title list | over_18 list | post_content stringlengths 0 9.37k ⌀ | C1 list | C2 list | C3 list |
|---|---|---|---|---|---|
[
"Does food temperature affects the nutritional absorption?"
] | [
false
] | null | [
"Not really, everything quickly becomes the same temperature as your insides, making the starting temperature a moot point."
] | [
"I can see why that would be true eventually, but would temperature noticeably affect the rate?",
"For example: I drink milkshakes fairly frequently, and I'm a fan of blending blueberries into it. I just switched to frozen blueberries so I could buy them in bulk. Assuming nothing is lost by freezing them, how muc... | [
"Everything is back to body temperature in a couple of minutes, the time it takes for the stomach to grind things up is longer. "
] |
[
"Did all winged insects evolve from a common winged insect, or did wings evolve multiple times in insects?"
] | [
false
] | null | [
"Theories on how wings evolved in insects come and go as more fossil evidence is found, but the current theories all point to a single evolutionary tree for flying insects. (It's slightly complicated because some lineages have lost and regained wings.) ",
"There are still competing theories on which body parts e... | [
"The vast majority of ant species have members of the colony with wings. Drones (males) and maiden queens will have wings, once a queen begins mating and starts building a nest she tears her wings off. Just like in bee colonies, the drones do no work, and exist seemingly to fertilize new generations of ants when ap... | [
"Would ants be a subset of that tree that lost the winged trait? Or do all ant species have a type of flight in their colony?"
] |
[
"Do prescription SSRIs affect brain development during childhood and adolescence?"
] | [
false
] | null | [
"this is kind of a double edged sword. ",
"On one hand, many drugs during the developmental process can have an effect on brain development. on the other, does the benefit outweigh the risk of taking said drug. (in this case SSRIs and SNRIs)",
"lets take an example, \nduring pregnancy, stress levels of the moth... | [
"it also important to not that these drugs are based on the monoamine deficiency theory (which is the deficiency of these neurotransmitters). there is another theory based on a BDNF (brain derived neurotrophic factor) deficiency. BDNF is important for neuronal plasticity, dendrite growth, stability of synapses etc.... | [
"Thank you! I got put on Prozac in 4th grade (not sure how/why) and 15 years later I'm wondering if I can ever stop, or if SSRIs caused my brain to develop in such a way that it would be more disturbing than normal to wean off them.\n ",
" "
] |
[
"What is happening in your body when you get the chills from reading a scary story?"
] | [
false
] | null | [
"An intense emotion activates the sympathetic nervous system, which triggers the contraction of muscles called ",
", attached to hair follicles. This contraction causes the hair to erect, causing goose bumps. Generally speaking, the sympathetic nervous system is activated by stress and prepares the body to a figh... | [
"I know a bird isn't a mammal, but when my canaries feathers are fluffing up, is he trying to make himself look bigger to scare off other birds/animals?"
] | [
"Awh. Poor baby. He'll always be alone. But if he had a female with him, he'd stop singing."
] |
[
"What actually gives elderly folk that \"old person smell\"?"
] | [
false
] | null | [
"The smell that we attribute to the elderly is largely attributed to one particular compound, ",
"2-nonenal",
". This particular compound appears to be a type of degradation product that increases with ageing. More specifically, certain lipids (fats) are oxidized on the skin, forming 2-nonenal, which occurs at ... | [
"Would that compound \"collect\" in their houses? Personally, I've never noticed a body odor type old-people-smell... I've always associated it with their houses."
] | [
"Since the compound is a result of oxidation, maybe the use of an antioxidant would help, such as vitamin E. Maybe also limiting the intake of any of the fats that could potentially be oxidized to this compound."
] |
[
"When running a statistical test, why do you have to make all of your decisions before testing or looking at the data?"
] | [
false
] | I just finished a stats class, and the professor was adamant that once you've decided on your hypotheses and the test you'll run, you can't change any of it after you've seen your data. For example, you can't make your initial alternative hypothesis "Group 2 has a lower mean that Group 1", then after testing realize th... | [
"When running a statistical test, why do you have to make all of your decisions before testing or looking at the data?",
"Because if you don't do this, you might inadvertently design your test based on the results you ",
" to see, or what you ",
" you've see when you peeked at the data. Instead you should \"b... | [
"Presumably, there must have been initial evidence to show that your hypothesis would have been the correct expectation. This would at least show that it made sense prior to the test to have made the hypothesis.",
"Not only that, the test results aren't invalidated because your hypothesis was wrong. It just sugge... | [
"Because after you've looked at the data you can always come up with a hypothesis supported by that data. It's the same as having an answer (data) and the picking a question (hypothesis) that gives you that answer."
] |
[
"Do vehicles painted black have a greater tendency to overheat versus those painted white?"
] | [
false
] | I'm no expert in auto engineering, but while shopping for a new car, I pondered this. | [
"While not the most credible of scientific sources, ",
"Mythbusters seems to suggest that black cars do heat up more"
] | [
"That was the interior of the car, I'm sure he's talking about engine overheating."
] | [
"I would think that in terms of the engine overheating, no. Cooling systems are quite advanced and incorporate not just the aqueous liquid circulating through the radiator and engine block, but also taken into account is the amount of cool air being drawn in on the intake stroke, the engine oil and the ability of t... |
[
"How do retroviruses become endogenous?"
] | [
false
] | I am really confused by the final paragraph of : Villarreal predicts that, without an effective AIDS vaccine, nearly the entire population of Africa will eventually perish. “We can also expect at least a few humans to survive,’’ he wrote. They would be people who have been infected with H.I.V. yet, for some reason, do ... | [
"Wow the author is jumping around on this subject. In general, one method of resistance is if the individual develops mutations in the receptor that the virus docks on to the point that the virus cannot dock on the host's cells. The virus needs to dock in order to be incorporated into the hosts cells. In this scena... | [
"That's what I was thinking. People with HIV immunity generally have a defective CD4 receptor, so the virus can't ever get into the T-cells, right? It's possible to get endogenous retroviral DNA if the virus gets into the cells, inserts its DNA, but then can't do anything after that, but it still needs to get in.... | [
"OK, so I'm not crazy/stupid. That paragraph still doesn't seem to make any sense though. He jumps from people having defective receptors to them incorporating HIV into their DNA, and I ",
" can't figure out why. "
] |
[
"How can does gene therapy work? More so, how can it help people with cystic fibrosis?"
] | [
false
] | I am researching gene therapy for a class I'm taking. I understand that doctors remove a cell that is affected by the disease, alter it so it can't spread, and then replace the cell back into the body via a virus. If I am understanding it correctly. It seems very simple, however I don't understand it. Specifically, how... | [
"The gene would be incorporated into the target cells (targeted in a number of ways, but that's beyond the scope of this...), and then it would function just like any other gene, including replication with cell division. It's the same phenomena as a virus incorporating viral DNA into a cell, causing the cell to exp... | [
"Gene therapy is a means of delivering a useful gene (DNA sequence) that may be transcribed and translated into proteins in the patient's cells in the same way all other genes are. For example, patients with hemophilia lack a gene that codes for a signalling molecule that's essential for thrombosis (blood clotting)... | [
"Wow thank you so so much. That really cleared it up for me. I'm repeating this just to make sure I get it. They place a replicating good gene into a virus, and inject it into the patient. This would in turn replicate the good gene, which would in a sense cure the disease. The problem with this method is that the c... |
[
"Why does turning on an electric blender in the kitchen cause my HD antenna signal to go out in a different room?"
] | [
false
] | null | [
"Cheaper blenders have non-brushless motors in which electrical contacts are repeatedly connected/disconnected during rotation, causing sparks and thus some radio-frequency radiation emission (basically the fourier frequency content of a square wave), some of which is probably overlapping with the frequency bands u... | [
"The rf noise produced by the blender is not going to be a constant frequency. It's noisy both in frequency and amplitude space, because sparks themselves have stochastic properties (basically the reason lightening is all jagged)."
] | [
"Wouldn't that only affect a signal encoded by amplitude modulation, which I'm assuming modern TV signals are not? ",
"If a TV signal is encoded as an FM or phase shift modulation, wouldn't that signal be immune to the RF signals emitted by the blender?",
"(Btw, my last telecom class was over 10 years ago so ... |
[
"Are deep water currents affected by the coriolis effect?"
] | [
false
] | Hello. I was wondering if deep water currents are affected by the coriolis effect. I have read about Ekman transport and how the coriolis effect plays a role in surface currents, but I was wondering if a similar process could occur in deep water currents? When I look at a map of the ocean currents, all I see for deep w... | [
"Yes absolutely. My PhD dissertation is studying exactly this effect. While the structure of the surface Ekman layer is determined by friction by atmospheric winds, the structure of the bottom layer is determined by a combination of bottom drag (the fact that the velocity has to go to zero at the boundary with soli... | [
"Wow, that sounds really interesting. Thank you for your answer. Good luck with your research! "
] | [
"Conservation of vorticity (how much a parcel of water rotates) is a super important concept in physical oceanography. The reason it is useful is because parcels of water rotate for two reasons: because they’re actually spinning around in a vortex (like an ocean version of a weather system) AND because they rotate ... |
[
"What happens if you flip a bullet mid-flight?"
] | [
false
] | null | [
"Either one you'd like. You're describing something impossible and asking what would happen if you did it, but once you've assumed that you ",
" do impossible things most questions lose meaning.",
"But say you shot a \"smart\" bullet that could somehow flip itself around in flight: ",
". The bullet isn't prop... | [
"I guess I'm thinking of the situation more along the lines of, I guess, the momentum that is pushing the bullet forwards.",
"\nWhen the orientation of the bullet is reversed, is the momentum also reversed with it?",
"\nOr does it remain pushing the bullet in the original direction, from point A to B?"
] | [
"Momentum doesn't \"push\" the bullet, the bullet was accelerated by the explosion in the gun. After it leaves the gun, there's no pushing (except for a tiny bit of air resistance pushing back on the bullet). ",
"Momentum is a quantity that the bullet has, equal to the mass times the velocity. The momentum can on... |
[
"Is the weakening of the arctic jet steam and collapsing of the arctic vortex early signals of a impending ice age?"
