title list | over_18 list | post_content stringlengths 0 9.37k ⌀ | C1 list | C2 list | C3 list |
|---|---|---|---|---|---|
[
"How are gem stones categorised?"
] | [
false
] | I’m not entirely sure what science this actually comes under so please correct me if that tag is wrong. I follow a gem stone sub on reddit who often post various gems and more often than not the colour isn’t what you’d traditionally expect from the type of stone, e.g. green garnets and pink sapphires. So, given that co... | [
"I'll answer this more generally for ",
"minerals",
", of which gems are just specific kinds of minerals to which we have assigned some value. Your question can be interpreted in two different ways, (1) On what basis to we catalog/classify minerals? and (2) How do we identify minerals? We'll touch briefly on bo... | [
"Dibs on this guy for my trivial pursuit team."
] | [
"When I was a pre-teen in the 1970s I got a \"rock computer\". You entered in pegs for color, streak, luster, hardness and cleavage/fracture. Then a lever was pushed against a stack of cards where it either had a cutout tab or a hole through which a peg was holding it. Any cards that got pushed up (not held in with... |
[
"Will my solution to end global warming work?"
] | [
false
] | null | [
"Hi FORMICA12345 thank you for submitting to ",
"/r/Askscience",
".",
" Please add flair to your post. ",
"Your post will be removed permanently if flair is not added within one hour. You can flair this post by replying to this message with your flair choice. It must be an exact match to one of the fo... | [
"'Planetary Sci'"
] | [
"Planetary Sci"
] |
[
"If you had access to more dimensions than just three, could you turn a left hand into a right hand? That is, making two chiral objects become achiral."
] | [
false
] | With three dimensions, you can turn a perfectly two dimensional object into its mirror image (For example, you can turn a "b" into a "d", by rotating them with the third dimension). Could you do the same with a three dimensional object? How many more dimensions would you need in order to do so? | [
"One more dimension would suffice.",
"Rotations and refelections in N dimensions are represented by so-called ",
". Rotation matrices have determinant +1, while reflections have determinant -1.",
"So if we have a 3-dimensional reflection that implements the transformation you want, you can embed the correspon... | [
"The underlying idea is most easily explained in the context of a plane. If you reflect in just one direction, you cannot achieve that with a rotation; thus, in OP's question, a 'b' and 'd' are reflections of each other, but not rotations of each other.",
"On the other hand, if you reflect in two directions, you... | [
"you're a smart 5 year old."
] |
[
"Does sound travel in absolute 0 temperatures?"
] | [
false
] | We learned in physics that the lower the temperature of the air , the slower sound will travel through it , so if there is 0 kelvin , will sound travel at all? | [
"Wouldn't the act of moving something at absolute zero raise it's temperature just slightly ",
" absolute zero?"
] | [
"Well, nothing can get to absolute zero anyway."
] | [
"Well, air doesn't exist close to absolute zero because it liquifies and then freezes. Sound can still travel through solids, so the solid nitrogen could have sound conduction. There are also unique forms of sound called \"second sound\" and \"third sound\" that occur in very cold liquid helium."
] |
[
"What direction is the solar system moving?"
] | [
false
] | What star would you point to and say 'that is where we are headed'? Is the direction aligned, at all, with the plane of the planets' obits. Also, how fast with respect the center of the Milky Way. | [
"Our solar system is currently travelling through the ",
"Local Interstellar Cloud",
" which it entered some 50-150 thousand years ago and will leave in around 10-20 thousand years. (",
": The Sun is moving towards Lambda Herculis at 20 kilometers per second (or 12 miles per second). Our own solar system is ... | [
"WOAH. I looked at the last picture/link you posted. So the solar system's orbit through the galaxy is NOT an ellipse or a circle but that oddly-shaped thing? Really?"
] | [
"Yeah, most stars in our galaxy move like this. This is what you get if a pefect ",
"orbit is pertubated",
" by a small amount, it then fulfills oscillations along the original orbit."
] |
[
"What specific risks are mRNA vaccine clinical trials evaluating?"
] | [
false
] | It's clear that COVID vaccine science is very well understood. For example, Pfizer's mRNA vaccine provides the body with the precursor to a spike protein found on the COVID-19 virus surface. The body manufactures the protein and the protein triggers an immune response. This chain of events is completely engineered: the... | [
"Clinical trials don't really test for any particular risk. They test for any and all side effects even those unrelated to the vaccine. From animal studies, you have a general idea of what side effects the vaccine may cause, but animals are not humans. The trial confirms this in humans. Sometimes from animal studie... | [
"Why is such an extensive clinical trial actually necessary? ",
"People aren't all the same, what can cure one person could kill another. The goal of a clinical trial is twofold, prove effectiveness and ensure there's no adverse reaction in a subset of the population the small scale trial didn't detect.",
"What... | [
"Because vaccines, if poorly designed, can both fail to protect you from infection ",
" make infection worse (more severe or deadly) when it does occur. Famous examples include the inactivated measles vaccine that caused high-mortality atypical measles and the RSV vaccine enhanced respiratory disease.",
"A vac... |
[
"Do you use your abdominal muscles when you sneeze? if so, does it make any significant difference over time for people who tend to do it more often than others?"
] | [
false
] | null | [
"Yes you do. An important breathing muscle is the diaphragm which sits below the lungs and is attached to the bottom edge of the ribcage. It pushes upwards when you breathe out which in turn causes air to move out of the lungs. ",
"Here's an animation.",
"Below the diaphragm is your abdominal cavity which is wh... | [
"Does that mean people who play wind instruments have more effective sneezes!?"
] | [
"Who knows. Maybe you can find someone who will pay you to do some research on that :)",
"I don't play an instrument but I do vaguely recall that people who use their voice a lot are taught to focus their breathing in their belly rather than their chest. This is really an emphasis on deliberately using the primar... |
[
"Would cars stop more quickly if they, instead of braking, started turning their wheels in the opposite direction?"
] | [
false
] | The question maybe applies better for trains, which have powerful motors and long brake distances. My gut tells me that they would stop faster, but then why isn't this the usual method of slowing down? | [
"Try to push a rubber block, say an eraser (or pretty much anything, but really noticeable with rubber) across some surface. You will notice that you need to push a bit harder to get it going when it is not moving, and then once it is moving the needed force is less. What you are seeing is the difference between st... | [
"What really matters here is friction. The friction from a rolling wheel is generally greater than the friction from a sliding wheel, which is why cars have anti-lock brakes.",
"If you had the wheel going the other direction, it'd be the same, physically, as a sliding wheel as it's not rolling across the surface.... | [
"I'm not saying that ABS is about stopping sooner at all, what I'm saying is that the friction between the car and the ground decreases if the wheels are not rolling with the direction of motion.",
"If the wheels lock up, then the car will be stopped by kinetic friction, which is a weaker force than the rolling f... |
[
"Do other animals enjoy their food in the same way humans do?"
] | [
false
] | For instance, I select my food based not necessarily on how nutritious it is, but instead on how it tastes. I will forego celery in favour of pasta, for example, because I'd rather eat the yummy thing than the healthier thing. Do other animals do the same, or are they strictly eat-everything-I-can? | [
"Animals clearly have preferences for food and do so for the same evolutionary reasons we do. In fact in chimp populations you can build and study an entire economy based around which foods they prefer.",
"http://phys.org/news111685361.html",
"Animals also aren't immune to diet related problems (obesity) either... | [
"True it is all mammals, I should have actually said that sorry. Mammals have different taste receptors depending on their diets, for example the giant panda has lost its taste receptors for meaty flavors because it isn't part of its diet. Any animal with a set of taste receptors will have a preference. Mammals do ... | [
"I think that's adorable!"
] |
[
"Can you get Vitamin D from the Sun passing through a window?"
] | [
false
] | null | [
"Normal soda lime glass (used in almost all windows) transmits no light under 350 nm. Optimistically, Vitamin D synthesis takes place at 280 - 310 nm, with an optimum at 295 nm. This means no measurable vitamin D synthesis through windows.",
"However, there are also applications of borosilicate glass in modern ar... | [
"Vitamin D relies on UVB rays hitting your skin, and window glass may well absorb these.",
"http://en.wikipedia.org/wiki/Vitamin_D",
"http://en.wikipedia.org/wiki/Ultraviolet",
"Ordinary glass is partially transparent to UVA but is opaque to shorter wavelengths, whereas silica or quartz glass, depending on qu... | [
"It takes UV light, primarily UVB, to produce Vitamin D in the skin. \nWindow glass is primarily opaque to short-wavelength UVB radiation\n",
"http://en.wikipedia.org/wiki/Ultraviolet"
] |
[
"Why is Australia so rich with mineral deposits?"
] | [
false
] | Australia is considered one of the top sources of mineral deposits for a wide variety of different resources. Is this due to the country having more prospecting work done to find these deposits than many other countries? Is this because of the aridity leading to less ecological cover to bury the deposits over millenn... | [
"A majority of the areas throughout the world that are especially rich in mineral / metal deposits are in ",
"cratons",
" and specifically old cratons (e.g. ",
"Archean",
" age bits of crust that have managed to survive). Ore geology is outside of my specialty, but this book chapter form ",
"Thiart & Wit,... | [
"AFAIK we don't have diamonds for example.",
"Diamond bearing Kimberlite pipes and economic diamond mines exist in Australia. I believe Western Australia and Northern Territory have the richest history of this. The most productive diamond mine is located in East Kimberly, the name of which should be a good indica... | [
"Aussie here. Hmm not really prospecting activity, it's just large and old. We don't have all resources but we have a lot of particular kinds, such as iron ore. \nAFAIK we don't have diamonds for example.",
"\nAny kind of mining relies on nature concentrating minerals in some way. the average crustal abundances a... |
[
"Explain CPT symmetry and the implications of this article."
] | [
false
] | article: OriginalPost: What i really don't understand is the article states that "Violations of C and P alone were first seen in radioactive decays..." To me if "violations" were observed then wouldn't CPT be shown to be wrong, violated, not correct? What is the significance of the T finding? The more information the... | [
"CPT symmetry means that if you flip C, P, and time, all of them, the particle will behave the same. It doesn't behave the same if you flip just C or just P or just T. "
] | [
"C, P, and T are all separate transformations. C is negating all charges, P is flipping all your spatial axes, and T is in some sense reversing time although it'a not quite the same thing. ",
"We believe the combined transformation of C, P, and T together to be a symmetry of nature as otherwise Lorentz invariance... | [
"FYI, ",
"Cosmic Variance",
" has an explanation clarifying about the arrow-of-time connection."
] |
[
"Given supernovae release neutrons, allowing heavier elements to be created, as well as the expanding universe, is it theoretically possible for there to be more heavy elements we have yet to find?"
