bacterial infection which forms cysts in the locations where bacteria have invaded, the cysts are fluid filled and patient's can be asymptomatic or symptomatic. Symptoms range due to the different areas in which the infection can manifest... | [
"That's the sort of explanation I was hoping to get started, but it seems as though this one didn't make it to the front page."
] | [
"Here's a link to the ",
"wiki",
" article for this disease. "
] |
[
"Would a laser sword cut a diamond sword or vice versa?"
] | [
false
] | null | [
"Well, they DO use lasers for cutting diamonds, but that doesn't mean that every laser can cut a diamond.",
"So the short answer would be: depends on the laser. If it was designed for cutting a diamond i suppose it would destroy the diamond sword, but if it weren't then the diamond sword would refract the laser ... | [
"So, would the refracted laser beams then become laser \"bolts\", of a sort, turning them into weapons themselves? Or does the refraction change the laser beam into some less \"powerful\" form of light. ",
"I know this is getting more and more sci-fi, but I know there are science-based explanations on how theore... | [
"Hmm, I suppose that would depend on how the beam gets split. For instance if it gets cut perfectly in half and each beam still transmits properly, then I guess it would burn two holes about half as large as the original burn hole would have been.",
"Keep in mind that the power of a laser beam is the intensity o... |
[
"Can the expansion of space be proved in other ways than the observation of distant things moving away?"
] | [
false
] | I took IB HL Physics (Highschool AP equivalent), and what I know is that Edwin Hubble discovered that distant stars, galaxies etc were moving away faster than the speed of light(measured with the Doppler effect), and things further away were moving faster proportionally. My question is that does this constitute proof o... | [
"Remember that there's no proof in science - all we can do is accumulate more and more evidence for something.",
"An expanding universe is implied by a pretty wide range of observations today, like the irregularities in the [cosmic microwave background](en.wikipedia.org/wiki/Cosmic_microwave_background_radiation)... | [
"Ah, that's a long and complicated story :) The CMB contains a ",
" of information. One of the simplest things we can do to the CMB map is to statistically analyze it by looking at how common hot or cold spots of a certain size are. The picture you get looks like ",
"this",
", using the latest data from the P... | [
"Not quite - energy isn't actually conserved in an expanding universe, for one thing. Photons, for example, lose energy as the Universe expands."
] |
[
"Can plasma electrocute you?"
] | [
false
] | null | [
"When it comes to lightning, are you sure it's the plasma that electrocutes you and not the electric current that created the plasma? The other answer given here says that plasma can't electrocute you, but the process which creates it can. So wouldn't the same electrical discharge that turned the air into plasma be... | [
"When it comes to lightning, are you sure it's the plasma that electrocutes you and not the electric current that created the plasma? The other answer given here says that plasma can't electrocute you, but the process which creates it can. So wouldn't the same electrical discharge that turned the air into plasma be... | [
"Plasma is a gas composed of positive ions and electrons in roughly equal amounts. By itself it can't electrocute you, but the process which created it could. Man made plasmas often use high voltage. A small neon bulb needs around 90 volts. A neon sign uses several thousand. A static electric shock creates a tiny, ... |
[
"What happens to concrete on a molecular level when it cures?"
] | [
false
] | I know it does not just dry out the water, otherwise buildings would melt when it rains. What exactly happens? Thanks. | [
"I'll keep this simple, but here we go:",
"Cement is a mixture of chemicals which undergo a reaction called Hydration. In the first stage, the powder particles react with water and forms a gel layer. Out from this gel layer crystals grow into a spine structure, like a microscopic hedgehog. These spines interlace ... | [
"Also notable is that concrete and steel tend to expand and contract at nearly the same rate with thermal variation."
] | [
"Concrete doesn't dry out, that's correct. Instead, it sets, or cures. Portland cement (what pretty much every concrete building uses) contains Calcium Silicates which react with water to form mineral hydrates, which are what give cement it's desirable properties as a binding material in concrete."
] |
[
"How do we choose anything \"randomly\"? Does our brain have tendencies or patterns, or can we achieve true randomness?"