] | [
false
] | null | [
"No. \n",
"https://www.theguardian.com/us-news/2019/jan/30/polar-vortex-2019-usa-what-is-it-temperatures-cold-weather-climate-change-explained",
"The opposite, if anything. A warming planet disrupts or weakens the jet stream, so cold air will blow down from time to time. But it's part of an overall warming tren... | [
"Let's get the terminology correct first: technically we are in an ice age right now, since there are permanent polar ice caps. We have been in this ice age for the past 2.5 million years...but we are currently in an interglacial period. I believe what you are asking is when we enter the next glacial period.",
"G... | [
"Well, about 32 million years, since it is still the Late Cenezoic Ice Age, due to Antarctica being where it is. Semantics, though.",
"If we released ",
" sequestered carbon reserves, we would induce a situation where more carbon is in the atmosphere then there ever has been at one time, so I presume we would e... |
[
"Emotions in animals"
] | [
false
] | Me and a friend were talking about intelligence in animals, when I said that some animals, if not all, have emotions too. He disagreed with me saying that they only have the basic instincts but are incapable of emotions. He gave an example saying that humans are the only species where the members use sex for recreation... | [
"Well I can't provide you with specific studies and I doubt any such studies exist. How would you perform such a study anyways when we can't even specifically nail down where all our own emotions come from? ",
"I can tell you that it is my ",
" that animals absolutely have emotions. You don't have to own an ... | [
"Well at least, we ARE NOT the only animals that have sex for recreation. I've seen documentaries where monkeys do it every morning just for the heck of it. If you see planet earth, they show how Chimpanzees rape and cannibalize nearby groups when there really is no need to. I'd take that as emotions at work.",
"... | [
"You get home from work one day and your dog has torn up the trash and has spread it all over the kitchen. When you chastise him he puts his tail between his legs, whimpers, and holds his head low (granted not all dogs do this). We as humans would interpret this as shame, but we have no evidence that they can feel ... |
[
"Why does it feel good when someone scratches you on the back?"
] | [
false
] | Just hit me, what is that makes it feel so good and relaxing when someone is scratching my back? Is it because the intimacy of another human being? | [
"what is the evolutionary benefit of bees",
"Pretty tired of people overextending the applicability of the theory of evolution."
] | [
"you've got part of it, but you're missing the initial impetus...which (as I've posted below) has deep evolutionary roots, linked to parasite defense in social animals."
] | [
"Point being?"
] |
[
"Are we, as human being, able to absorb water from moisture in the air via breathing ?"
] | [
false
] | If yes, are we able to absorb more water in a humid environment than a dry one ? If no, is there any living thing that does this ? | [
"Every time you breath the air is combined with water droplets which changes the partial pressure of oxygen. Based off that I think in higher humidity environments the partial pressure of water you breathe in would be increased and possibly decrease the partial pressure of oxygen. Maybe that’s why it’s harder to ca... | [
"Thanks, that would makes sense. \nBut as you \"breathe\" water droplet, are we able to absorb them in your body resulting in a better hydratation as opposed to a dryer environment ?"
] | [
"opposed to a dryer environment ?",
"It is mostly a matter of the equilibrium of water vapor loss. Your normal metabolism of carbohydrates produces water, which you exhale. In a wet environment, you would lose less water than in a dry environment, but still losing water.",
"https://www.ncbi.nlm.nih.gov/pubmed/2... |
[
"How can a particle Travel through Time?"
] | [
false
] | null | [
"I have always wanted to know about Space Time but even the books I was recommended have gone over my head.",
"Is there something anyone can recommend that will help me understand?",
"I have read \"Murray Gell-Mann and the Revolution in Twentieth-Century Physics\" by George Johnson, \"The Fabric of the Cosmos\"... | [
"Mostly it's due to the uncertainty principle, below a certain threshold energy conservation can be violated."
] | [
"An anti particle moving forward in time behaves the same way as a particle moving backwards in time.",
"Edit: I forgot about parity, but when a particle anti particle pair is created they have opposite parity, so in this case what I said is true."
] |
[
"What would happen if we \"equalized\" the Panama Canal?"
] | [
false
] | [deleted] | [
"I'm having some difficulty understanding what you mean. Are you referring to a situation where the panama canal was a simple horizontal slot joining the two oceans, with no lock gates between?",
"If so, there is a lot of speculation involved - particularly in terms of the biology part of the question. As far as... | [
"The canal would not be big enough to support a counter-current. Frictional effects would be too large. The canal is only 12 m deep by ~20 m wide. In comparison the Bosphorus is ~65 m deep by 1 km wide."
] | [
"You'd get an increase in invasive species passing between the west and east. The freshwater segment prevents fish and other things from simply swimming through or riding through stuck on ship hulls, so the only organisms that can pass through are ones that can survive in ballast water. Cut a sea level passage an... |
[
"What is the role of NMDA receptors?"
] | [
false
] | Why are they present on the membrane? I hear that they are important for learning and memory, but what differentiates them from AMPA receptors/ when is an NMDA receptor activated against an AMPA? | [
"This is an awesome question! NMDA receptors differ from AMPA receptors because they require glutamate binding and membrane depolarization (usually the postsynaptic membrane) in order to open. This essentially allows NMDA receptors to act as coincidence detectors - i.e. they detect activation of the presynaptic mem... | [
"Just going off of this, NMDA receptors can be considered to be on a longer time scale. They require glutamate binding, glycine binding, and membrane depolarization to activate. AMPA only requires glutamate. The reason NMDA receptors require membrane depolarization is because NMDA is nonspecific to cations, so any ... | [
"Oh I totally didn't mention the whole Mg",
" blockade. It's presence is what confers the NMDA receptor its coincidence detection abilities. Thanks!"
] |
[
"Are galaxies moving in circles relative to one another, like solar system do inside galaxies?"
] | [
false
] | null | [
"As a point of information, no orbit is ever a true circle.",
"This will help explain this and about how objects similar in mass orbit one another. ",
"https://en.wikipedia.org/wiki/Kepler_orbit",
"In direct answer to your question, it depends on whether they are gravitationally bound to one another. Galaxies... | [
"Thank you for responding!",
"Just to clarify, I'm asking not what galaxies do when clashing, but rather \"do the black holes at the center of each galaxy in the universe move on an orbit(like suns in a single galaxy) or remain stationary in space?"
] | [
"On the largest scales, most galaxies are moving away from most other galaxies, not orbiting some common universal center.",
"That's not to say they're moving away from a central point, they're moving away from every point, as all space is expanding.",
"If they're close enough, a collection of galaxies might or... |
[
"How accurate a reconstruction/projection of a human's facial characteristics could be made just from using a skull?"
] | [
false
] | Sorry my question isn't the clearest, basically if you had a skull and the sufficient technology and know-how, could you make a facial reconstruction and how accurate could it be? | [
"Two articles in Swedish but I guess you can google translate them:",
"http://www.svd.se/kultur/birger-jarl-rekonstruerad_4534225.svd",
"http://www.popularhistoria.se/artiklar/historiens-ansikte-tar-form/",
"They basically build up the face from the cranium up, by adding layers of muscles and everything else ... | [
"From the little knowledge I learned in an intro to Forensic Science class, they can determine approximate age, race, and gender based on certain class characteristics of bones. There are also individual characteristics like bone-wearing that can narrow things down. There's not much accuracy in these methods, but c... | [
"There is an element of art to facial reconstruction based on a skull, but you can get pretty darn close using good science. I've toured a few forensic labs and talked to the reconstruction artists and I've seen a reconstruction that was used to help identify a skeleton alongside the picture of the woman before she... |
[
"Do octopuses have a dominant right or left side?"
] | [
false
] | I'm drawing an octopus right now, and I'd really like to know. | [
"From \"The Soul of an Octopus\" by Sy Montgomery: \"University of Vienna researcher Ruth Byrne reported that her captive octopuses always choose a favorite arm to explore new objects or mazes... Tank-bound octopuses, at least, are known to have a dominant eye, and Byrne thinks this dominance might be transferred t... | [
"I'm amazed you found a cited response to such an obscure question. Bravo!"
] | [
"Each tentacle has its own nerve center independent of the other 7. So one tentacle may know how to open a jar while the ones either side would not. Some tentacles are probably preferentially used over others I don't know if there is a side bias, but if there is it would not be 4 on one side dominate to 4 on the ot... |
[
"Stupid question. What does it mean when somebody says \"a photon gets absorbed\" or \"a photon gets emited\"?"
] | [
false
] | So, the photon helps an electron to get in a higher orbit. How? And then the electron drops the orbit and emits it again. Why? What causes it to drop the energy level again? Is it a spontaneous process? Im sorry if the question is badly phrased, but english is not my native language. Im trying to get beter :_-) | [
"When an electron absorbs a photon, because of conservation of energy, it has to move to a higher energy state. ",
"As for the emission, yes, it can be spontaneous. Though it can also be stimulated, as in laser emission.",
"http://en.wikipedia.org/wiki/Spontaneous_emission",
"http://en.wikipedia.org/wiki/St... | [
"Thank you. That was very helpfull.\nWiki:\"Imagine trying to hold a pencil upright on the end of your finger. It will stay there if your hand is perfectly stable and nothing perturbs the equilibrium. But the slightest perturbation will make the pencil fall into a more stable equilibrium position. Similarly, vacuum... | [
"Photons and electrons are both particles, but you can think of them as waves, too.",
"A photon is a perturbation (a vibration or wave) in the \"electromagnetic\" field. An electron is a perturbation in the 'electron' field. They're both 3-d fields everywhere in space, so the following analogy isn't exactly rig... |
[
"Why is it that cocoa powder is almost impossible to emulsify with a large amount of liquid, but will emulsify easily when just a little bit of liquid is used?"
] | [
false
] | If you dump a large amount of water, milk, or other liquid into a cup filled with cocoa powder or if you dump the cocoa powder into a cup of liquid, the cocoa powder will float to the top and no amount of stirring will cause it to completely emulsify. However, if you start with the cocoa powder and add just a little bi... | [
"My informed but non-expert explanation: The problem is that cocoa powder as a substance has its own surface tension when in contiguous and sufficient quantities.",
"I found a link with ",
"some elaboration",
".",
"Wetting properties of cocoa powder",
"\nWetting by water is closely related to whether som... | [
"While you consider the hydrophobic nature of cocoa powder, you also have to consider the physical action of stirring vs mashing/grinding that OP doesn't state happens, but will actually happen when mixing various ratios of cocoa to liquid. When you take a little bit of cocoa and dump it into a large volume of wate... | [
"I think it comes down to wetting of the individual cocoa powder grains. I think a typical scoop traps a lot of air in it. The 1:1 slurry is really just a rule of thumb that makes it easier to wet the non-soluble bits of cocoa powder. When you finally mix it into the rest of the ingredients it will disperse easier.... |
[
"Doesn't the Earths crust just keep recycling?"
] | [
false
] | My understanding of techtonic plates is that one slides under another. So wouldn't this completely recycle all the rock on Earth eventually? How can we know we haven't lost information over time? | [
"Yes, we lose a lot of information over time, though not exactly in the way you describe. Only the oceanic crust is really recycled through subduction(well, the vast majority of it anyway - some can get preserved). Continental crust is too light to subduct back into the mantle in the same way. ",
"Continental cru... | [
"The minerals making up continental crust are less dense than oceanic crust. If two tectonic plates collide where one's continental and the other's oceanic, the continental crust stays on top. If both plates have continental crust at the plate boundary, neither one subducts and they just smash into one another, pil... | [
"No rocks have been dated to the age of Earth, unless you count meteorites. The oldest rocks we have dated are somewhere around 4.2 billion years old or so.",
"Now we have dated certain ",
", such as tiny grains of Zircon, to the age of Earth (of very close to it). But there is a distinction there."