] | [
false
] | null | [
"The question about superheavy elements has nothing to do with an expanding universe or neutrinos.",
"We can produce elements up to 118, and beyond uranium (92) their lifetime decreases with increasing element number - while uranium has a lifetime of billions of years the heaviest elements just live fractions of ... | [
"Physics are gonna physics wherever you are, though. There might be more elements beyond what we've found, but it's very unlikely that they'll be from a natural process or in any noteworthy quantity. ",
"If we stumble upon an area of the universe that produces a dearth of unknown elements then we're going to have... | [
"We've made elements much heavier than anything found in our solar system but they decay extremely quickly. There is a theory that there might be something more stable higher up on the periodic table we haven't tried yet that could be more stable. But I don't think there is any supporting evidence."
] |
[
"Why are particles in a superposition state 'forced' into a certain state due to observation/measurement?"
] | [
false
] | [deleted] | [
"This is an often asked question - and for good reason. While physicists agree on the basic ideas of measurement, they do not agree on the deeper (arguably philosophical) nature of it. ",
"I've always just wondered how measurement or observation can have an effect on a particle without directly interfering. ",
... | [
"It is possible to distinguish a superposed state from just another random state by doing the right measurements.",
"For instance, in the case of a pair of entangled photons. You know that the measurement on one side gives a random result. But once that is known, you immediately know what the result on of the mea... | [
"It is possible to distinguish a superposed state from just another random state by doing the right measurements.",
"For instance, in the case of a pair of entangled photons. You know that the measurement on one side gives a random result. But once that is known, you immediately know what the result on of the mea... |
[
"A few questions on colour blindness"
] | [
false
] | I was wondering to myself the other day on the nature of colour blindness, and came up with a few thoughts about it: Is the problem that causes it with the eye, or how the brain interprets colour? If it is with the eye, could a colour blind person still visualize the colour in their mind? I'm thinking that if the prob... | [
"In most cases, when someone says they are color blind they are referring to ",
"red-green colorblindness",
" which is a sex linked disorder that results in problems in the cone photoreceptors in the eye. ",
"Sometimes problems in someone's brain can lead to color blindness. An example of this is ",
"cerebr... | [
"It is in the eye. For the most common type, the color-blind person sees combinations of two colors (wavelengths) rather than the normal three. There is a shade of green that may appear gray. Theoretically, they can imagine the colors, especially if they study the science. In practice, they cannot be seen. The... | [
"Thanks for the answer"
] |
[
"What studies/theories are there that dialects of people in mountainous areas tend to have vowels pronounced so that they are easier to hear/distinguish in mountain air compared to other dialects of the same language?"
] | [
false
] | null | [
"Thank you for your submission! Unfortunately, your submission has been removed for the following reason(s):",
"For more information regarding this and similar issues, please see our ",
"guidelines.",
"If you disagree with this decision, please send a message to the moderators."
] | [
"I'm puzzled how it's too broad/vague. Some linguists believe that mountains/geography affect language, and I'm asking about evidence of it applied to a particular circumstance."
] | [
"Hi,",
"I was ready to leave a comment in the post: if you could make it a bit more specific with references to those linguists & their claims, that would be great. As it was, it was difficult to say whether you were referring to a linguistic theory or a pet theory.",
"Feel free to resubmit the question and mes... |
[
"What is the COVID-19 death rate among people who have been fully vaccinated?"
] | [
false
] | I'm not talking about deaths from vaccine complications or allergies, but people who are fully vaccinated (sufficient doses + wait time) and then subsequently die due to COVID-19. I know it's gotta be a tiny number, but I also know nothing is ever really 100% in situations like this. I'm normally pretty good at pulling... | [
"It may indeed be zero. At least, it's as close to zero as we have so far been able to measure.",
"One study was reported from a healthcare organization in Israel. They tracked 523,000 fully vaccinated patients. Out of more than half a million subjects, they reported 544 cases of COVID, only 4 of them serious, an... | [
"For comparison: The same study calculates 93% efficacy, i.e. a matching group of unvaccinated people would have had 7800 cases of COVID. Calculating the number of deaths we would have expected in that group is more difficult."
] | [
"Well with 90+% effective rate at preventing your probably not going to see data on this very soon. And given the amount of deaths its gonna take awhile to find those numbers. With deaths in the 2k range a day in USA that puts you at 14k medical records you gotta get permission from next of kin to view. Thats 50k a... |
[
"What is the Adam's apple and what is its function?"
] | [
false
] | null | [
"They do, it's just not as large as it is in men so it's less noticeable",
"https://www.medicalnewstoday.com/articles/324146.php"
] | [
"So Adam’s apples are just cartilage. In your bones you have what is called a diaphysial line or, as you would know it, growth plate. Your growth plates kind of turn into cartilage when you get older, and this causes your Adam’s apple to stick out."
] | [
"Growth plates start out as cartilage and eventually turn into bone when you stop growing. The Adam's apple, however, is not a growth plate, it's just a piece of cartilage that hangs out in your throat, protecting your vocal chords and providing them a scaffolding to attach to, among other things. It tends to stick... |
[
"Does a feather fall slower when affected by a horizontal wind due to additional horizontal air resistance?"
] | [
false
] | Compared to a feather falling in no wind. Edit: the feather creates NO lift, and there is NO turbulence in the air. | [
"A feather in a laminar (smooth, non-turbulent) horizontal wind will rapidly reach terminal velocity in the horizontal direction. It will then have zero horizontal airspeed, and will fall in precisely the same way as a feather dropped in still air.",
"Now we consider projectile motion when the horizontal airspee... | [
"Why?"
] | [
"No, because the drag references the air, not the ground. It would fall straight down through the air regardless of what the air is doing relative to the ground. ",
"There would be no additional air resistance due to the wind because the feather would not experience the wind.",
"Imagine jumping up and down in a... |
[
"Are monopole magnets theoretically possible?"
] | [
false
] | [deleted] | [
"\"Theoretically possible\" really just means that there are theories with monopoles in them. There are theories with all sorts of crazy things in them.",
"The Standard Model of particle physics, which is the theory that describes every electromagnetic-related phenomenon ever observed, does not have scope for mag... | [
"Magnetic monopoles are not known to existence, but their existence has some interesting consequences for physics. If even a single magnetic monopole existed in the universe, it would imply that electric charge must be quantized. Electric charge ",
" quantized but that still doesn't prove monopoles exist. It's al... | [
"Here's a try:",
"EDIT: There is also a purely quantum mechanical explanation, but this one is more intuitive."
] |
[
"If I add red dye to water and then boil it, why isn't the steam red?"
] | [
false
] | null | [
"If the dye or pigment has a far lower vapor pressure than water (which is very likely), than it's not evaporating with the water to any great extent. \"Steam\", if you're referring to visible clouds, is a misnomer for what is actually recondensed liquid water in tiny droplet form. It's essentially pure water (the ... | [
"I'm assuming that the red dye doesnt evaporate(or boil to be more precise) at the same temperature water starts boiling, so the water steam doesnt contain any dye or it contains so little that you can't see with bare eyes. (because evaporation happens in almost any temperature in liquid state, so it's ok to assume... | [
"No that's right. OP has discovered distillation.",
"And solids undergo sublimation and phase changes too. ",
"/u/Chemomechanics",
" has the thermodynamic explanation for it and it involves partial pressures."
] |
[
"Is there a more professional presentation of the Himba Tribe colours experiment than what is included in the BBC documentary \"Do You See What I See?\"?"
] | [
false
] | I was recently directed to a BBC Horizons documentary, titled "Do You See What I See", which includes an experiment whereby members of the Himba tribe - who are located in Namibia and whose language contains a radically different method of defining colours as many Western languages do - are asked to look at a series of... | [
"My issue is as follows. You say to the Himba subject \"find the colour that is different\". Now, the subject looks at the 12 squares and sees that 11 are what we would call \"green\", and 1 of what we would call \"blue\". However, the Otjihimba language calls both \"zoozo\".",
"What this documentary seems to imp... | [
"I've seen that doccie. It seems to me that it was a case of picking out the hue which was different. Himba people were better at picking the \"off green\" from the green than westerners, and westerners were better at picking the blue from the green than himba people. This measurement of better or worse was based o... | [
"My issue is as follows. You say to the Himba subject \"find the colour that is different\". Now, the subject looks at the 12 squares and sees that 11 are what we would call \"green\", and 1 of what we would call \"blue\". However, the Otjihimba language calls both \"zoozo\".",
"What this documentary seems to imp... |
[
"In 1996 NASA announced 'evidence of primitive life on early Mars'. In 2000, a second report supported the thesis. What happened next?"
] | [
false
] | In 1996, NASA published a press release titled . The release quotes scientists involved in the research making some pretty bold claims: 'we believe we have found quite reasonable evidence of past life on Mars', adding that 'what we have found to be the most reasonable interpretation is of such radical nature that it wi... | [
"https://en.m.wikipedia.org/wiki/Allan_Hills_84001",
"There's an article about the actual meteorite itself. I assume this excerpt from it is the basic reason why is never got popular but I'm not sure -",
"\"These claims were controversial from the beginning, and the wider scientific community ultimately reject... | [
"The claims have been controversial at best from the beginning. \nThere's another less known result from a Viking mission that found organic compounds on Mars but it's still seen as controversial at best and contamination by Earth-life at worst. ",
"None of those are widely accepted by the scientific community ... | [
"This question brings up a a couple of important notes about how science interacts with the public, which I wish everyone would know about:",
"1) It is extremely common for hypotheses to be proved wrong, and for exciting data to turn out to be misleading. This is a normal part of science. The problem is that th... |
[
"Is the blood moving in a pulsing manner (i.e. move - stop-move, in sync with the heart), or is it constantly flowing?"
] | [
false
] | null | [
"Yes and yes.",
"The amount of fluctuation in blood pressure (and therefore also the amount of fluctuation in the rate at which blood is flowing) diminishes steadily as you go from the heart (where fluctuation is greatest) and towards peripheral tissues (where fluctuation is smallest). By the time blood returns t... | [
"Well the aorta is elasticated so that it absorbs the force of the pumping action, thereby creating a more constant flow as it contracts back to its original size before the next pump (i.e. the aorta expands during systole and contracts during diastole). Therefore I'd say the blood is flowing constantly, but that i... | [
"You can consider it as pulsing in arteries (away from the heat) and flowing in veins (towards the heat)"
] |
[
"Most hydrogen has zero neutrons. Hydrogen fuses to make helium. Most helium has two neutrons. How does that work?"
] | [
false
] | Why does helium have neutrons if the hydrogen that makes it usually doesn't? | [
"Sure. Following along with ",
"this diagram",
", two protons fuse to form a diproton (helium-2). The diproton is unbound, so the vast majority of the time it simply splits back apart into two protons. However some tiny fraction of the time, it can beta decay instead. What's left after the beta decay is a deute... | [
"The way helium-4 is produced in this context is not a single fusion reaction. It's a chain of nuclear reactions and decays, the ",
" transformation being ",
"4p -> ",
"He",
"."
] | [
"...I don't understand hardly any of that. Can you explain the step by step process and what causes each step to happen/be possible?"