] | [
false
] | For example, asking to randomly pick a number between 1 and 10. You can choose one and not give a reason why. You just randomly choose a number from thin air. Is there a pattern or reasoning our brain goes through when choosing something randomly? | [
"Random number generators do not produce random numbers either, they are algorithmic, and they rely on the assumption that you don't know the input(s) to the algorithm that output the number."
] | [
"There is a way to avoid this. Just reference the state of some external thing that you don't already know the state of.",
"I'm saying roll a dice."
] | [
"Even if the universe it deterministic we could have apparent randomness depending on what we know about the current state and what we observe from the result set we get from our randomness generator. ",
"From our own brains if we spat out a list of random numbers with some bound we would almost definitely see a ... |
[
"If, using todays technology, we wanted to craft a set of Melee weapons and armor (sword, shield, armor), what materials and techniques would we use?"
] | [
false
] | null | [
"The best blade steel today is pretty much the same as it's been for hundreds of years...the difference is that today we know why it's good. A sword needs to be incredibly malleable (not brittle), as well as hard enough to hold a good point. The balance can be achieved by layering carbon inclusions, which harden th... | [
"Yes",
"To make a functional sword you need something that is durable and can retain an edge. Steel really is the best material for the job at this time. All you need to do is look at the knife industry. ",
"There are plenty of companies that make knives with ceramic blades. These blades will maintain their edg... | [
"You must remember that melee armour was really intended for battlefields only (and ceremonial tournaments).",
"In duels, fighters did not want to use armor, and preferred light blades like rapiers, optionally with a very small shield (like under 30cm diameter). The speed and mobility reduction from full plate an... |
[
"Let's say in each hand I have half a sphere made of Uranium-235 such that together they are supercritical. What happens if I slowly bring them together?"
] | [
false
] | null | [
"You will see blue light, feel a little bit warm, and die an agonizingly, excruciatingly, horrible, painful death from radiation poisoning. Under no circumstances should you do this.",
"When you bring them together you are eventually going to hit a point where the atoms are going to begin undergoing fission chain... | [
"about 500 pounds of explosives slamming the two pieces together with high energy."
] | [
"A certain mass-to-surface ratio is required for the Uranium-235 to attain the proverbial 'critical mass'.",
"Uranium-235 atoms naturally decay and shoot out a few neutrons when it does. In order to start a chain reaction, at least 1 of those few will need to hit another Uranium-235 atom, which will then also dec... |
[
"Why does liquid nitrogen freeze when placed in a vacuum?"
] | [
false
] | I teach science classes to kids at a camp, and in one of our experiments we put liquid nitrogen in a simple vacuum chamber. After a few seconds, it stops boiling and freezes. I was looking at the phase diagram for nitrogen and doing a bit of Googling, but I didn't find an adequate explanation. Can anyone tell me what's... | [
"Think of it this way: when you have a liquid that is boiling, the parts of it that turn into gas are the parts that have the most energy (or are the hottest). The nitrogen is made up of a bunch of different particles all jiggling around with different temperatures. By applying the vaccuum pump, you are basically s... | [
"Why the downvotes?",
"It's not \"atmospheric water\" as the top voted comment suggests. It's a well known phenomenon that you can freeze liquid nitrogen by putting it in a vacuum chamber. There's tons of youtube videos demonstrating it, here is one (you can think of it as a source): ",
"http://www.youtube.com/... | [
"That assumes that the temperature is held constant during the reduction in pressure. Lowering pressure induces evaporation, which will remove heat from the bulk, the same way that evaporation of sweat cools you down. ",
"The enthalpy of vaporization of nitrogen is pretty low, so you'd need a lot of evaporation... |
[
"Do we know whether Hash functions produce all possible outputs?"
] | [
false
] | Looking at SHA-256, it outputs 256 bits for any input. Due to the pigeonhole principle there are guaranteed to be collisions among them. My question though is if we have actually proven that every variation of the 256 bit output string is actually part of the result space or is there a possibility that one string is ac... | [
"Just from looking at the definition of a cryptographic hash function, it is computationally infeasible to generate a message with a given hash value. When we try and compute these, we are doing what is called a \"pre-image\" attack, and the fastest algorithms we have for these have complexity around 2",
" where ... | [
"However, there is a potential drawback to a hash function which can be proved to be surjective. If we can always find some string S such that Hash(S) is some given 256-bit string S', then we can generate collisions just as easily.",
"What if you had a non-constructive proof that some hash function is surjective?... | [
" Nothing really changes. ",
"This answer is specifically for SHA-256, so some numbers will be different depending on which hash function we are talking about. Surjectivity means that given any y in {0,1}",
" , I can find x (any string of length 2",
" - 1 bits) such that SHA256(x) = y. ",
"The other way to ... |
[
"dentist redditors. Is an electrical toothbrush really better than a \"normal\" manual one?"