] |
[
"If humans were never taught about sex, would our animal instincts kick-in or would we all die out?"
] | [
false
] | [deleted] | [
"As I understand, a woman's first time is not pleasant at all and actually quite painful, they know pain is like the bodies way of telling you \"Oi. Stop that\" and as the ladies have no knowledge of intercourse they'd go with the stronger pain feeling than their deep down need to have children?",
"For many women... | [
"I'm pretty sure we'd figure it out. We're not pandas..."
] | [
"They really don't. Getting animals to breed in captivity can be a real nightmare."
] |
[
"If electricity can create a magnetic field, can collapsing a magnetic field create electricity?"
] | [
false
] | null | [
"Yes, changing magnetic fields can be used to produce electricity. This is how generators work."
] | [
"Thank you for your response! So let's say you could make a flexible, ring shaped magnet, like the shape of a washer. Since it's flexible, if you stretched it out, the shape of the magnetic field would change, correct? And if so, would this changing shape of the magnetic field produce electricity? "
] | [
"You could use the field to produce electricity, yes. If you put a wire loop nearby as you change the shape of the ring, the changing magnetic flux through the wire loop would generate an electric current in it."
] |
[
"Are rapid SARS-COV-2 tests still as reliable with the new lineages BA.4 and BA.5?"
] | [
false
] | And how come the rapid test kits can still detect the antigen even though these new variants shows such affinity for immune evasion? Will we have to test for another antigen in the near future? Or is the antigen somehow better "protected" against mutations? | [
"The tests have already not been very reliable at all for Omicron strains: while a positive result is almost definitely true, a negative result has a very good chance of being false, especially early in the infection. I've seen doctors and public health officials estimating a 40% false negative rate based on clini... | [
"This is partly why kits come with two tests and you’re supposed to take both 24 hours apart. The odds of one false negative were fairly high even before the new variants (something like 1 in 4), but two false negatives would be much more unlikely (~1 in 16)."
] | [
"The vaccines targeted the spike protein on the outside of the virus which is evolving rapidly, but the antigen tests look for an internal structural protein of the virus which is evolving much more slowly. So yes, they’re still very reliable at detecting large amounts of viral antigen."
] |
[
"Are there any chemicals so deadly a mere drop on skin could kill?"
] | [
false
] | My grandpa (a known story stretcher) told me he used to haul tankers full of this chemical. It was supposed to absorb really fast and that it was so deadly a drop on your skin would kill you in a minute or two. It was used in the production of tires. He said it was phenol but phenol doesn't match up with his descriptio... | [
"There certainly do exist some chemicals where just a few drops on your skin can kill you. The chemical in question needs to have two properties:",
"the median lethal dose or LD50",
"A very famous example of a chemical that fits both criteria is ",
"dimethylmercury",
". This is a powerful neurotoxin that is... | [
"Last I heard, no one really works with or puts dimethylmercury to use, largely because it's so dangerous. Probably not something being transported in trucks. "
] | [
"Last I heard, no one really works with or puts dimethylmercury to use, largely because it's so dangerous. Probably not something being transported in trucks. "
] |
[
"Is a third vaccine justified by sinovac vaccines?"
] | [
false
] | [deleted] | [
"Sinovac is the company that manufactures the \"Coronavac\" vaccine. Coronavac is an inactivated SARS-CoV-2 vaccine adjuvanted with AlOH, a common and well-studied adjuvant. ",
"There's relatively limited data available on Coronavac, especially compared to several other vaccines that have been fairly open about ... | [
"Probably for the sake of resources and an overabundance of caution.",
"We give different formulations of vaccines all the time. The tetanus shot you got when you were a kid is probably not the same you got most recently, for example. I don't even live in the same country I got most of my childhood vaccines in."
... | [
"https://www.bbc.com/news/health-57636356",
"https://www.npr.org/sections/health-shots/2021/05/05/993882203/giving-2-doses-of-different-covid-19-vaccine-could-boost-immune-response",
"You wanted an opinion on mix and match boosters from a scientist, well, you're talking to one. My opinion is that it will impro... |
[
"How do shockwaves affect small organisms on the cellular scale?"
] | [
false
] | I.e. shockwaves from explosives affecting things like amoebas, bacteria, etc | [
"I can answer this question from the microbe side, not so much from the physics perspective. You can rupture cells with sound waves in a process called \"sonication\", but it works by creating very tiny bubbles which collapse and release energy that destroys the outer part of the cell. If a shockwave were strong en... | [
"I can answer from the physics side but not the microbe side. Shock waves from explosives start out much stronger than anything than any ultrasound that could be made in the lab, including from collapsing bubbles--in air, it's a pressure change of potentially thousands of atmospheres in about a nanosecond (correspo... | [
"Thanks for this!"
] |
[
"Do all electromagnetic waves bend in the same way light does when it changes media?"
] | [
false
] | Hey, so today in physics class we were going over some problems from the homework and then it hit me: If light waves are just electromagnetic waves, then does that mean they can be bent in the same way light waves are bent when they go through different mediums (i.e. can radio waves also be bent by changing mediums)? I... | [
"You can see this phenomenon with other electromagnetic waves -- ",
"here",
" for example is a material with an index of refraction of 38.6 for waves of around 10",
" Hz. As another example, radio waves undergo refraction when they travel into the ",
"ionosphere",
".",
"And it's not just electromagneti... | [
"Different frequencies of radiation behave differently in materials. That's why white light is spread into different colours when it goes through a prism: each colour has a slightly different speed, because the index of refraction is different for each frequency.",
"For high energy radiation like x rays there isn... | [
"Yes, absolutely. Radio waves and microwaves all refract when changing propagation media. However, for the most part the effects are not nearly as apparent at the lower frequencies, and for terrestrial communications, the effects are negligible. One place where we do model atmospheric refraction though, is for G... |
[
"How is heat death of the universe possible if energy cannot be destroyed?"
] | [
false
] | Does this mean all heat and light would be emitted into infinite emptiness? | [
"Laws of thermodynamics predict that work can only occur when there is a temperature difference. When the entire universe is the same temperature, no work will be possible. The laws of thermodynamics have been very successful predictors of experimental results."
] | [
"Right now energy is unevenly distributed. Picture it like a large basin with a divider in the middle. One side of the basin is filled to the top with water and the other side is empty. Now punch a hole at the bottom of the divider and the water from the full side will move the empty side, but only until both sides... | [
"It's the same reason why Engines can't have a 100% efficiency. While energy is conserved, it's converted into a form where it can't be used. Before that, lets talk about the heat death.",
"It’s one of the theories on how the universe will end: the ‘Heat Death’ – also known as the ‘Big Freeze’ or the ‘Big Chill’... |
[
"How do we know that what we interpret as quantum indeterminacy isn't just blank spaces that haven't been filled yet?"
] | [
false
] | To clarify/expand: My current understanding of our deterministic universe is that, on a macro level, every physical process can be predicted with the right tools and can only have one possible outcome. However, on the quantum level, a number of things can happen that are not predictable at all, or are only predictable ... | [
"It sounds like you're suggesting the existence of \"hidden variables\".",
"https://en.wikipedia.org/wiki/Hidden_variable_theory",
"Basically, quantum mechanics and hidden variable theory make slightly different predictions for certain experiments. We can rule out the existence of local hidden variables (local ... | [
"This isn't a solved problem in physics. I suggest searching ",
"/r/AskScience",
" for posts dealing with determinism and interpretations of quantum mechanics for discussions on this."
] | [
"How do we know that what we interpret as quantum indeterminacy isn't just blank spaces that haven't been filled yet?",
"We don't know that. There may be a majority of physicists who think that, but it's certainly not a consensus. While it's ",
" crude, there's a nice overview of interpretations of quantum mech... |
[
"As a follow-up to a question that was asked about bringing back the woolly mammoth - if elephants were also extinct, would that completely eliminate the possibility of bringing back the mammoth?"
] | [
false
] | null | [
"Nope, it's fine. We hold things in the spam filter to check them first, so this just wasn't released. ",
"If you respond to a panelist in a relevant portion of the thread, they should respond to you. However, they often ignore repeat questions, which is one of the reasons we avoid them."
] | [
"No problem, although I'm not a sir. Let us know if you have any more questions!"
] | [
"Have you asked this question to the panelists in that thread? We don't really allow multiple threads on the same topic at the same time."
] |
[
"Is there any substantial environmental damage from acquiring the materials necessary to make solar panels, wind turbines, or hydroelectric dams?"
] | [
false
] | null | [
"They take quite a lot of energy and raw materials to make. They aren't cheap.",
"With the case of hydroelectric, the \"substantial environmental damage\" isn't so much the result of acquiring the materials but the negative effects of the dam itself. The worst of these is a build up of sediment that would other... | [
"Speaking very generally, any mining or earthworks projects will cause environmental disruption and damage to the existing conditions. Of the three you listed one, hydroelectric is what I would consider the most different. But first I want to address solar panels and wind turbines. Just supposing that the materials... | [
"Just to illustrate the impact one particular hydroelectric dam project can have on the environment, consider the Three Gorges Dam in China:",
"https://www.businessinsider.com/three-gorges-dam-south-to-north-water-diverson-project-china-2010-7#the-three-gorges-dam-cost-37-billion-to-build-1",
"The adverse impac... |
[
"What chemically happens to water to create the \"old\" or \"stale\" taste?"
] | [
false
] | I am just wondering. When we diagnose water as stale, be it from it sitting out for several days, or just unfinished in a water bottle. What chemically causes us to recognize it is old. (I don't believe dust is the answer because bottled water, despite it being in plastic, metal, or glass, can still become stale.) | [
"As you probably know, the air you breathe is composed of Nitrogen, Oxygen, Carbon, and other gasses. Now, when you leave water sitting around, some of these gasses will get into the water. Most of the gasses don't do much, but the Carbon dioxide in the air gets into the water as well, and if you know your chemistr... | [
"So with atmospheric CO2 going up from ~310ppm in 1960 to 400ppm today, our stale water is actually tasting more stale today than 50 years ago?"
] | [
"All of the chlorine in chlorinated tap water will evaporate over the course of a day or so, so that will also contribute to the change in flavor and smell. "
] |
[
"How is magnetized plasma created and what kind of gasses produce them?"
