title list | over_18 list | post_content stringlengths 0 9.37k ⌀ | C1 list | C2 list | C3 list |
|---|---|---|---|---|---|
[
"What is the biological explanation for why we often feel nausea in waves rather than one sustained reaction?"
] | [
false
] | null | [
"MD here. I don’t really like any of the answers here. Mine probably won’t be great either though because I don’t necessarily agree that nausea comes in waves. ",
"You can have what’s called a “colicky” pain in the abdomen, this is pain that comes in waves, which is due to peristalsis (the intestines basically co... | [
"Is this your theory or is it truly scientific?"
] | [
"Is this your theory or is it truly scientific?"
] |
[
"Why is the binding energy within a nucleon positive?"
] | [
false
] | I posted this as part of another discussion, but it seems to have gotten largely lost in an excellent comment thread... First, my understanding of the basics. In nuclei, the binding energy nucleons is negative. We can tell because if you add up the mass of all of the protons and neutrons in a nucleus, the sum will co... | [
"Right. Here's the weird thing. If you consider, instead, a single nucleon and its quarks, then adding the mass of the quarks again gives a different number than the mass of the nucleon. This time, though, the mass of the quarks comes out dramatically less than the mass of the nucleon.",
"Not if you add up the ",... | [
"I think the answer to this question is more one of definitions. Nuclear binding energy is the difference between the the sum of protons and neutrons in a free or unbound state vs the mass Protons and neutrons when clumped together in a nucleus. The sum of the masses of these particles when bound is less than the... | [
"I understand this. But the question was regarding the binding energy within a ",
", not ",
". My understanding is that the binding energy within a nucleon is positive because, unlike that within a nucleus, it comes from the kinetic energy of the constituents, which is positive.",
": Thanks for taking the t... |
[
"When using a spectroscope to analyze light from a far away star, how can we sure that the light the device sees is indeed from that star and that star only?"
] | [
false
] | Won't the light from different stars and galaxies reach the spectroscope in a "mangled" or mixed state? Sure, we can analyze this light and see what elements caused those wavelengths to be emitted, but we would be analyzing a "mixture" of photons from various galaxies and stars not the "pure" light from that particular... | [
"You're kinda right, but it's something we take into account. The simplest way is to just make sure your target is by far the brightest object in the slit, so that the background stars and galaxies only contribute a tiny bit of noise. But often things are too close together to do that: the most striking example is ... | [
"Just to add to this: there are astronomers who devote their careers to the stuff lying in front of a bright object, and count on that stuff messing with the spectrum in a systematic way.",
"A common example is the study of \"quasar absorption lines\". So far as we can tell, galaxies extend significantly farther ... | [
"Good point. This is also how we've found out about the atmospheres of exoplanets, by looking at how the star's spectrum changes when the planet goes in front of it."
] |
[
"Why do sodas fizz up if you shake them?"
] | [
false
] | null | [
"Sodas are over saturated with CO2, as you know. The fizz is from bubbles of CO2 coming out of solution. The rate at which the bubbles form has to to with nucleation sites and surface area for the gas to escape into.",
"When you shake a soda you create lots of tiny bubbles which allows the CO2 to come out of so... | [
"Follow-up question. How is the CO2 held inside of the liquid?"
] | [
"It's dissolved in it and is constantly coming out and going into solution creating an equilibrium at the top of the bottle which is why if you leave it open it goes flat, when the gas comes out it just escapes instead of being able to redissolve"
] |
[
"How can Greenhouse gases affect so much the environment if their concentration is so low it has to be calculated in ppm?"
] | [
false
] | I've been casually reading about the greenhouse effect and I still don't manage to understand how can so little affect so much our planet. | [
"Carbon dioxide is at about 400 ppm. That's 0.04%. ",
"If you drink alcohol, 0.04% in your blood has an effect.",
"Paracetamol starts to be toxic at about 0.02% of body weight.",
"Lots of things can have a big effect in small amounts."
] | [
"The greenhouse effect is one of the more misunderstood scientific phenomenon at the moment. The simplified explanation that we tend to hear a lot off is the blanket analogy, that the gases trap the heat in the atmosphere. While this is a perfectly good analogy, the more in depth explanation is as follows:",
"Ene... | [
"Nice work!",
"Also take into consideration that everything in our atmosphere happens in front af a huge, inactive nitrogen background. If you leave out the parts of our atmosphere that \"don't do anything\" you wouldn't be talking ppm anymore."
] |
[
"How is it possible for stars in a binary system be \"touching\" each other instead of the larger star gobbling up the smaller one?"
] | [
false
] | Got this question by reading the following news item: | [
"It's probably a good step here to stop considering stars as monolithic objects, but as blobs of gas/plasma held together by their own gravitational potential well. Imagine water pooling on an underinflated airbed, where the weight of the water is pushing down the same bowl that it's resting in.",
"The 'surface' ... | [
"It's also important to note that angular momentum must be conserved. With the two stars' cores orbiting out at a significant radius that's a lot of angular momentum, and if the stars ",
" merge, the new star would have a much smaller moment of inertia and have to be spinning faster than the original orbital spe... | [
"You've got some good answers already. Look up ",
"Roche lobe",
", ",
"contact binary",
", and especially ",
"common envelope",
".",
"http://upload.wikimedia.org/wikipedia/commons/thumb/a/a1/Common_envelope.svg/500px-Common_envelope.svg.png",
"Contact binaries and common envelopes look about the sam... |
[
"If a blue giant star collapses into a neutron star and a medium sized yellow star collapses into a white dwarf; what does a small red dwarf star collapse and become?"
] | [
false
] | null | [
"Red dwarf stars have incredibly long life cycles(estimated to be 100 billion years long) - so long, in fact, that no red dwarf has yet reached it's final life cycle, because the universe in not old enough yet. However, according to star life cycle models, red dwarfs are expected to burn brighter and hotter as the... | [
"Good answer here."
] | [
"Because of their convection currents which allow them to burn nearly all of their hydrogen and the low rate of fusion, it's likely that there would be only a small amount of material released as a planetary nebula. The star would likely expand a bit, before the majority of it slowly contracts and cools, eventually... |
[
"According to the 2013 Estimated Energy Use in the US report released recently, 59% of energy used in the US ends up as \"Rejected Energy\". What does this mean?"
] | [
false
] | I saw this diagram on and was curious about what is meant by "Rejected Energy" over on the right side. It's clearly very important! I figure it's just talking about energy lost to heat and inefficient engines/turbines, but is it really that much!? 59% is a lot... | [
"It's actually worse than that, the total energy usage for 2013 was 97.4 Quads, so over 60.5% of energy was rejected. ",
"The reason is because of the cycles we use to create energy. Most nuclear and coal plants use a ",
"Rankine cycle",
", where the heat that is created is used to boil water. That steam then... | [
"Distribution losses",
" normally amount to around 7%. It is the ",
"carnot efficiency of thermal energy to mechanical energy",
" that is the major loss."
] | [
"Many years ago, in ee college course, instructor said\n that of all the power generated at US power plants,\n more than half was lost to resistance in the high-voltage \npower lines (the huge towers), and that's subtracting from\nWhat the plant finally does produce."
] |
[
"It is said that electrons have spin. What does that mean?"
] | [
false
] | [deleted] | [
"Hawking's analogy (and a couple of similar others, I think there was one by Penrose) is really the only way to make sense of quantum mechanical spin in terms of anything familiar to us. Spin is, succinctly put, the intrinsic angular momentum of particles (like leptons and hadrons). It is ",
" a quantum mechanica... | [
"So then what ",
" they doing? ",
"Or is the best way to describe it simply \"a thing that happens\"?"
] | [
"Or is the best way to describe it simply \"a thing that happens\"?",
"That's about the extent of it. Electrons don't exactly \"do\" much insofar \"doing\" is classically understood. However, the effects of spin can be experimentally observed in dramatic ways, the most well-known of which is the ",
"Stern-Gerla... |
[
"Could we have wifi in the visible spectrum of light?"
] | [
false
] | I know that wifi uses electromagnetic waves. Could you have wifi that sends signals in the visible range? Would our eyes receiving the light screw with it? I realize that it wouldn't work for actual use, because anything that we can see would block the signal, but is it theoretically possible? | [
"Yes, we already have this. It's called ",
"free-space optical communications",
". In the simplest example, if you stand on one mountain at night and your friend stands another mountain away from obstructions, you could communicate with your friend by pointing your flashlight at him and turning it on and off ac... | [
"My favorite example of this is attaching an audio signal to a laser diode and shooting it onto a photodiode."
] | [
"There's a bunch of infra-red communication standards developed by ",
"IrDA",
" and actively used (though these days bluetooth is more popular). Plus there's low-bandwidth stuff used in various remote controls.",
"Naturally if you point your remote control at your eye (or any other black enough surface), it s... |
[
"Is transportation of more than just a photon theoretically possible?"
] | [
false
] | I just read and found that in the book, the author claims that in 1993, a group of scientists used , defines as transmission and reconstruction over arbitrary distances ofthe state of a quantum system. The author explained the study, but I wanted to know: would it be possible to teleport bigger things? Like a molecule ... | [
"http://xkcd.com/465/"
] | [
"Quantum teleportation is not actual teleportation. Not at ",
". What's being teleported is only the state of a system; the ",
" still needs to be in both places. It is interesting only because it is not possible in general to make a perfect copy of a quantum state.",
"It has been done on atoms, though, and I... | [
"It's not even that close to sci-fi teleportation. It's literally just copying data from one location to another; making it spontaneously rearrange raw materials into some object would require hardware capable of building that object. You wouldn't argue that copying data from your hard drive to RAM will help sci-fi... |
[
"Can we genetically engineer a creature to be smaller when fully grown?"
] | [
false
] | As in, have we worked out the genes for size? Or would this be a multitude of different genes? I ask, as Little People and Gigantism seem to have been scaled one way or another. So does that mean the end size would seem to be a certain scale? that all organs/bones follow? or would beings (Like Miniature horses) who are... | [
"Well some work has been done to identify the genes that affect sizes difference among dog breeds:\n",
"http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.1000451",
"Basically, there are variations (SNPs) in only a few genes that can account in the size difference between, for example, a Chiwawa a... | [
"Are the SNPs found more often in the promoters/regulators of genes, leading to different levels of expression during development? or in the coding sequences?",
"I imagine both are true for different examples of genes involved, and if that is the case, how can SNPs in coding regions lead to differences in height/... | [
"Typically these are SNP found in non-coding regulatory regions (promoters/enhancers) and typically affect robustness of gene expression and/or the tissues in which a gene is expressed. Often these non-coding SNPS accumulate at the higher rate, as they are mostly non-deleterious when compared to coding SNPs.",
"S... |
[
"If a star falls into a black hole, can it still do nuclear fusion, and continue to combust?"