] | [
false
] | null | [
"Dentist here: There are a few main advantages to using an electric toothbrush.",
"Most have a built-in timer. This more of a plus than you might think. The majority of my patients simply don't brush enough, and when they do, they don't brush for long enough. It is recommended that you brush for around 2 min... | [
"Study 1",
" compares Sonicare to manual toothbrushes for orthodontic adolescents.",
"I did read another study on normal people, but I can't find the link in my 15 seconds of google searching. What makes sonicare more awesome is the fact that is moves the water/saliva/toothpaste mixture around so fast that the ... | [
"A 3-month clinical investigation comparing the safety and efficacy of a novel electric toothbrush (Braun Oral-B 3D Plaque Remover) with a manual toothbrush.",
"The effect of a new electric toothbrush on supragingival plaque and gingivitis. ",
"The long-term effect of an oscillating/rotating electric toothbrush... |
[
"How do snowflakes form so symmetrical?"
] | [
false
] | [deleted] | [
"Snowflakes are ice of course, which is crystalline water. Snowflakes grow and take their shape the same way that any other crystalline substance does, whether it's steel or quartz or diamond. Crystals are substances where the atoms in them are ordered in a repeating pattern, called a lattice. It's very similar ... | [
"Thanks for the reply. Yes there was no wind and the flakes were rather large. It was very soothing. Especially since I live in a place that only sees a little snow once or twice a year, if that. "
] | [
"A non-aggregated snowflake often exhibits six-fold radial symmetry. The initial symmetry can occur because the crystalline structure of ice is six-fold.",
"\n",
"http://en.wikipedia.org/wiki/Snowflake#Symmetry",
"\nYou have the world of information at your fingertips but no motivation to search it yourself."... |
[
"If Earth has an elliptical orbit, why can't we feel its acceleration?"
] | [
false
] | In an elliptical orbit, the orbiting body is much faster as it is nearer to its sun(What's the generic term for the center body?). Why don't the people on the leading side of the earth get pushed downward when the planet speeds up? | [
"That is accurate though. We are orbiting the sun."
] | [
"No.",
"We would not experience acceleration relative to Earth even if it were on a highly elliptic orbit. See other answers on this page."
] | [
"Even in an elliptical orbit, you are still in freefall at your apogee, perigee, and everywhere inbetween. The best way to get an intuitive idea of how orbital mechanics work is to play Kerbal Space Program for a few hours."
] |
[
"Is heated food in the microwave radioactive?"
] | [
false
] | null | [
"Microwave radiation is orders of magnitude less energetic than something as simple as visible light.",
"Artificial creation of radioactive isotopes is something that is typically limited to nuclear reactors, particle accelerators or similar devices. It's not just a matter of simply scaling up a microwave oven."
... | [
"No."
] | [
"How come?"
] |
[
"Proton size problem?"
] | [
false
] | A recent experiment showed that the proton size of a muonic hydrogen atom was ~0.84 fm, however regular protons have a size of ~0.88 fm. Couldn't a muon be "pushing" a proton together making it smaller while a electron be "pulling" the proton making it expand. Can someone explain why this has to point to a "new" scienc... | [
"The point is not that the proton must be .88 fm or .84 fm, but rather that these measurements of the proton size are inconsistent with each other -- and ",
" is what requires explanation. Within the Standard Model, there is no effect that would cause the proton size to vary in this way depending on whether it i... | [
"Can you link to a claim that this must require new science?",
"In ",
"this article",
" from members of the CREMA collaboration from 2010, several possible explanations are offered:",
"First of all we need to understand the origin of the observed discrepancy. It may be a computational mistake of the energy ... | [
"Sorry, was reading ",
"this ars technica article",
" and this line",
"That shouldn't be the case, and if it actually turns out to be, then it's a sign there must be some new physics out there. ",
"is what I am going off...",
"Also ",
"this phys.org article",
" states that ",
"Very interesting propo... |
[
"Why does meat not contain any carbohydrates when muscle tissue stores glycogen?"