] | [
false
] | Curious about magnetized plasma. How is it created in a laboratory? Is there special equipment needed to create/store it? What gasses will produce them? The more info the better. | [
"The gases can be most anything. Hydrogen (including its fusion-fuel isotopes deuterium and/or tritium) or helium are common choices. Storage generally requires some sort of magnetic confinement. A toroidal magnetic field geometry such as in a ",
"tokamak",
" is a common choice, though there are other geometrie... | [
"Thanks a tonne. That answers a lot. If I may bother you for one last question. If I had, say, a Neon tube laying around could, hypothetically, I use it to generate a magnetized plasma at home or is this something I'd need a physics lab for?"
] | [
"You could certainly generate a plasma at home--there are plenty of YouTube videos and amateur scientist magazines that will tell you how to do so. ",
"Make magazine",
" published plans for making a Farnsworth Fusor, for instance.",
"I'd caution you to be very careful if you do opt to start tinkering with pla... |
[
"is \"life\" possible without oxygen or water?"
] | [
false
] | Say a planet somewhere in the universe had an atmosphere of say pure nitrogen. Could something evolve into life on this planet? Life as we know it needs oxygen, but that's just as we know it. If you believe in evolution than don't you have to believe that it could be possible? | [
"There are plenty of solvents besides water. For example, Saturn's moon Titan has seas of liquid methane (it also has an atmosphere of mostly nitrogen - is this what you were thinking of?). There's no reason Titan organisms couldn't exist in these seas, eating acetylene and excreting ethane or benzene. They would b... | [
"Water has certain advantages - it is a good solvent for a broad class of compounds, it is very stable, and it is common in the universe. And we certainly have no examples of non-water-based life. But in principle, no, water is not necessary, and there is probably life without it out there somewhere. The cosmos is ... | [
"Yes - and a means of self-defense if there did happen to be life. I've actually considered writing this as a short science fiction story. "
] |
[
"What is the most efficient way to keep a home freezer: completely jammed full or with space for air to flow?"
] | [
false
] | null | [
"Thank you for your submission! Unfortunately, your submission has been removed for the following reason(s):",
"For more information regarding this and similar issues, please see our ",
"guidelines.",
"/r/AskScienceDiscussion",
"Please see our ",
"guidelines.",
"If you disagree with this decision, pleas... | [
"What makes my question speculative? Someone who knows something about thermodynamics should be able to tell me about my freezer! "
] | [
"Maybe not speculative, but it is a discussion oriented question that would be better suited for ",
"/r/AskScienceDiscussion"
] |
[
"What does the ISS do during meteor showers?"
] | [
false
] | I was watching the Perseids the other day and was blown away. Some of the meteors streaked across as much as 20-30% of the sky and some left long visible trails, which I imagine means they were probably quite big. How does the ISS avoid disaster when we move through these debris fields? | [
"Space is big, VERY, VERY, VERY, BIG. Debris for a meteor shower is small, like grain of sand size small and spread out tremendously. The chances of a single grain of sand hitting a single football field sized object is near 0. Even when it does we have ",
"high tech solutions",
" using astronaut fingers to plu... | [
"\"You just won't believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it's a long ways down the road to the Chemist's, but that's just Peanuts to space.\"",
"-Douglas Adams"
] | [
"Though in the case you cited, I thought it ended up being an assembly flub on the part of the Russians? Ie some technician at Energia accidentally drilled a hole through the pressure hull and rather than tell his superiors, figured that he’d hide it under a glob off epoxy. As it was on the orbital module, he figur... |
[
"Why are land animals so much smaller now than they were millions of years ago?"
] | [
false
] | When you see the bones of dinosaurs and even gigantic mammals they are MUCH larger than any land animals we see today. I am sure the answer is easy, however, I do not know it. Thanks, AskScience! | [
"Because humans killed them.",
"Mass extinction of megafauna have been shown to have happened in the Americas and Australia shortly after the arrival of humans.",
"Interestingly, the surviving megafauna are from Africa and Asia (think big cats, elephants, giraffe), where they did coevolve with humans. But when ... | [
"While I also think that humans played a significant role in the extinction of large megafauna, I think it's only fair to mention that many paleontologists today still don't buy into that story, at least not completely. It's perfectly possible that a combination of multiple factors resulted in these extinctions, of... | [
"You'll also notice that today, most of the large animals that exist are seriously endangered. Tigers, elephants, apes, rhinos, whales, polar bears, (for a while there) buffalo, etc. It's apparently in our nature to kill large animals to the point of extinction or endangerment. "
] |
[
"European Bat Lysavirus 1-2 less pathogenic than Classical rabies (RABV) ?"
] | [
false
] | How come they are less pathogenic than classical rabies ? Does it mean that humans immune system fights better these viruses ? | [
"They are closely related viruses. Couldn't comparing them to see why they act differently be useful?"
] | [
"There are literally millions of pairs of closely-related viruses, including more than a dozen lyssaviruses, all with different pathogenicity profiles. The European lyssaviruses are only moderately closely related to the rabies viruses, with the better-studied Australian viruses being considerably closer. ",
"In ... | [
"They’re different viruses. There’s no reason to expect them to be the same."
] |
[
"Question on cardiac muscle cells"
] | [
false
] | I read that The aerobic energy systems take longer to produce the ATP and reach peak efficiency, and requires many more biochemical steps, but produces significantly more ATP than anaerobic glycolysis. Cardiac muscle on the other hand, can readily consume any of the three macronutrients (protein, glucose and fat) aerob... | [
"How it happens is based off of metabolic processes - look up Carbohydrate catalysis, lipid catalysis, and protein catalysis (I'd linksauce it up but there's so many sources, just find what you think is most easily understood as some is overly simplistic and some is overcomplicated). I'll outline the basics if what... | [
"I don't think it has much to do with mitochondrial protein synthesis."
] | [
"Did you read the post?"
] |
[
"Does/would a person in zero g slowly start to spin due to blood circulation?"
] | [
false
] | null | [
"Purely internal forces cannot cause you to rotate overall",
"This is incorrect - see ",
"https://en.wikipedia.org/wiki/Reaction_wheel",
". This is how many spacecraft orient themselves.",
"As far as ",
"/u/Telewyn",
"'s question, no, for several reasons. If your circulatory system were more like a torq... | [
"If you read the question and then that answer, it sounds like \"rotate overall\" is talking about the body rotating. Otherwise, the answer doesn't address the question."
] | [
"You're right, but I'm not exactly incorrect either (not if \"overall rotation\" means \"total angular momentum of your body\"). Reaction wheels don't violate angular momentum conservation, obviously, they must take on whatever angular momentum you're trying to give to your object with them. It's pretty clear (as y... |
[
"What is the relation between the Higgs field and chirality?"
] | [
false
] | null | [
"The question is almost certainly about the chirality of elementary particles, same as is posted on SE. (In case not: the Higgs field has nothing whatsoever to do with the chirality of amino acids.)"
] | [
"Did you just post this on stackexchange as well? There's a highly technical answer with symbols and stuff that goes way over my head, but it seems to fit this exact question: ",
"http://physics.stackexchange.com/questions/45450/what-is-the-relation-between-the-higgs-field-and-chirality",
"Or perhaps you meant ... | [
"Not all mass in the Universe is due to the Higgs. In particular, composite particles like protons and neutrons (which are each composed of three quarks) get most of their mass not from the quarks making them up, but from the strong nuclear forces binding those quarks together. That binding contains a ",
" of ene... |
[
"where is the magnetic field of the earth generated?"
] | [
false
] | null | [
"There's a lot we still don't know about how the earth's magnetic field forms. But we have a pretty good idea and it has to do with the earth's core.",
"The inner core of the earth is solid iron/nickel and the outer core is liquid iron/nickel. The outer core is slowly crystallizing on the contact between the out... | [
"*at the surface of the earth. Take a fridge magnet 6,000km away and it'll be a lot weaker."
] | [
"The heat is not coming from friction. When a material goes from liquid to solid it has to release a small amount of heat in the process. Your air conditioner is based off the same principle just the other way around. It takes a liquid and turns it into a gas which consumes heat and makes the immediate area a bi... |
[
"Why do styrofoam coolers squeak so horribly?"
] | [
false
] | What makes them squeak and why do some forms squeak less than others? For example, I have a styrofoam coffee cup here that doesn't squeak. Yet, things like coolers and the kind that's used as cushioning/packing material is awful. ··· (Also, , "In the United States and Canada, the word styrofoam is often incorrectly us... | [
"Styrofoam is mostly air, and is otherwise walls of the polymer polystyrene. The reason that it is so squeaky is that when something rubs against it, on the microscopic level, there is a \"stick-slip\" interaction between the surface of the box and, say, your finger. When you \"stick,\" friction compresses the smal... | [
"To better clarify, the microscopic surface of the polystyrene, combined with its mostly-air composition, both help to create a squeak. If there is another polymer which does not exhibit sqeaks, it is due to its surface morphology and/or its volumetric composition. I'd imagine that if the polystyrene was extruded u... | [
"In Flemish its called \"piepschuim\" literaly translated \"squeaking foam\""
] |
[
"Is there a reason why denser planets are closer to the sun and gas giants are further out?"
] | [
false
] | null | [
"What's important here is a concept known as the \"snow line\".",
"Water can only exist in two states out in space - as a gas, or as ice. Since the pressure is essentially zero in space, water's phase will only depends on temperature. In our solar system, this threshold is somewhere around 5 AU (where 1 AU = the ... | [
"It all has to do with mass and velocity. ",
"In a cloud of gas where collisions are frequent (e.g. an atmosphere), the molecules are all moving with a range of different speeds, but the most probable velocity of a molecule will be:",
"v = sqrt(2kT/m)",
"...where ",
" is just a constant, ",
" is the tempe... | [
"It all has to do with mass and velocity. ",
"In a cloud of gas where collisions are frequent (e.g. an atmosphere), the molecules are all moving with a range of different speeds, but the most probable velocity of a molecule will be:",
"v = sqrt(2kT/m)",
"...where ",
" is just a constant, ",
" is the tempe... |
[
"What do you call a water molecule that is made of 1 deuterium atom and 1 protium atom?"
] | [
false
] | On the quest to determine if all slow flakes are truly unique, I stumbled upon an argument based on the idea that some of the water molecules would contain a deuterium atom. My curiosity struck and I realized I don't know much about this niche of chemistry. I am wondering if the following configurations of water can e... | [
"HDO is ostensibly \"semiheavy water\" but I don't really recall many people calling it by this name. It's usually just HOD or HDO. I am not aware of any common names for those other isotopomers you mention. Also, you missed out on the stable isotopes of oxygen that are possible. ",
"Tritium is radioactive, a... | [
"Oxygen has three stable isotopes: 16, 17, and 18. However, 16 is the most common. According to wikipedia, if you include the unstable isotopes, 14 radioisotopes have been characterized."