] |
[
"what will a <6 meter Tsunami do to coastal area ~20-30 meters high?"
] | [
false
] | I know tsunamis are alot of water, we are sitting in a bit of a basin, with 30 meters high ocean side, and range side, but 20 meters from the north descending into the ocean. We sit about 1km from the ocean. Just wondering if the water would rise 20 meters altogether, due to velocity + size, heh, no reason in particu... | [
"I checked the source for that. It also states:",
"Local disaster officials say atolls rarely see serious wave action as a result of earthquakes in the Pacific because their geology differs from volcanic islands and Pacific rim coastlines."
] | [
"Wow! The Wikipedia already has an article on the ",
"2011 Sendai earthquake and tsunami",
".",
"\"Northern Marianas Islands and Marshall Islands officials downgraded the tsunami alert after the expected arrival times passed without incident.[20][21]\"",
"If the above is true, I guess we don't have much to ... | [
"Take a look at the crazy ",
"energy map",
". I think that I'd be worried if I lived in a coastal area of the Hawaiian Islands. "
] |
[
"Why is there so little known about seizures?"
] | [
false
] | Two of my family members have varying degrees of Epilepsy. Both are healthy, no drug use, no brain trauma, but both of debilitating seizures. There are no answers or cures. Doctor's cannot even tell us why it happens. What makes seizures so elusive and hard to understand? | [
"I think we know more about seizures than you'd think, and are learning more and more with the advancement of technology. It's just that this information isn't yet to the point where it is truly helpful to doctors.",
"Doctor's cannot even tell us why it happens",
"Do you mean why seizures happen in general, or... | [
"If the medications just aren't good enough, shouldn't we be trying to determine what is causing the epilepsy so we can develop BETTER medications to treat it?",
"Yes, and that research is being done. Perhaps I wasn't clear. Research is being done to better understand why people have seizures, and they are also... | [
"\"Our treatments (medications) just aren't good enough that it really matters what's causing an idiopathic epilepsy and so there's no reason for the doctors to try to figure it out (though in most cases they likely could with some degree of certainty). If we develop better medications then you might see doctors st... |
[
"If you could raise your blood PH level, would there be any negative health effects?"
] | [
false
] | I was watching with Wim Hof, who uses a hyperventilation technique to increase his blood PH level. According to a study, he had a blood PH level of 7.75, well above the average range of 7.35-7.45. He claims to have raised his blood PH level even higher, to 8.0. Would there be any negative health effects to having a blo... | [
"The technical term for hyperventilating to increase pH levels is known as respiratory alkalosis. There are no serious side effects of respiratory alkalosis because your body has compensatory mechanisms to fix the issue over time. All you really get is some shortlasting effects that'll go away. The only thing I can... | [
"Respiratory alkalosis will eventually be compensated for by metabolic mechanisms. You may see hand and arm contractures as is common with panic attack patients (I believe this is because electrochemical signals fire somewhat uncontrollably in an alkaline environment). "
] | [
"Ok so here is the reason for the tingling/cramping/numbness during hyperventilation. ",
"Nerve membrane from inside is much negatively charged compared to outside. Nerves when touched/excited suddenly let some Hydrogen (H+) , calcium (Ca++) and sodium (Na+) form outside nerve cell enter inside cell; which genera... |
[
"What becomes diacylglycerol if it is not converted to triglyceride ?"
] | [
false
] | I'm a PhD specialized in genetics and cellular biology who is discovering the metabolism of fatty acid for a new project, so I'm not very keen on metabolism and organic chemistry and I would need some help on something I don't understand. Please don't use too much enzyme abreviation to be sure I can follow you, than... | [
"If it's required to go back into the phospholipid pool, the diacylglycerol kinase family of enzymes phosphorylates it. ",
"Here's a review: ",
"https://www.sciencedirect.com/science/article/abs/pii/S0898656800001133?via%3Dihub"
] | [
"No problem I understand, thanks to you I already have a part of the solution, if other people come, little by little I may have the answer. Thank you again and have a good day !"
] | [
"Thank you very much for your answer. So, if I understand properly, the scheme that I got become as follows: ",
"https://i.ibb.co/nBvfgns/Capture-d-e-cran-2020-01-15-a-14-56-27.png",
"Consequently, I went into the \"Subcellular localization and regulation of DGK activity\" part that is in your review in order t... |
[
"I've seen the charts for temperature rise, the scientific models predictions, the consensus statistics of scientific agreement on Climate Change. I believe it to be fact, but I do not actually understand WHY CO2, Methane, Water Vapor, etc.. cause this to occur. Can anyone explain *why*?"
] | [
false
] | I have done my fair share of trying my best to understand this issue, primarily to help explain to relative/friends/co-workers which are 'non-believers' but the truth is that I must not truly understand the issue either. I feel as though all of those skeptical also see "the charts for temperature rise, the scientific m... | [
"Sunlight is incident on the Earth's surface, warming it. That energy is reradiated as infrared upwards into the atmosphere, where it can either be transmitted and escape back into space, or absorbed by greenhouse gases.",
"A short diversion to explain what makes a gas a greenhouse gas: you're probably familiar w... | [
"Every atom and molecule has an absorption spectrum. Materials absorb light when the energy of incoming light is able to excite electronic, vibrational, or rotational states in the material. Greenhouse gases are just the molecules whose absorption spectra coincide with the range of radiation the earth puts out. For... | [
"I'm not going to say it's trivial to predict the exact warming effect of various atmospheric gases, but the physics concepts behind it is pretty simple. The earth has an average temperature that balances the amount of energy it receives from the sun and the amount of energy that it radiates back out into space.",
... |
[
"If you hooked up a 12 volt series of D-cell batteries to a dead car battery, would it charge up eventually?"
] | [
false
] | Would it charge up enough to start the car, at least? To my knowledge as long as the original batteries didn't run out it would slowly charge the car battery enough to get it started again. | [
"A couple things...while you could pump some charge into your car battery with 9 volt batteries, there are a lot of factors standing in your way. Above many people have mentioned putting the batteries in parallel to boost your current capacity, which would be important, not only to keep the battery charging. As you... | [
"Batteries in series increases voltage, in parallel increases current capability"
] | [
"Think of it like this, \nYour car battery is an empty 40oz bottle and your \"D\" Cell is a full shot glass, no matter how slowly you you tip the contents of your shot glass into the 40 oz it's never going to full it up "
] |
[
"What determines the temperature of space?"
] | [
false
] | I read that the temperature of space is -270C, although I can’t fathom why an empty vacuum would have a temperature. It doesn’t seem like there should be any source of heat or cold to influence this, so ideally, it should be 0. | [
"Objects in space warm up when they receive thermal radiation, and cool down as they emit thermal radiation. Most thermal control in space means calculating an equilibrium temperature in which the satellite emits as much as it receives plus the heat from internal sources (e.g. devices consuming electric power and w... | [
"I’m concerned by your use of the phrase “source of cold”.",
"0C is just what we called the freezing point of water, it’s not a baseline marking hot vs cold or anything, just a way of marking a scale we invented.",
"Heat is a measure of energy. Empty vacuum has no energy because there’s nothing in it to hold t... | [
"I can’t fathom why an empty vacuum would have a temperature.",
"The other answers are excellent, but I want to emphasize that even \"empty vacuum\" is not empty. It is permeated by quantum fields. It can be said that there's heat transfer from warm body to electromagnetic field (thermal radiation) and back (abso... |
[
"How can a HKPP(Hyper kalemic periodic paralysis) attack be triggerd by cold or pottasium rich food?"
] | [
false
] | Since it's a gain of function sodium channelopathy, I don't understand why pottasium would have an effect, I would also expect lower temperatures to have the Na channels activity decrease instead of seemingly strenghtening the effect. Cold could maybe decrease the pottasium channel activity wich would explain why the c... | [
"You're right, it is an outward driving force - I mistyped it. Good call.",
"The change is in Ek, but since Vm depends on Ek as there's a nonzero potassium conductance across the membrane, Vm will also change. So yes, your logic is correct there. You look to be on the right track."
] | [
"I just took a course dealing with a number of channelopathies including HKPP, so hopefully this might be of some help.",
"The biggest issue is the change in cell excitability due to the hyperkalemia as you mentioned, since now the membrane potential is raised and the ",
" outward driving force on potassium ion... | [
"Alright, so does the hyperkalemia cause a change in Vm or in Ek( potassium equilibrium potential). Also isn't it supposed to be outward driving force since K moves out of the cell? ",
"The way I was thinking about it was:",
"Ek= 60 log [K]out/[K]in\nIf [K]out increases Ek becomes less negative\nAnd so the driv... |
[
"Why do berries in the same bunch ripen at different rates?"
] | [
false
] | [deleted] | [
"Life is chaotic. For a parallel: would you expect all the eggs that were laid at the same time to hatch at ",
" the same time? ",
"Lots of stuff needs to happen for a fruit to ripen. There are a bunch of sequential and interacting steps. Chlorophyll degrades, pigment accumulates, aromatic chemicals build up, t... | [
"There's a much larger factor here that I think is being left out, which is that the flowers are pollinated at different times and single berries usually begin developing as soon as pollination is complete. Even if two flowers open at the same time, pollinators might not visit them equally and in some cases it can ... | [
"Wouldn't there also be an evolutionary advantage to having some diversity in when your seeds mature? If Wednesday and Thursday turn out to be bad days, but on Friday and Saturday the weather or other unpredictable circumstances are better, then the plants whose berries all ripened on the same day will eventually h... |
[
"What's the difference between a superconductor and a topological insulator?"
] | [
false
] | I was reading , and it states that "Stanene is predicted to be an example of a topological insulator" where "Electric current is not dissipated because most impurities do not affect the spin and cannot slow the electrons." To my layman's ear, that sounds like a superconductor. I thought the whole point of superconducto... | [
"From the article, ",
"\"Stanene is predicted to be an example of a topological insulator, in which charge carriers (such as electrons) cannot travel through a material’s centre but can move freely along its edge...\"",
"So topological insulators are defined by the fact that they have conducting states on their... | [
"Someone else already mentioned that TI's are insulating in the bulk, which is already very different from a SC. There's an important difference between superconductivity and ",
"ballistic conductivity",
", the latter of which is what's seen on the surface of a TI. Superconductors form a ground state whose tota... | [
"Don't the cuprates superconduct through the layers? What's the difference between superconductivity in each layer (I'm thinking here it's just like lots of \"surfaces\" stacked up) and in the bulk? "
] |
[
"If stem cells derived from a person are then injected into that person's brain, will the cells specialize to form additional neurons?"