] | [
false
] | Do animals (e.g. cattle) not store any relevant amounts of glycogen in their muscle tissue, or why does meat have no carbohydrates? | [
"Ah! Found the textbook(for humans anyway; ",
" by McArdle et al.). ",
"It's a distinction between concentration and total. For humans, the body might have 400g of muscle glycogen and 100g of liver glycogen, so you're right, in total, most of the glycogen is in the muscle.",
"But in terms of concentration ... | [
"Most of the body glycogen is stored in the liver. Muscle only contains around 1-2% glycogen, which is also broken down quickly so even less remains in meat (low enough to not count for nutritional labeling).",
"(this is memory from a textbook; source not directly at hand but Wikipedia article on glycogen kind o... | [
"Much of the intramuscular glycogen is lost when meat is cooked. Raw meat contains dietarily significant amounts if carbohydrate. "
] |
[
"Is quantum tunneling of DNA molecules the origin or one of the origins of DNA mutations ?"
] | [
false
] | [deleted] | [
"Short (pedantic) answer, no, tunnelling of DNA molecules is not an origin of mutations. Tunnelling is when something goes through a barrier that it seems like it shouldn't be able to (think of running at a wall and finding yourself on the other side). If a DNA molecule did this, that would not lead to a mutation (... | [
"Glad to be useful. PhD in physics and BSc in biochemistry. I currently do research in polymers and biophysics. "
] | [
"Thanks for the very good answer. For curiosity, what is your background ? Biology ?"
] |
[
"Hey, scientists: who decides what gets researched?"
] | [
false
] | Every day there are new headlines about the latest cool discoveries. Obviously these discoveries generally follow years of intensive research by scientists. Who decides what projects to research? I imagine some projects happen because DARPA, a nonprofit foundation, a corporation, or some other group offers funding fo... | [
"Professors come up with research ideas. They write up a grant application based on this. They submit it for funding, and then a panel looks it over and decides to give it money or not.",
"Generally, a grant panel has a certain amount of money to allocate and a certain number of projects, and they have to decide ... | [
"I'm probably not the most qualified person to answer this, but I'll give it a go. As for the first, it would probably be better to discuss your ideas with a knowledgeable friend first and see if he or she can put you in contact with a professor with similar interests, because most people who go to professors with ... | [
"A huge percentage of biomedical research funding comes from the NIH. In 2003, according to Wikipedia, it was 28%, or 26.4 billion dollars. Most of the rest of the funding is locked up in industry and not available to academic scientists.",
"Every year, the NIH puts out requests for grant applications. Many of th... |
[
"Does healing from injuries (bruises,cuts, ect.) \"burn\" calories?"
] | [
false
] | Does the act of healing from an injury use a significant amount of energy? Would eating more help you heal faster? Sorry if this is a dumb question, just wondering. | [
"Yes, it does burn calories. Unless the injuries are VERY severe, it won't be a noticeable amount. For example, the calories burnt from healing a broken leg are probably less than the calories you would burn through walking/running/exercising with that leg.",
"In some cases, severe burns for example, caloric requ... | [
"Interesting? Have any links for that? (Just wondering, would love to read up more on it!) And what about bruising and internal injuries such as joint hyperextension or tears? "
] | [
"I am actually our resident hematologist",
"No you aren't.",
"http://www.reddit.com/r/MDEnts/comments/23mkht/baltimore_county/cgyl9jm",
"http://www.reddit.com/r/AskReddit/comments/1ootpl/how_old_are_you_and_how_much_do_you_earn/ccu1wc4",
"http://www.reddit.com/r/philosophy/comments/1qbv44/internshipsjobs_fo... |
[
"What happens to human remains in shipwrecked submarines?"
