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[
"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 colour is not a feature that facilitates categorisation, what does?
|
[
"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 both.",
"In terms of classifying minerals, ultimately it comes down to their chemistry, but in practical terms we use a system similar in many ways to how we classify organisms, e.g., a series of distinctions which become increasingly more restrictive, i.e., ",
"group, series, species, and variety",
". It's a little confusing because many of these all get called a mineral depending on the level of specificity. Garnet is a ",
"group",
" of minerals which all have the basic formula X3Y2(SiO4)3 where X and Y can be a variety of elements. Within that there are essentially smaller groups (e.g. Pyralspite or Ugrandite) which contain individual species (e.g. Almandine or Pyrope). It would still be correct to call any of these a garnet, but you can also be more specific if you can identify the particular species of garnet. Generally for a mineral to be a particular mineral group it will have a shared portion of a chemical formula (like the (SiO4)3 part of the garnet), which is typically the part that makes up the ",
"crystal lattice",
", with then some variation in other cations that are within particular sites within the lattice.",
"In terms of identification, this is usually done on a suite of physical (or optical) properties. The common properties that are suitable for examining a hand sample are ",
"color, streak, luster, hardness, and how it breaks (cleavage vs fracture)",
". If we take the garnet example, the different cations will produce differences in some of the physical properties (e.g. color), but others, which are more reflective of the lattice structure of the mineral, like the presence or absence and/or number of cleavage planes, will be the same between all garnets. Some of the more suitable identifications require the use of ",
"petrographic thin sections",
" as the physical properties in hand sample may be ambiguous for multiple species, but will have distinct optical properties (again driven by the chemical differences). In some cases, to truly identify which mineral you have (e.g. which of the multitudes of garnet), you may need to do a chemical analysis using something like an ",
"ICP-MS",
" or ",
"electron microprobe",
". For minerals like garnet (and when the details matter), these small scale chemical analyses can be the only way to identify which garnet(s) are present because a single crystal may actually be the intergrowth of different kinds of garnet reflecting different chemical, temperature, and pressure environments present during the crystallization of that particular garnet."
] |
[
"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 a peg), were your candidate minerals"
] |
[
"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 following flair categories and contain no other text:",
"'Computing', 'Economics', 'Human Body', 'Engineering', 'Planetary Sci.', 'Archaeology', 'Neuroscience', 'Biology', 'Chemistry', 'Medicine', 'Linguistics', 'Mathematics', 'Astronomy', 'Psychology', 'Paleontology', 'Political Science', 'Social Science', 'Earth Sciences', 'Anthropology', 'Physics'",
"Your post is not yet visible on the forum and is awaiting review from the moderator team. Your question may be denied for the following reasons, ",
"/r/AskScienceDiscussion",
"There are more restrictions on what kind of questions are suitable for ",
"/r/AskScience",
", the above are just some of the most common. While you wait, check out the forum \n",
" on asking questions as well as our ",
". Please wait several hours before messaging us if there is an issue, moderator mail concerning recent submissions will be ignored.",
" ",
" "
] |
[
"'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 corresponding 3x3 matrix into a 4x4 matrix that has the 3-dimensional reflection matrix in its upper left, a -1 in the bottom right corner, and zeroes elsewhere. This 4x4 matrix is a four-dimensional rotation, but on the original three-dimensional subspace, implements the original reflection."
] |
[
"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 can write that as a rotation. So, you can turn 'd' into 'p' by reflecting vertically and horizontally, or by rotating -- still staying entirely in two dimensions.",
"The idea in the higher dimensional case is based on this. You have a reflection in three dimensions. Now you picture this in four dimensions, keeping the reflection in three dimensions but also adding a reflection in the fourth dimension. So now you have two reflections in the four-dimensional space, and as we saw with the 'd' turning into 'p' case, you can write the combination of two reflections as a rotation. Of course, this required adding a fourth dimension, so this is a four-dimensional rotation."
] |
[
"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 tipped by about ",
"63 degrees",
" with respect to the plane of the galaxy, so the planets orbits are in no way aligned with the path our solar system takes through the galaxy (",
"our solar system is not a vortex",
", as sometimes claimed). We're currently around 27.000 lightyears away from the galactic centre and move around it with an ",
" orbital velocity of about 218 km per second, also the sun is slowly moving upwards out of the galactic plane with ~7 km per second.",
" I found a ",
"nice picture",
" showing the solar system's way through the galaxy."
] |
[
"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: these scientists are not shooting in the dark. There is no risk of COVID infection: the virus cannot possibly be produced from mRNA alone. Clinical trials show 95% efficacy of the mRNA vaccine with a very strong statistical significance, so Pfizer must have tested the vaccine on tens of thousands of people. Now, it's finally ready for distribution. In the mean time, hundreds of thousands have died from COVID. Why is such an extensive clinical trial actually necessary? What danger could a new mRNA vaccine present aside from just *not working*? How could this danger be greater than COVID itself?
|
[
"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 studies, you look for certain side effects more carefully. This allows you to discover side effects that you could never imagine would happen. For example, someone in the AstraZenica vaccine trial developed a rare disease called transverse myelitis. That wouldn't be something you'd necessarily be looking for. Even if the side effects are all things you expected (e.g. fever), you need to know how frequently people get that, how severe it is, and how to manage it.",
"From an ethics standpoint, you cannot just give someone a drug and not know the risk and benefits before you give it, unless this person is enrolled in a clinical trial with tons of safeguards in place. Informed consent is one of the major underpinning of medical ethics."
] |
[
"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 danger could a new mRNA vaccine present aside from just *not working*? ",
"It's altering things to produce something the body hasn't before. Best case of failure, it doesn't work. Worst case, something is altered and the effects aren't made apparent for years. For example, it might produce the correct protein now, but maybe down the line an overabundance causes immosuppression or worsens common cold symptoms to the point of being dangerous.",
"How could this danger be greater than COVID itself? ",
"The covid fatality rate is estimated 4 to 0.4 percent depending the region or study. If there is even a slight chance the vaccine could cause more damage than that, then the danger is greater."
] |
[
"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 vaccine doesn't just need to stimulate an immune response. It needs to stimulate the right immune response, one that is protective rather than pathological. There were people worried that a vaccine could lead to antibody-dependent enhancement with covid. There are so many ways that a vaccine could potentially increase pathology or mortality if the immune response is ineffective ",
" pathological. ",
"A poorly designed vaccine could also cause autoimmune disease if it generated a strong immune response that cross-reacted with self proteins. ",
"That's why we need data before saying \"Well, what harm could it do...\""
] |
[
"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 where your guts go. Except for some air in your guts, it's mostly filled with water which is not compressible. The abdominal cavity is surrounded by the abdominal muscles, when they contract they squeeze the cavity like a thick belt, this compresses the contents of the abdominal cavity, but since it can't compress much it expands upwards, putting pressure on the diaphragm and making it move upwards. Your body takes advantage of this when you sneeze to give the sneeze more force.",
"I guess if you sneezed enough it might strengthen the muscles, but you'd probably have to sneeze a huge amount..."
] |
[
"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 primary breathing muscle, the diaphragm, rather than \"accessory muscles\" that run between your ribs, from your ribs to your shoulders and collarbones, and from your shoulders and collarbones to your upper neck. You can feel this difference yourself right now without any effort, just do focus your breathing on your belly and then try focusing on your chest. It feels different and if you do it in front of a mirror you can see that your ribs move in different ways. "
] |
[
"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 static friction (stiction) and dynamic friction. Stiction is quite a bit higher. ",
"When you brake a rolling wheel, no matter how strong the brakes are, the force slowing down the vehicle is limited by the stiction between the wheel and the road. As soon as you lock the wheel, or spin it backwards, you are limited by the -lesser- friction. So to stop fast, the aim is to brake as hard as possible without actually locking the wheel. Hence anti-lock braking systems on cars, etc."
] |
[
"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 friction present if there's traction. That means that not only do you not have the ability to change the direction of motion if the wheels are not turning in the direction of motion, but also the force to slow down will be less."
] |
[
"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 stemming from the abundance of preferred food types.",
"http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1789883/"
] |
[
"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 have them. Fish have them. And insects do as well, although sometimes in odd places (like butterflies having them on their feet)."
] |
[
"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 architecture, which is clearer, stronger, more heat resistent and ofcourse, much more expensive than soda lime glass. Borosilicate glass transmits around 30% of the emitted light at 295 nm. So through borosilcate glass you will form vitamin D, but more slowly. "
] |
[
"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 quality, can be transparent even to vacuum UV wavelengths. Ordinary window glass passes about 90% of the light above 350 nm, but blocks over 90% of the light below 300 nm.",
"http://en.wikipedia.org/wiki/Ultraviolet#Subtypes",
" ",
"Of course, in a northern winter if you are far enough north the raw sunshine might not be strong enough anyway."
] |
[
"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 millennia? What's the general consensus?
|
[
"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, 2006",
" is relevant. In this, they suggest that metallogenic enrichment of the crust was either more efficient in the Archean or that post-Archean tectonic processes became more efficient at returning metallogenic elements to the mantle. So, aspects of the current conditions of Australia (e.g. the aridity) may make it easier to find mineral deposits, but the reason for their existence relate to fundamental changes in how tectonics and other processes operated during early Earth history as opposed to now."
] |
[
"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 indicator (though the original Kimberly is in South Africa of course). The shire’s ",
"coat of arms",
" makes it pretty clear that the naming was no accident ;)"
] |
[
"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 are just not economic. And those processes are rare, so the more land you have the more likely you are to find those concentrations. There's plenty if types of mineralisation we have none of. Also the country is generally extremely old, up to several billion years, especially the western half where the most of the resources activity is. I think this is good for some types of deposits but not others. A lot of mining activity takes place in other countries where there's been more recent geological or volcanic activity in the past, as I understand it. Australia's mountain ranges are all so old they are severely eroded and much lower than even New Zealand. Even our youngest and highest mountain range is only 6000 feet."
] |
[
"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 better.
|
[
"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 would be violated (I'm not well versed on the proof of this and there may be some other conditions here).",
"We have experimentally observed violations of C, P, CP, and now T symmetry. That is, systems behave differently from those obtained by applying the above transformations to them. T violation is expected since if CP is violated T has to also be violated to conserve CPT but the recent measurements make that explicit. So as far as we know CPT is still fine. ",
"CP violation can be viewed as matter antimatter asymmetry and so people are quite interested. Likewise T violation is interesting because it suggests some asymmetry in the direction of time. "
] |
[
"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 a second. Even heavier elements could live a bit long",
" (maybe several seconds, maybe even days - \"island of stability\"), it is not expected that there are elements with a long lifetime. Even if supernovae can produce elements beyond 118 (which is unclear on its own), they would probably decay quickly."
] |
[
"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 some serious questions to answer"
] |
[
"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 certainly cannot. What physicists refer to as measurement requires interaction. What happens during interaction between two particles is that they become a pair of entangled particles. Let's say you have a, A, particle that is in superposition of spinning A={UP ",
" DOWN}. Now let's say we make it interact with another particle, B, and they become entangled as the state AB = {UP, UP ",
" DOWN, DOWN}. So they're in a state of both spinning up ",
" both spinning down.",
"Let's say we ignored particle B and just looked at A. If we perform an experiment on A alone after it has become entangled with B we would discover that the state of A is now A = {UP ",
" DOWN} . What's interesting is that this particle no longer behaves like it's in superposition. It's in one state or the other, not both. It looks like it has been measured! But if we performed an experiment with both A and B we would see that they're not measured. Entanglement is strange. I could show the math, but I doubt it'd help.",
"During what we call a measurement A doesn't just become entangled with a single particle B, but entangled with the entire measurement apparatus and the surroundings through a process called decoherence. The measurement apparatus is not just one particle more than 10",
" particles. Like before, performing an experiment on just A will make A look like it has been measured. ",
"If you wanted to perform the experiment that showed A was not measured, you would have to perform an extremely complicated experiment on the entire measurement apparatus. That is way, way beyond our abilities, so we say that for all practical reasons, the particle has been measured. And some people even go as far as saying that because we can't show that A is entangled with the measurement apparatus, there is no entanglement. "
] |
[
"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 measurement on the other side has to be. Even stronger than that, for certain types of measurements on both sides, we know that entangled states have certain probabilities of outcomes that non-entangled ones do not exhibit. ",
"The test have been performed for the first time by Alain Aspect in the 70's, but many more tests of this kind have been performed since then and quantum mechanics has passed all the tests with flying colors."