] | [
"In addition to the other reply to you question, it is important to note that all elments have multiple isotopes. The only thing that is limited in number is the amount of stable isotopes. An element is considered radioactive, like U or Tc, when it has no stable isotopes."
] |
[
"Why does sudden and rapid regressive autism only occur following vaccination?"
] | [
false
] | null | [
"You can find plenty of examples simply by searching for something like \"regressive autism\" in Google scholar which indexes scientific articles. ",
"Here",
" is a random one I found."
] | [
"I was hoping to find more anecdotal stories or case studies. ",
"Studies can often be flawed in one way or another and this can be difficult to detect. ",
"It just seems strange that I can literally find thousands of stories of a sudden and rapid regression into autism following a vaccination, but I can't find... | [
"This isn't the right sub to ask for stories. They have no meaningful scientific value. However, the article I linked was based on parental report which sounds kind of like what you're looking for."
] |
[
"Could anyone try to explain to me whole photon-electron relationship?"
] | [
false
] | null | [
"Can you be more specific?"
] | [
"The ways they interact with each other. I don't think I can be very specific. I just want to understand anything a little better. "
] | [
"The way that photon interact with charged particles is described by quantum electrodynamics. QED is too much to explain in a comment, but I'd start with the Wikipedia article on it to get some background about it."
] |
[
"What is that \"freezer taste?\""
] | [
false
] | What is that sort of metallic taste that gets on food when you put it in the freezer for a while? This taste is especially prevalent in ice cubes. Where does that odd taste come from? | [
"Because you have a frost-free freezer",
"Sublimation of ice cubes is normal, which causes them to shrink and therefore concentrate any mineral components of your water. The longer the ice cubes sit in the freezer, the more metallic they will taste. Particles from other foods in your freezer will also accumulat... | [
"As the solid water (ice) sublimates (changes directly to gas; bypassing the liquid stage) only the H2O in the \"ice cube\" will evaporate. The other elements suspended in the ice remain there. The longer the ice stays in the freezer the more water evaporates leaving more mineral and less water leading to a stronge... | [
"... so if you did this repeatedly you could theoretically accumulate ice-cube trays full of whatever minerals are in your water..."
] |
[
"If two frequencies, one or both of which is by itself OUT of the audible range, have a beat frequency that is IN the audible range, might someone perceive the beat frequency?"
] | [
false
] | Suppose there are two pure sine waves with frequencies created by separate function generators, playing aloud through separate (theoretically perfect quality, mind you) speakers. f is a high but audible frequency, and f' is just beyond the largest audible sound for a given person, who is standing in a room. Suppose f... | [
"You might hear a ",
"difference tone",
" that simply arises from the nonlinearity of the ear or of the air (",
"sound from ultrasound",
"). In this case, there is literally some physical object vibrating at f-f', and that's what you hear. No mysterious perceptual effects involved.",
"The difference frequ... | [
"This is correct. The confusion arises from a common error regarding beat frequencies vs. the heterodyne effect. ",
"When you simply add to frequencies, you get sin(xt)+sin(yt). When x and y are close, you can graph this, and you get what appears to be sin(xt) with a slowly varying amplitude (varying with frequ... | [
"Yes, an ideal sound recording system would not suffer from such problems.",
"If you're hearing it, it's in audible frequency. If it is being generated by non-linearities inside your ear, it's ",
" - you're hearing what's not there. If it's being generated further down (by spontaneous nerve impulses, for exampl... |
[
"Do black holes show any promise in the hunt for dark matter/energy?"
] | [
false
] | Wouldn't we have a greater chance of finding an example of dark matter/energy near a black hole? If they suck in everything including light, wouldn't they suck in dark matter/energy, therefor resulting in more dark matter near the black hole? | [
"Black holes don't really \"suck\", they have the same force of gravity that everything else does. The main difference is that black holes are denser so you can get closer to the center without diluting the mass. If we replaced the sun with a black hole of the same mass, the Earth's orbit wouldn't change a bit. As ... | [
"A black hole is just a region of spacetime within which the energy density is above a certain critical value such that light cannot escape; it doesn't matter (sorry) whether this is dark matter, normal matter or some other form of energy.",
"Is your question about using black holes to study these things in close... | [
"Black holes host some of the most extreme physics known in the universe. They will be used to test theories in the quantum gravity regime.",
"For example any time a signal passes by a black hole that can then make its way to Earth, for example if a pulsar (an incredibly accurate astrophysical clock) is eclipsed ... |
[
"When the sun goes red giant, will any planets or their moons be in the habitable zone? Will Titan?"
] | [
false
] | In 5 billion years will we have any home in this solar system? | [
"While Saturn will be in the habitable zone and Titan along with it you have to think of how these worlds will be affected by the increase in temperature. The average density of Titan suggests it is a good mix of rock and ice, so with an increase in radiation from the sun, most of the methane will be lost to space ... | [
"Yep. Both in the bombardment by cosmic rays and general increase in radiation. Saturn is more than 90% hydrogen and the increase in radiation (i.e. temperature at Saturn) would give that hydrogen enough kinetic energy to escape the grasp of Saturn’s weak gravity. As it loses hydrogen it loses mass and gravity weak... | [
"Wouldn’t Saturn lose a bunch of its atmosphere (and therefore mass) as the sun goes red giant? Would the increase in radiation from the sun strip it away?"
] |
[
"What makes jackscrews so capable at lifting heavy loads?"
] | [
false
] | I've been reading about the that was carried out in the 19th century to enable the construction of a modern sewerage system. I find it hard to believe something as mundane-looking as a can lift buildings. From the article, bolded emphasis mine: In January 1858, the first masonry building in Chicago to be thus raised—a ... | [
"IMHO, There is two aspects to the usefulness of a jack screw. ",
"The first one is lever. For one full rotation of the lead screw, you move up only pitch of the screw. As you make a reasonably fine pitched jack, it means you can apply reasonable amounts of torque on the jack screw to move an enormous mass. ",
... | [
"Very well explained. ",
"For OP's example, the building weighs 750 tons, and was lifted using 200 screws. That means that the shaft of each jack (excluding the threads) must be large enough to support 750/200 = 3.75 tons without failing. Standard ",
"A36 structural steel",
" is specified as having a minim... | [
"Crap. These are thought out explanations.",
"To summarize: Jackscrews are a combination of mechanical advantage through screws and leverage by simple levers through the jack. They're setup in a symmetrical arrangement that spreads load and allows for scaling. With hundreds of screws its possible to raise things ... |
[
"Why do I get light-headed when I start eating?"
] | [
false
] | null | [
"Hi dephress thank you for submitting to ",
"/r/Askscience",
".",
" Please add flair to your post. ",
"Your post will be removed permanently if flair is not added within one hour. You can flair this post by replying to this message with your flair choice. It must be an exact match to one of the follow... | [
"'Human Body'"
] | [
"Thank you for your submission! Unfortunately, your submission has been removed for the following reason(s):",
"We do not offer ",
"medical advice",
" on ",
"/r/AskScience",
". Please see our ",
"guidelines.",
" If you have concerns about your or someone else's health, you need to speak to a medical p... |
[
"How good a sword could you make with current technology?"
] | [
false
] | Improving swords has essentially stopped a few centuries ago, what with them no longer being up to modern combat. Yet you occasionally see super swords pop up in science fiction, like vibro blades and nanoswords. I've been wondering if significant improvement of swords, over the generally assumed peak in swordforging, ... | [
"A very similar question was asked a ",
"couple months ago",
" with a pretty good discussion of why it probably wouldn't be dramatically better than swords made a few hundred years ago."
] | [
"Thanks!"
] | [
"One of the problems that I think you overlooked (thanks to the meme that knowledge is ever-increasing, and never lost) is that we presently ",
" replicate some of the best historical swords, due to their maker's disappearance & general lack of interest in making decent swords anymore.",
"As a side note, I reme... |
[
"Why do the planets nearer a star become rocky and those farther out become gas giants"
] | [
false
] | Or is this not always a general make up of a system? It it's "generally but not always" true, have there been system discoveries of the opposite, with the gas giants in close and the rocky ones farther out? | [
"We discover a lot of close-to-star gas giants because they're easiest to see. I don't know if they are more prevalent.",
"From the number of hot gas giants we've detected, it appears that they're pretty rare. Something like 1% of stars have such planets. As you said, they're just much easier to detect.",
"Duri... | [
"The actual reason for this is the frost line ",
"http://en.wikipedia.org/wiki/Frost_line_(astrophysics)",
"The theory goes that inside the frost line, most light elements are fluid gasses, and thus tend to dissipate rather than coalesce (the thing required to start planetary formation). Because of this there i... | [
"I would repost your answers as a new top level comment, as the one you're replying to is pretty wrong."
] |
[
"Why are the reproductive systems of so many animals tied to their waste-disposal system?"
] | [
false
] | Is there an evolutionary advantage to this? Wouldn't the increased risk of infection slowly migrate the reproductive organs elsewhere. Is there some example of an animal that has evolved multi-personal copulation, but also has their reproductive organs as completely separate from their waste disposal? (Ie; not sharing ... | [
"I can speak to the development of vertebrate urogenital systems, and particularly that of humans. The urinary and genital systems are tied developmentally. They both develop largely from a specific part of the mesoderm (the middle layer of cells in an embryo). You can't decouple them to move the reproductive syste... | [
"Reproductive systems do not have to function for an organism to live. They have to function for an organism to reproduce. This is an important distinction when talking about evolution, because reproductive success is what is central to evolution by natural selection. ",
"Also, there are equally fundamental aspec... | [
"Another way to look at this: Energy intake (and hence also waste disposal) as well as reproductive systems are absolutely fundamental to any organism (if it doesn't just self-replicate). How many arms a being has, whether it has an endo- or exo-skeleton, how many eyes it has (If any.), etc., that's all arbitrary i... |
[
"Do flames have mass or any weight at all?"
] | [
false
] | null | [
"If, by flame, you mean the glowing part of the fire, then yes it has mass, because t is hot gas. It rises because its density is less than that of the surrounding air - it \"floats\"."
] | [
"The relation ",
"c",
" only holds for massive objects at rest. The general relationship in special relativity is ",
" ",
"c",
")",
"+(",
"c)",
", where ",
" is the object's momentum. Light has no mass, so its relationship between energy and momentum is ",
"c. ",
"TL;DR: Light is never at r... | [
"Well, it depends if OP has in mind the gas that is emitting the light or the light itself. It's not obvious to me which. ",
"One could probably put mass on energy as follows: m=E/c2",
"This is not correct, or at least very misleading. Light has energy, but no mass."
] |
[
"Does liquid iron continue to be shiny (like liquid mercury) or does it stop being shiny after it starts emitting light?"
] | [
false
] | [deleted] | [
"Here",
" is an example of molten copper being shiny when under a bright light."