] | [
false
] | My intuition says no, but I'd like to know ? | [
"But what about the big black holes with huge event horizons. I once read that the largest of black holes wouldn't even tear a space ship apart but that you couldn't escape it once you fell through it.",
"Would a black hole at the centre of a large galaxy swallow a star whole before tearing it apart?"
] | [
"At the event horizon, yes.",
"Source: ",
"http://en.wikipedia.org/wiki/Supermassive_black_hole"
] | [
"I'm sorry I stole your thunder, I didn't even read further before I posted above. The density of stars varies from low to extremely high (depending on what depth you're looking at), so I'd like to see calculations for your statement (concerning black hole mass) before I agree with everything you said."
] |
[
"Are there mental benefits to lifting weights regularly?"
] | [
false
] | I've been lifting at home for a week now and I'm just curious. | [
"Yes, there are mental benefits. There are many studies on the positive effects of the many chemicals your body creates both during and after working out - take a look here ",
"https://cathe.com/5-brain-boosting-chemicals-released-during-exercise/#:~:text=Brain-Boosting%20Chemicals%3A%20Norepinephrine%20When%20y... | [
"Yes, sorry, I was thinking more exercise in general. I can't think of any mental benefits to lifting weights over other exercise."
] | [
"My understanding is that these benefits come with basically any form of exercise, including but not limited to lifting weights. Is that right?"
] |
[
"AskScience AMA Series: My name is Franck Marchis, and I am a Senior Planetary Astronomer at the SETI Institute and Chief Scientific Officer at Unistellar. AMA!"
] | [
false
] | I am passionate about astronomy, and I have dedicated most of my research to the development of adaptive optics on large telescopes to study asteroids and search for exoplanets. I am proud to also work for Unistellar, a private company whose goal is to create the largest network of citizen astronomers around the world,... | [
"Amazing. Thank you for this. Obvious question: what it the most interesting or promising thing you have encountered thus far in the project?"
] | [
"Have you found any aliens yet?"
] | [
"Have recently read about phosphine on Venus that could be a bio marker. There has been a good amount of speculation as to how it got there. Do you have an opinion?"
] |
[
"I want to learn science...."
] | [
false
] | [deleted] | [
"As for books, I HIGHLY recommend ",
"The Demon Haunted World",
" by Carl Sagan. It will enlighten you on so many issues that have lead our society to where it is, and hopefully show you how to think clearly in this day and age. After reading this book (it is not quick read) I'm sure MANY idea's will spawn insi... | [
"Bill Bryson's Brief History of Nearly Everything would also be a great place start. "
] | [
"I recommend starting with a course of lectures on ",
"Academic Earth",
", if you're really committed to studying then watch one lecture a week and spend the rest of the week reading the books from the previous lecture's reading materials. ",
"Use ",
"The Khan Academy",
" to brush up on your mathematics a... |
[
"What does Math in Quantum Physics \"look like\"? Is it still much like applied math, or does it start to look more like doing proofs?"
] | [
false
] | [deleted] | [
"The two main ways of \"doing\" quantum mechanics are through the Schroedinger equation and through Heisenberg matrix mechanics. The path integral formulation is generally used in quantum field theory.",
"The Schroedinger equation is a second order differential equation, which is solved according to the boundary ... | [
"In general, quantum physics is very broad. ",
"There are people doing hard numerics, writing complicated code for high-performance computing on large grids. There are people designing models that match the results of such simulations and are intended to provide insight. And finally there are people who really th... | [
"Quantum mechanics is mostly linear algebra. While there is a level of abstraction that can make linear algebra seem more \"theory-heavy\" than calculus and differential equations, linear algebra is actually ubiquitous in real world math applications, and if taught correctly should not feel much different than thos... |
[
"Is there one big, planetwide weather system, or does each country calculate their own? If so, what sort of communication exists between them?"
] | [
false
] | null | [
"Most countries have their own weather system, but that doesn’t mean they will only study their own country. For example, in Brazil they study the weather for most of South America, even if other countries have their own system"
] | [
"to add to this: ",
"The basic of a weather forecast is always a global model (like GFS or ECMWF as mentioned above). With that as boundary conditions, weather services run regional models. The advantage of the regional models is the higher resolution, which is especially useful in mountainous regions. ",
"The ... | [
"There are several regional/country models, but there are some that do global models (though they may have a special focus for their country/region of origin). Probably the two most well known world models are the Global Forecast System (GFS) and the European Center of Medium-Range Weather Forecasts (ECMWF or just ... |
[
"A catalyst lowers the activation energy for a reaction. Is there something that increases it, like an anti-catalyst?"
] | [
false
] | null | [
"Oh yeah, there are tons of things which can do this.",
"Some will object to this example, but I think ",
"protecting group chemistry",
" is a demonstration. You're basically adding something in solution that provides a barrier to a reaction you want to discourage. Another thing you could maybe call an anti-c... | [
"This is maybe a bit of a tangent from the intention of the original question, but insofar as biological enzymes can be grouped as catalysts, a lot of things can be called \"anti-catalysts\". ",
"Enzymes employ conformation dynamics to catalyze reactions. In fact, an accepted theory for enzyme function is that en... | [
"I'm going to say no. The reason a catalyst reduces the activation energy is because it provides an alternative pathway for the reaction to take place. For example, if C is the catalyst and A+B are your reactants, your full reaction would go from:",
"A + B > AB",
"to",
"A + C > AC, ",
"AC + B > AB + C ",
... |
[
"How much energy does it cost to dry your hair with a towel vs a blow dryer?"
] | [
false
] | Considering you have normal should long hair and a modern blow dryer. Is it even possible to answer this? | [
"By and large, the two methods will consume close to the same amounts of energy, with the hair dryer wasting a noticeable deal more energy in the form of heat.",
"It may not seem like the towel is using that much energy to dry your hair, but that's because the work of evaporating the water is being done very slow... | [
"I was actually thinking more of energy burned in my body when drying the hair with a towel. But I guess that depends on how intense I do it."
] | [
"You know, google is awesome : )\n",
"http://answers.yahoo.com/question/index?qid=20081002115619AAQLZlR"
] |
[
"When an object at rest begins to move, does it experience infinite acceleration in the very first moment it begins movement?"
] | [
false
] | null | [
"No (in almost all cases) because it would require an infinite force or zero mass. Newton's second tells us F=ma and that sets the acceleration in classical systems."
] | [
"I just wanted to add to JConXtsy response, that the equation you wrote should be dx2/dt2.. or d",
" x/d t"
] | [
"This is AskScience, not 4chan. If you can't cite your information and present it civilly, don't post."
] |
[
"Can we expect a decisive answer about the existence of a ninth planet any time soon? Or is progress difficult and slow?"
] | [
false
] | null | [
"Experts in this field believe they've ",
" discovered all objects of Pluto size or larger in the plane of the solar system, out to about twice Pluto's distance. \"Probably\" because there's a small chance some may be very black and hard to see, or camouflaged in a few very starry regions of the sky.",
"There ... | [
"Unless are you talking about the gravitational anomaly announced like 2 years ago? I think that that one is still up in the air for lack of visual detection",
"Yeah, I suspect he’s asking about the realistic odds of visual confirmation of a large planet way past Pluto. I’m curious too."
] | [
"I think the only thing holding back right now is definitions. There are a couple we found that got disqualified back when they were debating Pluto's status. Unless are you talking about the gravitational anomaly announced like 2 years ago? I think that that one is still up in the air for lack of visual detection"
... |
[
"What happens to electrons during chemical reactions?"
] | [
false
] | I'm take organic chemistry and we are doing acid base reactions, but I'm wondering for all reactions in general. We have electrons transferring from species to another, but what actually happens to the electrons in a reaction. When the bond breaks, does the electron dissipate and a new pair come into existence when a n... | [
"When a bond breaks, the bonding electrons adopt one of the atoms. There are two types of bond cleavage: in heterolytic cleavage of a single bond, both electrons go to one of the atoms (if the original molecule was neutral, you now have a cation and an anion); in homolytic cleavage of a single bond one electron go... | [
"This is how we were taught, but I'm wondering how accurate it is. It's like saying there are alternating single and double bonds in a benzine ring. All the carbon carbon bonds are the same length, not what you expect from alternating single and double bonds. It's all about resonance structures and the rings have m... | [
"Electrons are real, and they really do move between atoms and molecules. They are not created or destroyed in reactions. In many ways chemistry is just the study of what electrons do in different situations. ",
"We have different theories to describe what the electrons do. I gave you an analogy that uses an ... |
[
"Do you think that paleolithic humans exhibited the same levels of nurturance to their young that we do today?"
] | [
false
] | [deleted] | [
"To be honest, I'd think that paleolithic humans care more about their children than people do today."
] | [
"IIRC, there are ",
" fossils of old individuals with evidence of years of poor or no dentition. This indicates that probably some other member of the group was chewing or cutting their meat and nuts for them. ",
"They likely did develop faster than modern ",
", so the span of time for nurturing was much sho... | [
"seems like such behavior only evolved over the last 200 years or so",
"This change wouldn't be evolution, but a cultural shift; evolution can't operate on the time scale of just a few generations.",
"It seems to me that attitudes towards raising children in general are a highly cultural phenomenon, differing n... |
[
"Is there noticeable evolution taking place in humans today?"
] | [
false
] | null | [
"Yes.",
"This study",
" looked at multiple generations of women in Massachussets, comparing various medically relevant traits with the number of children each woman had. Because evolution occurs based on who has the most offspring, they were able to detect subtle but significant ongoing trends in human evolutio... | [
"The most recent example of evolution occurring in humans I can think of is the retaining of lactase, or the enzyme for breaking down lactose, even after weaning. Many people are saying that the ring and pinky fingers will be lost in the future, but I have yet to find evidence for this. Has a use for the appendix i... | [
"Just because it's vestigial doesn't mean it's going to disappear. For that to happen the appendix would have to affect the ability for people to produce offspring, and a genetic anomaly that leads to appendix-less people, and said people being better at passing on said genes has got to be quite rare."
] |
[
"What is the etymology of the names of the nucleobases?"
] | [
false
] | I want to know how scientists came up with words like adenine, cytosine, guanine, thymine, or uracil. Also, if you know: where did the names of the twenty amino acids come from? I at least want to know if there is a general theme or way of going about naming these things. Ie, chemical groups, latin, greek... pure fa... | [
"The names will have a variety of etymologies, but their suffixes are from their chemical classification as pyridines or pyrimidines.",
"Adenine: “Aden”, a Greek root, from the word for the Pancreatic gland. It was so named because the first isolated sample of Adenine by Albrecht Kossel was from the Pancreas.",
... | [
"Fun question! Yes, pure fancy, actually, albeit with a tendency toward the circumstances of their discovery.",
"Since ",
"u/Gothic_Analogue",
" already did the DNA bases, I'll supply a few amino acids: asparagine was first isolated from asparagus; serine was first isolated from silk (l. ",
"); cysteine was... | [
"Extremely satisfying to learn, thank you."