] |
[
"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 measurement on the other side has to be. Even stronger than that, for certain types of measurements on both sides, we know that entangled states have certain probabilities of outcomes that non-entangled ones do not exhibit. ",
"The test have been performed for the first time by Alain Aspect in the 70's, but many more tests of this kind have been performed since then and quantum mechanics has passed all the tests with flying colors."
] |
[
"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 problem is in the brain then they can't, but if its just a case of the information not being sent properly by the eye, it might be different. For someone who cannot see red, for example, how far out from that colour does the blindness extend? Can they just not see colours between certain exact wavelengths, or would colours fade out and in? So for the person who can't see red, would colours nearby in the spectrum look different too; maybe yellow-oranges as normal, but orange starting to change from normal - a gradual loss of the colour.
|
[
"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 ",
"cerebral achromatopsia",
". Another brain related color problem is ",
"color agnosia",
" which is the ability to see colors but not recognize them as being a certain hue.",
"Be careful when thinking about color blindness as the inability to see a color though. Many people with red-green color blindness can see red and green perfectly fine, but are unable to visualize them in combinations such as with ",
"Ishihara plates",
". These people would easily be able to visualize red or green in their minds."
] |
[
"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. There is a retroviral treatment, which worked on two monkeys, but they are afraid to try it on humans. For the ordinary red-green colorblind guy, blue and purple may look similar, as may red, green, and brown. ",
"Web Site",
" converts images to make them look like what a color-blind person sees. "
] |
[
"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 message us so we can release it. Thanks!"
] |
[
"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 up random data but I'm finding here.
|
[
"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, and not even one of them fatal."
] |
[
"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 month ... youd need an army of propper trained medical investigators... sounds daunting."
] |
[
"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 out in men because it experiences a particularly fast burst of growth during puberty, which is also the reason their voice changes to a lower pitch during this time."
] |
[
"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 airspeed remains significant over the course of the fall. We fire a spherical bullet (with no spin) horizontally into still air. The equations of motion for drag are nonlinear, and the horizontal component of drag force is NOT decoupled from the vertical component. In this case, it turns out that a bullet fired horizontally falls ",
" than a bullet which is merely dropped."
] |
[
"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 an airplane. You would not experience any horizontal component to your jump even though you're going 300+mph relative to the ground. That's because the air you're in is also moving.",
"Interestingly, this is actually a major consideration for skydivers - we fall vertically through the air, but the air may be moving and so we will not fall vertically relative to the ground. The point at which leaving the airplane will mean you will drift over the landing area at the appropriate time is called \"the spot\", and a bad spot may mean you will land somewhere you didn't intend to land."
] |
[
"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 magnetic monopoles; but there are some very good reasons to look for theories beyond the Standard Model, and many of these do predict magnetic monopoles.",
"On the other hand, there are some very good reasons to believe that the conditions shortly after the Big Bang would have caused any magnetic monopoles to ",
"spread so far apart",
" that there could easily not be a single one in the entire observable Universe.",
"Whatever theories you adopt, there is no evidence for their existence. When things apparently don't exist, that tends to put a bit of a block on any potential applications."
] |
[
"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 also possible to create materials that act like magnetic monopoles, called spin ices."
] |
[
"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 dye having been left behind) and is thus colorless.",
"In other words, you've rediscovered a way to purify contaminated water."
] |
[
"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 some of the dye would vaporise along with the water steam). I think the first explaination applies for solid dye materials while the second is for liquid dye.\nPlease correct me if there is any flaw, as i mentioned this is an assumption based on my highschool chemistry knowledge. :) "
] |
[
"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 similarly coloured squares and pick the one that stands out. The documentary seems to imply that their language's method for identifying colours leads them to physically see colours in a different way. However, I am concerned that the question itself is too focused on Western expectations of the experiment. It seems to me that, depending on the wording of the question, the subjects may be able to physically tell the difference between the coloured squares. However, since they are being asked to select the square which has a distinct colour from the rest, they may be seeking to select the colour which would fall under a different category within their language, not their range of sight. Does anybody know what I'm talking about here? Is there some more professional publication of the experiment - say, in a peer reviewed or academic article - with which one could more closely examine how the experiment was carried out and the results? Thanks!
|
[
"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 imply is that because the subject knows both colours by the same name, it makes it physically more difficult for that person to spot the difference. My concern is that the subject may be confused by the wording of the question. Is it not possible that the subject identifies the \"blue\" square as being a different shade of \"zoozo\" from the \"green\" square right away, but spends time seeking for a colour other then \"zoozo\"? And that this delay is what the researchers take as evidence of how the Himba tribe identifies shades?",
"Note: This comment copied in another response, so that you'll both get \"new message\" alerts"
] |
[
"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 on time taken to choose the different hue correctly. ",
"Himba language does not differentiate blue from green, but does differentiate the yellower hue of green from green."
] |
[
"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 imply is that because the subject knows both colours by the same name, it makes it physically more difficult for that person to spot the difference. My concern is that the subject may be confused by the wording of the question. Is it not possible that the subject identifies the \"blue\" square as being a different shade of \"zoozo\" from the \"green\" square right away, but spends time seeking for a colour other then \"zoozo\"? And that this delay is what the researchers take as evidence of how the Himba tribe identifies shades?",
"Note: This comment copied in another response, so that you'll both get \"new message\" alerts"
] |
[
"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 will only be accepted or rejected after other groups either confirm our findings or overturn them'. An article, titled , was published in the 16 August 1996 of Science. (Unfortunately, I don't have access.) Then in 2000, NASA published this: . They said the new research 'strongly support[ed] the primitive life on Mars hypothesis of David McKay and coauthors in 1996'. From having personally worked with NASA scientists who were involved in recent Mars missions, they spoke openly about their belief that our evidence of primitive life on Mars was conclusive, and had progressed their research towards seeking the environmental factors that would allow such life to have developed. Despite all of this, a Google search suggests that the original research has – and that was fairly deep into a comment chain, and received only a single upvote. Is this research relatively unknown? If so, why? And if, as I suspect, there are very good reasons that these findings aren't more widely acknowledged, what are they?
|
[
"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 rejected the hypothesis once all the unusual features in the meteorite had been explained without requiring life to be present.\" "
] |
[
"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 as firm proof that anything ever lived on Mars. "
] |
[
"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 the exciting new data gets a huge amount of media coverage, and it quickly gets overblown to \"OMG NASA proves there's life on Mars!!!\" But the careful analysis that happens later which shows that data was misinterpreted is usually highly technical, and kind of a downer, so it doesn't get any news coverage. It's great that ",
"/u/hopkinsonf1",
" took the time to take another look at this story: very few people do. A related problem: because people tend to take the exciting initial report as truth but never hear about the disappointing followup, when we ",
" discover more evidence, the public thinks it's old news. \"Life on Mars? I thought we already found that 20 years ago.\"",
"2) NASA is not one thing. It really bothers me to hear \"NASA announces such-and-such\", especially when followed up with \"NASA denies such-and-such\", suggesting they're kinda schizophrenic. NASA has ten different research centers, each with tons of scientists looking at the same problem from different angles, plus it funds and collaborates with hundreds of universities and private research institutions around the US. Some of them may discover something interesting and put out a press release; then other scientists at another lab may find something that contradicts it. Sometimes NASA headquarters may make an official statement (as in the Mars asteroid case), but they're just amplifying what a research group found, and it doesn't mean it's the last word.",
"NASA is a community, and like all communities, it's made of many people with many different beliefs, saying many different things. We shouldn't treat it like it's one very smart person."
] |
[
"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 to the heart, it's flowing very smoothly."
] |
[
"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 it moves faster for a moment every time the heart pumps because the aorta does not absorb all of the energy. That's why arterial wounds can appear to 'spurt' blood."
] |
[
"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 deuteron (hydrogen-2), a positron, and a neutrino. Then the deuteron can capture a proton and become helium-3. And two helium-3 nuclei can react to form helium-4 plus two protons.",
"This is one possible series of reactions and decays which can happen in an astrophysical environment. It's part of the ",
"pp chain",
"."
] |
[
"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 particular, why do you ask? oh and if I could get a decent answer in the next 5 hours, that'd be nice. damn usgs isn't good for much. oh, and no tidal wave warning for west coast America? B.S. they are just leaving us to our own warning system, which was updated ~2 hours after the rest of the world was in a warning.
|
[
"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 worry about."
] |
[
"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 why they happen to your specific family members? From a research perspective we are beginning to understand more and more the genetics, heredity, childhood illnesses, previously unknown brain anomalies, etc that are associated with seizures. The problem is that there is a huge gap between where the research is and the clinical side of things. 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 start to try to determine what is causing the epilepsy. ",
"Using technology (MRI, fMRI, SPECT, Wada, MEG, scalp EEG, intracranial EEG, EEG with depth electrodes, Video EEG monitoring) we are getting really good at identifying exactly where in the brain the seizures originate for a given individual, and often times can surgically remove that area and drastically reduce the frequency and severity of a person's seizure disorder. ",
"There are no answers or cures",
"I'd agree that other than surgery there is no clear cure, but I think there are lots of answers. If you have more specific questions I'm happy to try and answer them."