] | [
"Metals are shiny because they are conductive (mostly). I would expect it with iron as it's still conductive when molten. My googling says its true for aluminum and mercury.",
"With that said, I can't find any pictures, to see the shinyness you really need a bright flash to drown out the glow of the molten iron."... | [
"Why are conductive materials shiny? What is their property that makes them interact with light in a certain way?"
] |
[
"How do male animals know that offspring is theirs?"
] | [
false
] | I was watching a documentary on zebras, and in it, the narrator mentioned that the stallion will kill any offspring that is not his. I have also heard of this behavior in hippopotamuses. Are animals aware that insemination causes pregnancy? Or is it some chemical in the offspring's body that gives off an odor that s... | [
"Usually infanticide (the killing of babies) occurs when a new male takes over a polygynous group (one male mating with multiple females). Because the new male hasn't mated with these females, he can assume the infants aren't his. He won't kill the infants sired during his tenure as the male in charge of the group,... | [
"You aren't giving enough credit to innate behavior. It can be quite complex, like a spider weaving a web. It doesn't have to mean that there is conscious thought. "
] | [
"Zebras and hippos are both species that tend to live in small groups known as harems. These harems consist of one breeding male and several females that the one male alone breeds with. The killing of offspring generally happens when a new male challenges the current owner of the harem for ownership of said harem... |
[
"Since dinosaurs were discovered far below the earths surface covered in dirt, how does the earth gradually pile dirt on itself, forming layers covering up history over the past few centuries?"
] | [
false
] | null | [
"Okay, a lot of these are wrong. I'm an archaeologist so let me try to clear some of these misconceptions up. ",
"You are generally going to find fossils within sedimentary rock, and there are a few types of sedimentary deposition. The most common is by water, where tiny pieces of sediment (not dirt, sediment is ... | [
"Tar pit, or at the bottom of a shallow sea, quickly covered by a landslide to create an anaerobic environment. "
] | [
"I think the root of your question is: the whole earth getting bigger? Where does that extra material come from?",
"And I think the answer is no, it doesn't happen everywhere, just locally. Some spots get more material, some get worn away. We only find fossils where it's been net built up over the time since t... |
[
"Does the deep ocean have seasons?"
] | [
false
] | Times of the year where there are pronounced temperature differences? | [
"No. The seasonal ",
"thermocline",
" only extends down to ",
"a few hundred meters",
" below the ocean surface."
] | [
"Maybe temperature will be constant but the flow of 'snow' - the stuff that constantly rains down on the ocean floor is likely to change with changing conditions on the surface. A lot of the bottom feeders rely on this."
] | [
"Okay, thank you!"
] |
[
"Why is methane plumes in the arctic significant?"
] | [
false
] | [deleted] | [
"I believe that the methane is stored in frozen methane hydrates on the seashore. It is speculated that a warm tendril of water destabilised the methane on the arctic slope and so it is rising. Regardless of the cause they are measuring around 10 times the concentration of methane compared to normal ocean condition... | [
"Is this related to the recent permafrost 'explosions' in Siberia?"
] | [
"The two events wouldn't have a direct causal relationship even accounting for the most extreme case of the butterfly effect. This is simply because the oceans act on Timescales that are much longer than the atmosphere due to higher inertia both to motor and thermal changes. The release of methane from the ocean wa... |
[
"Does the chlorine used to disinfect drinking water in cities all over the country actually cause severe and chronic problems with our gut microbiome over time?"
] | [
false
] | When you google it, the first answer is: 'No studies have confirmed this is a problem, but you should take pro-biotics just in case.' 'No studies have confirmed it... yet, if you've ever had a betta fish and lived in the city where I live- the tap water kills the fish within 5 minutes (if you don't let it rest, or use ... | [
"No. The amount of chlorine in the water is too small, and it will be destroyed completely - to basically salt - by stomach acids.",
"'Probiotics' mess up your natural internal biome, and are only of use if you are already messed up. Even if you have just taken a course of antibiotics, your microbiome recovers so... | [
"I think this quote from the article is telling (emphasis is mine):",
"Leach suspects that several factors may impede bacterial diversity in Americans, among them the profligate use of antibiotics, overconsumption of processed foods, and, at least to some extent, consumption of chlorine in tap water. “It’s someth... | [
"One of the most egregious sins that mainstream journalism persists in making is drawing a straight line from the results of animal studies to consequences for human beings. If this were reasonable, we wouldn't need to do human trials at all and go straight from animal studies to commercial sale of drugs. These g... |
[
"How does gene therapy actually work?"
] | [
false
] | [deleted] | [
"These viruses you speak of are modified to have no pathology, and are used to spread genetic material through a host the way a virus normally would. Viruses have this ability, because it's the manner in which they reproduce. The modified viruses inject this new genetic material into all of the target cells it come... | [
"To expound upon the best general answer:",
"Viruses are not structured the same as what living things are made of, cells. Cells have complicated membranes and internal organelles and are generally much larger. Viruses are thousands of times smaller and pretty much just a strand of DNA or RNA in a protein coat wi... | [
"Right, and the delivery mechanism is varied, but typically they will either take cells from the patient, engineer them, and stick them back, or inject the virus directly into a tumor (the virus would be carrying p53 or something else which is anti-cancer). You can not take cell lines and transplant them into pati... |
[
"Why do things \"produce\" light when they get very hot?"
] | [
false
] | [deleted] | [
"This is called ",
"black-body radiation",
". The cause is because all warm object will emit some of their heat. The way they emit heat is via photons (light particles). The hotter something is, the more heat it emits, thus the more energy it will release. The energy of a photon his given by the equation E = hf... | [
"We often see red, orange and yellow when a light is warming up(or on a heating element).",
"Why don't we generally see metals go green and blue? We do see UV lights as violet... and it would seem that if lights are giving off white light then they must have passed the blue / green wavelengths... so just curious ... | [
"why we never see that.",
"The colour of the total light emitted is different from the peak light, it is the peak emission that increases in frequency as the temperature increases. When the peak is in near infra red there is a lot of red light and still but not much blue so the thing glows red. When the peak is i... |
[
"What's the best way to approximate the square root of ANY number precisely?"
] | [
false
] | null | [
"Example: 76\nIs between 64 and 81, so the whole number will be 8. The rest: 76-64=12, 81-64=17. So an approx. is 8 12/17 or 8.705882, actual root is 8.717798"
] | [
"You can find the denominator easily because it's 2N+1 where N is the whole number."
] | [
"Your number is A. To find the square root of A:",
"Pick a number X that is kinda close to the square root of A.",
"calculate (X + A/X)/2. Replace your current X with this new number.",
"Do step 2 a few times until X is good enough. That's it.",
"From the ",
"wiki page",
" for computing square roots. It... |
[
"How do coupled reactions ensure that the entropy of an organism is always increasing?"
] | [
false
] | I know that life doesn't violate the 2nd law of thermodynamics because organisms aren't closed systems, but apparently that answer isn't good enough. My professor gave me the hint of coupled reactions, but I'm not seeing how coupled reactions answer the question. | [
"The entropy of an organism is not always increasing, the entropy of the universe is always increasing. Living things tend to decrease entropy, for example a tree sucks up CO2 gas and locks carbon into cellulose molecules where it has less entropy, but it is only able to do so by absorbing light from the sun, and ... | [
"It's hard to know what your professor is getting at, but I can think of an example that might be relevant.",
"Let's say you're concentrating a type of molecule inside a cell, pumping it inside. Moving up a concentration gradient like that increases entropy, so it's not going to occur spontaneously.",
"What bi... | [
"Thank you, this is exactly what I was looking for. I actually had a huge sudden understanding of how coupled reactions answer the question before you even responded, but thanks for the answer all the same!"
] |
[
"Has the average IQ of people in North America increased or decreased in the last 100 years?"
] | [
false
] | null | [
"This is an odd question because by definition the average IQ is 100 -- the test is standardized. So every few years, test-takers take a new test and it's standardized so that the average score is 100. However, if these same test-takers take the old test (standardized on a different set of subjects a while ago), th... | [
"That's surprising to me. I may just be a pessimistic, nihilistic cynic with a superiority complex, but it would seem to me that a large portion of people seem to lack the ability to think and process information intelligently, along with having little to no common sense. Shooting yourself in the testicles with a p... | [
"Among people who take IQ tests, performance has improved relative to previous years. It is questionable whether IQ tests measure anything beyond ability to take IQ tests. An argument could be made that a certain portion of the population that takes these tests is simply being better trained to be test takers of a ... |
[
"Why do bugs fly into lights?"
] | [
false
] | [deleted] | [
"Because they use the moon to navigate. The moon is far enough away that all the light rays coming from it are (effectively) parallel. When a bug sees a light on the Earth, it uses it to navigate like it would the moon. The rays coming from a light on the Earth, however, are not parallel. Following them leads the b... | [
"And the cases where it doesn't spiral inwards would be much less likely to be noticed by us, because the insect would not get close enough to the light for us to see it."
] | [
"I understand how keeping the lamp at a constant bearing would fly you in a circle. However it does not explain why it spirals towards the light. Why does it not spiral away, or orbit at a constant distance?"
] |
[
"What would code for a quantum computer program look like?"
] | [
false
] | I can't even begin to wrap my head around it. | [
"The way we describe quantum algorithms is not via a programming language as you're used to seeing them. Instead, we describe a sequence of quantum processes that embody the calculation. Each step involves what's called a unitary transformation; it means there is a step in which the quantum state is made to evolv... | [
"I think the 'nearest-neighbour' of current programming languages to a future quantum-code-language is either VHDL or Verilog (used to \"program\" transistor circuitry). In these, you clearly define input signals (analogy:qubits), the logic gates they interact with (quantum gates/processes), and the output signals ... | [
"Well, but if you think about it in this way, the quantum computer programming language would not look too dissimilar from assembler code at first. And then it's easy to imagine a higher level code around that.",
"For example: in assembler, you can deal with gates directly, e.g. you have two bytes in a register a... |
[
"Can a microwave oven be repurposed as a Wi-Fi and Bluetooth signal jammer since they're both 2.4GHz?"
] | [
false
] | null | [
"Yes. In fact, microwave ovens with defective or very poor radiation shielding (usually very old models) already disrupt Wi-Fi connections.",
"However, Wi-Fi isn't exclusively 2.4 GHz, a lot of devices these days use the 5 GHz band which would not be affected."
] | [
"I feel it should be noted that broadcasting a signal strong enough to jam is illegal in most places. In the US, the FCC ",
" find such devices if left online or used frequently, and the fines are significant."
] | [
"You can reduce the effective range or fry the radio's. 200-500 Watts is a big hammer. Also dangerous to mess with.",
"It's not the most efficient way to do it those because usually a microwave produces RF at a single frequency. Wi-Fi uses spread spectrum. The effect of that is from the Wi-Fi receivers point of v... |
[
"do bugs have brains? if so are there any animals without brains?"