] |
[
"Are black holes really infinitely dense?"
] | [
false
] | So I have heard several times that black holes are infinitely dense. But if gravity is connected to mass, that would imply that black holes have infinite gravity, which would mean that everything would be sucked together instantly. Is my thought process wrong somewhere? Are black holes really infinitely dense? Do we ha... | [
"It means exactly what it says. A gravitational singularity is a mathematical construct that appears in black hole equations when you are essentially forced to do exactly as you've said - divide by zero. It basically says \"Either something is very wrong with your numbers or something we can't fathom is happening h... | [
"Are black holes really infinitely dense? ",
"AFAIK, we don't really know. All we know is that in a black hole, currently accepted models don't really work. Hence the term \"singularity.\""
] | [
"That's the problem with gravitational singularities. The math stops working at the point where one is formed."
] |
[
"What are some good science experiments to perform for my son?"
] | [
false
] | null | [
"This thread",
" is full of ideas and instructions. I'm sure some of them are good enough for your son."
] | [
"How old is he, and what kind of material do you have access to? ",
"*Edit: Link to the pdf of ",
"The Golden Book of Chemistry Experiments",
"*EditEdit: This is in no way an endorsement of this book, as it is not exactly safe for your son to do alone. Be very careful when doing any of this, and fully researc... | [
"Oh, that book is definitely too high level for a nine year old. If you have a university near you see if they have an outreach program though the chemistry or physics department. Ours puts on demonstrations for kids. Otherwise, ",
"Steve Spangler",
" has all kinds of neat stuff. "
] |
[
"would pure hydrogen gas in a sealed chamber burn?"
] | [
false
] | If you had a chamber of pure hydrogen gas, no other elements, especially oxygen, and tried to ignite said hydrogen, would it burn even though it has nothing to bond to? | [
"No. It could dissociate into hydrogen atoms but if there really is no oxygen, it can't burn."
] | [
"Definition of Fire: Combustion or burning, in which substances combine chemically with oxygen from the air and typically give out bright light, heat, and smoke."
] | [
"Fire has three principles, i.e. the triangle of fire",
"So the hydrogen would be the fuel, but without oxygen, or heat, it would not burn. To create fire, you'll need all three elements."
] |
[
"If I were to get enough viruses in a small space to be able to see them without a microscope, what would it look like?"
] | [
false
] | [deleted] | [
"White goo. Back in college we had to filter seawater for microbes and that's what we came up with. White goo which turned out to be billions of bacterium, single cell doo dads, and various microscopic muck all in a big giant coffee filter the size of a damn laundry basket. EDIT--NEVER DRINK OCEAN WATER Edit 2 -cra... | [
"Awesomeness."
] | [
"These membrane ribbon thingies",
" are actually made of thousands of viruses smooshed together. They are still too small to see with your eye, but they can give you a sense of what an aggregate of viruses looks like. "
] |
[
"If two balls filled with water hit each other, how do the shock/pressure waves propagate?"
] | [
false
] | [deleted] | [
"The wave front would be circular/spherical like ",
"these",
", and, as you suggested, would travel from the impact spot outward until the wave reached the opposite end of the ball, \"filling\" the ball."
] | [
"video",
"Something like but not exactly like above. I couldn't find the actual experiment I was looking for. Apologies."
] | [
"The experiment I posted involves cavitation so it is not exactly answering the same question. However, it does show how the pressure waves reflect around inside a sphere, which is part of what you are asking. The weirdness happening with the cavitation bubble moving around has to do with reflection from the surf... |
[
"Are there any strange fears or mental disorders that exist only in specific cultures?"
] | [
false
] | null | [
"Fan death",
" would certainly be an example of the former.",
"Mental illness is hard because we don't, as yet, have a good objective idea of mental illnesses. There's a push towards a greater biological understanding and definition of common disorders, but our knowledge of the mind and brain is still too limit... | [
"https://en.wikipedia.org/wiki/Koro_(medicine)",
"\"Koro is a culture-specific syndrome delusional disorder in which an individual has an overpowering belief that one's genitalia are retracting and will disappear, despite the lack of any true longstanding changes to the genitals.\""
] | [
"Because there are a number of things named Koro and this way it specifies which thing.",
"https://en.wikipedia.org/wiki/Koro",
"So it's Other:",
"Koro (band), a hardcore punk band from Knoxville, Tennessee",
"Koro (incense burner), a Japanese incense burner",
"Koro (medicine), the syndrome in which someo... |
[
"What would it mean if we proved that P = NP, or P != NP ?"
] | [
false
] | What are the implications of proving one way or another? For example, proving that P = NP would it mean that cryptography is "useless"? | [
"A side remark: polynomial time is usually taken to be a short amount of time, and in the limit of large inputs it is much much ",
" smaller than exponential time. However, even if someone proved that P=NP, it could still be the case that the complexity of a problem scales as n",
" or something ridiculous like ... | [
"Proving P=NP would have vast consequences beyond cryptography assuming that the algorithm for reducing an NP problem to a P problem is efficient. For instance, it would put mathematicians out of a job. Checking that a mathematical proof is correct is a problem that is in P. If P=NP, then if a proof is of reasonabl... | [
"Almost everyone thinks P=/=NP, for the intuitive reasons stated above. But no one has any idea how to prove it one way or the other - in fact, it has been proven that two promising avenues which have been used to prove other things in computer science will not work for the P vs. NP problem."
] |
[
"Can you help explain this Mythbusters result?"
] | [
false
] | Mythbusters examined whether you can save gas by only making right turns. In their final experiment they drove a delivery truck around various locations - once with left and right turns, once with only right turns. The path with right turns only: Was longer Took more time Consumed less fuel Why would this be the case? ... | [
"I'll give my best explanation here for you. I've logged more than a half million kilometers driving almost any vehicle imaginable over nearly any terrain you can think of. I have a firm grasp of what affects fuel consumption in vehicles.",
"A trip using right hand turns in of itself does not, and cannot change ... | [
"I can't believe I had to scroll almost to the bottom before anyone mentioning acceleration. The only reason you need to burn fuel when not accelerating is because of air/ground resistance. Every time you break you essentially throw away all your kinetic energy and convert it to heat and earth momentum because norm... | [
"They also did the myth completely wrong. The way they did it, they took 3 rights instead of a left, the way UPS does it is they have an algorithm that creates routes with maximum rights and minimum lefts. with a fleet of trucks, they reach every destination."
] |
[
"Could Venus one day become what Earth is now?"
] | [
false
] | Scientists have found that Mars used to store water millions of years ago, until it's atmosphere was swept away and became what it is now. That lead many to speculate that Earth could one day become Mars. But could Venus terraform into a sister Earth? After all, Earth used to be highly volcanic and full of CO2 like Ven... | [
"Consider for a moment the proximity of Venus to Sol. Earth is perfectly far enough away to avoid being scorched to a relatively barren wasteland. While Venus has a thick layer of insulating cloud cover that protects it from the majority of solar radiation and blasting heat, that same effect traps greenhouse gasses... | [
"This leaves out magnetosphere, rotation period, and a satellite relationship like that which our planet has with the sun and the moon, and the possibility of increased water content. For starter, the lack of magnetosphere allows lighter gases such as helium, hydrogen and oxygen to be \"burned off\" by radiation a... | [
"Oh, by all means, go in to further detail. I was just giving a very basic assessment of what I know. I'm not much of an astronomer or anything, just studied a bit about these things. :)"
] |
[
"Can we say which molecules are more likely to occur in a soup of elements?"
] | [
false
] | Is it possible to estimate which molecules are more likely to occur in a mix of elements under a specified temperature? | [
"Using thermodynamics, it is possible to estimate, to some extent at least, which molecules will predominate at equilibrium. One would need to know the entropy and enthalpy of formation for every possible compound. However, since it can take an exceedingly long time to reach equilibrium, this approach is limited in... | [
"This is a major concern in aquatic chemistry.",
"We gibbs free energy and other thermodynamic properties to calculate equilibrium coefficients that describe the distribution and speciation of compounds at equilibrium. Because there are so many possible compounds that can form, and if all compounds are assumed to... | [
"Welcome to the field of astrochemistry. In fact this is exactly what we [try] to do. From reasonably simple kinetic models, we can start with the basic atoms (C, O, H blahblah) and the build up which and how many molecules will be made from these at the interstellar temperatures (typically CO, OHCH3, H2CO, NH3 e... |
[
"Can earthen or concrete houses sustain damage from fire?"
] | [
false
] | I am specifically thinking of brushfires and wildfires, and if concrete or earthen structures would be shelters if surrounded by fires, or they would still either get too hot or sustain some short of damage. Is the answer different if the structure is above the height of the surrounding ground, or build into the ground... | [
"Regardless of what happens to the structure in a wildfire, the air itself will become hot and be a problem for any life on the inside of the structure.",
"That being said, concrete is far from invulnerable from damage from extreme heat. Heat above 700F can cause significant damage to concrete, and heating of me... | [
"If a structure is built into the ground I would imagine it would barely be affected due to the fact it wouldn't really feel the heat. Dirt a decent enough insulator that it wouldn't be affected. Stone and brick should be fine but concrete can crack and break in extreme heat. The big problem is still smoke though i... | [
"Bush fires and wildfires do not usually burn that hot but if it gets hot enough any type of wrong heat treatment could make the steel inside the walls (even the concrete)loose some of its strength as you can see in ",
"this",
"\n diagram any temperature above ~750deg C could entirely change the crystal lattic... |
[
"Is there a way to speed up radioactive decay by \"proactively\" harnessing energy instead of passively harnessing the decay emission? If so, can you shorten the time frame of that element becoming inert?"
] | [
false
] | null | [
"It is possible to produce fission or fusion on demand. Fission can be produced by bombarding atoms with high energy particles, as happens in a nuclear reactor, nuclear bomb. Note that both reactors and bombs use a chain reaction wherein fission produces the very particles which cause fission. Fusion requires only ... | [
"Relativity is a very good asterisk to add to the above. Since time itself is effected by relativistic considerations, so is radioactive decay. However, time moves slower for bodies undergoing relative motion. E.g. radioactive waste blasted at near the speed of light and then blasted back to Earth at similar speed ... | [
"This is a great answer, thank you. ",
"Would the half-life decay be increased by moving at relativistic speeds? If we launched a large block of nuclear waste into space and accelerated it, would it decay faster than an equal sized block on earth, or does relativity not apply to half-life decay?"
] |
[
"How is the “habitable zone” of a star calculated?"
] | [
false
] | null | [
"It's based on sunlight available, but more specifically it depends on the feedback cycle that keeps Earth's climate stable, the carbon-silicate cycle. Volcanoes continuously produce both CO2 and fresh rock, and that rock reacts with CO2 to pull it out of the air and sequester it as carbonate minerals, which are th... | [
"Radiation as a form of heat transfer is an inverse square relation with regards to distance as it is just another form of electro-magnetic radiation (like light, radio waves etc). Find the source radiation, and with known values for min and max temp for life, calculate distance. ",
"I’m not sure if it only depen... | [
"Well, from what little I’ve read I understand the basic requirement is that planets be allowed have liquid water, so it would make sense that it be based on temperature... then again I understand there are factors such a as tidal friction that affect the surface temperature of a planet, so, idk..."