] |
[
"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 trying to develop better medications that will stop people from having seizures, without having side effects. The thing is that right now most (nearly all) the medications that we have that are helpful in preventing seizures do so by in some way inhibiting a neurons likelihood of firing (this is a VERY oversimplified explanation). They don't actually fix what is causing the neurons to fire abnormally in the first place, they just stop it from happening. Most of the time there is some area of damaged brain tissue (cortical dysplasia, mesial temporal sclerosis, a cyst or tumor, etc) that is the area where the abnormal firing starts (called the epileptogenesis), and with better technology we're able to find these areas of damage that we weren't able to find before. The problem is even if we know where they're coming from, the medications we have can't just \"stop\" that area of the brain from firing abnormally. However, some medications are being tested that could theoretically \"target\" those specific areas, instead of just having an effect on the whole brain. Since the side effects of seizure drugs can be significant, we often have to use lower doses to avoid side effects, when a higher dose would be more helpful in stopping the seizure. If we could target just the area of epileptogenesis, then we could use higher doses without the side effects and have a better chance at stopping the seizures all together. Right now when I see a patient with seizures, it doesn't ",
" matter (sometimes it does, but not usually) where the seizure is coming from, since any medications I prescribe will effect the entire brain. Does that explain my train of thought a little better? I guess my point is that better research is needed on both sides of things, and we need to have better understanding of both the cause and the treatments.",
"This may be dumb, but when you say they can surgically remove an area of the brain, does this only include small areas or can it involve entire lobes? How would the brain cope with an entire area missing?",
"Sometimes we remove an entire hemisphere (half) of the brain. It all depends on what's causing the seizures. Usually the area of the brain where the seizures start is damaged, and it's not \"working brain tissue\". The things that brain region normally does are now being done by another area of the brain. So, we can surgically remove it without causing a ton of problems. Some surgeries come with more side effects than others, and we carefully explain the possible risks of surgery before a patient and their family makes that decision. When people have things like ",
"status epilepticus",
" it's often better to remove the damaged brain tissue even if it causes problems. In most cases, surgery isn't really an option because we aren't sure if the epileptogenesis is really damaged tissue or not, and we don't want to risk taking out functioning brain tissue. Or, if the damaged tissue is too close to a very important brain region, the surgeon won't do the surgery.",
"Surgery really isn't an option because although the seizures tend to originate in one place, they move to other areas of the brain.",
"It doesn't matter if they secondarily generalize, it only matters if they know where the seizures start and whether or not that's an area that can be removed. If you stop the seizure from starting, it won't go to other areas of the brain. Unfortunately, some people have seizures that start in more than one place in the brain, and often those people are not surgical candidates.",
"My sister is 9 years old, and she explains that her seizures feel like she's in a bad dream and she's scared. Why is this?",
"I don't usually like making comments about a particular patient over the internet, so I'll keep this pretty simple. A seizure is simply abnormal firing of neurons in a specific brain region. When the neurons fire in an area that controls motor movements, you see the movements (shaking) typically seen in seizures. For your sister, wherever her seizures are happening is causing her to experience a fear response. It's most likely a mesial temporal lobe epilepsy, but without more information this is just a guess.",
"My little brother has only had 4 seizures (this just started happening a couple of months ago) and he can \"sense\" when a seizure is about the happen and will typically sit or lie down and call for help before. Is this normal or common?",
"Yes, incredibly common. It's known as ",
"aura",
". Yes, generalized just means that the entire brain becomes involved in the abnormal firing of neurons.",
"There are so many TYPES of seizures, what makes seizures so different?Tonic-clonic, absent, complex partial?",
"Yes, there are. The classifications we use are really only a description of what happens during a seizure. Tonic/Clonic describes the movements, absence describes that the person appears \"absent\". You might find ",
"this",
" helpful. Partial just means that the seizure stays in one part of the brain, complex just means the person loses conscious awareness, etc etc. Those descriptions really don't tell you anything about where the seizure is coming from or why thy're having them in the first place. We don't classify them that way because there are SOOO many different reasons a person could be having seizures. ",
"Hope this helps. I wish you and your family all the best."
] |
[
"\"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 start to try to determine what is causing the epilepsy.\"",
"I'm not quite understanding this statement and your train of thought. 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? Do we have to develop better medications before trying to determine the cause of epilepsy? This just seems backwards to me. Understanding the problem typically help when developing treatment for it.",
"My younger sister have complex partial seizures with generalized tendencies. Surgery really isn't an option because although the seizures tend to originate in one place, they move to other areas of the brain. This may be dumb, but when you say they can surgically remove an area of the brain, does this only include small areas or can it involve entire lobes? How would the brain cope with an entire area missing?",
"My sister is 9 years old, and she explains that her seizures feel like she's in a bad dream and she's scared. Why is this?",
"My little brother has only had 4 seizures (this just started happening a couple of months ago) and he can \"sense\" when a seizure is about the happen and will typically sit or lie down and call for help before. Is this normal or common? His seizures are categorized as generalized and he will convulse and is really disoriented afterwards.",
"There are so many TYPES of seizures, what makes seizures so different?Tonic-clonic, absent, complex partial?",
"I know I have a lot of questions. If you could even point me towards some good resources?"
] |
[
"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 blood PH level that high? I've attempted to look into this, but I haven't found any reputable sources. There are sources like which say that blood PH levels as high as Hof claims to have can cause death. I've seen other sources saying alkalosis can have negative effects, but there doesn't seem to be much consistency among any of the information. EDIT: Here's the study:
|
[
"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 think of that may be somewhat dangerous (though really unlikely) is arrhythmias from it. ",
"edit: didn't really wanna write out all the side effects, so I just googled them for you. ",
"http://www.anaesthesiamcq.com/AcidBaseBook/ab6_4.php",
". This source says that the only major problem is that cerebral vasoconstriction may be an issue in sickle cell patients."
] |
[
"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 generates a positive increased charge in the neural membrane from inside. This is the reason for 'normal' firing. ",
"The respiratory alkalosis as mentioned above increases your pH. Because there is less of H+ ions (alkalinity) in the plasma around the nerve cell ; competition for the influx of Ca++ in the cell decreases so relatively more Ca++ enters cell. Secondly; as there are less H+ outside the cell; the cell membrane from outside becomes relatively negatively charged. While inside negativity decreases with very slight Ca++ influx causing ultimate decreased potential difference between outside and inside membrane which fires the trigger for impulse. ",
"I was in medschool some 10 years back and was pretty good at physiology. I think I remember this correct. I will review it and get back to you again in case I am wrong. \nCheers"
] |
[
"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, thank you very much. So basically, I understood that generating a triglycerid can be done by linking together a glycerol with three fatty acid-CoA. The first two can be done without further manipulation, giving a Phosphatidic Acid. Then, you need to remove the phosphate group on the third alcohol residue of the glycerol before adding the third fatty acid-CoA, giving you diacylglycerol first. And here is my problem, I'm using a review (Currie & al., Cellular Fatty Acid Metabolism and Cancer, Cell Press, 2013, 10.1016/j.cmet.2013.05.017) which focus on triglycerids and fatty acids. The main figure shows that diacylglycerol can either become a triglycerid by adding the third fatty acid-CoA or go to the pool of phospholipids of the cell. However, if I understood correctly, diacylglycerol IS NOT a phospholipid since it has lost its phosphate group. Can someone describe to me or give me a clear reference to understand what happens to diacylglycerol if it doesn't become a triglycerid ? Unfortunately I don't manage to find this answer by myself. Thank you very much.
|
[
"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 to see in which condition this pathway would be prefered, in which condition diacylglycerol kinase are activated to rephosphorylate diacylglycerol. And I found this at the beginning : ",
"",
"\"In this biosynthetic route, and contrary to the PI cycle, DAG is derived from PA through the enzyme PA phosphohydrolase in the endoplasmic reticulum. Conceivably, in this compartment DGK activity is absent or strictly suppressed to allow supply of DAG for phospholipid synthesis. \"",
"",
"How can DGK activity could be absent or suppressed \"to allow supply of DAG for phospholipid synthesis\" since DAG becomes again a phospholipid only if DGK is active ? I understand the fact that DGK cannot be activated everywhere but the end of the sentence means that I still miss something somewhere."
] |
[
"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 models for the future, and the consensus statistics of scientists agreement of climate change happening rapidly", but if you really think about it - none of those things give reasoning or logic as to WHY this is happening. They are just things that you see that show it is happening. I had one co-worker give me the classic argument, "well yea that chart shows the temperature is rising but that doesn't mean CO2 is causing it." Another statement I get when trying to explain, "The the scientists have may agree, but you know how many assumptions we have to make for models here [at work, engineering], imagine how many assumptions they have to input for the globes climate and atmosphere/ocean circulation. is climate change occuring due to CO2, Methane, Water vapor, etc...?? Do the molecules vibrate or hold vibration (temperature?) longer than simple air (O2, N2, etc etc)?? Is it because CO2 is more dense and therefore creates a denser environment which in turn holds the heat down on the surface easier?? Any insight is appreciated. I would like to be able to debate those without facts and actually be able to explain. If this takes further education/reading on my part, I'm not afraid to spend time learning. I hope my question makes sense. Any responses like "It happens because CO2 causes warming" obviously don't understand why I'm asking. I'm asking why that exists. This is my plea for logical understanding. Thanks in advanced for your help. is very helpful in addition to all of the other information below so far.
|
[
"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 with a neon lamp, which glows with a particular colour because it contains neon atoms which have been excited to a higher energy state (by passing an electric current through them). These excited energy states are not arbitrary, but have specific energies dictated by quantum mechanics. So when the atoms de-excite by releasing the extra energy as light, every atom releases the same amount of energy and so the light they emit always has the same colour.",
"Greenhouse gases are then those which undergo this same process but in reverse. They are gases with excited energy states corresponding to the energy carried by the infrared radiation emitted by the warm Earth. This means they can absorb some energy, trapping a portion of it inside the atmosphere and raising the temperature above that expected if all the infrared simply escaped into space. Increasing their concentration makes it more likely that the radiation is absorbed and trapped, thereby causing additional warming."
] |
[
"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 example, ",
"this",
" is the absorption spectrum of CO2 with the peak wavelengths of solar and terrestrial radiation indicated. Greenhouse gases tend to have lots of degrees of freedom that are possible to excite, for example the bonds in CO2 can vibrate (stretch or wiggle) and the molecule can rotate around itself in several ways. A single atom can only have its electrons excited, and diatomic molecules like N2 and O2 have less available vibrational and rotational states."
] |
[
"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.",
"The very first step is to assume that the earth absorbs all solar energy incident on it and radiates it outwards uniformly, ie that it is a black body. This results in a temperature a little lower than reality. Then you include albedo, the fraction of incoming radiation that the earth reflects. This actually cools the earth further, since less energy is actually being absorbed.",
"Finally, you include the atmosphere, which does several things. First, the atmosphere itself reflects some incoming radiation, however it is mostly transparent to solar radiation. It also absorbs some incoming radiation, heating itself, and then allows most radiation to go through and be absorbed by the Earth's surface. Then, the Earth's surface radiates energy outwards, and this is where the real greenhouse effect comes in. Since the earth is much cooler than the sun, the radiation it sends out is primarily infrared. This range is much more likely to be absorbed by greenhouse gases like CO2. Some of this radiation leaves the atmosphere, some is reflected back down, and a lot is absorbed. By the time the heat is ultimately released back into space, it has warmed the earth a significant amount.",
"In summary, greenhouse gases are mostly transparent to incoming solar radiation, so they let the energy in, but are opaque to outgoing thermal radiation, so they don't let energy out."
] |
[
"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 charged the car battery, the voltage of the D batteries would drop until eventually the entire system reaches equilibrium. Think of it this way: the force pushing current into the car battery from the D's is the same force you are building up the in the car battery. Eventually, you would equal out.",
"But you might not get that far.",
"Its pretty hard to properly match the impedance of batteries. This means the current draw from each of your D's will not be equal: in fact, there will probably be 1 that drains faster than the rest. ",
"This",
" is a simplified model of how a battery acts in a circuit, with the constant voltage slowly dropping as you gain charge. This discharge rate, as well as the resistances shown, is not matched for the D batteries, and is completely different than that of your car battery. Without any control circuitry to keep the current even from all the D batteries, one of the batteries could get overtax, overheat, or even explode. ",
"If the voltage potential of 1 of your batteries drops below the car battery, you could even get a back-flow condition, and if your batteries aren't rechargeable, the battery will probably overheat or explode.",
"So I definitely would NOT do that."
] |
[
"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 warming up as a consequence).",
"The major heat sources in space are the Sun and, if close to a planetary surface like Earth, albedo (reflected sunlight) and planetary infrared. Then there's radiation from the ",
"Cosmic Microwave Background",
", which is equivalent to the emissions of a black body at 2.7 °K (very approximate to the -270°C figure you're pointing out). In theory, an object in deep space, far away from the Sun or any planet, would reach this equilibrium temperature, given enough time to cool down.",
"But in practice the CMB means nothing, as the Sun and the Earth are dominant for most satellites. I'd say space has no temperature, we can only talk about the temperature of an object in space given its thermal environment and design of external surfaces.",
"Edit: clarity"
] |
[
"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 that energy, so has the minimum possible temperature, -273C. Others have pointed out that this isn’t the best way of saying it though, as a vacuum just wouldn’t really have a temperature.",
"However, put something in space, like a space ship or asteroid, and that thing won’t be at about -270C. Since there’s nothing to pass the heat too, things don’t lose that heat easily in space - if you were on earth you would freeze in -90C temperatures in moments, in space it might take hours and hours in space just to freeze (0C)",
"Stars pump out a bunch of heat as various radiation, so things in space might get warmer due to the suns heat (although internal activity, like machinery or body heat is a bigger problem for space craft).",
"So if we got all of space and all the temperatures of all the things in space, and shared that temperature energy out equally over all that space, the average temperature would be about -273C."