] | [
false
] | The discovery of the USS Grayback prompted me to wonder: what happens to human remains in shipwrecked submarines? First, is it necessarily true that all compartments of a submarine flood if it wrecks? If so, I would assume normal ocean decomposition. If there are air pockets, what happens to the bodies of the crew in t... | [
"u/somewhat_random",
" touches on some important factors - even if a submarine has a sealed compartment, these seals will eventually fail. Water is quite capable at, with enough time, dissolving, corroding or otherwise wearing away at ",
". Plus, submarines are rated for a particular maximum depth - below this ... | [
"I know this thread is about ocean water, but interestingly, water in the Great Lakes gets so cold decomposition doesn’t always happen. The average temperature of Lake Superior is about 36 °F, inhibiting bacterial growth. This is why bodies on the wreck of the Edmund Fitzgerald are still there and intact.",
"OPs ... | [
"They found the body of a diver in Lake Tahoe who had been missing since the 90s that was really well preserved. He was floating upright a few hundred feet below the water, had no idea he was a corpse at first."
] |
[
"Does the probabilistic nature of quantum mechanics extend to non-quantum phenomena?"
] | [
false
] | My understanding of this topic is very basic, but from what I can gather, everything (?) at a quantum level is described in a probabilistic sense rather than a deterministic one. Not because of measurement error, but for more fundamental reasons. My question is this: does the uncertainty we observe in quantum mechanics... | [
"What happens as things go from one to a few to many particles is that the total uncertainty for the system goes down relative to anything you would want to measure. So, simplistically speaking, the total amount of momentum could go up with the total number of particles, while the uncertainty of the momentum goes u... | [
"Signals in the brain are as much chemical as they are electrical. Action potentials progress an electrical potential across their surface by depolarizing-- the cells keep Na ions outside itself and K ions within, creating an electrical potential and, when the gates for these ions open, a voltage. Theres a lot of i... | [
"Once you get up to lengths, times, masses, etc. well above the scale of Heisenberg's uncertainty principle, things behave deterministically. The ħ/2 of the uncertainty principle is the scale factor that tells us at what point we have to switch from thinking deterministically to thinking probabilistically.",
"The... |
[
"Why can't we manipulate the pituitary gland to grow taller?"
] | [
false
] | You read articles about people with tumors in or on their pituitary gland that ends up causing gigantism. How does this work and why can't we reproduce this phenomenon artificially for a short period? Disclaimer; 5"9 wouldn't mind being taller haha | [
"So what if a scientist gave a pubescent child a little bit of GH. Would that lead to some sort of feedback loop that results in gigantism or would it make them grow just a little bit more than they otherwise would have?"
] | [
"It is my understanding that very short people are given GH as teenagers so they get a little extra height."
] | [
"At the end of the pubertal growth \"spurt\", the ",
"epiphyseal plate",
" fuses and the long bones of the body stop growing. After this time, only bones such as in the skull and hands continue to grow in response to GH. Before/during puberty excess GH results in gigantism and after results in acromegaly. Look... |
[
"According to chemistry, ionic bonds are strongest, but in biology, covalent bonds are. How can this be?"
] | [
false
] | I just completed AP chemistry in high school, and in chemistry it is taught that ionic bonds are strongest. However, my AP bio friends informed me that in biology, covalent bonds are strongest. Can someone explain why the two classes teach this differently? | [
"Covalent bonding is dominant in organic chemistry, but ionic bonds generally have higher dissociation energies. I'm not sure why your friends have been led to believe that covalent bonds are stronger, as that's generally not true. Certainly more common in biology, but being more common obviously doesn't mean that ... | [
"As a chemist I am going to say the way this is taught in biology is sort of right and the way it is taught in chemistry is confusing. Ionic bonds are stronger. It takes more energy to pull the two atoms apart to infinity than it does in a covalent bond. But, that is an energy measured in a vacuum. In the presence ... | [
"Its a matter of stable against what? ",
"Ionic and covalent bonding are rather good explained in MO-theory. ",
"Look at ",
"this",
" picture. When two atoms with half occupied orbitals encounter each other, the orbitals form an bonding (lower) and an antibonding orbital. Both electrons from the half occupi... |
[
"Detecting the solstice: how much angular resolution?"
] | [
false
] | If I wanted to make a device that could detect the date of the solstice by measuring the elevation of sun every day, how much angular resolution would it need? By 'detect the date of the solstice' I mean, in the case of the summer solstice, to be able to say something like 'Yesterday was the day on which the sun reache... | [
"That makes no difference. The OP wants to measure the ",
" of altitude of the sun for a few days before and after the solstice, which is exactly the same regardless of location, so long as the Sun is visible at all."