] |
[
"What happened to Thermal Depolymerization?"
] | [
false
] | Remember this thing that was going to turn all our trash and organic wastes into tasty methane and a kind of light crude? What happened? Here's the If memory serves, the idea is to use heat and pressure manipulations to crack hydrocarbon chains in the feedstocks in a close, anaerobic system. It sounded good but we hav... | [
"Oh it (and related waste-to-fuel technologies) are still quite a hot topic within chemical engineering and research. Nothing's really stopped. ",
"What happened Carthage pilot plant specifically, seem to be what often happens with new technologies - some guys are so eager to be first-to-market that, rather than ... | [
"It's still alive and kicking. I was at the Plastics Recycling Conference back in March and they had a whole afternoon session about it. "
] | [
"Looking over my notes, it seems lik Polyflow has a pilot plant, Agilyx has a demo pland and JBI is fully operational in Niagara Falls. You end up with a very sweet crude that is taken to the local refineries, as they already have in place the distribution/sales/... structures.",
"The speakers all seemed to push ... |
[
"Is there an area of effect for radiation?"
] | [
false
] | There were experiments on the demon core which took several lives due to radiation exposure. If the incident hadn't been quickly stopped, would the core have just remained in a critical state until it eventually decayed or would it over heat and melt or would it explode? Also, what sort of area would be consider lethal... | [
"Yeah I probably shouldn’t have said it would explode. I do know there have been cores that wreck themselves in (non-nuclear) explosions, but completely forgot that those are all based on the water turning into steam REALLY fast.",
"The reactor probably would melt itself though. I do know that those small, bare m... | [
"According to ",
"this article",
", the reaction stopped itself due to thermal expansion. ",
"Here is a quote from Schreiber, who witnessed the incident:",
"“But the screwdriver slipped. The thing dropped completely closed, and that made it super critical, prompt critical. It was stopped by the expansion of... | [
"The core would undergo “rapid unplanned disassembly” which is nuclear engineer speak for turn into a bunch of little pieces. That thing had no cooling or any of the other pieces needed to let it operate indefinitely. In addition, neutron poisons would build up over time and slowly kill the reaction. This would ha... |
[
"What's with the Tapir continental distribution?"
] | [
false
] | I understand there are four species of Tapir, three in South and Central America (the mountain, lowland, and Baird's) and one in Southeast Asia (the Malayan). How did this happen? Do we know on which continent they first evolved?Are they an example of convergent evolution? If not how did a rouge Tapir get to a whole di... | [
"According to the source I found, fossils of relatives of modern tapirs are found in not only Asia and South America, but also North America. They likely first evolved into what we know as tapirs in Asia, then crossed the Bering Land Bridge into North America. From there they continued on to South America as well."... | [
"This is mostly correct, but to add on to/clarify it, tapirs are also known from Europe and it's not exactly certain where they first evolved. Also, the land bridge they crossed isn't the famous Pleistocene Bering land bridge, but an older connection between the two continents that occurred in the Miocene...still ... | [
"The first tapir-like animals evolved in North America about 30 million years ago.",
" From there, they spread rapidly into Asia; the tapirids in Asia and in the Americas (North America only for most of tapirid history) diverged ",
"20-30 million years ago",
". At that time the Earth was about 4 - 6 degrees C... |
[
"Compared to the strong interaction, to what degree does gravity contribute to holding particles together?"
] | [
false
] | Given that the closer two objects get, the stronger the gravitational pull, I am wondering how physicists proved that it isn't gravity holding nuclei and particles together. Is the idea of "really close and therefore really strong" just bogus? Or is gravity just demonstrably not that strong? | [
"No. Gravity is so negligible on the quantum level that we can completely ignore it and get effectively identical results in our experiments. "
] | [
"Gravity is demonstrably not that strong. Even using our equations, placing particles that close together wouldn't even cause a force close to that of the strong force. ",
"Besides, we have evidence of a non-gravitational strong force in the form of particle reactions and decays. "
] | [
"The really big difference is that the strong force gets stronger with increasing distance. It behaves somewhat like an elastic band. The more you try to pull it apart the harder it gets. It is mediated by gluons. They are passed back and forth in what is known as a flux tube. Eventually the force becomes so great ... |
[
"Can anyone explain the Risch λ and threshold of Risch?"
] | [
false
] | I came across this reviewing an article on a meta-analysis of GWAS for Crohn's Disease. I had never seen this statistic before, and I am having a hard time finding a good description of it. Anyone familiar with this? | [
"Link to article?"
] | [
"It is behind a paywall, ",
"http://www.nature.com/ng/journal/v42/n12/full/ng.717.html",
"The PMID is ",
"http://www.ncbi.nlm.nih.gov/pubmed/21102463"
] | [
"Kind of a ",
"random place to find it",
", but:",
"Risch's lambda (λ) is defined as the risk to a relative of an affected individual divided by the population risk."
] |
[
"How much radiation am I exposing myself to when I reach into a microwave after it's finished heating my food?"
] | [
false
] | null | [
"As ",
"/u/rupert1920",
" said, microwaves dissipates very quickly, as quickly as visible light. By the time the \"pling\" or \"beep\" indicating that the microwave oven is done reaches your ears, the energy in the microwaves will have dissipated. ",
"If you by radiation mean \"nasty radioactive stuff\", the ... | [
"NMR (nuclear magnetic resonance) was not renamed to MRI (magnetic resonance imaging). We scientists still say we have NMR labs and perform many experiments that have nothing to do with imaging whatsoever. Imaging is a very specific subset of NMR techniques that is actually mostly used in medicine and associated re... | [
"None. Microwaves are not ionizing, so they are not \"radiation\" as it is popularly thought of.",
"Science has multiple definitions for radiation, so you might be confused because of that. Usually, when scientists talk about radiation they mean electromagnetic radiation, which is usually non-ionizing.",
"Scien... |
[
"Some planes from WW2 were designed in such a way that the bullets they fired had to go between the propeller blades. How did the designers make sure they won't hit a blade and was the fire rate affected?"
] | [
false
] | null | [
"How did the designers make sure they won't hit a blade",
"As far as I know the trigger mechanism to fire each bullet was coupled via a ",
"cam",
" to the shaft of the propeller. As the propeller shaft turned to a particular position the cam would trigger the gun to fire the bullet. This would mean that the b... | [
"The best way to fix this problem is to create a mechanical linkage between the engine and the trigger mechanism of the gun. The gun is triggered only when the prop is known to be out of the way.",
"This requires several things: ",
"a gun that fires exactly when you tell it to (within hundredths of a second), n... | [
"Synchronization was a big enough problem that later designs went away with it and just placed guns on the wings, even if it meant difficulty in placing the ammo, and gun convergence limiting effective targeting range and other details.",
"Germans instead just fired one big cannon through the center of the propel... |
[
"A deck of cards is split in two. I only choose from one pile. Does it affect the probability of choosing x card?"
] | [
false
] | [deleted] | [
"No. Probability is the same; the size of the two splits don't even have to be the same size. ",
"An example; let's say you want the probability of choosing the ace of spades. One split has 30 cards, the other 22.",
"\nThe prob that the ace is in the first split is 30/52; and 22/52 in the second split. \nThe p... | [
"Yes, that's exactly right. \nIn the extreme case lets say the split is 51 and 1 cards. In that case, if the ace is in the small stack it's 100% that you'll draw the ace. On the other hand, there is only a 1 in 52 chance of it being there. "
] | [
"I get a normal shuffled deck of 52 cards. You name a card. I split the deck in into two piles, one with N cards and the other with 52-N cards. You pick a card at random from one of the piles. Call it Jack of Spades (JS).",
"Suppose you pick which pile you will choose from at random. You have 1/2 chance to pick N... |
[
"[Math] Why is 1/x continous?"
] | [
false
] | null | [
"When we say a function is continuous we mean \"continuous on its domain\", unless otherwise specified.The function f(x) = 1/x has domain D = (-∞, 0) U (0, ∞), and ",
" is continuous on that domain, being the quotient of two continuous functions whose denominator is never 0.",
"(This may seem like an odd conven... | [
"I have taught Calculus I for many years, and I can confidently say \"no\". (But obviously I don't teach your course, so you should not take that as definite answer.)",
"That's also not to say that you should think \"if I see a single explicit formula for a function, it must be continuous\". And you should certai... | [
"The definition you gave is perfectly fine and correct. The function f(x) is continuous at x = a if lim",
"f(x) = f(a). (This one condition is enough since the validity of this equation implies that f(a) exists, i.e., that x = a is in the domain of ",
", and that the appropriate limit exists. For some reason, c... |
[
"How big would a volcano blast need to be to have the same effect as greenhouse gasses released by human activity in six months?"
] | [
false
] | null | [
"A large volcano blast typically throws a huge cloud of soot high into the atmosphere. The soot blocks a significant fraction of incoming solar energy (by absorbing it and re-radiating it to space), and can stay aloft for several years. Except in the immediate vicinity of the volcano, the net effect is to cool Ea... | [
"Humans are putting about 26 billion tonnes of CO2 into the atmosphere per year. That's over 130 times more than ",
". A moderately large eruption, such as the Eyjafjall or Mt St Helens eruptions might be expected to put up to 300,000 tonnes of CO2 into the atmosphere per day. So, lets say it's erupting for 100 d... | [
"Wow ty for such a great answer. "
] |
[
"Is the angle a photon can travel quantized?"
] | [
false
] | Is the angle a photon can travel quantized? If not, then is the information capacity of a single photon essentially infinite, since there are an infinite number of angles it can travel and all we have to do is position a mirror to whatever angle we need to designate an arbitrarily long mantissa? (Okay, steering or meas... | [
"No it's not, it can go at any angle you want it to.",
"The information capacity is then still limited by angular resolution, which is governed by beam diffraction, the size of your detector and so on."
] | [
"No it isn't. The ultimate capacity limit would be the Heisenberg uncertainty in the mirror's angular position (assuming you're bouncing the photon off a mirror)."
] | [
"Ah, yes, you are very correct.",
"I was thrown off by your mention of angular resolution which I mistook immediately as simply an engineering problem."
] |
[
"Can someone please explain the String Theory as simply as possible?"
] | [
false
] | Pretend that you are describing the String Theory to a(n) 4 year old. Thank you! EDIT: Thanks for all of the answers! | [
"It says that at the smallest level, fundamental particles can be described by a vibrating string. Just as a guitar string plays a different note depending on the type of vibration, a string would be a different particle depending on how it was vibrating."