] |
[
"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 (absorption of electromagnetic energy).",
"Even completely empty vacuum with no matter and no radiation in it is filled with zero-point energy of the electromagnetic field."
] |
[
"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 cell would become more exitable. The added extracellular potasium could lower the driving force for potassium flow outwards wich would also result in a more exitable cell. Could anyone correct me if I'm wrong or provide the correct explanation? Thanks Clarification: I screwed up in the title, I meant a cold environment, not cold food.
|
[
"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 ions is lessened. ",
"Basically, sodium channel mutations in hyperkalemic periodic paralysis interfere with the inactivation of the muscle sodium currents - so after an action potential triggers a sodium current, the current does not inactivate as usual. ",
"Since that current is persistent and inward, there's a bout of periodic paralysis. The hyperkalemia simply increases the probability of the channel opening in the first place due to the change in excitability and membrane potential.",
"I don't have anything regarding the cold environment right now, but I'll try to come back to it."
] |
[
"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 driving force becomes less positive: (Vm-Ek): (for example)",
"before: (-70 --88)= +18",
"After (-70 --80)= +10",
"And so hyperpolarizing (and Vm stabalizing) K currents outwards would have less driving force so the Vm would be more depolarised and then the cell is more excitable. And the HKPP",
"Thanks for replying, this is all very plausible, now the cold... ",
"I have an exam on this stuff the day after tomorrow... While this isn't core material I'd still like to know."
] |
[
"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, the texture of the fruit softens, etc. The rate of these individual processes is dependent on a lot of things, mostly hormonal and environmental signals. Even small deviations in these processes caused by minute differences in the microenvironment of different berries can build up and slow down or speed up these processes in noticeable ways. Because life is imperfect, the exact same amount of hormone won't be delivered to every single berry. There may be minute temperature, light access, etc differences that also play a role."
] |
[
"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 be multiple days between pollination of one vs the other."
] |
[
"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 have bad luck."
] |
[
"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 superconductors was that they could move energy without resistance. How are these two concepts different?
|
[
"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 surface but not in the bulk. ",
"Superconductivity doesn't (afaik) make any claims about conductivity in the bulk vs. the surface. In superconductivity a material goes through a type of phase change that very nearly eliminates resistive heating due to electron flow (a simple mental picture is that the electrons flow around impurities instead of crashing into them). The quote about electric current dissipation is most likely saying that the conduction is high but I don't think they're implying some sort of phase change that occurs with superconductors. It's \"just\" a material where electron conduction happens only on the surface of the material."
] |
[
"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 total momentum can flow without dissipation because there are no excitations available to slow the net motion down. In contrast, it is the excitations at the surface of a TI which are carrying the current, and these cannot be slowed down by impurities because a certain symmetry (time-reversal invariance) prevents backscattering.",
"Another important distinction is that superconductivity comes with the Meissner effect, which expels all magnetic fields from the material. This is often what people use to distinguish it from \"just\" a perfect conductor. Also, after the external voltage is turned off, an SC would continue to conduct while the TI would stop conducting.",
"I'm also pretty sure the conductivity of the TI is not infinite like in an SC. IIRC, it should be something like the ",
"conductance quantum",
" (I think there are extra factors, but I'd need to re-familiarize myself with this stuff)."
] |
[
"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 difficult to work with because the cells must come from the specific part of the body they hope to replicate (you would need to harvest stem cells from a person's brain to create more neurons). For example, stem cells from bone marrow can become platelets, white blood cells or red blood cells but not skin cells. With embryonic stem cells you can't just go injecting them into people all willy-nilly like. If you did, it would most likely cause a tumor to grow. (I am not completely familiar with the process of growing the stem cells into specific cells to be transplanted.) Stem cells are truly wonderful and have the potential to cure and treat a variety of diseases and conditions. They are already widely established in bone marrow transplantation. ",
"Hopefully others can add on to the information I have provided. I figured it was a good starting point for the discussion."
] |
[
"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 cells based upon certain factors in the surrounding environment. The central issue is that if you're injecting stem cells of any variety into a tissue for regenerative purposes, you run the risk of causing the cell to differentiate incorrectly--see the wikipedia article on ",
"teratomas",
" (WARNING: Google image searches of teratoma, while SFW, may be NSF for life). As such, the goal with introducing stem cells to regenerate tissue is to figure out the right \"recipe\" for causing them to differentiate and integrate with the tissue in the correct way.",
"The reality of how this takes place is leagues more complex, however, and that's why the field is so challenging."
] |
[
"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 known about differentiation of human embryonic stem cells (hESCs) as well as the pluripotent adult stem cells. But it seems from research that the common consensus on pushing stem cells towards a certain cell line has to do with a whole plethora of factors. So far stem cell differentiation is thought to be initiated by environmental factors the cells are placed in. Putting it simply, sticking the cells into an area or environment similar to the cell you want it to turn into. This includes things like the space the cells are made the grow into, the temperature, the physical sheering of the cells. There is also a chemical aspect to it to, such as the amount and the type of proteins it has to be around (ie: collagen). So as you can see, simply putting stem cells into the brain won't cause it to specialize and form neurons that easily. But the idea is a stepping stone to figure out what really is going on. It really is quite fascinating right now with stem cell technology.",
"You can find out more about differentiation by looking up articles are articially created organs. First a physical scaffold of proteins are made in the shape of the organ. Then stem cells are applied to it. Next the scaffold is stuck into some sort of machine or contraption that simulates the environment its supposed to be. In the case of a heart, they stick valves on it and pump fluid through it to simulate a blood flow. They also shock it with electricity to at precise intervals to simulate the heart pumping. Its quite complicated."
] |
[
"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 physical explanation without doing deep into the theory?
|
[
"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 evolution is fairly intuitive just like ripples on a pond or EM waves, except you have \"particle\" like ideas like momentum, energy, etc defined as operators upon that wave equation.",
"Just as EM waves can actually pass through large wave impedance changes (albeit with significant reflection), quantum mechanical waves can pass through large potential barriers with significant \"reflections\". ",
"The position of particle as mentioned earlier is also some sort of operator upon the wave equation, but the weird part is that the operator actually gives you the probability density of the particle, not the position itself.",
"The whole probability thing is just a way of reconciling particle-like traditional behavior and the underlying quantum mechanical wave. In reality, the full behavior is always better described in terms of wave equations.",
"So to answer the current question of what's the intuitive explanation for quantum particles going through otherwise impassable potential barriers--they just do, because the whole concept of a particle is just a convenience, a way to simplify the actual underlying quantum mechanical behavior. The intuitive explanation for me is that any barrier presents some sort of change in the wave conditions, and whenever a boundary like that happens, you always get reflections, and you also get some wave passing through into the \"other side\" (if the other side supports the wave)."
] |
[
"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?",
"It's pretty simple to calculate. Take the heat cap of ocean water (~4000 J/kg K), multiply by the mass of the ocean (~10",
" kg), and put that under the energy produced in a year. ",
"Wikipedia gives 143 petawatthours for 2008, so I'll use that, ~10",
" J",
" (that last number is about 1/1000th of what the earth gets from the sun per year). The reason I'm using the global energy consumption number is simple- all the energy that we use ends up as heat eventually. If you burn coal to generate electricity, you're making heat. When that electricity gets to your lamp or your laptop, it does it's work and conservation of energy and entropy says it's gotta turn into heat. ",
"Answer: dT= 0.00025 K, so not a lot. "
] |
[
"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 a much larger factor."
] |
[
"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 was able to happen quickly because South Africa was a fairly difficult place to reach easily by the Europeans and the Dutch speaking majority of European settlers were surrounded by the English, Portuguese, and indigenous African population (Khoisan, mostly).",
"As the mass, global media came about, Afrikaans took on more English loanwords.",
"The same person in that thread asked specifically about Swiss and German dialects of German and if the media is merging those two together. This is where morphology took a funny turn: With higher (>99%) literacy and more text-based communication, spoken language is more of a ",
" thing, so your question can't simply be answered with, \"Well, divergence is decreasing or divergence is increasing.\" The languages continue to diverge due to cultural isolation, but some aspects are ",
"verging due to higher international communication— basic (conversational) communication continues to stand alone while more technical communication is merging.",
"What will the linguistic landscape look like in 100 years? It's impossible to tell, but it's highly unlikely we'll see, say, Swedish and Norwegian becoming closer because Swedish will be ",
". Instead, with globalized media and better education, we're more likely to see a greater understanding of foreign languages— the Swiss will still speak their own version of German while they ",
" German German as an alternative. We can see this with Scandinavian languages and English dialects: Norwegians just learn Danish and they communicate in their own native tongues respectively and they understand each other perfectly. With globalized and social media, Americans are fully capable to understand the English without changing the way they speak.",
"So will they eventually ",
"verge? Give it 1000 years and we'll see what happens. But as it is now, we're actually becoming more multilingual, which isn't doing much to slow the divergence of languages."
] |
[
"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 these three zones would be. I am just curious how.
|
[
"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). Assuming similar rates as on Earth, movement of plates could slowly (mm to cm per year) move portions of plates between these sides, but that's about it. That is not to say that active plate tectonics would not influence the climate of a hypothetical world. (",
").",
", on Earth, plate tectonics do have a variety of large impacts on climate, primarily through influences on atmospheric dynamics (i.e. disruption or change in air currents), atmospheric composition (i.e. regulating concentration of greenhouse gases), influences on ocean dynamics (i.e. changes in ocean currents), and influences on the albedo of the Earth. The majority of these interactions operate on long timescales (10",
" - 10",
" years), with the shorter timescale (10",
" - 10",
") climate variations mostly driven by orbital dynamics, i.e. ",
"Milankovitch Cycles",
", controlling the amount of solar radiation reaching the Earth (and its distribution across the surface). ",
" collisional plate boundaries which produce large mountain ranges can have several climatic implications. On a local/regional scale, depending on their orientation with respect to prevailing winds, they can create ",
"rain shadows",
" with relatively moist conditions on the windward side and arid conditions on the leeward side. More broadly, the development of large mountain ranges and orogenic plateaus can have relatively significant impacts on a host of regional to semi-global climate patterns, e.g. ",
"this paper exploring the role of the Tibetan plateau in climate, development of the East Asian Monsoon",
". At a truly global scale, the growth of large mountain ranges (and the accompanied exposure of lots of fresh rock) potentially drives increases in weathering rates and the draw down of CO2 in the atmosphere (leading to cooling), e.g. ",
"Berner et al, 1983",
" or ",
"Raymo & Ruddiman, 1992",
", however the efficacy of this mechanism remains debated, e.g. ",
"Willengbring & von Blanckenburg, 2010",
". ",
"Outside of collisional tectonics, volcanoes have an important contribution to climate as well, however it is complicated as intense periods of volcanism (or single, very large eruptions) can cause both ",
"global cooling via injection of aerosols / sulfur compounds into the atmosphere or global warming by contributing greenhouse gases",
". Specifically, large scale, explosive eruptions can lead to short term cooling via ",
"volcanic winters",
", but volcanoes (especially globally extensive eruptive systems like mid-ocean ridges) are an important natural source of CO2, and thus background concentration of CO2 (in the absence of anthropogenic influences) is strongly controlled by the rate of volcanism, e.g. ",
"Marty & Tolstikhin, 1998",
".",
"The movement of plates in general can also have important impacts on global climate. Changes in ocean currents, from the opening and closing of oceanic gateways / changing the shape of ocean basins via plate movement can have pretty profound climatic impacts. For example, the onset of Northern Hemisphere glaciation has been attributed to a major change in ocean circulation driven by the formation of the isthmus of Panama, e.g. ",
"Bartoli et al, 2005",
". Similarly, the distribution of continents can have important implications for global climate as the presence or absence of large landmasses at / near the poles can control whether large continental ice sheets can form (i.e. no land, no ice sheets, only sea ice if the climate is cool enough). The presence of large ice sheets can be important in the ",
"ice-albedo feedback",
" whereby large bodies of long-lasting ice have a higher albedo, reflecting more solar radiation, leading to more cooling, leading to more ice, etc.",
"Finally, you might be interested in ",
"this",
", basically some NASA scientists messing around with a global climate model to imagine climate on an exoplanet."