] | [
false
] | Along these lines, if a portion of the brain is damaged or destroyed (e.g. the optic nerve / occipital lobe) could stem cells be injected and regenerate or rebuild the damaged or destroyed area? Thanks to everyone who's responded, I greatly appreciate it! | [
"Embryonic stem cells are totipotent and become any type of cell. Whereas, adult stem cells are pluripotent and can be many types of cells, but not all. Embryonic stem cells can proliferate (make more of themselves) almost indefinitely, unlike adult stem cells. Related to your question, adult stem cells are more di... | [
"could stem cells be injected and regenerate or rebuild the damaged or destroyed area?",
"Therapies along this line in many different tissues have been tried, and they had limited success in the best cases. The key to understand is that, as katedid, explained, that stem cells differentiate into certain tissue cel... | [
"Stem cells are currently a hot topic of research right now. However, simply injecting them into the body and getting it to change into the cell you want is a lot more difficult then you think. Katedid said that if you did that it has the potential to form a tumor which is definitely true. Relatively little is know... |
[
"Why would a classically allowed barrier still have a reflective wave?"
] | [
false
] | According to this article which reddit can't handle the link,( ), and , even when the energy of a travelling wave is higher than the barrier, there is a probability that the wave will be reflected. So far, the sources that I've found on the subject only mention mathematical explanation. Is there no easy to digest phys... | [
"Let me ask you a question to gauge what your thought process is to help tailor how I want to say this: what is your intuitive explanation that there is a probability that quantum mechanical waves can pass through a potential barrier?"
] | [
"OK, so one way to understand the whole quantum field idea is that there are no such thing as particles, and literally every \"particle\" is just some sort of localized disturbance in a magical field called a quantum field.",
"These quantum fields generally behave much like any wave equation, and the time evoluti... | [
"My understanding of that situation is very limited. I know that it happen due to the wave nature of the particle. I see how the math work out but I don't really understand the underlying principles."
] |
[
"Heat capacity of the oceans"
] | [
false
] | I am idly thinking about how much heat civilised humanity produces both through industry and the sheer mass of living bodies. How much of the excess heat we produce can be absorbed by the world's oceans? | [
"How much of the excess heat we produce can be absorbed by the world's oceans?",
"Is oddly phrased; the oceans are tremendously large and water holds a fuckton of heat. How about I put it this way: if we dumped all the heat generated by humanity in one year into the oceans, how much would the temperature change?"... | [
"impression we had a much bigger impact than that!",
"We do, but it's not in just dumping heat. ",
"We increase the planet's heat absorbed from sunlight (decreased albedo), and decrease the heat lost to space (greenhouse effect). In essence, we use the sun's power to heat the earth's oceans and atmosphere by ... | [
"Mind you: ",
"the heat content of the oceans is increasing by a lot more than that",
", but it's largely because of how we've changed the atmosphere."
] |
[
"What causes languages to diverge so quickly, and will mass media have a slowing effect on the divergence?"
] | [
false
] | null | [
"Yes, and it does. However, that doesn't necessarily mean that languages are converging. Languages have been taking loanwords since languages began diverging. All that means is that other languages' vocabularies are increasing."
] | [
"I touched on this question a bit ",
"here",
". To paraphrase the part relevant to your question: Languages diverge due to isolation and exposure to other languages. Afrikaans (or \"Cape Dutch\"), for a more recent example, came about due to isolation from its mother tongue and exposure to other languages. This... | [
"we're actually becoming more multilingual",
"Shouldn't more multilingual people lead to more \"cross-fertilization\" between languages?",
"Just curious about your thoughts, not expecting you to have a crystal ball."
] |
[
"How would Continental Drift Affect the climate on a planet around an M type star?"
] | [
false
] | I am a bit of a world builder, but I would like a more scientific answer. I know that the planet (if it is habitable) will be divided into rough day, night, and twilight sides, but those would seems variable in range. Plate tectonics, mountains, and volcanic eruption would certainly all play roles in how big each of th... | [
"To clarify, active plate tectonics would not have any real impact on the orbital/rotational characteristics of a planet (i.e. it sounds like you're describing a planet that is tidally locked with respect to its star where different portions of the planet would either be in perpetual day, night, or in between). Ass... | [
"Hi OP. I'd like to add that a habitable planet around an M-type star would have a rough go of it. I did a research paper on exoplanet habitability recently. You've already considered the day, night, and twilight sides of tidal locking, but lets expand on a few things",
"-M stars exhibit a ton of flare activity. ... | [
"Thank you this was very helpful"
] |
[
"Using the methods at the LHC, are we guaranteed to find the Higgs-Boson if it exists?"
] | [
false
] | In other words, does a failure to find the Higgs at the LHC imply the nonexistence of the particle? | [
"we don't know of any way to show ",
" what the Higgs boson mass should be. We know from a variety of measurements which masses are inconsistent with theory and data. ",
"Also, the LHC probably won't run for 100 years. Maybe 20 or so. They may do upgrades and whatnot to it. But we'll probably know if the ",
"... | [
"The search window is wider than that. ",
" due to certain backgrounds they've only ruled out that window (145-440 GeV), but a lot of talk about the Higgs has been in the 120-130 GeV window, which the LHC ",
" probe, but takes longer to distinguish signal from background."
] | [
"The search window is wider than that. ",
" due to certain backgrounds they've only ruled out that window (145-440 GeV), but a lot of talk about the Higgs has been in the 120-130 GeV window, which the LHC ",
" probe, but takes longer to distinguish signal from background."
] |
[
"Why do heavy weight lifting champions look \"Fat\", while those who take part in muscle competitions look like all muscle (Arnold Schwarzenegger)?"
] | [
false
] | null | [
"If the competition is about actually using the muscles, then the athletes involved don't have to bother with lowering their body fat enough for the muscles to be seen clearly under the skin. Body-builder competitions are basically a beauty pageant. It's awfully hard to get your subcutaneous fat down far enough tha... | [
"The sport of Weight Lifting is also classed by weight. The super-heavies will usually have lots of body fat because they are eating tons for maximum possible strength. All other weight classes have to carefully balance weight and strength. ",
"Check out Kendrick Farris from the 2012 US Team. He is in the 85kg cl... | [
"Yes, in heavy weight lifting, you train for strength. Look at the strongman competitions and such. In body building, yeah those guys are probably pretty strong, but they're training for looks. Emphasizing muscle groups qnd cutting bF%. Whatever they do will be sub optimal for the maximum strength, power etc... Cut... |
[
"If a person breaks their neck and becomes paralyzed from the neck down, how does the brain continue telling the heart and other organs to keep working?"
] | [
false
] | null | [
"It doesn't whem it happens high enough. The heart has an intrinsic pacemaker that keeps it beating at 60bpm and below. The sympathetic and parasympathetic innervation is lost so the heart may not speed up or slow down on command. However there are receptors that are chemical, stretch in nature and they do what you... | [
"Slight correction: intrinsic pacemaker rate is 100 bpm and parasympathetic innervation to the heart goes through the vagus nerve, so a spinal cord injury would leave it intact."
] | [
"A lot of our vital functions are not controlled by the brain directly, but by the spinal cord and the base of the brain, in what is called the medulla. The spinal cord and the medulla work like a small brain that just transmits signals to keep things like respiration and heart beat working autonomously.",
"The b... |
[
"Long term effects of shaking a Earthquake resistant building. (concerning Japan)"
] | [
false
] | [deleted] | [
"Even after small earthquakes, some level of permanent damage is expected in structures. So yes, the stress in a structure could be cumulative. Fortunately, this damage is relatively easy to spot in most modern structures so that the buildings that are no longer habitable can be spotted. Also, it is unlikely that t... | [
"It is more of a question of energy then of peak acceleration. Although a higher peak acceleration can cause more severe damage, even low accelerations for extended durations can cause significant damage. Buildings that absorbed energy during the first quake had less energy absorption capacity during the 2nd quake,... | [
"Peak acceleration is the most common figure used because it is the simplest term that can be correlated with damage. There is also no guarantee that another more severe earthquake could happen in Japan."
] |
[
"Why do some animals (eg. cats) have 'ridged' palates?"
] | [
false
] | [deleted] | [
"This is called \"incisive papilla\". It helps filter scents back to the Jacobson's organ. The Jacobson's organ is a specialized scent organ that is mainly used for detecting pheromones.",
"Here's the relevant part of ",
"the wiki article",
":",
"Some mammals, particularly felids and ungulates, use a dist... | [
"Are your cats fixed? It's related to pheromones which are mostly tied to reproduction."
] | [
"Are your cats fixed? It's related to pheromones which are mostly tied to reproduction."
] |
[
"For lithium ion batteries, is it better to keep it fully charged or let it deplete and recharge?"
] | [
false
] | [deleted] | [
"I've done extensive research into batteries. Someone else here said ",
"In effect, it doesn't really matter what you do with your battery, leave it on the charger as long as you like.",
"While I respect the point he's trying to make, that isn't strictly true. It depends on the sophistication of the charging co... | [
"What you wrote is correct for nickel-based batteries but it is not correct for lithium ion batteries. ",
"While trickle charging is used for both lead and nickle-based batteries, it is definitely not used for lithium-based batteries. Lithium-based batteries have extremely low self-discharge and they are very ... | [
"Trickle charge still happens with Li-ion batteries, it's just not called \"trickle charge\". It's called \"constant-voltage charging\" and is the last stage of the battery's charging cycle. ",
"The Li-ion trickle charge state is performed at constant voltage, and therefore there's no danger of overcharging durin... |
[
"Our moon rotates to match earths orbit, hence we always see the same side of the moon. My question, are there any other moons in our system that exhibit the same behavior?"
] | [
false
] | null | [
"Basically all big moons in the solar system are tidally locked. Ours, Io, Europa, Ganymede, Callisto, Titan, Triton, and a whole bunch of others. Charon is locked to Pluto, and also Pluto is locked to Charon. A lot of known exoplanets are also tidally locked."
] | [
"That's interesting, thank you. Off to do some digging, probably have another question or two later."
] | [
"To add to this, ",
"here's a list",
" of moons that are known to be tidally locked, followed by a list of moons that are presumed to be tidally locked (but have insufficient data). ",
"The largest moon that's known to ",
" be tidally locked is Nereid, satellite of Neptune, with a radius of only 175 km, and... |
[
"Does every human have unique sex chromosomes? My father and I are both XY, but is my X unique from his X? What about any given stranger?"
] | [
false
] | null | [
"This is mostly right with ",
"one addition",
". Due to recombination during meiosis, your X chromosome is a mix of your mother's 2 X chromosomes. So your sibling most certainly has an X chromosome (or two) that are different from yours.",
"It gets more interesting with the father. For the most part the X ... | [
"This is mostly right with ",
"one addition",
". Due to recombination during meiosis, your X chromosome is a mix of your mother's 2 X chromosomes. So your sibling most certainly has an X chromosome (or two) that are different from yours.",
"It gets more interesting with the father. For the most part the X ... | [
"Chromosomes do something called crossing over. Everyone has two copies of their chromosomes, one from each parent. During meiosis (the production of gametes) you two versions of your chromosome link together at points, and then come apart, with each chromosome having a portion of the other!",
"Crossing over is f... |
[
"Why don't humans have a mating season? Why do we have sex for pleasure unlike most other animals?"