] | [
"If you're looking for a good book that can give you a general understanding of string theory, The Elegant Universe and/or The Fabric of the Cosmos by Brian Greene do an excellent job of providing a layman's understanding"
] | [
"In utter seriousness, this is the best layman explanation I have seen:",
"http://xkcd.com/171/"
] |
[
"Why do things get darker when wet?"
] | [
false
] | null | [
" of a material is the ratio between speed of light in vacuum and speed of light in that material. Light tends to bounce back when encountered with a sharp change in refractive index. Being wet means that there's a water film covering the material, mediating the change in refractive index, resulting in reduced ref... | [
"Layman's example!",
"Your shirt is a fabric, but zoom in and there are many tiny broken pieces of thread sticking out. Each of these catch and refract light, making the fabric appear a bit lighter. This is also part of why clothes 'lose color' in the wash as more threads break, and wear begins to become more n... | [
"This is the simplest explanation I can make.",
"A layer of water sits on top of the fibres. \nThis re-refracts the light that’s bouncing off the fibres back onto the fibres, instead of a single refraction like what would normally happen when the material is dry.",
"This allows the material to absorb more light... |
[
"I still have trouble understanding how two objects can have differing weight, and yet fall at the exact same speed in vacuum. And why do spinning gyroscopes fall slightly slower than non-rotating objects in vacuum?"
] | [
false
] | And if you had a solid gold bowling ball and a solid aluminum bowling ball of the same size, the gold would outweigh the aluminum bowling ball yet fall at the same rate... How is this even possible? Does gravity interact on an atomic level with individual atoms and creates "inertia" in the process due to heavier eleme... | [
"Somebody ",
" explained what causes gravity. That question was conclusively answered nearly a hundred years ago. It's just not a simple answer.",
"The first thing you have to accept is that space and time are related. Changing the way you move through space changes the way you move through time … ",
"The sec... | [
"You know that old saying about how sharks have to keep moving or else they'll die? Sharks — so the legend goes — lack the power to draw water over their gills, so they have to keep swimming in order to get oxygen. So a shark — according to myth — must always swim to stay alive.",
"Imagine a shark that works by t... | [
"No, you basically have it right.",
"Let's go through it step-by-step. Let's imagine first that you and I both possess ideal clocks. What I mean by that is that these clocks are ",
" in a way no real clock could ever be. They tick off once per second ",
" and nothing in the universe can change that. Bump them... |
[
"How do astronomers store and access data about stars, galaxies, etc.?"
] | [
false
] | Does all research in astronomy require new observations? I'm guessing no, but that leads me to wonder how astronomical information is stored. I'm interested in how it is logically organized and stored for analysis and study, as in a database/datawarehouse, etc., not in physical storage. Is there a recognized standard t... | [
"There's a lot of questions in there...",
"At the most basic level, optical and infrared astronomers have a data format called .fits (flexible image transport system) that is pretty much a recognised standard in terms of data storage. It's basically horrible, but it works, and it's hard to shift such an entrench... | [
"A lot of it is done through sky surveys, where the results of telescope observation is accessed from a database. An example is the ",
"Sloane Digital Sky Survey",
", which you can use to get ",
"pictures from the telescope",
", or more technical information like spectra."
] | [
"The ",
"VAO",
" is the US organization responsible for coordinating the efforts of the IVOA. The VAO directory is a repository for astronomical data and service providers. You can search the directory by keywords to find the type of data you are interested in. \nAnother interesing tool is VAO SkyQuery, which c... |
[
"Can plants form addictions?"
] | [
false
] | null | [
"No. OP is asking if a plant can be an addict, not that if you can be addict to that plant."
] | [
"Dependence can be both physical and psychological. We can rule out psychology in plants but physical dependence or formation of tolerance might occur in plants. And you would only need basic nervous system like that of plants for this to happen. "
] | [
"Yes, thanks for reminding me. Plants do not have a nervous system, so they cannot obtain an addiction."
] |
[
"What type of porcelain glaze reduces surface tension?"
] | [
false
] | [deleted] | [
"You're dealing with an extremely complicated set of physics: Wetting and contact angles.",
"There are no easy generalizations that can be made. ",
". There is ",
" a set of equations that can be used to calculate the wettability of a specific material, with a specific fluid.",
"Every fluid will behave diff... | [
"All you can do is test different materials",
"To this excellent answer I'd only add: \"...and different surface treatments and coatings.\" As you note, there are a very large number of knobs that one can turn to adjust wetting."
] | [
"The surface isn't reducing the surface tension of the water. What defines whether the water beads up, is a competition between the surface energy of the solid, the surface energy of the liquid and the interfacial energy between the solid and the liquid (as well as a few other things). Have a look at ",
"this wik... |
[
"How big/fast would an asteroid have to be to split the earth in half or shatter it completely?"
] | [
false
] | I mean... scientists are always taking about asteroids wiping out LIFE on earth... but what about wiping out the planet entirely? | [
"According to ",
"this table",
", you'd need 2.9*10",
" J of energy to break the Earth up into small pieces (remaining in the same orbit). Any object orbiting the Sun won't be traveling more than about 40 km/s in the vicinity of the Earth, or it would escape the solar system entirely.",
"Using those numbers... | [
"Of course, if they remain in the same orbit, I imagine they will one day fall back together and Earth will be back... with a vengeance!"
] | [
"You want to ",
" the Earth? As in, make is so there's no planet here?",
"You can get a good first-order approximation of that by calculating the gravitational binding energy of the Earth. That's two hundred and forty thousand billion billion billion joules, or the kinetic energy of the moon accelerated to 180,... |
[
"Why does taking Accutane cause so many problems during pregnancy?"
] | [
false
] | My brother was recently prescribed Accutane and there are warning labels all over the packaging telling women to not take it while pregnant. I am aware of the birth defects it creates, I am just interested in the science about why it is so dangerous. | [
"Firstly, a lot of drugs cannot cross the placenta because of solubility or other physical factors, but accutane is fat soluble and a derivative of vitamin A, so the placenta has a natural proclivity to uptake it for fetus building purposes. Most of the teratogenic effects it causes such as vision abnormality, ment... | [
"Accutane, also known as isotretinoin, has a close resemblance to retinoid acid which is the active form of vitamin A.",
"Retinoic acid functions as a central signal molecule during the embryonic development by mediating correct development of posterior part of the embryon through interaction with Hox genes. This... | [
"Wow, thanks for the response. Thats more thorough than I could have asked for, thank you!"
] |
[
"Why do I get different values for the molar mass of a mixture depending on how the moles are counted?"
] | [
false
] | I was looking on a few different websites on how to calculate the molar mass of dry air. They all give roughly the same answer - multiply the molar mass of each constituent by its percentage concentration, and add everything up. This gives about 28 g/mol for dry air. However, I noticed that oxygen was counted as 32 g/m... | [
"Diatomic oxygen (O2) constitutes 20.95% of the molecules in a volume of air. Let's say we're talking about a 22.4-liter volume at standard temperature (0°C) and pressure (1 atm), which contains 1 mole of molecules, of which 0.2095 mol will be O2 molecules.",
"If, in your hypothetical scenario, each O2 molecule ... | [
"Here's an even simpler explanation:",
"Calculating the effective molar mass of the molecules that make up a gas mixture (air) is equivalent to determining the average size (mass) of the parts (molecules) that make up a whole thing (the air). As an analogy, consider a whole pie (the air), that has been sliced in... | [
"I think I understand where you are coming from: more molecules, more objects for the total mass to be distributed amongst. The only thing is: if you have a smaller number of pie slices, shouldn't the average size of a slice be ",
"?"
] |
[
"What specifically about ginger/menthol/wasabi causes one's sinuses to open?"
] | [
false
] | Is there some chemical component that each plant shares, or do we just react this way to certain concentrated flavours? | [
"It actually doesn’t open the sinuses, It gives the feeling that your sinuses are opening from a cooling effect. It’s a trick on the receptors in your nose even if you can’t smell. \nActual nasal decongestants have active chemicals and can have added menthol but it’s not required."
] | [
"I'd like to add to this with: subjective feeling of decongestion is related to perception of airflow, and substances OP mentioned provide an additional \"cooling effect\" by chemically stimulating the cold receptors. This is interpreted as increased airflow - similarly to how after using a cooling spray on your sk... | [
"Wasabi contains allyl isothiocyanate which is an irritant. Your body increases mucus production and secretion in an attempt to protect the nasal tissue and flush the chemical from your nose. Horseradish contains the same chemical."
] |
[
"Why did the pages of my book wrinkle as they dried after I dropped it in the toilet?"
] | [
false
] | null | [
"You know how napkins/toilet paper/tissues tend to completely disintegrate when you let them soak in water for a while? That's what's happening, but on a smaller scale.",
"The presence of water in paper disrupts the intermolecular forces that hold individual cellulose molecules together. So instead of staying in ... | [
"I've actually got SEM images of paper towel before wetting and after wetting from a middle school science fair project last year and let me tell you they look ",
" different when they've dried after wetting. If anyone's interested, ",
"here's the science fair poster",
"."
] | [
"I didn't get to play with electron microscopes until I got into grad school. No fair!"
] |
[
"What is the difference between an island and a continent?"
] | [
false
] | What is the cutoff? Why is Greenland an island but Australia is a continent? | [
"So then why don't we call the Arabian Peninsula or India continents? Or perhaps more accurately, is it appropriate to call them continents if you're not specifically referring to the tectonic plates?"
] | [
"There really is no easy answer to this question, it depends on who you ask. Australia is considered by some to be an island-continent and a continent by others. ",
"India was once very much like Australia before it collided with Asia (or Eurasia) and is now considered part of Asia, even if it is tectonically dis... | [
"It depends on if you are trying to answer \"why is Australia defined as a continent and why is Greenland not, geologically\" or \"why do they have different words in the lexicon\". ",
"Also, North and South America are on separate tectonic plates, so they definitely have a reason to be two separate continents, h... |
[
"Are there any other body parts that are able to pick up oxygen besides my lungs?"
] | [
false
] | [deleted] | [
"All parts of your body utilize oxygen. Your lungs just get the oxygen into your body, from there the oxygen is absorbed into the blood and distributed to your entire body. So to answer your question; Yes, your whole body is capable of picking up oxygen, however only the lungs are able to convert atmospheric oxygen... | [
"The cornea is, afaik, the only organ that is oxygenated independently of the cardiovascular system. Owing to its position and its lack of blood vessels, the cornea is able to meet its needs via oxygen naturally dissolved in tears. ",
"http://www.aclm.org.uk/index.php?url=04_FAQs/default.php&Q=3"
] | [
"There are several requirements for ",
"gas exchange",
" to occur, such as a moist environment and a short distance to diffuse across. Ideally there would also be a large surface area for the exchange to take place.",
"In humans, the only organ that meets these requirements are the lungs. So short answer is t... |
[
"Does literature support subconscious competitiveness while driving?"