] |
[
"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. Hope your planet has a strong magnetic field and that your technology isnt solid state, because shits getting fried. Life will have adapted to deal with this. Maybe tech harvests energy from em induction due to flares? Lots of cool stuff you can do with this.",
"-unless you have massive oceans with strong currents pushing warm water onto the night side to keep it temperate, the night side will be like a permanent antarctic winter. And if you have glaciation with no vaporization, the day side is going to get dryer and dryer and dryer as more water gets locked up in the ice cap on the night side. I dont know what time scales youd be looking at but you might have a dying civilization on your hands thats facing massive desertification of their once arable homeland. In addition, because your day side is temperate and your night side is frigid, the twilight area will be pretty consistently racked with strong winds and storms, cold snaps and heat waves."
] |
[
"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 ",
" standard model Higgs is ruled out within a year or two from now. We may find or reject more complicated Higgs models, or find evidence that supports Higgsless models."
] |
[
"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 that your well-developed muscles can be seen underneath. "
] |
[
"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 class. He has really low body fat, showing lots of muscle, and is a very good lifter. He has set several american records in his weight class: ",
"http://imgur.com/mP5FcvC"
] |
[
"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... Cutting the BF definitely robs them of strength."
] |
[
"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 think they do. With other organs, you do not have control over them anyway so they function just how they normally would because of receptors and feedback loops through spinal cord. With Cranial 3 and above cord transections, the diaphragmatic innervation and nerve control of muscles of respiration is lost so people will require mechanical ventilation.",
"The interesting thing is that the body still perceives noxious stimuli and feedbacks it as abnormal response with compensation above and below the level of injury. With injuries to Thoracic 6 and above a patient may suffer from Autonomic Dysreflexia, where a noxious stimuli below level of injury causes vasoconstriction and sweating with sympathetic response above with hypertension, pounding headache, stuffy sinuses."
] |
[
"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 brain is used for more advanced functions such as reasoning, language, image processing (seeing through the eyes), audio processing (hearing), motor skills, etc."
] |
[
"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 the failure of a structure after an aftershock would be catastrophic; more than likely it would be localized to particular floors or could just result in a leaning building. ",
"That being said, the factor of safety in these structures is likely fairly high, so i wouldn't be too concerned about sudden collapse after an aftershock. If another large earthquake comes however, some structures may not be able to handle the damage. This was an issue for some structures in Christchurch- they had a large quake several months ago and when the most recent one happened, some of the structures had not been fully repaired and subsequently collapsed."
] |
[
"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, leading to more failures. The fact that some structures may have been temporarily structurally compromised for the sake of repairs may have also played a role."
] |
[
"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 distinctive facial movement called the flehmen response to direct inhaled compounds to this organ. The animal will lift its head after finding the odorant, wrinkle its nose while lifting its lips, and cease to breathe momentarily. Flehmen behavior is associated with “anatomical specialization”, and animals that present flehmen behavior have incisive papilla and ducts, which connect the oral cavity to the VNO, that are found behind their teeth. However, horses are the exception, they exhibit Flehmen response but do not have an incisive duct communication between the nasal and the oral cavity.",
"You will notice that the animals which have these ridges are all animals that have a Jacobson's organ and use their Jacobson's organ by deeply inhaling and curling the lips."
] |
[
"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 controller. Some of the better designed smart chargers actually cycle your battery gently (which is good for the battery), but others are kind of dumb and just let them \"trickle charge\" (this is when the charger just gives it enough juice to overcome the battery's internal discharging).",
"Trickle charge is very useful when you're leaving a battery in the charger for a little past its charging time; it'll keep the battery topped off in a responsible manner. However, it's not good for the long-term, because the battery needs to be cycled to keep its chemistry active.",
"Since you don't know how smart the device charging your battery is, ",
". If you're talking about a laptop, unplug it for a bit and let it dip down to 70% or 50%, even if you don't \"need\" to use the battery. This will keep your battery alive as long as possible. Leaving the laptop in charge mode all the time will [usually; again, this depends on the design of the charging circuit] kill the battery faster.",
" it's strictly ",
" to leave your Li-ion battery at a constant cell voltage of 3.9V. My point is that many Li-ion chargers are \"dumb\" and will leave your battery close to its max cell voltage of 4.2V. Since you don't know whether your charger is smart or dumb, allowing gentle daily charge cycling will keep your cell in the 3.8 - 4.0V range, which is better than leaving it permanently near 4.2V. Too much cycling too often will kill your battery faster, and no cycling with a constant cell voltage of 4.2V will also kill your battery. I advocate gentle & shallow cycling for the strict purpose of keeping your cell voltage as close to 3.9V as possible while also minimizing the amount of charge entering or leaving the cell."
] |
[
"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 sensitive to overcharge - both of which are not true of nickel-cadmium and nickel metal hydride batteries. So while a cheap charger can trickle charge a nicad battery, you would never see this on even a cheap lithium ion charger.",
"Lithium ion (laptop batteries) and lithium polymer (cell phone batteries) are extremely sensitive to overcharge. Even a mild overcharge can lead to electrolytic breakdown resulting in permanent damage to the cell, and if it's continued it will lead to out-gassing and potentially a fire.",
"See:\n",
"http://batteryuniversity.com/learn/article/charging_lithium_ion_batteries",
"The Li‑ion charger is a voltage-limiting device that is similar to the \nlead acid system. The difference lies in a higher voltage per cell, \ntighter voltage tolerance and the absence of trickle or float charge \nat full charge. While lead acid offers some flexibility in terms of \nvoltage cut‑off, manufacturers of Li‑ion cells are very strict on the \ncorrect setting because Li-ion cannot accept overcharge. ",
"Li-ion is a “clean” system and only takes what it can absorb. \nAnything extra causes stress."
] |
[
"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 during the trickle charge (sorry, \"constant voltage charging\") stage (the charging current decreases as the battery cell voltage approaches its 100% SOC value).",
"Our disagreement is one of terminology; \"trickle charge\" is used for the constant-current charging of NiCad and lead-acid batteries. With Li-ion batteries, it's not called \"trickle charge\", but it's still constant-voltage charging, which will make up for the internal discharge of the battery--this is simply the Li-ion analogue to NiCad \"trickle charge\", which is why I called it \"trickle charge\" above. Your source confirms this; that's what's meant by \"the Li-ion charger is a voltage-limiting device.\"",
"Please see \"Battery Charging\" by Chester Simpson at National Semiconductor for more information; it directly confirms what I've said.",
"Edit: regardless of terminology, light charge cycling of Li-ion batteries is still important for their longevity, and leaving the battery in the charger (again, unless it's a very smart charger) doesn't allow for cycling. My primary point is that you can't be certain exactly what your laptop or phone's charger is doing, so you should allow the device to discharge slightly every day."
] |
[
"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 a very eccentric orbit suggesting it was a captured Kuiper Belt object."
] |
[
"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 and Y do not cross over. But ",
"small areas",
" apparently do."
] |
[
"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 and Y do not cross over. But ",
"small areas",
" apparently do."
] |
[
"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 fairly random, and so each recombinant chromosome in each gamete is different. Now, the SEX chromosomes are weird. X can cross over in your mother, who has two X. Males always have XY barring some genetic condition. Youd think Y never crosses over, right? I did too! But at the tips of both sex chromosomes is something called the psudeoautosomal region. The X and Y cross over here and ONLY here, as opposed to the normal chromosomes crossing over in far more varied ways.",
"So yes! All human chromosomes are recombinant! This was fun to read up on!"
] |
[
"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 estrus at the same time is beneficial for the population for many reasons ranging from male notification to herd activity patterns. 2) Pregnancy may be easier during certain times of the year. 3) Predator concerns may be varied by time. 4) Resources may be more available for progeny during a certain time of year. There are likely more evolutionary pressures, but these are just the ones off the top of my head. ",
"Second question: From the Wikipedia:\n \"It is often assumed that animals do not have sex for pleasure, or alternatively that humans, pigs (and perhaps dolphins and one or two species of primate) are the only species that do. This is sometimes stated as \"animals mate only for reproduction\". This view is considered a misconception by some scholars. Jonathan Balcombe argues that the prevalence of non-reproductive sexual behavior in certain species suggests that sexual stimulation is pleasurable. He also points to the presence of the clitoris in some female mammals, and evidence for female orgasm in primates. On the other hand, it is impossible to know the subjective feelings of animals, and the notion that non-human animals experience emotions similar to humans is a contentious subject.\"",
"Fair point... we can't ask them why they're having sex so we don't know for a fact that they're 'having sex for pleasure' or not. We can say that not all sexual activity among animals results in offspring, for what it's worth. "
] |
[
"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 around the first moving object you see after you're born\"",
". The releasing mechanisms may be consistent enough from one generation to the next that the resulting behaviors look the same, but sometimes they can be dissociated from the actual adaptive benefit of the behavior, e.g. instead of Mother Goose, little goslings hatched in an incubator might follow around ",
"a bearded Austrian racist",
".",
"Closer to my expertise, but maybe a little too specific, ",
"a somewhat recent paper in Cell",
" found that not only could particular sex-specific mouse behaviors be mapped to certain genes, but it only took one gene to knock out each particular behavior. That's fairly surprising because you'd expect it would at least be more complicated and ",
"polygenic",
"."
] |
[
"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 finely tuned interplay of all those genes.",
"Well, I don't know if you've ever taken a close look a kidneys, but kidneys are pretty damn complicated if you look at their tissue structure. As is the brain. But I guess it's easier for people to accept that the blueprint for kidneys can be coded genetically. ",
"If the blueprint for a brain can be coded in the genome, then why can't behaviors be? Behaviors are just a series of muscle contractions, in reaction to visual, aural, and tactile stimuli, when you break it down. How an animal reacts to stimuli is dictated by the structure and connections of the brain, which in turn is built according to the genetics of the animal."
] |
[
"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 atmosphere won't vary enough to matter. "
] |
[
"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 nitrogen atom are still gonna be damn good. "
] |
[
"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. The waterlogging of the wood causes structural changes, followed by the collapse of the material when the water leaves. This is why conservation is so vital for waterlogged wood from an archaeological site.",
"Keep wood in good environmental conditions, and it can last for a very long time, as you've noticed.",
"Other organics can survive as well, if given the right conditions. Leather and bone can both survive in good shape for centuries, if proper conditions are met. Organics (of many kinds, including textiles) are frequently found on shipwrecks, especially where they've been buried in mud. This is because they reach an equilibrium with their environment, and because no microorganisms are eating them (the mud prevents oxygen from reaching the artifact).",
"When ",
" in the right conditions, organics are frequently eaten by animals or microorganisms, in addition to the physical weathering processes."