] | [
false
] | [deleted] | [
"http://www.nature.com/nrurol/journal/v9/n9/abs/nrurol.2012.151.html#top"
] | [
"First question: Let's presume that the default mating schedule is anytime. The existence of a mating season is therefore a function of evolutionary pressure. Here are a few examples: 1) the female going into estrus may use significant resource and thus only experience it once a year. All females going into est... | [
"But if we don't have a mating season because of the reasons you gave, does that mean before having any of that we did? So is it an instinctual thing we grew out of? "
] |
[
"How is instinct in all animals encoded within DNA or the brain?"
] | [
false
] | I am wondering how natural instinct has the ability go to through generations. Why/how do animals have the capability to naturally do something encoded within them. I thought it was a good random question to ask! | [
"So I'm not an expert in ethology, but I can recommend you read about ",
"fixed action patterns (FAPs - yeah, I know)",
". Oftentimes, what is really programmed is not a totally specific behavior like \"follow your mother around\" but a reaction triggered by a simple releasing mechanism, like ",
"\"follow aro... | [
"but it only took one gene to knock out each particular behavior. ",
"To me this just tells that the behavior depends on that gene, not that it's controlled by that gene only. I would expect very complex behavioral trait to be very fragile to any changes in the genes that control it. "
] | [
"I just don't see how something as complicated as nest building or a turtle knowing how to find the same beach year after year could be encoded in DNA that simply has genes that code for proteins. How could these simple sequences of nucleotides make a brain that somehow has this information??? It must be in the fin... |
[
"Do oxygenated and deoxygenated blood look the same when exposed to air?"
] | [
false
] | I know oxygenated blood is bright red and deoxygenated blood is dark red, but do they look the same outside the body? Could you tell the difference in appearance between venous blood and arterial blood if a vessel were cut open and you bled outside your skinn? | [
"http://www.reddit.com/r/askscience/comments/lbgxr/does_all_blood_appear_the_same_when_exposed_to_air/",
"odd timing"
] | [
"Wouldn't the oxygen in the air be enough to fully oxygenate the blood? "
] | [
"I can ignite woodcurls but not a block of wood with my lighter. Its about surface (exchange) area. But if you wait long enough (the erys are probably dead then) yes."
] |
[
"Does Carbon dating rely on our atmosphere being constant?"
] | [
false
] | If our atmosphere were thicker or thinner, affecting how long solar rays remain in our atmosphere, would it mess with the accuracy of Carbon dating? | [
"cosmic rays, not solar rays (ecven though they come from the sun, they are properly called cosmic rays). and they aren't really rays, they are particles. moving at VERY high speed. So high a speed that thickness of the atmosphere will have very little effect on their velocity, so the amount of time spent in the at... | [
"thicker or thinner atmosphere that is still within parameters that support life would not greatly effect the solar ray penetration enough to make much of a difference in carbon 14 formation.",
"The atmosphere is MOSTLY nitrogen, so even with thicker or thinner atmosphere, odds of an alpha particle hitting a nit... | [
"Awesome info, thanks. Just a follow up question : if the atmosphere was thicker, wouldn't solar rays be trapped in our atmosphere for longer making things that are carbon dated appear older than they actually are? "
] |
[
"Why does wood not decay/rot and stay strong, when other natural plant/animal matter rapidly decays?"
] | [
false
] | null | [
"Wood can decay and weaken, depending on the environmental conditions.",
"One thing that ruins wood quickly is constant humidity and temperature changes. Ever seen an old fence or deck that's all warped and cracked? In many cases, that's because the constant inflow and outflow of water is ruining the cell walls... | [
"Wood consists of both lignin and cellulose, but also cellular byproducts from the tree's natural pathways. In many of the conifers, these are resins, while in heartwood of deciduous trees, you can find tannins. These both resist decay by fungal and insect operatives.",
"Non woody plants do not contain as densely... | [
"Yup. Organisms have a heck of a time with those big molecules. They're nature's own (almost) non-biodegradable polymers.",
"Expanding on that in another direction; It's worth noting that cellulose is just a chain of sugar molecules - the same as starch, yet we can all digest starch. That's because starch molecul... |
[
"Do we understand the physical makeup of Mars? What is the core made out of, what's the estimated temperature?"
] | [
false
] | [deleted] | [
"The core is an iron-nickel core with 16–17% sulfur. Its temperature is about 1500K. See also:",
"https://en.wikipedia.org/wiki/Mars#Physical_characteristics",
"\n",
"https://en.wikipedia.org/wiki/Geology_of_Mars",
"\n",
"https://en.wikipedia.org/wiki/Composition_of_Mars"
] | [
"How about the core of Vesta?"
] | [
"Vesta is thought to consist of a mostly differentiated metallic iron–nickel core 214–226 km in diameter, an overlying rocky olivine mantle, with a surface crust. Its current and past core temperature is a matter of debate ranging anywhere from 1200K to 1850K see for example ",
"here",
" and ",
"here",
"For... |
[
"If a gas giant, lets say Jupiter were to have a slower rotational speed would it grow or shrink due to centrifugal force acting upon the gases, flinging them outward, with the gravity of the planet itself pulling the gases back?"
] | [
false
] | null | [
"With less rotational velocity, your planet gets more compact, less of an equatorial bulge, and therefore has a smaller radius at the equator. ",
"Let's make an analogy to help you intuit the situation:",
"Earth's equator has a slight ",
", because even this \"solid\" planet can't retain a perfect spherical s... | [
"Ha ha I feel like that's one of those things that may not motivate people to publish papers on it much.",
"Abstract: We took a picture of Jupiter with a Mickey Mouse Magic Maker Zoooom! Camera for Young Photographers. The photo was printed out using a Pokémon Ezey Printomatic printer on Kirkland Signature 3x2 Ec... | [
"Wikipedia is saying that, and doing a terrible job of citing their sources. ",
"In fact, I can't find a single peer-reviewed source to back up that claim, even though the numbers are everywhere. ",
"Here's a ",
"photo",
" I tracked down by the Catalina Observatory which shows the obvious bulging--the diame... |
[
"Can someone explain to me how quantum computers work?"
] | [
false
] | null | [
"This piece",
" by Scott Aaronson does a nice job of explaining what quantum computers are and why they'd be useful."
] | [
"Essentially, a company has managed to produce a limited form of quantum computer. It can solve a subset of problems involving optimizing systems. The more general quantum computer that most people think about when invoking the name can solve a larger range of problems.",
"Think about it this way: the technology ... | [
"The jury is still out on whether what D-wave is seeing is actually quantum in origin. (See ",
"http://arxiv.org/abs/1305.4904",
", though there is also a reponse ",
"http://arxiv.org/abs/1305.5837",
"). See ",
"this",
" for links to various claims and counterclaims. "
] |
[
"At what point are different types within a species considered its own species?"
] | [
false
] | null | [
"In addition, there are animals that are considered different species because they \"won't\" reproduce with each other, even though it would be successful if they did. This is generally due to differences in mating cues/courtship rituals (behavioral isolation), seasons (temporal isolation), or physical incompatibi... | [
"They would be considered different specie, when they cannot reproduce with each (and produce fertile offsprings)."
] | [
"A liger is not fertile, thus cannot make more ligers. Therefore, it can't be its own species."
] |
[
"How sure are we that nuclear fusion reactors are possible?"
] | [
false
] | I know that nuclear fusion occurs in labs all the time here on Earth and that there are a few different groups trying to make a fusion reactor where you get more energy out than you put in. My question is, how sure are we that these attempts at net positive fusion reactions are actually possible? Asked another way, I a... | [
"Net energy positive fusion reactions exist both in thermonuclear weapons and inside stars. Therefore we know that this is definitively possible.",
"If it is technically and economically feasible for commercial power generation is still open."
] | [
"Ooo good answer. This is what I figured, but I appreciate you explaining it!"
] | [
"Kilogram for kilogram, the average person emits more blackbody radiation every second than the sun."
] |
[
"When I put ice cubes in a glass of water, what exactly is happening when the ice visually and audibly cracks."
] | [
false
] | null | [
"It's cracking because the ice blocks do not raise in temperature uniformly across their entire volume, but that the change in temperature propagates. As things change size when changes in temperaature occur, it is not hard to see how this may cause a dislocation in some area. Once a crack has been initiated then i... | [
"Funny, I asked this same question: ",
"http://www.reddit.com/r/science/comments/e8dp8/why_do_ice_cubes_crack_when_you_immerse_them_in/"
] | [
"Also, when dishes aren't microwave-safe, often it is because they will crack due to uneven heating in the same way. I've lost a few bowls to this phenomenon."
] |
[
"Can someone please explain superluminal jets to me?"
] | [
false
] | Most difficult for me to grasp is how does mass get ejected from a black hole, how is it even possible, and how is this ejected mass moving faster than light? | [
"It isn't. Superluminality is an optical illusion.",
"We model black holes as being these simple, isolated things, because that's how we understand the basic principles that govern them. But in the real world, a black hole is a ",
" nightmare of high-energy interactions, not within it, but just around it. Any m... | [
"No. There's a difference of some dozens of orders of magnitude. The Big Bang was bigger and bangier than you might be inclined to imagine."
] | [
"Are the conditions ",
" close (but outside) the event horizon be comparable the conditions at the very beginning of the universe? (I ask because I imagine both situations something like \"too little room for too much energy\".)"
] |
[
"Can we infer from genetics the baseline lifespan of a person?"
] | [
false
] | I know that genetics offer clues to the chances of developing diseases and cancers before environmental factors. Can this be extended to general aging to offer an outlook on someone's lifespan? Is there even a genetic component that significantly impacts lifespan? | [
"Note: by \"lifespan\" I mean the time it takes for normal, inevitable aging processes to kill someone; disregarding cancers and other diseases (even typical)",
"Cancer and other diseases are complications of aging. They are part of aging. You can't just take them out of equation. ",
"That said, ",
". We can ... | [
"There are genetic factors that influence lifespan, but there are way too many variables to accurately deduce anything meaningful from genetics alone. The biggest issue is distinguishing between genetic and environmental influences on an individual. The debate is similar to the ol' \"nature versus nurture\" debate,... | [
"We have a lot of evidence to suggest that telomeric length helps waylay the effects of aging. Telomeres are the segments of non-coding DNA on the ends of chromosomes that basically protect a given person's genome from degrading. We don't have very exact numbers on how much telomeric length corresponds to years of ... |
[
"Does your body adapt to weather overtime? If so, why and how?"