] | [
false
] | Often, while attempting to pass another car on a highway, the other car will increase their acceleration before I am able to overtake them. Is this a subconscious impulse on behalf of the other driver? | [
"I am actually doing research on this sort of thing now, but kind of a different explanation.",
"Based on what vehicle we drive and what situations we are put in, we can be primed with aggression. People driving a sports car or truck are typically moreso primed this way than other vehicles. We have to attribute t... | [
"In terms of you not realizing what is going on, yes. Unless you've been taught about the two things, you probably won't figure out the process you're going through."
] | [
"Thanks so much for answering! I didnt think anyone would. Question though, is cognitive dissonance and self-discrepancy subconscious in this situation? Is it usually?"
] |
[
"How come chemists never consider whether their compounds are interacting with the silicon in glass test tubes?"
] | [
false
] | There's lost of experiments where chemists create vacuums because they are worried about interactions with air, but they never seem to account for the silica in glass. Is it because it's pretty stable? But shouldn't it still be considered as possibly a variable in chemistry experiments? | [
"Yes, it's pretty stable. It is considered though. For instance, if you're working with hydrofluoric acid then you can't use glass and must use plastics or certain ceramics that don't include silicon."
] | [
"Air contains oxygen, which is a decent oxidizing agent and reacts with a lot of things. Borosilicate glass, which is what most laboratory glassware is made of, is pretty inert, and therefore, unless dealing with certain extreme chemicals, it's not an issue."
] | [
"On the contrary, there is a great deal of research looking into passivation of silicon or silica walls with boundary layers, because at short distance it has a significant role. ",
"See for example section 7"
] |
[
"When we hurt something like our wrist we either wrap it up to make it warmer or put ice to make it stop swelling. Whats wrong with just the regular body temperature?"
] | [
false
] | null | [
"Not a bad question. The point of an ice or warm wrap isn't to control the body's temperature. Rather, it's using temperature as a tool to illicit a response from the body that could assist healing or manage pain. Ice, for example, can help reduce swelling in a broken wrist. Heat can relax injured muscles and incre... | [
"Ice: ",
"Numbing the pain. The nerve endings in the area can't function very well when cold, and thus the amount of pain signals from this area is reduced. ",
"cool the area down, thus decreasing blood flow to the area, thus limiting the amount of swelling or the amount of bruising in the area. Less bruising =... | [
"This is right.",
"Also, if you're just wrapping something in tape or an Ace bandage, that's not intended for warmth. It's to stabilize the area and prevent further injury. When we want extra heat in an area we provide it from outside, such as with heat packs, hot compresses, or a hot water bottle."
] |
[
"Why doesn't air unmix?"
] | [
false
] | If "air" is a mixture of light and heavy gasses, why doesn't air unmix? (I am sorry for not knowing a better word to use here) Why exactly don't lighter gasses like oxygen float above a layer of heavier gasses like carbon dioxide, like some fluids would? | [
"The real reason air doesn't separate into layers is entropy. There is an enthalpic component to mixing that would favor the heavier gases being on the bottom (that depends on the strength of gravity), but the dominant factor at room temperature is the favorable (positive) entropy of mixing. ",
"It's not a ques... | [
"This is the best answer here.",
"To elaborate: while it is true that there is an enormous amount of mixing in the atmosphere, as another poster mentioned, a sealed container of air at a uniform temperature ",
" (under normal conditions; the behavior starts changing when nearing the condensation point of a gas,... | [
"That's because the cold CO2 hasn't had a chance to warm up and mix with air yet, not because it naturally separates."
] |
[
"I have a porcine and now bovine heart valve. Are there any other human replacement parts taken from animals?"
] | [
false
] | null | [
"I know in the 60's they looked into transplanting chimp kidneys, but it didn't take. Apparently you want the donor parts to be genetically unrelated enough to prevent diseases from the original species popping up in the recipient, but not so different that you can't use them.",
"Like, monkey livers are too close... | [
"Do only body parts count ? Cause insulin used to be from pigs and if I recall correctly, anti tetanic immunoglobulins were taken from immunised horses. \nThere are also temporary skin grafts from fish skin, which are used to cover and protect a big burn for which it is difficult to have enough skin to graft direct... | [
"You could and you do implant mechanical valves that are made of metal and plastic (Vs biological valves which are of animal origin). They have the benefit of being very long lasting, so no need for further surgery, because the valves won't degrade. However they have some inconveniences (like anticoagulants for lif... |
[
"How do other animals display similar or better coordination of limbs with such smaller cerebellums?"
] | [
false
] | [deleted] | [
"First, notice that the best predictor of brain size in general is body size, not behavioral complexity. Other anatomical features can be more revealing. In the case of the cerebellum, you can start with the ratio of its size with respect to that of the rest of the brain. Animals with particularly enlarged cerebell... | [
"One thing to keep in mind about the cerebellum: it is not motor function only. ",
"Probably only 10-20% of human cerebellum is motor-related, the vast majority projects to and receives projections from association cortex.",
" A more interesting comparative anatomy question is why does human cerebellum have so... | [
"Thank you! I have a BA in Neuroscience and am starting a PhD program this year :)"
] |
[
"How do you measure the strength of a magnet?"
] | [
false
] | I guess I would measure it in Newtons by using a graduated cylinder full of distilled water of known height, the magnet, a metal ball of known masse, and a stop watch. I would measure the time the ball reaches the bottom of the cylinder from where it is dropped at water level (0 acceleration) and calculate from there s... | [
"I'm sure there are many ways to measure the strength of a magnet. As a person who has done some experiments with an accelerometer, I would try setting up an experiment using the magnet in question on a ferrous material at a prescribed distance that is hanging on a wire. If the wire is taut enough, gravity shouldn'... | [
"Normally you use a ",
"magnetometer",
", although that's not particularly descriptive, given that the name means \"thing you measure magnets with\". The article discusses a variety of possible techniques. "
] | [
"What you described is somewhat functionally similar to a crude ",
"Gouy balance.",
" Magnetic balances are an old and time-tested method but they aren't really used much anymore.",
"Magnetic properties are measured with different things depending on the information you want.",
"SQUID",
" (",
"upercondu... |
[
"Are the animals living in the city of Pripyat (the city that was devistated by the Cherynobil disaster) deformed from radiation?"
] | [
false
] | null | [
"Oh boy, my favourite topic! ",
"While the Chernobyl wildlife do have large degrees of deformities, they largely manifest in their internal organs, immune systems, and reproductive sucess-- no three-headed deer, just birds with smaller brains, fewer eggs, and fewer babies that are born alive and make it to adulth... | [
"please don't upvote comments like these that don't contribute to the discussion. There are countless other reddits for that, keep this one for science."
] | [
"Go to Detroit and find buildings that were abandoned in the mid-80s. I'd be willing to bet they look at least similarly decayed inside."
] |
[
"Can someone explain the Frank-Starling mechanism to me, and how it relates to circulatory shock?"
] | [
false
] | [deleted] | [
"The Frank-Starling mechanism describes how stroke volume increases to match end diastolic volume of the heart. This means that the heart will eject the amount of blood returned to it with each beat. It helps to keep arterial supply in line with venous return.",
"Shock has many many causes, and I'm not certain h... | [
"Here is a diagram to supplement Teedy's definition",
"Just to tack on a further definition, Frank Starling refers to the fact that there is an \"optimal length\" of stretch of the muscle fibers of the heart. This is the point at which the most cross-bridges are formed in the sarcomere (muscle unit) so the greate... | [
"Bang on correct.",
"I'd guess that he's thinking of either cardiogenic or hypovolemic shock, but I want to be sure before getting into those as they get in depth fairly quickly, and I'd rather not spend all night typing an essay."
] |
[
"Could a magnetic field kill a human being ?"
] | [
false
] | [deleted] | [
"At the very far extreme in terms of magnetic field strength is the ",
"magnetar",
", which produces magnetic field strengths so strong that it'll begin to affect water in your tissue due to diamagnetism. So... it'll tear you to pieces.",
"Things like ",
"transcranial magnetic stimulation",
" affects the ... | [
"MRIs use static magnetic fields to generate the Larmor precession in the first place, not to mention a static gradient field along the Z-axis is required in order to obtain slices. That field is somewhere along the strength of 1.5 T, if I remember correctly.",
"Edit: Grammar"
] | [
"Yes, but but aren't we talking about fractions of a picosecond?"
] |
[
"Why does hair change as you age? ie in colour, curly to straight..."
] | [
false
] | When I was younger I had straight blond hair. Now I have completely different curly ginger hair with the opposite texture. I have heard of hair going straight to curly, but not so much the other way round. Why is this? Edit: Front page! Thanks for all your insightful responses, I've enjoyed reading them. | [
"Part of this is due to the changes in hormonal balance and the length you keep your hair. As you age the hormone levels in your body will change impacting your hair texture and sometimes the color. There are other environmental effect other than length as well. For example, humidity will increase the curl potentia... | [
"Is there a way to make pubes grow really, really long? Since they tend to stop growing at a certain length. Like, trick it into thinking it was just shaved? ",
"Edit: I want monster pubes"
] | [
"Every hair on your body has a terminal length -- a length beyond which it just won't grow. That length is different for different hairs and different for different people. So, if you've never cut those hairs, then whatever length they are now is probably already at the terminal length and they won't grow any fur... |
[
"What is a computer doing in the ~ 60 seconds it takes to start up? That's billions and billions of instructions correct?"
] | [
false
] | Also, how is data stored in memory when there's no power? | [
"When there's no power, data can only be saved in persistent memory - magnetic storage (HDD) or flash memory storage are the most common. These don't require power to hold data. \nData in RAM or cache isn't persistent, but it's much much quicker than persistent storage for reads and writes. (This is effectively the... | [
"It does a ",
" of testing..",
"It was about a year ago when I covered this in college and I havent really looked at it since, but from memory it goes something like:",
"1) The power supply does its own test- it checks all the different components and makes sure everything is in order. Once thats done it send... | [
"Yup, a lot of it is just copying everything the operating system needs into the RAM, which is why replacing your Hard Drive with an SSD can bring startup time down from over a minute to around 15 seconds. "
] |
[
"How does digital information degrade or become corrupted?"
] | [
false
] | null | [
"A very vague question, but here is one example: A digital signal is a stream of 1s and 0s. So if you want to send a digital signal over a wire you must use low and high voltages to represent the signal. But as the cable becomes longer and longer, the differences between the low and high voltages become less. This ... | [
"To add to this: most digital media storage and transfer formats have extra data embedded in them that allows a limited number of bit failures to be corrected ",
".",
"This is why (small) scratches in a CD surface have no effect on the audio quality; the effect of these errors can literally be calculated away p... | [
"It mostly has to do with the storage medium. Hard drives, SSD's, DVD's, etc have a very small life span. The problem is that in a lot of cases, if a segment of the file goes missing for some reason, the rest of the file is typically unreadable. This can happen because of the storage medium, but it can also happ... |
[
"[Physics] Why do charges flow from positive to negative?"