] | [
false
] | null | [
"Bugs have brains, yes. ",
"There was just a front-page post in /r/science about the evolution of insect brains.",
"Sponges are animals with no nervous systems. They don't have digestive or circulatory systems, either. They just sit around and let water go through them, delivering nutrients."
] | [
"Bugs have brains, naturally they are small, Little more than a bundle of nerve cells.\nMany animals do not have brains, invertebrates like jelly fish do not have brains or even nervous systems as far as we can tell."
] | [
"Jellyfish have a nervous system",
" but not \"central nervous system\" or brain."
] |
[
"[Physics] Water's boiling point - the temperature at which it becomes a gas - is 100°c, so why is there water vapour - gas - in the air at lower temperatures?"
] | [
false
] | Please explain in layman's terms if possible :) | [
"Because some of the molecules in the water can have sufficient energy to escape the fluid and become vapor, even though not all of the molecules have enough energy. Temperature is a bulk property, and the energy of individual molecules can deviate from average.",
"http://www.reddit.com/r/askscience/comments/1cy... | [
"The boiling point of a substance is the point at which it begins to be more energetically favorable for the liquid to exist in a gas phase instead. But this is usually referring to the 'bulk' of the material. That means the boiling point describes the conditions at which a chunk of water surrounded by a bunch of ... | [
"Water molecules attract each other because water is a highly polar molecule",
"It's important to remember that attractions can arise from other intermolecular forces than polarity"
] |
[
"Where does the sand in deserts come from?"
] | [
false
] | My son asked me this today and I realized that I never even thought about it before. How did a desert like the Sahara get filled with sand? Did it come from somewhere else or did it get left behind when the other soil, plants, etc. got removed? | [
"I'm studying for my finals, so I think I can answer this roughly. Apologies for occasional grammar mistakes, German here.",
"When we are talking about 'hot', 'dry' deserts, like the Sahara, Gobi or Atacama, about 80% of the desert are made of rocks, stones and other bigger grains. (Those kind of deserts are call... | [
"Some deserts are ancient seas and the sand formed from the tides back when there was water. But sand is only 20% of the surface area of deserts; mostly there are exposed, rocky plains. It's also important to remember that there are mountain deserts, cold deserts, rain shadow deserts, and more, not just the stereot... | [
"Not all deserts were oceans, although there are some which were, for example the \"Whale Valley\", or Wadi al-Hitan in Egypt. 40 million years ago, there used to be the Tethys Ocean. It dried up gradually, leaving a huge amount of skeletons of sea dwellers, including whales. But basically, every area with a tiny a... |
[
"Why does it feel so good to pee?"
] | [
false
] | For most guys, at least, peeing is like having a miniature orgasm. But it's just water running down from the bladder through the urethra. So why does it feel so damn good? | [
"I don't actually know anything about the mechanism of why it feels good, but I would imagine that it's evolutionarily adaptive for urinating to feel good for the same reason that it's adaptive for eating and drinking water and pooping to feel good - because it's bad for the body if you don't do these things. Conve... | [
"My general impression is that things with an evolutionary imperative are generally associated with pleasurable feelings. Since peeing is important for survival, you are compelled to do it by positive reinforcement which has evolved over millenia to make sure you don't hold it in too long and hurt yourself."
] | [
"A full bladder puts pressure on the intestines around it and it's uncomfortable. Same for a full colon."
] |
[
"Why are some men's facial hair a different color from their hair?"
] | [
false
] | I was never able to understand how that works. Any ideas? | [
"Hair color is one of those things used as an examples in simple genetics problems but is not understood well. Pigmentation is polygenic and we see the production of several different protein products. I suspect that in different tissues (ie scalp, chest, chin) expression of the genes are different and the differen... | [
"Because secondary sex characteristics in males (like facial hair) develop in response to pubertal rises in androgens (namely testosterone), it is possible that those follicles are more responsive to this hormone. Testosterone may be regulating some of the genes responsible for pigment production by either promoti... | [
"Not to hijack the thread, but I was also wondering why I have a few stray red hairs on my face. I'm dark-haired all over, and I never had any that color until about 3-4 years ago (I'm 29 if that helps)",
"Only in my stubble, not down there, or in my eyebrows or head. "
] |
[
"From the perspective of an outside observer, when does the Schwarzschild radius of a black hole grows?"
] | [
false
] | As I understand, from the perspective of an outside observer, an object falling into a black hole approaches its event horizon asymptotically and takes infinite time to actually reach it. So, when would the observer be able to register the Schwarzschild radius of the black hole increase, if, as far as they’re concerned... | [
"The infalling object has a gravitational field way before it merges with the black hole. The event horizon is a global thing and will grow accordingly. You can see this animation for two black holes ",
"https://youtu.be/Tr1zDVbSjTM",
" . So all the time dilation business is never an issue."
] | [
"From the perspective of an outside observer, she sees a \"last photon\" from an in-falling object. For a stellar-mass BH, this last photon comes within milliseconds of the object falling in. So there's no need to worry about the asymptotic behavior, since the discrete photon behavior is so different.",
"As for r... | [
"I think you're suggesting that gravity wave measurements and optical (infrared) measurements might give conflicting results. That would be a fantastic finding! But it isn't going to happen, because you need really really huge masses falling into the BH, in order to detect gravity waves. I'm thinking at least Jupit... |
[
"Could you still see through an eye that's knocked out of its socket?"
] | [
false
] | Imagining something like the scene here: (NSFL, fake movie violence) where the eye is forced out of the socket and hanging by a thread. Would it still be functional? | [
"Yes and no. Your eyes does manny sudden movements and fixations every second, since the nerves in the retina are not at all even distributed (highly focussed in fovea). You would still be receiving information, but without being able to saccade you would only have detailed information about a very small part of yo... | [
"For the sake of argument, let's accept that an eye could be removed from the orbit without damaging it so badly that intrinsic function was compromised. Possible, but quite the trick shot to accomplish, as the extraocular muscles and orbital tissue are quite strong (muscles are about 10x the strength needed to mo... | [
"It's been a couple of years since I was certified in first aid, but for some reason we actually covered this topic. IIRC, you should immediately attempt to place the eye in a styrofoam cup or similar container. And by that I mean putting the cup over and around your eye socket with the eye. This has the double ... |
[
"Why is electricity transmitted at high voltage? Confused about interaction with Ohm's Law."
] | [
false
] | So I get the money saving part with lighter wires (If you did high current low voltage you'd need bigger wires to handle the current), but I don't get the I loss and transmitting at high voltage low current. It seems like when you subsitiute with Ohm's Law if you raise voltage resistance goes up since R=V/I. Conceptu... | [
"To clear things up: You want to transfer power over long distance.\nThis Power is P=VxI (Lets use DC current for simplifying stuff)\nNow you want to minimize losses and/or material cost. With high voltage for the same Power P you have less current. This smaller current need smaller diameter in the transmission lin... | [
"In most situations, including this one, resistance is just a function of the material the wire is made out of. So the resistance will not go up; R = V/I means that if voltage rises, current also hast to rise."
] | [
"P_loss=I",
" x R_line.",
"Isn't P_loss also equal to V",
"/R_line? And when you raise the voltage/current ratio, isn't that the same thing as adding resistance?"
] |
[
"Domesticated animals are known to be a source of many diseases in humans. Historically, are there any pandemics that have been caused by canine diseases? If not, why do dogs not carry plague-worthy illnesses, or why are humans immune?"
] | [
false
] | When Europeans migrated to the New World, they brought with them many diseases that ravaged the native human populations, which had no immunity due to a lack of domesticated animals. However, both populations already had domesticated dogs. Were there any major infections caused by a canine disease? Or did human proximi... | [
"Our immune systems and cell biology are certainly similar enough for the potential of zoonotic transmission of disease from dogs to people; rabies is one example. The lack of major disease outbreaks related to dogs may be related to the conditions in which humans keep dogs versus other domesticated animals associa... | [
"Another thought is that dogs have lived with humans for ~ 35,000 years and mutual immunity is helping. (",
"https://www.boehringer-ingelheim.com/our-responsibility/animal-health-news/human-dog-relationship-historical-perspective",
")."
] | [
"Plus, taking something like BSE (Mad cow disease) as example, most societies do not eat their dogs.",
"*1 Another aspect worth mentioning: Thanks to extensive research on Covid as a virus group, we know that there are thousands, potentially tens of thousands Covid variations per year that do cross over to humans... |
[
"Does Gravity travel at different speeds in different mediums?"
] | [
false
] | Light travels at different speeds in different mediums. Gravity is said to travel at the speed of light, so is this also true for gravity? | [
"No, it always propagates at the same speed. If its path was warped by another gravitational field, it might appear to travel slower because it's taking a longer route.",
"edit: see ",
"here",
" for a very small effect due to absorption of gravitational waves in different media."
] | [
"Sorry, ",
"/u/iorgfeflkd",
", but this is not correct. See for example Sec. 2.4.3 of Kip Thorne's lectures at Les Houches (1982) where he works out the absorption and dispersion of GWs in media (I put up a scan ",
"here",
"). Of course this leads to a dispersion relationship and hence a different phase and... | [
"So let's say we had an ideal gas of black holes..."
] |
[
"Magnetic fields as propulsion in space?"
] | [
false
] | I was just thinking about that Train in Japan that set the speed record, and it made me think aren't there magnetic fields in space, and can we use those as way of propulsion of a space craft? | [
"Kind of. Maglev trains are propelled by magnetic fields, but they are applying a reaction force on the tracks. In space, with no matter around, this wouldn't be so easy.",
"Fortunately the solar wind exists, it's very weak but present. In theory it would be possible to use a magnetic field to deflect those charg... | [
"on a similar vein why is nuclear power not talked about much in regards to space travel\nas it allows submarines to be at sea for a very long time before returning home\nand of course keeps nuclear plants going indefinitely and nuclear bars would be a lot easier than gallons of fuel "
] | [
"While it might be useful when near planets as the above comment points out I guess It wouldn't be of much help in trying to cross our milky way with huge gaps between large bodies but I do like that question and have wondered could we not use magnetism to push a space craft of the earth? thus riding ourselves of t... |
[
"Do any chemical reactions occur in the plasma phase?"
] | [
false
] | Or are all interatomic bonds broken in a plasma? If so, is it possible to control how the atoms recombine into molecules when you cool the plasma back down into a gas? | [
"Plasma",
", the so called fourth state of matter is when \"the gas phase is heated until atomic electrons are no longer associated with any particular atomic nucleus. Plasma s are made up of positively charged ions and unbound electrons.\"",
"Chemistry is concerned ",
"with",
" \"atoms and their interactio... | [
"They certainly won't coalesce into anything orderly on their own. Any hot gas has an enormous amount of entropy, and a plasma has even more. To control which atoms go where, could probably induce some ordering with strong gravitational or magnetic field to separate the high/low mass/charge particles.",
"Keep i... | [
"Ok, so what about the part of the question I posted in the text box? Can you control how the atoms bond to each other when you cool the plasma back down into a gas?"