] | [
"You can use ",
"an ephemeris",
" to see that within a day or two of the solstice, the sun moves somewhere in the range of 0.3 to 0.5 arcminutes in declination per day. So you would need at least that resolution to be able to say anything.",
"At this desired level of accuracy, the experiment, of course, would... | [
"You can use an ephemeris to see that within a day or two of the solstice, the sun moves somewhere in the range of 0.3 to 0.5 arcminutes in declination per day. So you would need at least that resolution to be able to say anything.",
"Excellent, thank you.",
"At this desired level of accuracy, the experiment, o... |
[
"What would a large-scale experiment to simulate the origins of life look like?"
] | [
false
] | Assume you have one billion dollars and an army of scientists ("the right stuff") to solve this problem. seems like it was pretty small-scale... what if they had had much more resources and a modern understanding of molecular biology? and what kind of results would it be reasonable to expect? | [
"Okay, so this is not exactly going to be a grant proposal, but here are some thoughts...",
"Firstly, what questions are we trying to answer here? The broad question is : \"What conditions are necessary to produce self-sustaining chemical replicators?\". We assume that there are various stages, and that we are no... | [
"We don't know how life originated and therefore can't simulate it. Even if we could create life artificially it would not necessarily be how life began on Earth, and has the pitfall that human life was required to create it (albeit you did say simulation and this is more of a philosophical issue).",
"Regardless... | [
"I don't think a billion dollars and an army of scientists would come close to being enough resources to create what you have in mind.",
"One has to remember that the entire ocean was essentially a giant organic chemistry experiment for a ",
" long time before life emerged.",
"One could imagine computational ... |
[
"My buddy's dad found this rock on their farm. Apparently a meteorite may have hit the region, could this rock have been affected by that collision?"
] | [
false
] | This was found near the Flint River in middle Georgia. Some scientists are starting to believe a rather big meteorite hit this area causing a pretty big topography change for the area. Apparently the river should not run the way it does through the topography it goes through unless a change happened after the river alr... | [
"First off, it's probably not a meteorite. ",
"Hullabazhu linked to a good site",
" that describes what a meteorite looks like.",
"The only rocks that are created by meteor impacts that I know of are ",
"Tektites",
". However, tektites usually look very smooth due to being melted by the meteor impact. ... | [
"I haven't found a lot of peer-reviewed journal articles about the impact, but what I've found seems to indicate it happened 83 million years ago. At that time, that part of Alabama/Georgia was under a shallow sea. I'm rather skeptical that a rock that large would be found in overlying sediments, especially a farm.... | [
"That is definitely a volcanic or metamorphic rock. I would guess it is a metamorphic rock and most likely an amphibolite (",
"http://geology.com/rocks/amphibolite.shtml",
")",
"The color change you see around the outside is called a \"weathering rind\" (like the rind on a watermelon) which is the weathering ... |
[
"What is the physical meaning of Fourier analysis concerning limited-time lasers?"
] | [
false
] | Hi everyone I learned this term that a laser emitting at a frequency x but for a limited amount of time was actually not considered mono-chromatic because when the Fourier analysis is done, we observe more than just the frequency x. How is this physically possible? If you emit at precisely 440Hz from t=0 to t=5, where ... | [
"If you emit at precisely 440Hz from t=0 to t=5",
"These requirements are mutually incompatible. If you want a signal which is a perfect ",
"step function",
" in the time domain, its Fourier transform is not a perfect delta function in the frequency domain.",
"And if you want a signal with a perfect frequen... | [
"Because the signal starts and stops, which represents a low frequency effect. If you had a 440Hz sine wave signal that spread backwards and forwards in time infinitely, that would be truly monotonic. A signal that starts and stops over 5 seconds clearly needs a 0.2Hz component, plus all the other frequencies near ... | [
"And if you want a signal with a perfect frequency (a Dirac delta function in the frequency domain), it will not be a pure sine wave in the time domain.",
"Are you making the distinction between sine waves and plane waves or is there some typo here?"
] |
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