] |
[
"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 packed lignin and cellulose, however, they may concentrate cellular byproducts in the stems. What I'm getting at is that the densely packed cellulose is what helps preserve the structure and resist decay, however, the heartwood will take quite a bit longer to decompose if left out in the elements than lets say, last year's annual shrub."
] |
[
"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 molecules are branched chains, whereas cellulose chains are linear. That allows the cellulose molecules to get close to each other and pack together into tight, indigestible bundles.",
"No 'higher' organisms (to my knowledge) have the ability to digest it. But some bacteria and fungi can, so the animals who eat grass and hay and such (cows, horses, rabbits) survive by having bacteria in their guts that digest the cellulose down for them.",
"Same goes for lignin - a big branched network that's indigestible to all but bacteria and some fungi. It's even difficult to turn it into useful chemicals in the lab. A lot of research going into that though, since it's produced in huge quantities as a byproduct of paper manufacture (lignin is what turns paper yellow, and is undesirable). Today it's usually burned to power the process, which is easily the least-valuable 'product' you could get from it."
] |
[
"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 more general info see here:\n",
"https://en.wikipedia.org/wiki/4_Vesta#Physical_characteristics"
] |
[
"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 shape under high rotational velocity. ",
"The gases of a giant like Jupiter may have a smoother bulge, but the effects of rotation are still present. At the equator, its rotational velocity is about 45,000 km/hr, compared to 1,670 km/hr at the earths equator. The gravitational pull on the nominal 'surface' of Jupiter is about 25 m/s",
" or roughly 2.5 times that of Earth. So the rotational effect on Jupiter's equator will be much greater than here on Earth. ",
"That force goes like (v",
" where v is the rotational velocity and R is the radius, and that force ",
" the equator away from its center of mass. So taking away that force, by reducing velocity, causes the material at the equator is fall back a little closer to the center of mass. ",
"You may find this ",
"wiki page",
" helpful. In particular, the table under the section \"Other celestial bodies.\"",
"The effect on Earth is about 1:300, while the effect on Jupiter is about 1:14. "
] |
[
"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 Economy Photo Paper, and we used a Home Depot Tough Basics caliper for the measurement. Along the symmetry in the poles the planet's image measured 100mm at peak, while along the symmetry of the equator the planet measured 107mm at peak. Therefore the data shows we have a 1.07 ratio of poles to dimensions which confirms the thesis. ",
"Authors: Snuggly Wuggly Puff the Teddy Bear, Buddy the Dog, Radiatin",
"Contributing Researchers: Radiatin's Mom (Thanks mom!)",
"This kind of paper needs publishing!"
] |
[
"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 diameter at the poles is about 94% the diameter at the equator. ",
"Unless someone tells me otherwise, it seems like this sort of visual observation is the ",
" of claims about the equatorial bulge of Jupiter. ",
"I'll do some more digging. I may just be bad at researching right now. ",
"edit: more photos. these from Hubble",
" ",
"Edit 2: even NASA's fact sheet on Jupiter doesn't point to peer-reviewed work. It's an endless loop of the internet referencing itself. Someone save me. ",
"Edit 3: the main wiki page for Jupiter references ",
"this paper",
" for its measured radius, and literally ",
" a source for the flattening of 6.5%",
"That paper only claims the radius of Jupiter in Table 4 on page 23, which you ",
" use to show its flatness. However, it doesn't source any published measurements for those number, and states \"the mean radii in tables 4, ... are from the original authors and have not been computed from the other radii ....\"",
"It later says \"The uncertainties in the values for the radii and axes in Tables 4 and 5 are generally those of the authors, and, as such, frequently have different meanings. Sometimes they are standard errors of a particular data set, sometimes simply an estimate or expression of confidence. The radii and axes of the large gaseous planets, Jupiter, Saturn, Uranus, and Neptune in Table 4 refer to a one-bar-pressure surface.\"",
"This seems to indicate that this report represents the ",
" published reference by the various authors to their radii results, probably determined internally and then justified to the rest of the authors before included in the paper. It also implies that they ",
" the radii to a one-bar-pressure surface instead of measure, but I could be wrong--maybe it's from data collected by the probes. ",
"It's baffling to me that I've spent this long searching and have not found a single primary source that claims direct measurement/observation of the radius of Jupiter, notwithstanding one that elaborates on their methodology for determining that value. "
] |
[
"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 inside a scientific calculator and inside an iPhone are pretty similar: both use electrons moving through circuits to process an input and give an output. Both are \"computers\": they compute an output based on the input. The \"quantum computer\" bought is a machine that uses quantum mechanics to compute solutions to specific problems. The \"quantum computer\" you're thinking of is the fancier, more versatile big brother. That's not to say that NASA and Google wasted money on their joint venture, they have demonstrated that for the problems it's supposed to solve, the new guy is faster than a traditional computer."
] |
[
"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 incompatibility (mechanical isolation)."
] |
[
"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 am wondering if fusion reactors are something that we can definitely make it is just a matter of figuring out the technology... Or if it's something that hypothetically can totally exist (thermonuclear bombs work, after all) but scientists are still unsure if the constraints of 'a continuous reaction that gives off more energy than it requires' can be reasonably met. A sort of parallel idea here to illustrate what I'm talking about: we know that small flying vehicles (ie: flying cars) can totally exist, but that they are totally impractical as a solution that everyone will use to get around. EDIT: Thanks so so much for all the amazing answers! I guess we'll see in the next decade of these things can work as an energy source at scale
|
[
"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 it can propagate due to the stress the material was already under from the propagating temperature change. This is why it cracks suddenly. ",
"A good example is putting a pin in a balloon. The air doesn't slowly leak out of a pin sized hole but rips the balloon apart because there is now a stress concentration around the hole, where before the tension was distributed in a balanced way."
] |
[
"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 matter that falls through the event horizon, of course, vanishes, but before it does it gains an astonishing amount of energy from its fall, and interacts like crazy with all the other similarly intensely energetic infalling matter.",
"Most matter in the universe carries electric charge, and whenever charges move, magnetic effects appear. So a black hole, surrounded by a large collection of inwardly spiraling charged matter, is surrounded by an intense magnetic field. This magnetic field influences the way the charged matter moves, which can result in \"jets\" of matter being ejected from the magnetic poles — not matter that fell ",
" the black hole; that, again, vanishes. But matter that passed ",
" the black hole's event horizon, relatively speaking, and gained a great deal of kinetic energy in the process.",
"The matter that flies away from the black hole in this fashion is, again, highly energetic. Highly energetic matter emits light. If the jet of matter is oriented toward the observer — us, basically — at a shallow angle, it can ",
" that light from near the black hole reached us sooner than it should have, which implies that some sort of superluminality is happening.",
"But what's really going on is that the ejected matter is emitting light all the time, not just when it's close to the black hole. So what looks like superluminality is really just a trick of the light — "
] |
[
"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 say if person has increased likelihood of some diseases (e.g. he/she will undoubtably have cancer or heart problems at later stages in life).",
"To complicate matters even further, we know that some types interventions can alter the process of aging. For example, caloric restriction is probably the most famous intervention. In pretty much all animals (with possible exception of primates) it increases mean, median and maximum lifespans by significant percent. Now, in case of primates there were two experiments started in 80's one of them suggest that CR does increase lifespan, another suggest there is no increase in median and mean lifespans but both experiments suggest decreased risk of old-age diseases (cancer, diabetes, heart diseases, etc.)"
] |
[
"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, and the truth is probably the same: both influence just about everything about you. Compounding the issue even more is that certain genes are only activated by an environmental trigger, which only further connects the two.",
"In theory, if you knew all there is to know about a person's genetic code, as well as everything that person has ever experienced in his or her environment, you could accurately predict that person's lifespan. In practice, it's essentially impossible because there are far too many variables (and those variables influence each other, too)."
] |
[
"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 life, if those are the metrics you want to use, and also very long telomeres tend to come with an increased likelihood of developing cancer. It's a little hard to separate cancer and aging, unfortunately."
] |
[
"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 of the summer in Virginia to the point where I wouldn't sweat so much? Or is this more tied into your DNA? I'd assume this would likely take more than a couple months if true? I work at a historical plantation and I wondered whether those that lived before AC in the 1700-1800s, and all historical civs, dealt with such heat. Was their bodies more accumulated to the climate? Hopefully, I'm wording this question right. A few drinks might have derailed it slightly, but hopefully you'll get the gist. Thanks.
|
[
"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 person moves to a hotter environment, their hypothalamus (in charge of most things having to do with thermoregulation of your body), goes, \"oh! the body temperature is running too hot! [not an outright fever]. I should vasodilate those cutaneous blood vessels some more.\"",
"But not quite at that speed. Your hypothalamus is slightly retarded so it takes maybe 7-10 days for it to work through the calculations needed to come to the conclusion that maybe it should vasodilate those cutaneous blood vessels some more.",
"As an interesting corollary to this... the way that cutaneous vasodilation leads to heat loss is via ",
"radiation",
". When the external air temperature is less than ~35C, radiation accounts for about 2/3 of heat dissipation by your body.",
"The other 1/3 is evaporative losses (hooray for sweating!) - as water has a positive ",
"enthalpy of evaporation",
".",
"As external temperature increases above 35C though, heat transfer to the external environment via thermal radiation becomes ineffective; in fact, thermal radiation will drop to 0% of heat transfer to the external environment once external air temperature is equal to body temperature (~37C). ",
"At this point, the only way your body has to dissipate extra heat is via evaporation (sweating!). However, as the air gets more and more humid, the equilibrium between the liquid water created in your sweat glands and the gaseous water in the atmosphere gets a little too one-sided, and as a result evaporation slows down and your body can't effectively cool itself through evaporation any more. As a result, the sweat just drips off you (this is wasted water! as sweat can only dissipate heat if it evaporates).",
"At this point, you're fucked. This is why temperature greater than 35C and high humidity are the most dangerous conditions for developing heat stroke - they completely overwhelm your bodies ability to dissipate extra heat.",
"The only solution to this is to try and dissipate extra heat via either convection (heat transfer via air blowing across the surface of your skin - convective losses are proportionate to the square root of wind speed - the faster the fan, the more heat you dissipate), or via conduction (put that cold beer in your armpit, and transfer heat via direct contact).",
"Anyways, that was a huge digression from your question, but heat injuries and physiology are fun - nothing is more awesome than when thermodynamics meets medicine. "
] |
[
"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 some knowledge on this?"
] |
[
"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 of both is similar and macromolecular structure is compatible.",
"Edit: to all those comparing this to hot / cold water, there is minimal difference in density there. For everyone talking about surface tension - yes, I'm sure there is some effect but it's not the major one. Finally, there is a coil in the bottom to distribute heat and direct the flow of wax. It's not there to break surface tension."
] |
[
"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 fusion, or paperclip sinking, is more stable, there is a barrier to the transition. Since the wax blobs are fluid themselves, they can't concentrate pressure at all, thus they may frequently fail to flow together just from that tiny film of water. "
] |
[
"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 liquid nitrogen, expand it back out to some ambient pressure and it will condense into liquid helium."