] | [
false
] | null | [
"They don't. Or rather: the abstract definition of charge flowing from the positive electrode to the negative is inaccurate.",
"In reality, a current can consist of a various species of particles: electrons, positive ions, negative ions. Since electrons are by far the lightest, in most situations the current is m... | [
"Thank you so much man. Your explanation agreed to ",
"this",
". I just wanted to find out if this was still accurate since it's not recent. "
] | [
"Yep, it's just an arbitrary choice that was made long ago that we stick with.",
"Similar to rotational motion having \"counter-clockwise\" as the positive direction. I believe that was also 100% arbitrarily chosen."
] |
[
"What is the world's strongest acid?"
] | [
false
] | I've come to learn that there is no such thing as the "strongest" acid. But what acid is generally considered more powerful than the other well-known acids, for example sulphuric acid? | [
"Perhaps ",
"superacids",
" interest you?"
] | [
"The strongest known acid (according to the chemical definition) is ",
"fluoroantimonic acid",
", with a pKa of -25."
] | [
"I have a feeling by \"strongest\" you mean \"most corrosive\" rather than \"dissociates the most hydrogen ions.\" It depends what you're dissolving. If you're trying to dissolve organic material, then piranha (a mixture of sulfuric acid and hydrogen peroxide) is up there. If you want to dissolve metals like gold, ... |
[
"The Kepler Space Telescope is discovers planets when their orbit crosses the light of the star. Doesn't this limit our discovery of planets to planets with short orbit periods?"
] | [
false
] | [deleted] | [
"Yes it does. It also limits us to planets whose orbits are angled towards us. It's remarkable that it still detects so many planets, which hints at how common planets are.",
"Clarification: I'm just talking about Kepler, not every exoplanet search method."
] | [
"Here's the ",
"Kepler planet candidate period distribution",
" as of right now.",
"Notice how the number of planets drops off toward periods of 100+ days. This is because",
"It's less likely a planet that far away is going to pass directly between the Kepler telescope and its star to block the light. So ev... | [
"And that's not to mention that it was only looking at a sliver of our galaxy.",
"http://en.wikipedia.org/wiki/Kepler_(spacecraft)#mediaviewer/File:LombergA1024.jpg"
] |
[
"Since gravitational waves are real, does that mean all gravitational orbits are decaying?"
] | [
false
] | As the waves would use up energy | [
"Yes. Even for a simple binary system like the Earth-Sun system, gravitational waves are constantly being produced. The reason is that such orbits cause a change in the so-called ",
"quadrupole moment",
" of the total mass distribution of the system. This change is the key requirement for shooting off gravitati... | [
"If you waited for the Earth and Sun to spiral inwards through this process and crash together, you would have to wait more than 1013 times the age of the current universe! ",
"And obviously that's ignoring other effects, such as the Sun losing mass and the Earth's orbit therefore moving outwards."
] | [
"I just added that in, it would take about 10",
" years, which is roughly 10",
" times the current age of the universe. Needless to say, we are at least safe on this front :D. "
] |
[
"Would it be possible to create a spacesuit or device that could help astronauts resist Io's intense radiation environment so a manned mission to this exotic and amazing world would be possible?"
] | [
false
] | Granted its an inhospitable hellhole, probably even more so than Venus, but its such a beautiful, dynamic, and bizarre world, one would just love to get a glimpse of what it looks like to walk around on that surface. Will the radiation, however, make this a total pipe dream or will we ever devise a method to shield our... | [
"You're right to assume that radiation can be tricky. If you walked unprotected on the Jovian moons you'd absorb a lethal dose of radiation in a matter of hours, develop radiation sickness and probably die a few days later.",
"But whether we can protect you from that is a bit harder to answer. We have two main as... | [
"Enough shielding for Jupiter's radiation? Sure.",
"Enough shielding for GCR? No, not even nearly enough.",
"But anyway the point of my comment was \"too thick and massive to be launched with any realistic budget\". If you do the math, shielding the equivalent volume of 1 ISS module would be more massive than t... | [
"For low level radiation, low enough to not cause acute radiation sickness, the solution could just as well come from medicine as from physics. If cancers can be easily treated in future getting one will be no big deal.",
"Of course such a cancer treatment is far from easy to develop."
] |
[
"Does a person with XYY syndrome require both Y chromosomes to contain affected genes to have a Y-Linked recessive condition?"
] | [
false
] | null | [
"To my knowledge, there are no Y-linked recessive diseases."
] | [
"Dominance and recessive requires the assumption that the person inherits one copy of a gene from each of their parents. In the case of the Y chromosome, if a person inherits a Y chromosome, it is always from the father. If the person happens to inherit two Y chromosomes, it is due to nondisjunction during meiosis ... | [
"Is that because there aren't any, or because they don't need to figure that out? It could well be that there is a recessive Y-linked disease, but since (allmost) every male has 1 Y chromosome it may seem like they're all dominant and therefore noone has ever researched it. It could also be because no male with XYY... |
[
"Question About Genetic Modification In Human Fetuses"
] | [
false
] | I've been asked to do a basic science based lecture based on genetic modifications. I'm having some trouble finding specific answers. Has this been done successfully yet, and to what extent? How do they go about doing it, as in a basic step by step process? What laws (in the UK or US) are in place about this? What are ... | [
"Try \"gene therapy\" there have been a few attempts in infants for diseases such as severe combined immune deficiency. It's very preliminary and there are many ethical and practical issues. "
] | [
"I'm almost certain that this is not being done in human fetuses.",
"Gene therapy stumbled a bit after initial success with treating SCID [1] with a later consequence of blood cancer. SCID is an immune disease in which an important gene is totally non-functional, so in these trials the researchers removed marrow ... | [
"i did a research paper on SCID. i think the therapy adds 2 years with almost 75 % survival, but after 10 years it drops to about 33% survival"
] |
[
"Why do we shake when we're nervous or scared?"
] | [
false
] | null | [
"While I appreciate everything paramedics do (they are a vital and necessary part of the medical system) I feel compelled to point out the following about this response:",
"Paramedics are not Doctors",
"Paramedics are not scientists",
"The article does not provide links to actual science",
"The article is a... | [
"adrenaline",
"http://www.emergencymedicalparamedic.com/hand-tremors/"
] | [
"Yes it is anecdotal, no paramedics are not doctors, no they are not scientists. Still, it gives an example of what you would be experiencing with your hands shaking.",
"The answer is still adrenaline. It doesn't require hard science showing how the brain triggers the release, etc. etc. There is no point in us... |
[
"If the sun were to disappear right now, how would the planets arrange themselves ? Will we obtain some funky configuration where the planets orbit Jupiter and Saturn or will the planets simply be flung out into space ?"
] | [
false
] | [deleted] | [
"If the sun were to disappear right now, all the planets would fling off of their orbit in a manner roughly similar to the shape of the letter J (without the serif at the top). There might be slight deviation from the pull of other planets but it would be virtually insignificant. Collision would be possible but unl... | [
"By a larger factor, most of the mass of the solar system is in the Sun. Without the Sun, the planets would basically just keep going in straight lines, with only tiny deviations due to each other's gravity. If two planets happen to cross very close to each other, then they'll have a stronger deflection, but most l... | [
"you could always buy the game Universe Sandbox off steam, take out the sun and find out yourself in a realtime simulation."
] |
[
"By what process do we increase neuron activity through attention?"
] | [
false
] | When we "pay attention" to an area in our visual field, the neurons fire more rapidly and the surrounding off center neurons are somewhat stifled. Through what process does this happen? Is there an originating signal that comes from somewhere? | [
"Attending to a given area in our visual field is more evident in areas V4 and FEF, in the latest studies at least ",
"(Georgia et al 2009)",
".",
"V1 neurons fire more rapidly in response to input from the Lateral Geniculate Nucleus, which in turn receives input from the retina; this is simply because you ar... | [
"It seems biased because that's the sensory modality that we know the most about, so the other senses just haven't been experimented with in as much depth. There have been some experiments that have touched upon audition that suggest the patterns of oscillations may translate well to other sensory modalities.",
"... | [
"A lot of this literature seems to be biased towards the visual sense. Do similar processes occur when you pay attention to an auditory or olfactory cue? Is it the same top-down regions effecting increased firing rates?"
] |
[
"What is real world example of a fourth order control system?"
] | [
false
] | In my Mechatronics class, we're going over some basic control systems and we were given examples of first, second, and third order control systems. We were told that a Cruise control is a good first order example, a Spring-mass damper is a good second, and a PID controller is an example of a third order control system.... | [
"I didn't know off-hand of any applications but a quick Google search found that it is frequently of concern in robotics and mechatronics with respect to motion and vibration control. Conceptually, if you have mass-spring-damper (or even just mass-spring) systems connected to each other in series, you will end up ... | [
"Because you're forgetting the mass term in the total force equation. Spring force is proportional to displacement, damper force is proportional to velocity, and mass force is proportional to acceleration, which is second derivative, thus second order."
] | [
"When talking about \"order\" as the OP means it, it's only referring to the order of the equation that you're working with, not necessarily what you're trying to control. You can end up with a fourth order equation by having two mass-spring-damper systems connected in series.",
"To put it another way, it doesn't... |
[
"Could you Skype at Relativistic Velocities?"
] | [
false
] | If I'm on a ship traveling at relativistic velocities and I attempt to Skype with someone back on Earth (assuming Wi-Fi reached that far and the receivers were tuned to account for the red/blueshift), what would it look like to the people on either end? If they could connect, would either one be able to notice the tim... | [
"As long as the ship is traveling at velocities below the speed of light (c), communication is possible.",
"But as the velocity increases, all communication signals get shifted towards longer wavelengths. This means that the \"bandwidth\" of the signal decreases, and you can't pass as much information through it ... | [
"Accelerations are indeed the key here. If you fly very fast to Alpha Centauri and back, you will be younger than your twin that stayed on Earth.",
"If you fly to A. Centauri and stay there, you will be younger than your twin because you were the one who experienced the acceleration. If he flies to join you later... | [
"Both parties will observe that the time on the other end runs more slowly.This will be independent of whether they are moving towards each other or away from each other, or even past each other.",
"This is a consequence of special relativity. I fully understand that. Two observers who are in motion relative to... |
[
"Will plasma from vaccine recipients be as effective of a therapeutic as plasma from those previously-infected?"
] | [
false
] | I’ve heard (anecdotally) that giving critical patients plasma from someone who has recovered from COVID-19 seems to be a very helpful treatment. Presumably, this plasma is in short supply. Should vaccine-recipients be similarly encouraged to donate plasma? Would the plasma from the vaccinated be as effective or more ef... | [
"Convalescent plasma, though it has been talked up a lot, really hasn't shown efficacy in randomized clinical trials. Here is a large one published recently in ",
"NEJM",
".",
"No significant differences were observed in clinical status or overall mortality between patients treated with convalescent plasma an... | [
"Thanks. Those studies seem to be pretty conclusive thus far. Anecdotally, I know two people who turned a corner after receiving convalescent plasma, but I acknowledge that doesn’t override real studies in the topic. I’m surprised to see it having such poor outcomes given what I thought I knew."