] | [
false
] | Currently, I live in Eastern Virginia and the recent weather has intrigued my mind with this question. Overtime does your body adjust to the climate? For example, I sweat quite a bit, however if I were to never to use AC and bask in the weather as is, would my body eventually adjust to the massive humidity and heat o... | [
"Yes.",
"One example is when someone who lives in a colder climate goes to somewhere where it's much hotter. Say, going from Yellowknife, Northwest Territories, to Hong Kong.",
"One of the ways that your body thermoregulates itself is via vasodilation of small blood vessels in your skin. As this hypothetical pe... | [
"As a follow up - how does the temperature of food or water affect your body temperature?",
"I've lived in some really hot places (e.g. Indian desert) and they drink scalding hot tea in the summer time and claim it cools you faster. All I can think is that it makes you sweat more thus cooling you. Can you lay som... | [
"Eating will almost always warm you up regardless of the temperature of the food, due to ",
"specific dynamic action",
"."
] |
[
"If I dissolved Lithium Chloride in water, why would the temperature of water change if the mass of salt changes?"
] | [
false
] | null | [
"If you did have chemistry homework questions I would actually try ",
"/r/chemhelp",
" as it usually seems to be pretty active."
] | [
"If you did have chemistry homework questions I would actually try ",
"/r/chemhelp",
" as it usually seems to be pretty active."
] | [
"You will have better luck with this question on ",
"/r/chemistryhomework"
] |
[
"In a lavalamp, why do the wax blobs \"bounce\" off each other? Why don't they combine with each other on contact?"
] | [
false
] | Recently purchased a lavalamp, and was curious | [
"Wax bubbles bump into each other when one is on the way up (hotter, lower density) and one is on the way down (cooler, higher density). The differences between densities means that the structures cannot integrate when pressed together. However, when bubbles sit at the top or bottom they coalesce as the temperature... | [
"There is a thin layer of water that gets trapped between them. Surface tension interactions are weird... but essentially the water is attracted to itself, so for two blobs to fuse, they have to break through that thin layer of water. It's like floating a paper clip on water, even though the end state of blob fusio... | [
"Often, though, blobs will sit at the top and not pop - they will just bob together for a while before falling down"
] |
[
"If liquid helium is the coldest substance we have commercially available to us today, how did we first cool helium down to that temperature without the use of something colder?"
] | [
false
] | null | [
"Use a refrigeration cycle. Compress it and raise it's pressure (and thus temperature), cool it (reject heat) while at a relatively constant pressure, then expand the gas back to ambient pressure, thereby cooling it further.",
"Repeat this process using different coolants. Eventually: compress it a lot, cool with... | [
"The current way labs experimenting with ultra-cold materials do it is to magnetically contain an amount of super-cooled (let's say helium) in a way that the magnetic containment looks like a cup with sloped sides. The most energetic atoms (highest temp) will eventually fall out of the \"cup\" leaving only the cold... | [
"Cold is the absence of heat. One way to cool something down is the passive way of equilibrium, put something cold near the object you're trying to cool down, and equilibrium will have heat travel from the warmer object to the colder one, cooling one and warming another. Another way would be to modify the propertie... |
[
"How deep would we have to go to accomplish protection from radiation on Phobos?"
] | [
false
] | null | [
"Mars doesn't shield Phobos very much. The radiation on Phobos' surface will be a bit higher than on Mars' surface due to the Martian atmosphere protecting the planet.",
"Phobos is made of relatively low-density rock. It's either very porous or has a decent amount of ice in it or both. If you get dug in a good 3-... | [
"From wikipedia:",
"For instance, a NASA design study for an ambitious large spacestation envisioned 4 metric tons per square meter of shielding to drop radiation exposure to 2.5 mSv annually (± a factor of 2 uncertainty), less than the tens of millisieverts or more in some populated high natural background radia... | [
"Thank you so much for your reply but I want to ask how you came to the number 3-5 meters. Not that I doubt you but I don't really know much about radiation so I was wondering how you know that the material of Phobos is sufficiently protective at that depth. If there are any articles you could refer me to that woul... |
[
"At what altitude could a marble orbit assuming it could almost travel at speed of light?"
] | [
false
] | [deleted] | [
"If you're talking about orbiting the Earth, it can't, ",
" for any altitude. It's also too fast to orbit the Sun and too fast for the galaxy.",
"Typical speeds for nearly circular orbits are 7.6 km/s around Earth, 30 km/s around the Sun and 200 km/s around the galaxy. Of course, that varies a lot depending on ... | [
"The question is not assuming the marble IS moving at the speed of light. It's just saying the upper limit is the speed of light."
] | [
"Oh, when I read \"almost\" I interpreted that way.",
"In that case, Earth orbits at an altitude of 300 km are stable enough for artificial satellites. Lower altitudes are possible but orbits decay quickly due to atmospheric drag. A marble has a low area to mass ratio, so a higher orbit (say 600 km) may be necess... |
[
"How much energy do our bodies lose as heat on average?"
] | [
false
] | And how much of the heat lost is via infrared radiation versus direct contact with air? I realize there are a lot of variables in this, such as the room temperature, what you're wearing, and what you're doing (resting, running, etc). I'm not sure what kinds of studies have been done on this, so any numbers or explanati... | [
"According to the Stefan-Boltzmann law, humans at 37 C in an atmosphere of 20 C with a body surface area of about 2 square meters, gives about 200 watts. This is about 4000 calories per day, which is more than most people consume. I think the discrepancy lies with the fact that human skin is colder than their inter... | [
"NASA has been all over this for a long time with space suit design. That would be a good place to start in terms of research. To answer your original question (which was less specific):",
"From: ",
"http://www.faa.gov/about/office_org/headquarters_offices/ast/media/ECLSS%20AC_460.11-1-A%20for%20publication.pdf... | [
"An interesting calculation, but of course human bodies regulate to the same temperature regardless of environment. It can be 0 outside or 35 degrees, the human body temperature will still be 37. This is because it will expend energy to stay warm, or sweat to stay cold.",
"Bottom line is that assuming you arent ... |
[
"Why is it that, overall, smaller animalia live shorter lives than larger animalia, but within a species, the larger the individual, the shorter the life?"
] | [
false
] | The two examples to best elucidate this are: insects vs. humans, rabbits vs. dogs, etc. I am aware that there are outliers such as birds and tortoises, but overall this seems to hold. Any explanation? | [
"There are various factors in play (such as heart rate) that explain the mortality rates of varying sized fauna. Firstly, smaller animals must satisfy the order of the food chain to maintain balance; more small animals means more food for larger ones and so the quicker they die, the quicker they are encouraged to r... | [
"But what about, say, birds, who can live forever? Like immortals?"
] | [
"it has to do with heart rate. smaller animals tend to have a faster heartbeat.\n",
"http://www.beholders.org/mind/scienceandfacts/124-1billionheartbeats.html"
] |
[
"what could be the next BIG THING in science?"
] | [
false
] | null | [
"Reddit does not have that functionality. You will have to make a new post in that sub."
] | [
"Such questions are better suited for our newish sistersub ",
"/r/asksciencediscussion",
". Please post there instead."
] | [
"so...... how do i change the sub?"
] |
[
"Why does it hurt when disinfectant is applied to wounds?"
] | [
false
] | null | [
"Disinfectants are not picky about the type of cells they kill.",
"Alcohol",
" dehydrates cells and denatures proteins. Proteins and cell walls have the shape they do partly from interaction with water and if you change the solvent everything dies. Antibiotics are an off switch for bacteria and disinfectants ar... | [
"Yep, Benzalkonium chloride for example, or a number of iodine preparations. If it really hurts to put it on a wound, you probably shouldn't be putting it on a wound."
] | [
"Aren't there actual wound desinfectants? I usually use octenisept for that and it does not burn at all."
] |
[
"Is it possible to project the 'voice' in our heads?"
] | [
false
] | null | [
"What do you mean?"
] | [
"Like the subconscious voice when we think or narrate speech in our heads"
] | [
"What does it mean to project it? You can say things out loud. That's about it"
] |
[
"We can measure brainwaves via probes on the outside of the skull. Can we change these brainwaves via impulses pointed into the skull?"
] | [
false
] | Please, only provide strong research topics. I know this is where the entire tinfoil hat idea originates. | [
"First, we don't really use the term \"brainwave\" in neuroscience. Yes, we can measure the electrical activity of the brain at the scalp, and yes, that activity often has oscillatory properties that can be accurately described as wave-like, but the term is misleading for a number of reasons and I would discourage... | [
"Thanks so much for your response!",
"Can TMS work on deeper brain circuits than what we have on the inner surface of the cranium?"
] | [
"To add to this question, if we ",
" probe deeper with this technique (rather than, I assume, just the tissue on the surface of the brain, directly under the probe?), would there be any risks associated with it?"
] |
[
"Can one device pull power from multiple outlets?"
] | [
false
] | Hi, I'm currently studying electrical engineering at college (I'm not very far into it yet though, which is why I'm not able to answer this for myself!), and also am a musician/sound tech. I was wondering if it would be possible to create a distro box that draws power from multiple 15 amp outlets to allow a single devi... | [
"Yes, some guys put blown-in insulation into my attic, and they had to plug 3 cords into 3 separate 15 amp circuits to run the one machine. Thank goodness for polarized plugs!"
] | [
"Polarization is not sufficient when there are multiple phases. Many North American houses have two 120 V AC phases 180 degrees apart, with 240V AC between the hot wires. In other words, you have 240V AC with the center tap of the transformer connected to ground. If you directly connect the wrong pair of outlets, y... | [
"Yes, you're right! Perhaps the unit is powering different pieces of machinery with the different plugs. Seems that the easiest way would be to convert all 3 to DC and draw from all of them."
] |
[
"Helping endangered sea turtles question."
] | [
false
] | So we have all seen the documentaries that show a long stretch of beach somewhere in the tropics with thousands of baby sea turtles climbing up out of the sand and dashing for the ocean. The vast majority of them are eaten by predators before they get to the water. If the population of sea turtles were to drop to dange... | [
"Humans have destroyed a lot of rivers with hydropower plants. To compensate for the loss of fish production, we have a lot of fish hatcheries where the eggs are protected from predation and juvenile fish are released into the river at 0+, 1+, or 2+ years (they hatch in the winter and are released in the summer, he... | [
"No, it's not just about using sperm from more males, that is the smallest part of the problem.",
"The main problem is that you have a large survival rate from a small number of parents.",
"Young animals are supposed to die at a high rate. That is natural selection. It weeds out the weak and keeps the species s... | [
"Remember that turtles have evolved to withstand natural predation levels, in that these predators have always been taking eggs or hatchlings from the beach. Part of why turtles are so successful as a group is that they were able to evolve ways of dealing with predation. This is the same for any other predator-prey... |
[
"Why do I get a headache when I am hungry? And why do I get hungry after not eating for only 4 or 5 hours, when there are people who survive on one or less meals a day?"
] | [
false
] | null | [
"This has been removed because seeking ",
"medical advice",
" on ",
"/r/AskScience",
" is against our guidelines.",
"Please see our ",
"FAQ."
] | [
"I wasn't seeking medical advice at all. I was wondering why something happens, not what I should do about it. I know what to do about it, I should eat when I am hungry."