] |
[
"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 coldest behind. ",
"In this way you can isolate only the coolest members of a material resulting in a lower temperature than the bulk material.",
"There is a really good Nova 2 parter about this called The Conquest of Cold. ",
"http://www.pbs.org/wgbh/nova/tech/conquest-of-cold.html"
] |
[
"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 properties within the PV=nRT gas laws. If you change one side, the other side will change as well to maintain equilibrium. To get the extreme cold temperatures, you'd heavily compress the gas, which will increase the temperature, then cool it down to a reasonable temperature like room temp, and once you expand it out, it will heavily cool down. "
] |
[
"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 3-5 meters in such material, you will be safe from cosmic rays. In fact, people have suggested ",
"using asteroids as transport to Mars",
" because the asteroid would be effective shielding."
] |
[
"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 radiation areas on Earth, but the sheer mass for that level of mitigation was considered practical only because it involved first building a lunar mass driver to launch material.",
"Phobos' density is ~1800 kg/m",
". A three-meter thickness of its material will provide over 5 metric tons per square meter. There's the issue that shielding made from lighter elements (especially hydrogen) is better protection from cosmic rays than that made from heavy elements like metals, because it is less likely to produce secondary particle showers. Ice, since it's H",
"0, contains a decent amount of hydrogen and makes pretty good shielding.",
"3-5 meters is a rough ballpark; the exact number will depend on the specific composition of Phobos and how rigorously you want to shield people from cosmic rays. Either way, the difference between tunneling 2 meters into Phobos' surface and tunneling 10 meters into its surface isn't that great; the biggest issue is that you have to get heavy mining equipment to Phobos."
] |
[
"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 would be cool. "
] |
[
"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 altitude (though the galaxy is a special case), but the speed of light is almost 300000 km/s so the difference is several orders of magnitude."
] |
[
"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 necessary to get some stability."
] |
[
"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 explanations would be helpful. Could we use this information to create better heat-retaining/dissipating clothing?
|
[
"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 internal temperature."
] |
[
"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",
"Cabin air receives metabolic heat from the humans on board, which includes the latent heat of exhaled water \nvapor, and evaporated perspiration. The average metabolic heat generation rate per person is 136.7 watts (467 \nBtu per hour or 11,200 Btu per day) for normal activity.13 This average rate is comparable to the instantaneous \nnominal metabolic heat generation rates for light to medium workloads, 450 to 550 Btu per hour per person. \nThe average heat generation by a comfortable, sedentary person is about 70 watts (240 Btu per hour).12 Cabin \nair receives sensible heat from avionics and other electrical equipment in the habitable areas of the vehicle. \nAdditional sensible heat can be transferred to or from the cabin air through the vehicle’s pressure shell, \ndepending on the flight profile and vehicle design. In the cabin of commercial airplanes, a supply of about 1.4 \npounds per minute per person of conditioned air is necessary to maintain a comfortable temperature.12",
"The original reference is a NASA document on life support, but I couldn't find a link to the text. Might be dead-tree only."
] |
[
"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 gaining or losing weight, you spend what you consume. so roughly 2000 kilocalories a day. I would saw less than 10% of human energy is spent on useful work on a given day. Obviously lance armstrong would disagree (plus it is probably 6000 kilocalories for him when racing), but for you or I it is all heat.",
"It also varies by activity level, but basically it is just over 100 watts for daytime low activity.",
"(2000 kilocalories) / (1 day) = 96.8518519 watts",
"Also, I remember hearing this years ago, and I have nothing to back it up, but I believe a big auditorium is designed to accomodate about 120 W / person for HVAC."
] |
[
"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 reproduce, and the quicker they reproduce, the quicker there is more food. While heart rate seems to be a direct answer, it is only so for closed circulatory animals (not arthropods). So essentially, smaller animals are evolutionarily programmed to reproduces efficiently and die quickly (which actually also makes more room for advantageous mutational changes)."
] |
[
"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 are nuking the site from orbit. ",
"Ethanol burns partly because you're losing a few cells and partly because it triggers the same ",
"VR-1",
" heat receptors as spicy food.",
"For small wounds you usually ",
"aren't really supposed to use disinfectants much.",
" Cuts and scrapes should be ",
"carefully washed with clean water.",
" This is how I was trained as an EMT. If you really need topical disinfectants then they will probably be applied by a doctor or a nurse."
] |
[
"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 you from using it. For one thing, there is no specific phenomenon that can properly be called a single \"brainwave\". ",
"Well, now that we've gotten that out of the way, on to your question. Can we alter the electrical activity of the brain through the skull? Yes we can. ",
"One common technique for doing this is ",
"transcranial magnetic stimulation",
", or TMS. TMS works by passing current through a loop to create a temporary magnetic field. A magnetic field that changes over time will induce a current, so by turning the magnet on and off very quickly we can generate a current in the brain tissue just underneath the coil. Depending on how the TMS coil is pulsed, it can be used to temporarily activate neurons, or to temporarily disrupt them. For instance, if you send a single pulse over the motor cortex, you can see individual muscles twitch. ",
"Another technique is ",
"transcranial direct current stimulation",
" or tDCS which simply delivers direct current to the scalp. ",
"All of these techniques are rather crude in that it is difficult to contain stimulation to a very specific area of the brain or to be sure of the exact effect you will have on the neural circuits. "
] |
[
"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 device to draw more power without tripping breakers? Thanks!
|
[
"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, you end up with a short.",
"Also, you have to think about whether all the outlets are on the same circuit. If you want to draw more than one circuit can supply, you need to make sure you actually connect to multiple circuits."
] |
[
"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 dangerously low levels, could we bring a team of conservationists onto a beach to oversee and protect hatchlings and chase away birds and other predators, etc? The number of hatchlings that make it to the water would be huge then. I know that there are many predators in the water as well, but is this a viable option?
|
[
"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, hence the +).",
"These conservation tactics lead to a lot of problems for the fish. First of all, a lot of genetic information is lost. Then, these fish compete with the wild fish for food and may completely destroy the last few remnants of wild fish. Also, migratory fish who are produced from hatcheries are less successful spawners, but they still go to spawning grounds and compete with wild fish so yet again there is a risk of destroying the small remnants that remain of the wild population. ",
"In short; protecting a species by reducing predation and increasing human protection for the first few years is a bad idea. You should only do this if it is the last remaining option. Kind of like taking a pain-killer if you have broken your leg; it's not going to get better even if you stop the first alarming symptom. ",
"(I'm working on a PhD thesis in this area, could provide you with a looong list of references, but this is the internet and I'm lazy)"
] |
[
"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 strong. If you \"help\" by increasing survival, you make the entire species weaker."
] |
[
"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 relationship that maintains a certain balance. Of course these relationships may be thrown out of balance, but on the whole they remain stable over long periods of time. So natural predation, or \"background predation levels\" are not really the problem. For many turtles the real and significant problems come from humans. We add on to the \"background predation levels\" by harvesting eggs, hunting adult turtles or through by-catch fisheries, or pollution or by creating unsuitable habitat for nesting. The difference between us and a natural predator is that: ",
"Humans generally take way more then a natural predator would. Say a predator harvests their prey at about 10% of the population per year, humans typically harvest between 40-60% of the population per year.",
"Predators are selective about the age-sex class they take from or from the old/weak. Humans tend to select from every age class and we harvest the strong/fertile. ",
"Humans are very new predators for most species and they have not had the time to adapt to our hunting techniques or harvesting levels. ",
"Beaches around the world are ",
"covered in lights",
" and people, turtles need complete darkness and quiet to lay their eggs. ",
"People eat turtle eggs and in many places they are dug up on unprotected beaches. ",
"There are more unprotected beaches then protected beaches. ",
"Relocating nests in high traffic human beaches to designated turtle beaches. ",
"Educating coastal beach communities about either sustainable harvesting or restricted harvesting of the turtle eggs. Educating coastal beach communities about reducing light pollution and beach traffic especially during nesting seasons. ",
"Hatching turtles and releasing them when they are a little bit older so that they have a better chance of surviving marine predators. ",
"Safe guarding the protected beaches from both human and non-human predators. ",
".",
"Sea Turtle Conservancy",
" has more information for you. "
] |
[
"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 it back out into a large shell it's once again bouyant enough to float on the surface as it displaces much more water. "
] |
[
"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 caffeine molecule?
|
[
"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 to uptake the drug to be used. They have serum levels but receive no benefit. This is possibly also similar for caffeine where some may receive no effect due to a change that no longer allows it to bind or simply be resistant to its effects by decreasing the binding ability of caffeine. "
] |
[
"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; this prevents the neural suppression that adenosine causes when it attaches to the receptor. Some people may have altered adenosine receptors to which caffeine can not attach to as well as in other people. And as germican mentioned, genetics can play a big factor in how effective a drug is. Many drugs have indications for altered dosing based on ethnicity of the patient or specific genetic testing."
] |
[
"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 seat, the space station is constantly \"falling\" away from the astronauts, so they seem weightless. And the space station doesn't crash to Earth because it is falling around the Earth (for more information on this, look into Newton's description of orbit)"
] |
[
"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 for an astronaut the difference in height is so small that it can be neglected.",
"About gravitons, there is no significant gravitational radiation emitted so there aren't any to observe in either case (supposing they had the means to detect them)."
] |
[
"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 \"yes\", does the free falling astronaut also not observe gravitons that would be observed by someone who was stationary (relative to the Earth)?"
] |
[
"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, what would be the consequences of a scenario where one of these "wizards" stole too many electrons in a very small area (~1 cubic cm of air)? If this isn't even close to a plausible scenario where one could produce energy, how would one go about harvesting electrical energy from positively charged ions "magically," and what would the consequences of such an action entail? I know it's a wonky question, but I'm trying to create a somewhat physical interpretation of magic.
|
[
"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 bigger ones can top 300. ",
"But I'm at the end of my ability to analyze further here - how fast and how energetic the result is, I don't know."
] |
[
"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. ",
"When we wash our hands, the scrubbing motions that we make, alongside the soap we use tends to loosen what we can't see on our hands and is washed away. In hospitals, most clinicians (and I say most because some people still don't do it) wash/gel their hands every time they walk into a patient's room and every time they walk out of a room. It's to prevent a possibility of carrying bacteria over to a different patient's room. With multidrug resistant organisms popping up all over the place, it's best to be safe and wash your hands.",
"On the other hand, it depends on the sanitary conditions of where you did all that. Did the environmental services staff/housekeeping use the appropriate wet times of the agents to clean the surfaces? Did they use the appropriate solutions? Do other people hold the same hygiene principles as you do?",
"The answer really leans more towards a \"yes\" if all that above is answered with a \"yes\". "
] |
[
"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 easier job. ",
"Nuke. Everything. ",
"But without dissolving our outer skin layers which are already dead.",
"It drives me nuts when someone turns on a tap in my kitchen with chicken juice on their hands. They contaminate the tap and soap dispenser head with their suspected pathogen hands, proceed to wash, then recontaminate their hands when turning off the tap. I practice my muay thai by activating lever taps and dispensing soap with my elbows. Alternatively I handle pathogen potentials with my left hand only (if the task can be performed one handed) leaving my right hand ready for handling things I don't want to cross contaminate.",
"It's kind of like wiping my ass with my left hand so I can scratch my nose and rub my eye with my right until I wash my hands."
] |
[
"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 periodic table."
] |
[
"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 these could be combined to create what are essentially the elements we know of but composed of antiparticles. "
] |
[
"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 subjects would probably realize halfway through whether their therapist was a professional or a layperson (which would lead to ",
"unblinding",
")."
] |
[
"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) the study would be confounded by the fact thay peoples doubt or giesses about whether they had a psyche or an actor would need to be measured to see how it would effect the thereputic impact. Another confounding factor would be that how would you standardize the actors so what they did was the same as each other? Some of them might be more empathetic or just more initiative, or just better actors.",
"You would also have to find or conduct researh to establish that actors using jargon wouldn't do any harm to people who were getting the fake therapy (it would be a legal nightmare if someone told an aactor they were suicidal and the actor did nothing and the person killeded themsrlves.)",
"There are other issues like control - a therapist can be deregistered - but an actor that breached confidentiality cant really be prosrcited.",
"This is all off the top of my head - there would be many other thins I'm sure."