] |
[
"Why can't you see your own eyes move in a mirror?"
] | [
false
] | null | [
"Your visual processing system of your brain-eye system (they’re very closely integrated) filters out anything that happens during saccades (movements of the eye to fixate on something else), because it would just be a confusing blur. In fact, it replaces that time interval with something else, either “stretching” ... | [
"Just like the brain uses photoshop-like skills to cover up that permanent blind spot where your optical nerve cable plugs into your vision-screen. Reality is a lie, can't even trust your own brain nowadays."
] | [
"I think that’s pretty much the same mechanism. The brain always creates an internal “movie” from fragments it catches with the eyes. That input is always incomplete and most of that movie is actually interpolated from moment to moment. The blind spot is one such thing causing incompleteness, but the difference bet... |
[
"How are diamonds attached to saw blades that they can manage to stay on while cutting through steel and diamonds?"
] | [
false
] | null | [
"There are three common ways to hold the diamonds.",
"2 (a) Resin bonding",
"\nDiamond grit is mixed in a resin, which is then cured (chemically and/or heat and pressure)",
"2 (b) Metal bonding\nDiamond grit and fine metal powder are mixed with a temporary binder then pressed into shape. The assembly is put ... | [
"Corrosion resistance. Diamond saws and grinding wheels are usually water cooled."
] | [
"Thank you. Do you also know what is special about nickel that makes them such metal of choice for attaching diamonds? "
] |
[
"If everyone stayed indoors/isolated for 2-4 weeks, could we kill off the common cold and/or flu forever? And would we want to if we could?"
] | [
false
] | null | [
"Unfortunately, influenza can also spread through many animals, such as pigs, so no, the flu would survive."
] | [
"Being that no-one has touched on it yet, I thought I'd add a bit about the second part of your question when you ask \"would we want to?\" ",
"Removal of any organism from an environment is likely to have an effect. Take smallpox as an example (which as far as I knew is fully eradicated), there is starting to be... | [
"This is the most important point, IMO. Any disease that has any \"reservoir host\" or a carrier will not be eradicated. At least not with the technology we currently have."
] |
[
"Can bugs sneeze?"
] | [
false
] | I was talking with my brother about animals sneezing and this came up... Can they? | [
"Many insects are thought to passively exchange air through these tubes without any muscular involvement.",
"While many others ",
"actively breath",
": "
] | [
"No, not in the way that you are thinking. Insects unlike reptiles, birds and mammals don't breathe through their mouths. ",
"Insects have tubes, called spiracles that exit on their abdomen and allow for air to exchange with their internal structures. Many insects are thought to passively exchange air through the... | [
"Interestingly, while insects can't necessarily sneeze ",
", they can (and frequently do) vomit! ",
"In fact, this is the ",
"mechanism",
" by which ",
" (the bacterium that causes the bubonic plague) gets into the blood of humans and other mammals: the bacterium infects a flea and begins growing in the i... |
[
"How easily is nicotine absorbed through the skin? Does different skin have different absorption rates? & does nicotine act differently when absorbed through your skin compared to inhaling it?"
] | [
false
] | null | [
"Due to the permeability barrier of the skin (in particular, the outermost layer, called the ",
"), there are very few drugs that can be absorbed through intact skin. Nicotine is one of the few that can be delivered transdermally. It is able to diffuse through the stratum corneum in part because it is a small m... | [
"I have spoken with people that hand harvested tobacco, usually as children or teenagers. They all talked about getting nauseous and \"wired\" from the physical contact with the plants. It essentially rubbed off on their exposed skin and sickened them. They do not recall it fondly."
] | [
"They may be looking for the transdermal bioavailability, which according to ",
"this paper",
" and ",
"wiki",
" is around 68%."
] |
[
"How is LSD made?"
] | [
false
] | I am not looking to make it, but from what I understand it is one of the most difficult drugs to make. Using dark rooms, perfectly sterile labs and only putting enough of a dose to get someone to the level they want. Seeing as such a minute amount is used to get someone there. What is the process to make it and synthes... | [
"He's changed the question since I answered it. ",
"LSD is hardly one of the most difficult drugs to make, it's not even on most total synthesis people's list of remarkable challenges.",
"Compare ",
"Brevetoxin",
" to ",
"LSD",
", or even ",
"Stychnine",
"LSD is the type of thing you do for a probl... | [
"http://learn.genetics.utah.edu/content/addiction/drugs/mouse.html",
"This will answer your second question."
] | [
"A few additional comments:",
"The total synthesis would be quite a task. But of course, starting from lysergic acid, making the amide would not take that much effort. As far as the OP's comments about dark/sterile rooms, much of this has to do with retaining LSD's psychoactivity. LSD will isomerize in base and a... |
[
"Granted that humans walked to the different inhabited continents, how did we wind up on tiny polynesian islands?"
] | [
false
] | Aboriginal tribes, Hawaiians, and especially the really tiny islands nobody really talks about like Wallis et Futuna, all seem by my recollection to have had native tribes upon being discovered and mapped. How did they get there to begin with? Is it as anthropologically easy as "people went sailing and got lost"? | [
"The ",
"Kon-Tiki",
" experiment certainly provided some scientific validity to this theory."
] | [
"US airmen Louis Zamperini and Russel Phillips survived 47 days and drifted about 2000 miles on a life raft in the South Pacific after being shot down in WWII. And that was with the occasional strafing. So it is certainly quite possible."
] | [
"Or a small family or group of families to get lost and manage to survive on a fertile island."
] |
[
"Would keeping an \"injured\" body part at higher temperatures make it heal faster?"
] | [
false
] | I recently worked out my calves and walking kind of hurts. That got me think. If ice makes things numb and generally slows down bodily functions, would keeping a body part at a higher than normal temperature make it heal faster? | [
"While being cold could slow down bodily functions, the reason you ice injuries, or sore muscles, is that it reduces the swelling which reduces the pain. I don't think heating up a limb would help very much because your body is pretty good at knowing what temperature to be. A lot of the metabolic pathways in your ... | [
"Ice and heat are often used interchangeably during sports injuries. Ice is used to reduce pain and swelling as when damage occurs you have vasodilation in the area which leads to edema, ice helps prevent this and therefore prevents swelling.",
"Heat on the other hand should be used if the injury lasts for more t... | [
"Either way you're simply reducing pain by using ice or heat on an injury, they wont significantly help speed up or slow down the healing process.",
"This is false. Cold can be used throughout the injury and recovery stages, but heat should not be applied until after the acute inflammation period (~3-4 days). \"I... |
[
"If it wasn't for air resistance would balloons rise with the same acceleration as gravity?"
] | [
false
] | I realize that there needs to be air for the balloon to rise | [
"Ignoring air resistance, the forces on the balloon are gravity and buoyancy.",
"F = rho_air * V_balloon * g - m_balloon * g\n",
"where rho is a density, and g is the gravitational acceleration. We can also write",
" V_balloon = m_balloon / rho_balloon\n",
"so",
"F = m_balloon*g*(rho_air/rho_balloon - 1)\... | [
"Imagine a tennis ball in a swimming pool. If you let go of it from the bottom of the pool, it travels upward. Both the water and the tennis ball are pulled toward the earth by gravity. But since the water is more dense than the tennis ball that has air in it, the water is pulled underneath the tennis ball, caus... | [
"The same situation arises with an imbalanced counterweight.",
"Say you have a 10 kg mass you want to spring upward. You attach a string to it, make the string go around a pulley, and attach a 20 kg counterweight to the other side.",
"The initial answer many will jump to would be that it accelerates upwards at... |
[
"When I am all alone, and there is no noise in the room, and it is all still and quiet, there is a sound in my ears/head that is similar to a ringing of the ears, but it's not quite the same. What causes that?"
] | [
false
] | null | [
"Tinnitus",
": \"the perception of sound within the human ear in the absence of corresponding external sound\". ",
"Causes are varied, so check the ",
" link for more on that. "
] | [
"It's a fairly sly reference to the ",
"Legend of Zelda",
" video game series where the protagonist, a boy called Link, is often referred to as Zelda, actually the princess that Link is trying to save, by players who haven't followed the story and dialogue. You obviously don't spend much time 'round ",
"r/ga... | [
"Tinnitus is not a disease, but a symptom that can result from a wide range of underlying causes ",
"I think he is talking about a sound of blood running through veins near to his ears. You can hear it clearly if you are in a silent room and shut off your ears with your fingers."
] |
[
"Does anyone still bother to read papers by the giants of theoretical physics?"
] | [
false
] | Their most highly-cited papers (of people like Yang, Oppenheimer, Teller, Feynman, etc.) are surprisingly readable. And they're deep. They're highly cited for both of those reasons, after all. But no one seems to touch them anymore. - Teller's "On the Change of Physical Constants" - Feynman's most highly cited paper - ... | [
"TBH, it seems to me that papers are the invention of an idea, but textbooks are more expansive/better explanations of said idea. Most of us have learned these things through classes on the ideas I guess."
] | [
"Yeah, that seems to be the standard assumption. But I do wonder if some ideas are lost in the textbook's explanation. By reading papers, you sort of do get a better idea of what inconsistency prompted the invention of a new theory (or technique) to correct that inconsistency. And this helps with formulating furthe... | [
"What's lost in a text will be picked up by a person's interactions with their peers. Often, I think, reading older papers will give a person insight into where a certain style of thought comes from; but unless you were actively reading a paper to really fight with the claims being made, I'm not sure how much insig... |
[
"Not sure how to classify neuron on their properties of excitatory vs inhibitory effects(very stupid question too)"
] | [
false
] | Before I go on, I want to make sure that everyone knows I don't know ANYTHING about neurons or biology. So please forgive this stupid question ahead time. At It talks about groups of neurons and how they are excitatory or inhibitory, but I would like to understand what that means and how this works exactly. My question... | [
"Glutamate is typically excitatory and GABA is typically inhibitory, but there are situations in which ",
"GABA has an excitatory effect",
", and ",
"inhibitory glutamate receptors",
" are known. So it cannot be said that each neurotransmitter can only be either excitatory or inhibitory, since this depends... | [
"tl;dr To see if a neuron is grouped as excitatory or inhibitory, look at the change in voltage in the downstream neuron. (Cheater method that mostly works: look at the neurotransmitter released.)",
"The voltage on the \"in cell\" side of a neuron is lower than on the \"out of cell\" side of the membrane. Raising... | [
"It's nice to finally have an answer. Much appreciated"
] |
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