] | [
"Please read this: ",
"http://www.reddit.com/r/askscience/comments/s4chc/meta_medical_advice_on_askscience_the_guidelines/"
] |
[
"Professor had a balloon cooled with liquid nitrogen, which he placed on a bench. The balloon floated to the ceiling as volume increased. Why?"
] | [
false
] | What was going on? Would it happen with any gas less dense than air, or was it a property of a specific gas? Was the gas just in the liquid/solid phase when cooled and therefore more dense than air? | [
"It should work with any lighter than air gas, cooling it causes it to condense down to a denser state where it's no longer lighter than air. If you imagine it like a big ship that can float on water, if you crushed that ship down into a cube of steel it would drop to the sea floor like a rock, but if you expanded ... | [
"I was using the entire ship as an analog to the molecules of gas, not the steel itself, but yes you're right. "
] | [
"Their density would increase even if it is not to the point where it becomes liquid. The density only needs to increase enough that it becomes more dense than air. "
] |
[
"Why does caffeine effect some people but not others?"
] | [
false
] | For most people, caffeine has an effect on them whether it is soda, 5 hr energy or coffee/tea. For some, it wakes them up mildly, for others it has them bouncing off the wall. Others though seem to be immune to its effects, even in high doses. Is this because some people have very low amounts of receptors for the caffe... | [
"Most pharmacogenomics have to deal with mutations in receptors. In this case other people may have a slight variation in the receptor that causes decreased binding affinity. ",
"I actually developed a pharmacogenomic test for metformin because 20% of hispanic patients have a mutation that does not allow for them... | [
"This is the most likely reason someone would have a diminished or no effect from a drug. Another possible reason is decreased absorption of the drug, but as far as I know that's not an issue with caffeine. ",
"Caffeine binds to adenosine receptors in the brain and blocks adenosine from binding to receptor site; ... | [
"Exactly correct Glad to see another Pharmacy person on here."
] |
[
"Microgravity is referred to as \"free fall\". Does that mean all the objects in the universe are falling toward something?"
] | [
false
] | null | [
"Microgravity is a misnomer for objects that are in orbit around the Earth. Gravity on the space station is approximately 90% as strong as it is on Earth. The reason the astronauts appear weightless is because they are in free-fall, just like when you go over a hill on a rollercoaster and are lifted out of the se... | [
"For a uniform gravitational fields, the answer is yes. The ",
"equivalence principle",
" states that there is locally no way to feel the effects of a uniform gravitational field in a free fall.",
"Earth's gravitational field is not uniform, since it changes with the distance to the center of the Earth, but f... | [
"A very good answer, though I wonder if it's complete. If we account for general relativity, is there any sense in which the free falling astronaut can legitimately say \"There is not a gravitational field here\"?",
"Someone who actually understands relativity, please weigh in. Also, if the answer to the above is... |
[
"Theoretically what would be the result of millions of atoms in a very small density all losing electrons simultaneously?"
] | [
false
] | The title may be confusing, and I didn't know how to properly word it, so I'll provide an example. I'm writing a novel in which, "magic" wielders essentially steal the electrons from an atom and transmute them to other forms of energy (Obviously not 100% scientifically plausible, hence "magic.") My question then being... | [
"You'd get something called ",
"Coulomb explosion",
". This can happen without wizards getting involved."
] | [
"This would be for solids only. I don't think you would notice anything special for gases. You'll have a very short-lived localized plasma."
] | [
"So, a cubic centimeter is something in the neighborhood of a milligram of air. That would contain somewhere in the neighborhood of 10",
" electrons zapped away, so the remaining air would have a total charge of about 100 Coulombs.",
"A typical lightning bolt transfers about 15 coulombs of charge, although bigg... |
[
"How effective is washing your hands, when taking in to account all of the potentially dirty surfaces you touch in the process?"
] | [
false
] | Went to the bathroom today. Post rinsing my hands I touches the following: Taking all of this in to consideration, am I better off having washed my hands? | [
"The short answer is an \"it depends\".",
"A microbiologist would be able to describe this better in detail - hundreds of thousands of bacteria can live on a single square centimeter of anything (try growing a swab off your keyboard, for example). That's a lot of bacteria that could possibly be pathogenic. ",
... | [
"Antibiotics have the difficult task of killing, or rendering ineffective, bacteria without being significantly harmful to important things like human blood cells and human tissues. This is an incredibly narrow definition of \"kill\". Antiseptics which are not typically injected into the blood stream have a much ea... | [
"Taking all of this in to consideration, am I better off having washed my hands?",
"Yes."
] |
[
"Is there (Could there be) a periodic table of elements for antimatter?"
] | [
false
] | Could it be just one element or could antimatter be made up of a number of elements similar to matter? | [
"It is exactly the same periodic table as the one you know.",
"Antimatter behaves the exact same way as matter when interacting with other antimatter particles."
] | [
"Theoretically, yes. But at this point, its only theory because the majority of the antimatter elements have not been created in a way that allows for reliable measurement of their properties. A table with properties of Anti-Hydrogen and maybe Anti-Helium wouldn't really be a comparable table to the current periodi... | [
"Is there not a antiparticle for each particle that composes atoms, and would there not then possibly be an antimatter equivalent to every element which exists in normal form?",
"Layman speculation here but I believe that there exists antiprotons, antineutrons, positrons (anti-electrons) so I would assume that th... |
[
"Is there evidence that psychotherapy by a professional is effective compared to a control group in which the professional is replaced with a random person? Or with a book or similar text-based method?"
] | [
false
] | [deleted] | [
"Most clinical psychology research uses a ",
"wait list control group",
". In other words, the placebo group just waits for a callback from the researchers.",
"There's no good way to control this research unfortunately. Your suggestion of using a \"random person\" would also lead to problems, because the subj... | [
"It wouldnt be ethical under the guidelines in Australia at least - and i believe the ethics are the same in most developed countries.",
"The main issues is that you are not allowed to use deception and so you would need to tell people upfront that they might get an actor. Even if this was allowed (iit wouldnt be... | [
"I think you're asking the wrong question.",
"Psychotherapy simply means therapy for the mind. It encompasses a lot of reason for why someone might need therapy. Because of this, there are going to be a large number of methods for therapy.",
"So I think a question that makes more sense is asking about which m... |
[
"What are the benefits of using heavy water (compared to light water) as a neutron moderator in a nuclear reactor and why do they work?"
] | [
false
] | E.g. in a CANDU reactor. | [
"Okay, so hydrogen is the difference between light and heavy water. Heavy water has deuterium, which is hydrogen with a neutron attached. The normal percentage of deuterium in water molecules is very low, less than a percent. Heavy water has a much higher amount.",
"The advantage of using heavy water is the abili... | [
"The best moderator is a material containing hydrogen-1, because the hydrogen-1 has a nucleus with a mass closest to that of a neutron.",
"But hydrogen-1 will also capture neutrons to become hydrogen-2.",
"Hydrogen-2 is less optimal for moderation because of its higher mass, but it’s also less likely to capture... | [
"Yes, the neutron bombardment would result in water that was heavier than you started with. However, the mass of the coolant is large relative to the amount of fuel in a standard reactor, and most commercial reactors intentionally bleed out and replace a portion of their primary coolant, so under normal operating c... |
[
"Do small insects such as Thripses have hearts and brains too? If not, how do they operate/live?"
] | [
false
] | null | [
"Yes, they have brains. While insects do not have a heart or blood vessels per se, they do possess a valved dorsal vessel that pumps \"blood\" (i.e. hemolymoph) to the head, from where it circulates into the rest of the body."
] | [
"I'm not sure about thrips, but scientists have modeled the brain of a tiny worm which is only 302 cells.",
"https://en.m.wikipedia.org/wiki/OpenWorm"
] | [
"How complex are their brains? Or is it just a tiny lump of nerves doing basic things?"
] |
[
"How many years after the last reported \"wild\" polio case, will polio be declared to be eradicated the way smallpox is?"
] | [
false
] | null | [
"So it took about 50 years of widespread vaccination in Europe & North America to mostly eradicate it there, then about another 70 years to inoculate the rest of the world, with the last cases of each strain in 1975 & 1977. It was officially declared eradicated just a few years later, in 1980. ",
"Polio is a litt... | [
"The World Health Oranization considers a region polio free after they have gone ",
"three years",
". According to the their eradication planning ",
"documents",
" oral polio vaccine will continue for one year to ensure that there are no additional cases that are missed after which they will cease usage of... | [
"I want to add that only the cheap and easy-to-use oral vaccine has a risk of mutating. \nIn most of the world an injection vaccine is given, which cannot mutate. ",
"However, this vaccine is more expensive and harder to use. The vaccine mostly used in less developed countries is an oral vaccine."
] |
[
"Why does a 4 window car make that loud thumping noise when you roll down two windows?"
] | [
false
] | [deleted] | [
"As air flows faster, it's pressure decreases. The air outside your car is flowing quicky past the still air in you car. As such, the inside of your car is at higher pressure than the outside. When you lower the windows, the air pressure in the car changes as it interacts with the outside and the pressure different... | [
"I don't know the answer to the original question, but I would guess it has much more to do with resonance. It's not a simple change in pressure as you imply, but a very powerful, rhythmic boom that I've experienced and that I believe the question is referring to. "
] | [
"Thanks for the insight, I totally just visualized a giant whistle!"
] |
[
"Why does the air pressure in the car fluctuate and hurt your ears when you are driving fast with only one window open?"
] | [
false
] | EDIT: “Pain” probably wasn’t the best choice of word. It causes a “tolerable discomfort” that is more annoying than it is painful. | [
"The open window in your car makes your car act as a ",
"Helmholtz resonator",
". This is characterised by fluctuating air pressure in the cavity (which you're sitting in).",
"As to why your ears hurt, that's a medical question that I cannot comment on."
] | [
"This guy",
" did a little research on it in response to a query from a local paper. So, ",
"not exactly peer reviewed research, but he found",
":",
"First, although humans can’t truly hear that rear window noise, it certainly is powerful: it hits peaks of pressure of 100 pascals, ",
". There’s a good re... | [
"OR close the window or crack a window opposite, there I just saved you a few bucks."
] |
[
"the physics of mousepads"
] | [
false
] | So all the major gaming accesory companies have released anodized aluminum surfaces as mousepads within the last 5 years and sales of these are strong. Over time, the center of the pad will start to have a "mirror like" finish that is actually too quick and unusable because a small amount of tacticle friction has been ... | [
"Why would an optical mouse need friction?"
] | [
"the mouse itself doesn't need any friction for tracking; however the player would like a very minute but noticeable amount of tactile feedback from moving a mouse."
] | [
"I don't understand. I assumed he was talking gamers here, i.e. small rapid movements with the fingers and wrist, not whole arm movements.",
"For example, one (of the many) ways of doing it, is to anchor the heel of the palm on the table and move the mouse by wrist rotation and small movements of the thumb and sm... |
[
"Why is the maximum to the graph of y=x^x equal to e? Is this how e was determined?"