] |
[
"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 methods are effective and which aren't. There are certainly scientific experiments for used methods.",
"The success of a trained therapist compared to a random person would really be a question of who knows and executes the methods better."
] |
[
"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 ability to use unenriched uranium as a fuel source. When a U235 fissions, it emits about 2-3 neutrons, depending. To maintain a steady reaction, you want an average of exactly 1 neutron from each fission to cause another fission event. Unfortunately, fissioned neutrons are traveling very fast (~7% the speed of light). Fast neutrons are very unlikely to cause fissions in other U235 atoms. A moderator is a material with a high scattering cross-section, i.e. one that is good at slowing neutrons down. Hydrogen is great as a moderator but it also has a chance of capturing those neutrons rather than slowing them. Since a neutron needs many collisions to slow down to \"thermal\" speeds which are good for fission (say, mach 10 at STP), many neutrons would be absorbed by hydrogen and turn it into deuterium.",
"However, the chance of a deuterium absorbing a second neutron (its \"absorption cross-section\") to become tritium is very low. So if your water has a lot of deuterium, you won't lose as many neutrons as they slow to thermal speeds. This means you don't need as much U235 to maintain your fission reaction, and properly balanced you don't need to enrich at all. The increased cost of using heavy water as your coolant is lessened by not needing the uranium enrichment process."
] |
[
"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 a neutron of a given energy."
] |
[
"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 conditions the coolant maintains a steady level of deuterium."
] |
[
"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 little bit different. Currently the only wild cases are in Afghanistan & Pakistan, and despite both sides of conflicts in the region’s supporting vaccination, organizationally complete immunization has not been achieved yet.",
"In particular, the polio vaccine has a small, but real chance to mutate within the immunized person, creating a generally mild but none-the-less infectious strain that can spread through a community. ",
"In 2018, there were 33 cases of “wild” polio in Afghanistan & Pakistan, but 104 cases in 7 other countries that were caused by the vaccine itself.",
"So we are in a little bit of a wild goose chase here - eradication can’t happen until EVERYONE is vaccinated, and then NOONE is vaccinated 😅",
"But once we do that, itll probably be just a year or two until we “declare” it as “officially” eradicated."
] |
[
"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 the oral vaccine world wide."
] |
[
"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 differential across your ears changes. ",
"source"
] |
[
"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 reason why our ears can’t stand it for long."
] |
[
"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 eroded over the months due to mouse use. Mouse feet are typically almost always a slightly soft plastic. Is there a better surface that won't wear out? If the mouse feet and the mouse pad are constantly being rubbed against each other, over time, the pad will get worn down. Is this due to the physical hardness of plastic over the surface coat of anodized aluminum? If you moved the mouse with weight on top over an indefinite amount of time, would you eventually eat away at the pad till there was a hole in the aluminum? Could there be better raw materials for mouse feet? (i asked a similar question xposted from )
|
[
"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 smallest finger. In which case the feedback is from knowing the position of your hand, and not the mouse.",
"I wonder if his issue is ",
" resistance on the mouse due to the wear on the mousepad, and not the lack of friction per see? Or perhaps the mouse is \"skating\" out of control, which he could solve by putting weights into it or using the opposing finger?",
"Anyway I don't understand specifically ",
" the OP's actual issue is."
] |
[
"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 also the minimum, and not the maximum. Maybe you're thinking of x",
" ?"
] |
[
"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 lipase to break triglycerides into glycerol and free fatty acids for use in metabolism, a process called lipolysis.\"",
"See ",
"the article",
" for more info."
] |
[
"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 acids bonded together. We can't use the triglycerides themselves for energy.",
"Lipolysis = diglyceride + 1 free fatty acid --> monoglyceride + 2 free fatty acids --> glycerol + 3 fatty acids.",
"The 3 free fatty acids get broken down in a process called ",
"β-oxidation",
". They fuel redox reactions that culminate in the creation of ATP in the mitochondria in a process called an ",
"electron transport chain",
", which, put simply, is a 'relay race' of electrons. At the end of this relay race is oxygen (O2), ",
"which becomes water (H2O) as a result of this process",
".",
"Anyway, this is the same way glucose (sugar) provides energy for cells, it just follows a different process called ",
"glycolysis",
".",
"Glycerol can actually be converted into an intermediate in the process of glycolysis and be used for energy much the same as glucose.",
"Excess energy beyond our daily needs is simply not used, which makes sense - utilizing all that extra energy creates heat, and too large a change in body temperature or the local cellular environment can seriously mess things up!",
"Excess energy is stored in two main forms: glycogen and triglycerides. Glycogen is a bunch of glucose molecules branched together. We've already mentioned that triglycerides are composed of glycerol attached to 3 free fatty acids. Per calorie, triglycerides store more energy per unit volume - it's much more efficient to store more fat than it is to store tons of glucose; plus, all that glucose is attracted to water and we would need increased water intake to allow easier storage - not very efficient in times of survival eh?",
"Anyway, I'm getting off topic. We use more stores triglycerides (versus dietary fats, carbohydrates, and proteins) for energy in times of decreased energy intake."
] |
[
"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 dioxide. Water is excreted or used in cellular metabolism, and carbon dioxide is transferred through your blood via various carrier molecules and forms to the lungs, where it is exchanged for Oxygen. Thus, the respiratory system comes full circle: we breathe in oxygen which is transported to cells, where it is converted to CO2, and travels back to the lungs and is exhaled. You lose weight through air!"
] |
[
"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 atoms. So no chemical reactions will take place."
] |
[
"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 image returns. If a polarizer simply allows one type of light wave through and blocks another, how can this behavior be explained?
|
[
"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 passes through the first (let's say horizontal) polarizer, that light is 100% horizontally polarized. You can pass it through as many more horizontal polarizers as you want and the intensity won't diminish. And if you try to pass that horizontally polarized light through a vertical polarizer, 0% of it will get through. That makes sense.",
"Here's where the quantum mechanics comes in. It turns out that I can't measure both how much a ray of light is horizontally polarized and diagonally (let's just think about 45",
" for now) polarized. These measurements, in the language of quantum mechanics, \"don't commute.\" Another way of saying this is that when I pass light through a diagonal polarizer, it's now 100% diagonally polarized. But because of the relationship between horizontal and diagonal polarizations, 100% diagonally polarized can thought of as a superposition of horizontal and vertical. If I pass a single photon through a diagonal polarizer, there is no longer a good answer to the question \"is it vertically polarized or horizontally polarized?\" It's a superposition of both.",
"So let's follow a bunch of photons through the three polarizers:",
"1) A beam of unpolarized light (each photon has a random polarization) passes through a vertical polarizer. Half of the photons make it through but all the photons that make it through are now 100% vertical.",
"2) The 100% vertical photons are equivalently in a superposition of diagonal and cross-diagonal. So when they pass through the diagonal polarizer, only 50% of them make it through. Those photons are now 100% diagonal.",
"3) The remaining quarter of original photons are 100% diagonal, which is a superposition of vertical and horizontal. That means that half of those are going to make it through the next polarizer, which is the horizontal one. ",
"So, in total, 1/8 of the photons make it through.",
"Hooray, quantum mechanics!"
] |
[
"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 I stick another strainer at 45% between them, some will go through.",
"And (like Bell's if I understand it right), if I put a whole bunch of similar strainers at gradually increasing angles -- so it's kinda like a spiral ramp for the pasta -- they'll practically all get through."
] |
[
"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 this out in classical EM, the mathematics of the situation is the ",
" as it is in quantum. This is the only place I know of where the quantum and classical theories are so beautifully analogous. One of the better graduate textbooks on QM (Sakurai) actually uses the classical polarizer as an example to motivate quantum mechanics."
] |
[
"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, removing a hydrolyzable bond, etc. In this case, the substitution of the hydroxyl group with the chlorine makes it bind to the receptors more strongly.",
"Other halogens may have different effects, as the polarity of the C-X bond and the polarizability of the atom itself can affect binding.",
"This article",
" gives an interesting mention of why sucralose is sweeter in the court case between Splenda and Equal."
] |
[
"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 ",
" the molecule binds to the receptor.",
"This site",
" lists a few of the interactions, including a crude drawing of the receptor. As explained, the presence of chlorine alters the hydrophobicity of the fructose ring. Since that's the case, one can make the argument that making the ring ",
" hydrophobic would indeed increase the binding affinity. However, one must take other factors into consideration - ease of synthesis, solubility, specificity to target receptors, and metabolic breakdown can all be affected.",
"Bridging the gap between theory and reality is what rational drug design is concerned about, and it's the reason ",
" binding affinity testing is a huge part of it."
] |
[
"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 contribute to overall climate change compared to other factors affecting the Earth?
|
[
"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 the most succinct overview comes on page 697, in the form of ",
"this chart",
", which illustrates CO2's role as the primary forcing agent in the climate system today."
] |
[
"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, and if we don't want our children's children to grow up on a planet dramatically warmer than the one we grew up on, we have to do something about it. Unfortunately, all too often people point to Milankovic cycles or anything else they can get think of as an excuse to avoid that."
] |
[
"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 several caffeinated drinks indistinguishable from water."
] |
[
"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, and a sports drink were not different from the response to water ingestion.” Source: ",
"https://academic.oup.com/ajcn/article/103/3/717/4564598"
] |
[
"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 from you, you feel it cooling since you are losing that heat.",
"In the bottle it is confined, so it can't all evaporate and there is not enough heat."
] |
[
"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 structure is being used?",
"",
"There's a HUGE amount of variables involved, across millions of different potential scenarios. Designing \"optimal\" fans for all of them is effectively impossible. As a result, we generally have a series of 3 or 4 all-purpose fan designs, with tweaks applied to lean them a little more towards one role or another."
] |
[
"\"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 cooling capacity for just $6, but if only 100W is needed, the $5 will be taken.",
"Noise is another factor that might be a different priority for different manufacturers.",
"And at the end of the day, the marketing team might come in and demand that the fan leaves enough room for a massive RGB logo, regardless of the hit on performance."
] |
[
"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 condition where as porosis is from hormone or vitamin deficiencies"
] |
[
"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 doesn't explode when used. Is the lightbulb controlling this with resistors? Are they lowering amps or volts? Where is the extra going? Is some being restricted then some being given off as heat energy? Lastly, and the biggest question. How does the electric company see this? Edit: Thank you guys all so much for the awesome answers. You really cleared this up for me!
|
[
"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 exactly right because the LED bulb is not a pure resistive load. The LED is controlling this though some complicated circuitry that amount to a constant-current driver, which is beyond the scope of this comment. ",
"Roughly speaking, a power source controls volts, and a power consumer controls amps. So the only option the LED has is to control amps. Volts are determined by whatever it's plugged into.",
"There is no \"extra\". Each draws exactly as much power as it needs. The difference between the two never enters your house, and it stays with the power company, presumably going to other people as needed. ",
"The electric company sees this because a single electron coming out of your wall outlet carries more-or-less the same amount of energy. (There are some subtleties here because your wall power is AC, not DC, but it works out fine for the purpose of this paragraph.)",
"Since your LED bulb is using less energy, and it's getting that energy from electrons, what happens is that your LED is pretty much asking for fewer electrons (that's what lower current means, as calculated above). The electric company has a counter between your home and the rest of the grid that effectively tells it how many electrons you used up."
] |
[
"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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