] | [
"I would note that the immune reaction after a vaccine - even different types of vaccine - is different to the immune reaction after infection. The actual virus is trying to hide from our immune system, while the vaccines we're using are actively trying to agitate our immune system. Especially the RNA vaccines whic... |
[
"Why are there two individual hybrids between horses and donkeys?"
] | [
false
] | Mules are from a male donkey and a female horse. Hinnies are from a female donkey and a male horse. If either are still the offspring between a horse and a donkey, why is there a difference? (Same question applies to Ligers and Tigons) | [
"Sperm and eggs aren't created equal. In addition to DNA there are many cellular factors transmitted from ova to offspring. This results in differences in the new hybrids based on what the mother species was. "
] | [
"they aren't all sterile, most are though. or more like, its harder for them to conceive due to chromosome issues. "
] | [
"Ligers and Tigons",
"This has some sexy tangential biology to it. ",
"Male ligers are the largest living cats.Two factors play in here through imprinting (explained beautifully above) and another effect.",
"Maternal size impacts offspring birth weight impressively. A comfier womb with less restrictions lets ... |
[
"What, other than their intended use, are the differences between a CPU and a GPU?"
] | [
false
] | I've often read that with graphic cards, it is a lot easier to decrypt passwords. Physics simulation is also apparently easier on a gpu than on a cpu. I've tried googling the subject, but I only find articles explaining how to use a GPU for various tasks, or explaining the GPU/CPU difference in way too technical terms ... | [
"They differ greatly in architecture. In the context of CUDA (NVIDIA's GPU programming offering) the GPU runs a single program (the kernel) many times over a dataset and a great many of those copies execute at the same time in parallel. You can have dozens of threads of execution all happening simultaneously.",
... | [
"(or are there extra cores?) ",
"They aren't 'cores' as you'd traditionally think of them, but they act the same. You can think of it like a whole bunch of cores all packed together and sharing some hardware but having to execute the same program on different bits of memory. You can't branch off into different ... | [
"As a crude analogy, compare a very small team of highly skilled employees against a large group of minimum wage temps. ",
"Certain tasks are done much better by the skilled team with more access to company resources and who know how to best approach the problem and to prepare so that no one is idle because a det... |
[
"Why are song tunes much more easily remembered than the lyrics?"
] | [
false
] | It's always easier to recall a tune than the lyrics to that tune, and I find this intriguing as words can be paired with physical objects and experiences, unlike notes. | [
"While those assumptions may not apply to everyone and my answer may not be as 'sciency' but the instrumentals to music with lyrics are extremely repetitive, more so than any of the lyrics. Try playing a more classical song in your head and see if you can make it through the entire thing, I think you'll find words ... | [
"The brain is hardwired to operate on patterns. See here: ",
"https://en.wikipedia.org/wiki/Pattern_recognition_%28psychology%29",
"Your brain operates almost entirely based on patterns. Think of the way you read. You don't actually recognize the order of the letters in a word. Your brain recognizes the first a... | [
"Late to the party, but I'll add my two cents:",
"A lot of neuroscientists are waking up to the idea that the brain is, essentially, a prediction organ. Its main function is to extract patterns from its environment and to use these to predict what is likely to occur next.",
"Even the most simple form for learni... |
[
"With many devices today using Lithium to power them, how much Li is left in the earth?"
] | [
false
] | null | [
"In 2015 the USGS predicted that we have over 365 years of lithium left at current production rates, and that doesn't take into account recycling. It's also with noting that there are a number of emerging battery techs that will replace lithium ion given time. ",
"https://www.greentechmedia.com/articles/read/Is-T... | [
"I'd like to add that if this works anything like oil, you're talking about proven deposits and the current possible production output. The amount of estimated resources left can change as new deposits are discovered, or even as existing sources are found to have more or less capacity than previously estimated."
... | [
"A small but important thing that many people don't know: The resource constraint for Lithium-ion battery power is not actually the Li, but the metal used for the other electrode, which nowadays is mostly cobalt."
] |
[
"With an estimated 1,000,000 nematode species, what distinguishes them all?"
] | [
false
] | I was on a Wikipedia safari, and read that there are 25,000 known nematode species, and 1,000,000 estimated total species. I'm wondering what could possibly distinguish between 1,000,000 variations of a little worm. Could someone explain the minimal distinguishing characteristics of a species of nematode? | [
"Many of the distinctions are on the genetic level. Two worms may look the same to the unaided eye and even live in the same habitat, but be vastly different genetically and totally unable to crossbreed."
] | [
"How do they know who to breed with and who not to breed with? Smell? Pheromones? Or is there some other way in which they can distinguish between members of the same species?"
] | [
"Nematodes are found everywhere on the planet, literally everywhere. Each type of environment is going to require a different strategy for optimal survival. Then you have to think about how many types on environments there are. Just considering a blanket term of the ocean floor is not enough. Different depths will ... |
[
"Can Ice X or other phases of ice be stable at atmospheric pressures?"
] | [
false
] | [deleted] | [
"Phase changes are reversible. If taking ice above ~65 GPa changes it from ice VII to ice X, taking it below 65 GPa will send it right back to ice VII. It's the same way as taking water at 1 atm below 273 K and then back above 273 K. It'll freeze then melt again. There's no magic way you can have a material un... | [
"My problem exactly, which is why I was asking honestly, some phase changes are stable, some reverse. So I basically wanted to know if ice X XI XII XV etc are stable at 1 atm :/.",
"Though looking like they might not be but do you have a source for reversibility of ice phase changes due to pressure?"
] | [
"Your best bet would be to look up kinetic studies of condensed phase water. The source for reversibility of ice phase changes due to pressure is any thermodynamic PT diagram of water, or those found on google - thermodynamically, as ",
"/u/staus",
" said, ice X is unstable at 1 atmosphere, and will revert to t... |
[
"Will a solar panel generate more electricity when moving towards the sun?"
] | [
false
] | For a real-world example, if the ISS's solar panels were maintaining the same angle relative to the sun while orbiting the earth would the energy collected be greater during the portion of its orbit where it moves towards the sun than when it's moving away? | [
"I can't give you a full answer, but there are two main effects that have to be taken into account. As the panels move towards the source, the energy of the photons gets blue-shifted, so the panels would be receiving a greater energy flux overall. However, solar panels are optimized to collect a specific frequency ... | [
"Excellent answer. Ive heard this question asked before and it got out of hand before the idea of designed wavelength was mentioned that I don't know if the OP ever noticed or considered it as an important consideration. "
] | [
"Not really, at 70 km/s the frequency would shift by like 0.02%."
] |
[
"Can you or can you not see stars out of the space station windows, or for that matter, on the surface of the moon?"
] | [
false
] | I answered my own question. | [
"You can.",
"However, stars are so faint that they don't show up in the background on most pictures from the moon/the space station, because the exposure settings are mostly set to illuminate some object(s) in the foreground."
] | [
"I had heard an interview with Armstrong saying otherwise, but I cannot recall for certain. So if the exposure was corrected, would you see a wonderful vista, more so than the best location on earth?\nAlso, if you have any links on the subject I would be grateful. Not easy to search this on Google. Thanks."
] | [
"Yes, you could probably see more stars from space as there are no ",
"light pollution",
" or other atmospheric noise.",
"Some links about the moon pictures and why they don't have stars in them:",
"http://en.wikipedia.org/wiki/Examination_of_Apollo_Moon_photographs#Absence_of_stars",
"http://earthobserva... |
[
"How do scientists calculate the age of planets, stars, and galaxies?"
] | [
false
] | I was trying to search on Google about this, including the age of the Universe, and the sources kept saying we can tell from the age of the stars and galaxies around us. How do astronomer's figure out how old stars and galaxies are though? Also, kind of related, I also read that our Milky Way galaxy is 100,000 light ye... | [
"I assume you read the wikipedia entry on \"age of the universe.\" which is a good starting point. From that you should at least gather that the age is based on how fast the universe is expanding. If we know how far everything is from us, and how fast it is moving (including its accelerating) then we go backwards t... | [
"I'm at the University of Manchester and we use noble gases to find out how old certain rocks are such as moon rocks, mars pieces and meteorites. Noble gases tend to not react with other elements, cause they're too \"noble\", and so act as great tracers. This brought about certain dating techniques like Ar-Ar dat... | [
"as a follow up, here is a really good summary of the above methods as well as quite few more that have been developed in recent years. there is a good diagram at the top that summarizes all these methods and what distances they are used for. ",
"http://en.wikipedia.org/wiki/Standard_candle#Standard_candles"
] |
[
"Between Eusthenopteron and Panderichthys what happened to the anal fin?"
] | [
false
] | Looking at the charts of evolution of land animals the anal fin disappears between Eusthenopteron and Panderichthys. Do they become part of the pelvis? Do the bones of the anal fin simply stop being being created? Some combination or do they change in some other way all together? | [
"The dorsal and anal fins are unpaired fins, and form separately from the pelvic girdle from which the paired pelvic fins are attached. In the Elpistostegalia, the dorsal and anal fin are lost and don’t reappear in any later tetrapods. The tail (caudal) fin is retained in some forms, and still observed in some la... | [
"Seconding what meat_popsicle13 said. Just in general, midline fins like the anal and dorsal seem to be more labile than the paired fins. There are widespread losses, gains, and subdivisions of the dorsal(s) in particular, but the anal is also lost in all kinds of lineages, even some sharks. It's probably easier to... | [
"Depends on what you mean by homologous. All fins, both paired and unpaired, share a “deep homology”, meaning they share a set of conserve genetic and developmental mechanisms that regulate their formation. This deep homology may be “redeployed” as appendages reappear in lineages."
] |
[
"Can petroleum extraction cause tremors/earthquakes?"
] | [
false
] | Petroleum is being extracted from the subsoil and years of continuous extraction could leave the cavity where petroleum used to be empty. Could this cause the ground above the cavity to collapse, possibly leading to a tremor/earthquake? | [
"Let's break your question up a bit, first:",
"Petroleum is being extracted from the subsoil and years of continuous extraction could leave the cavity where petroleum used to be empty. Could this cause the ground above the cavity to collapse",
"There are some misconceptions about the nature of oil/gas deposits ... | [
"I don't know if followup questions are allowed, but I'll try... Can the induced seismic activity be compared (in gravity, frequency and consequences) to the normal seismic activity? Is there any basis for fear mongering about oil and/or gas extraction through \"fracking\"?"
] | [
"First off, most of the worries regarding induced seismicity are not from fracking, but rather waste water injection (you end up with large amounts of waste water whether you've fracked or not, it's more about the local geology than the technique). In the case of Oklahoma, a lot of the wastewater that's being injec... |
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