] | [
false
] | The graph starts looking something like y=sqrt(x) between x=0 and x=e, but after e is reached on the x-axis (e, ~1.44) it looks like y=1/x, why is this? Why is e the turning point? Why does it approach 1 but never reach 1? EDIT: I meant x not x! | [
"I think you mean x",
", which has derivative x",
"(1-ln(x))/x",
" which is zero when x=e since 1-ln e=1-1=0.",
"We have (1-ln(x)) > 0 for x<e and (1-ln(x))<0 for x>e while x",
"/x",
">0 so the derivative is positive to the left and negative to the right. Hence, x=e is a local maximum for x",
"."
] | [
"The derivative of y=x",
" is dy/dx=(1+ln(x) )x",
" . You can show this by differentiating the logarithm of both sides of y=x",
" .",
"For this to be zero, ln(x) has to be equal -1, which means x is e",
" (e is 2.78..., not 1.44). The value of the function at x=1/e is (1/e)",
" which is .69. This is als... | [
"Lesser values at the extremum and the fact that this only one zero in the derivative makes it global maximum. "
] |
[
"What is the molecular process of weight loss?"
] | [
false
] | Like, we know that exercise can reduce weight loss by increase fat metabolism, but what are the detailed physioogical and molecular processes and genes involved in it? | [
"This is a HUGE question. To summarize from wikipedia's article on fatty acid oxidation:",
"\"...when hormones such as epinephrine are secreted, or when insulin levels drop in response to low blood glucose levels, this triggers an intracellular secondary messenger cascade that phosphorylates hormone-sensitive lip... | [
"Lipolysis does not = using fat for energy. Let me clarify.",
"The human body stores fat in a compact structure called a trigylceride. These are 3 fatty acids attached to a glycerol molecule. Glycerol is small and stable, and can be produced from sugar in the body.",
"SO, a trigylceride = glycerol + 3 fatty aci... | [
"Skimming through the comments, I still don't see the direct answer to your question. Yes, fats are broken down via beta oxidation, and the electrons gathered from that are used to set up a proton gradient inside the mitochondria. Cells pass excess protons onto water, and electrons into oxygen to produce carbon dio... |
[
"When a star fuses oxygen, does it always react with available hydrogen to form water?"
] | [
false
] | Or is this reaction not favorable under the extreme conditions inside a star? Is there any O2 in the universe that doesnt come from a process like photosynthesis? | [
"H2O is formed via a chemical reaction between the valence electrons of hydrogen and oxygen atoms. Stars are so hot that the atoms themselves have been disassociated into their component ions (i.e. it exists as a plasma). In other words, there is so much energy that electrons are not even bound to nuclei to form ... | [
"The hydrogen-oxygen chemical bond is not stable at the extreme temperatures found inside a star, so no, I wouldn't expect there to be any water inside a star.",
"\nQualifications: PhD, Chemical Engineering"
] | [
"Some stars do indicate the presence of stable molecules, although I don't think water is a possibility and it certainly isn't common. Also, form my understanding, it is true that those molecules are not present in the part of the star were fusion is taking place, for the same reason you stated."
] |
[
"How can one polarizer \"cancel out\" another?"
] | [
false
] | I was playing with a couple photographic polarizers today and I noticed something odd. Whenever I hold one at the proper angle to my LCD screen, the image goes black. This is to be expected, since the light from the screen is polarized. However, when I place another polarizer between the first and the LCD screen, the i... | [
"This is a ",
" question. You've accidentally stumbled upon one of my favorite demonstrations of quantum physics.",
"Let's ignore the screen (since the reasons why emits polarized light are interesting but ",
"somewhat technical",
") and just think about three linear polarizers. When unpolarized light pas... | [
"Why does this need quantum mechanics?",
"If I'm dropping toothpicks or pieces of spaghetti on some strainer that has long slits in it:",
"after passing through that strainer, they'll all be lined up the same way; so if I follow it with another strainer at a 90% angle from it, they won't get through. But if ... | [
"Why does this need quantum mechanics?",
"It absolutely does not, you can treat the light in terms of classical EM waves. ",
"The 45 degree polarizer chops away some of the wave, but the portion of the amplitude that makes it through is now diagonally polarized.",
"What is really cool is that when you work th... |
[
"Why is sucralose so much more sweeter than sucrose?"
] | [
false
] | Why is a compound obtained by merely substituting three of the hydroxyl groups found in table sugar with chlorine 600 times more potent than its precursor? Would using other halogens instead produce similar effects? | [
"It has 3 chlorides in place of 3 hydroxyl groups... I'd assume this is enough to change how the molecule bind to a receptor in aqueous solution."
] | [
"One key thing in medicinal chemistry is that binding is all about intermolecular interactions, and the substitution of functional groups at the right sites can make a world of difference. It is common practice to modify existing drug candidates this way to obtain some desired effect - increasing lipophilicity, rem... | [
"It depends mostly on the active site of the receptor you're targeting. If the -OH group is involved in dipole-dipole interactions, then naturally altering the nature of one of those dipoles will change it. If the -OH group is facing ",
" from the receptor, there may be no effects at all. It comes down to ",
" ... |
[
"Compared to albedo, magnetic fields, solar flares, and other greenhouse gases, how big of a factor is carbon dioxide in global warming?"
] | [
false
] | Or compared to any other factors you may think are significant. Links to scientific literature on the subject would also be much appreciated. My father is convinced you can't predict climate based on carbon dioxide levels because of the many other factors at play in the Earth's climate. How much does carbon dioxide con... | [
"If you're interested in this, I really do recommend reading from the definitive report on the subject, the ",
"IPCC Physical Science Basis",
", most recently compiled in 2013. They devote a chapter to anthropogenic vs natural climate forcing. It's a dense, fairly technical read, but it's worth it. Probably ... | [
"What's warming the world",
" from NASA and Bloomberg has all of this put beautifully in graph form. It shows timeseries for volcanic, solar, and orbital changes, plus greenhouse gas emissions and other anthropogenic factors."
] | [
"I'm not disputing the ",
" of other forcings, and if we do eventually start sliding toward an ice age in 1000 years (or 10,000), we'll have to figure out something to do about it, but ",
" its anthropogenic greenhouse gas emissions (primarily if not exclusively in the form of CO2), that are driving the climate... |
[
"Caffiene is a diuretic, so it pulls water out of you, causing dehydration. But since it's typically served with water, that rehydrates you. How many beverages are net hydrators?"
] | [
false
] | null | [
"Almost all of them.",
"This popular press article",
" has links to several interesting studies, including one showing that people build up a tolerance to caffeine's diuretic effects quickly, and another proposing a 'hydration index' to study which beverages are most effective rehydrators. The latter found seve... | [
"Notion that coffee causes dehydration comes from a 1928 study involving 3 people that were abstained from drinking coffee for 60 days.",
"A scientific study on the matter shows that “Cumulative urine output at 4 h after ingestion of cola, diet cola, hot tea, iced tea, coffee, lager, orange juice, sparkling water... | [
"It's common advice that stranded persons should never drink sea water as it leads to net dehydration. Do we have a clear idea of how saline water would have to be \"hydration neutral\"? "
] |
[
"Rubbing alcohol... cool to the touch?"
] | [
false
] | I use spray bottles at work with 70% isopropyl alcohol, and I notice that there is a cool feeling associated with the alcohol. It sits at room temperature all day. Am i just imagining this? | [
"alcohol evaporates which pulls uses energy, leaving less heat on the area it evap'd from. this makes it feel cool (ianascientist)"
] | [
"You are not imagining this.",
"To evaporate, a liqiuid must gain enough energy to escape it's liquidy confines. To do so, it can take heat from the surrounding environment. When the isopropyl alchohol gains enough energy to evaporate it will turn from a liquid to a gas.",
"When it removes this energy as heat f... | [
"great answer, that makes a lot of sense thanks!"
] |
[
"Why are so many computer gpus filled with completely different cooling fans? Don't we know the optimal shape and number of fins by now?"
] | [
false
] | null | [
"Fans and cooling systems are dependent on the architecture of what is below them. So a given configuration is only \"optimal\" for a given chip and power bus shape as well as dissipate power and price point."
] | [
"Optimal for what?",
"Airflow?",
"Pressure?",
"Speed? ",
"Noise?",
"Any of a million combinations of all of the above?",
"Are we talking about pure air cooling? Radiators for a liquid system? A hybrid approach?",
"What exactly is being cooled? Where do we need airflow to go? What specific cooling ... | [
"\"Optimal\" is a function of many variables. What works best for one graphics card, might not be the best for another one.",
"Cost will be a very significant factor. There might be a $5 design that is sufficient for a card that needs 100W of cooling capacity. A \"more efficient\" design might offer 300W of cooli... |
[
"What is the difference between osteoporosis, osteopenia & osteopetrosis?"
] | [
false
] | null | [
"Petrosis is when they become much denser, porosis and penia they become less dense (more brittle); penia is not as bad as perosis and both involve reduced bone protein and mineral content, main difference as far as I know between penia and perosis is obviously perosis is often more severe, penia is more a medical ... | [
"Osteoporosis is a more severe form of osteopenia. Both represent a decrease in bone density from loss of bone. Osteopetrosis is the opposite in a way - in this condition, too much bone is laid down and you get an increase in bone density. All of these conditions make the bone more brittle and prone to fractures."
... | [
"Bone needs to be strong but also flexible. Normal long bones have an internal network of trabecular bone that acts as a shock absorber. Osteopetrosis replaces the shock absorbing bone with hard compact bone which is much less flexible and more prone to damage with even normal use."
] |
[
"If I switch a bulb from a 65W incandescent to a 7W led, where are those extra watts going?"
] | [
false
] | Hey there. Kind of a newb to electricity. I've been looking it up a lot, just so I understand it I realize volts are like the "pressure" of the electricity and amps are like the "volume" of electricity coming through. Here's what I don't get. A light bulb can power both a 65W bulb and 7W bulb, and the lesser bulb does... | [
"A 65W incandescent powered by 120 VAC draws 65W / 120V = 0.54A of current.",
"A 7W LED powered by 120 VAC draws 7W / 120V = 0.06A of current.",
"You could think of that as being because the incandescent has resistance of 120V / 0.54A = 222Ω, and the LED has resistance of 120V / 0.06A = 2100Ω.",
"That's not e... | [
"The energy doesn't go anywhere because it's not drawn in the first place. It's like opening a faucet all the way compare to half way. If you open it all the way, you use all the water that you can get from the pipes. If you open it up halfway, you use less water and the rest stays in the pipes. "
] | [
"The energy doesn't go anywhere because it's not drawn in the first place. It's like opening a faucet all the way compare to half way. If you open it all the way, you use all the water that you can get from the pipes. If you open it up halfway, you use less water and the rest stays in the pipes. "
] |
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