title list | over_18 list | post_content stringlengths 0 9.37k ⌀ | C1 list | C2 list | C3 list |
|---|---|---|---|---|---|
[
"Is hypnotism a myth?"
] | [
false
] | [deleted] | [
"check out ",
"feynman's description of being hypnotised",
". he addresses the \"faking it\" thing:",
"He started to work on me and soon I got into a position where he said, \"You can't open your eyes.\"",
"I said to myself, \"I bet I could open my eyes, but I don't want to disturb the situation: Let's see ... | [
"check out ",
"feynman's description of being hypnotised",
". he addresses the \"faking it\" thing:",
"He started to work on me and soon I got into a position where he said, \"You can't open your eyes.\"",
"I said to myself, \"I bet I could open my eyes, but I don't want to disturb the situation: Let's see ... | [
"Hi! Hypnotist here. Hopefully I can help shed some light on these questions for you.",
"1) What is a hypnotic state?",
"This will be the most difficult question to answer. Especially because even among hypnotists there are state versus non-state theories. I'll give you my personal take on things, though. ",
... |
[
"At this point, why isn't the COVID-19 vaccination required for grade school students?"
] | [
false
] | null | [
"Not really a science question but more of a policy one. Perhaps try a politics-related sub"
] | [
"Perhaps you're right. I chose ",
"r/askscience",
" because crossing into politics is a complete mess I'm uninterested to involve my time with. Politics shouldn't influence protecting my (our) children, which of course protects you, them, me, us, etc. My post is somewhat vague I suppose, but I'm questioning why... | [
"*More specifically, what warrants mandatory immunization?"
] |
[
"May sound stupid but here goes , when we are in the womb and are slowly growing where do those atoms come from that make us or do we make those atoms in the womb ?"
] | [
false
] | null | [
"They come from the food your mother eats while you're developing, as well as your mother herself. No new atoms are created, just rearranged cleverly from food and air and water."
] | [
"I would add that you can't make atoms without an enormous amount of energy. E=mc",
" where mass is m, c is the speed of light and E is energy. Energy in the universe can not be created or destroyed. All elements bigger than hydrogen were created in stars or explosions of stars (except for a few heavy elements li... | [
"Thankyou my greatest mystery has been solved"
] |
[
"Why is it that you can put so much weight on one side of a barbell without it tipping over?"
] | [
false
] | I was at the gym today and I was able to put 90 pounds on one side of the barbell without it tipping over. Why doesn't any imbalance of weight cause it to tip over? | [
"If the barbell is supported at each end, then it won't tip over until it's center of gravity is outside the interval between the points where it's supported. If those points are quite close to the end compared to the length of the bar, then the weight you add needs to be much larger than the weight of the bar alon... | [
"This explanation is correct, just wanted to add something.",
"For the bar, that's a small weight times a large distance (half the distance between the supporting points)",
"In addition, barbells aren't light. 20kg is standard. That's lighter than two plates (90lbs = 40kg) but only by a factor of 2."
] | [
"Using dimensions obtained from: ",
"http://www.allaboutpecs.com/wp-content/uploads/2013/04/olympic-bar-dimensions.png",
"The distance between the collars of the barbell is 131 cm, so that means the center of mass of the barbell is about 65 cm from the collar. The collar is where the bar would pivot if you plac... |
[
"How are sunglasses made to block UV light?"
] | [
false
] | I've seen conflicting information on exactly how sunglasses are made to block UV light. Some people say that the plastics used in the lenses naturally blocks UV light so that even the cheapest sunglasses will do an excellent job, while others say you need special 'treatments' to make them UV blocking. So do the plastics used in the lenses for sunglasses naturally block UV light? If not, what 'treatments' are applied to them to make them block UV light? Do these 'treatments' degrade over time? Do they rub off? | [
"The clear plastic (CR-39) used in typical eyeglasses is a ",
"pretty good UV blocker",
" on its own. Polycarbonate, another common material, is ",
"even more opaque to UV.",
"Add a gray tint, and it becomes an ",
"effective UV filter",
".",
"There are coatings that can be applied to any plastic to re... | [
"Polarizing lenses are tinted plastic so they have the UV characteristics of tinted plastic, independent of their polarizing effect. I don't think anybody sells polarized lenses for the UV benefits. Well, unless you want...",
"There are two classic situations where polarized sunglasses really pay off.",
"Light ... | [
"What about a polarizing filter? I know what it does, but why people slap it on to sunglasses? Do polarized lens make the glass more \"UV resistant\"?"
] |
[
"Have we been able to bond any noble gas element with any metal, and if so, what is the longest we've been able to maintain this bond?"
] | [
false
] | Just wondering if there are any computational, theoretical, or experimental areas as far as this subject goes. I'm a applied math student who will be attending school for graduate level physics next semester, and I'm very interested in this subject. Very specific on the noble gas + metal, for example argon and gold or something of that nature. Maybe some sort of high vacuum and high energy process to create these bonds, if only temporarily. Thanks in advance for any answers! | [
"I've found you not only a compound with a noble gas metal bond (was expecting this), but I actually found your utterly insane suggestion of a direct nobel gas and gold bond. The ",
"Tetraxenonogold(II)",
" cation present in AuXe",
"(Sb",
"F",
" ",
") Florine makes for weird chemistry."
] | [
"Bonding has been observed between noble gases and fluoride, but that has to do with fluoride being a ridiculously strong oxidant. Also, bonding between these species is rather weak and only really stable at temperatures around something like 5K. ",
"A metal with strong oxidizing power that comes to mind is the 3... | [
"I have nothing to add except that the compound Xe[PtF_6] has been known to exist. Perhaps an expert could elaborate upon it."
] |
[
"How many virus cells are needed to make a human ill?"
] | [
false
] | null | [
"First viruses != cells, by definition. They are protein based capsids containing nucleic acids. Sometimes with a lipid envelope. But nothing more.",
"Second, it depends on the virus. There's actually a metric in microbiology called ID50, \"Infectious Dose 50\". It's similar to LD50. However, instead of lethality... | [
"Not equal to."
] | [
"What is '!='?"
] |
[
"What is the significance of RBMK nuclear cores not exploding?"
] | [
false
] | null | [
"The significance in the TV show is that they were denying something that had obviously happened. Reactor 4 was an RMBK and it did explode, but the higher-ups denied it and said that it’s not possible."
] | [
"So it's a political statement rather than anything to do with science?"
] | [
"I'm not sure what you mean by that."
] |
[
"Could self aware robots one day make it to other solar systems or galaxies and outlive humanity? And could self aware robots one day be considered living non-carbon based beings?"
] | [
false
] | null | [
"Such hypothetical / speculative / open-ended questions are better suited for our new-ish sister sub ",
"/r/asksciencediscussion",
". Please consider reposting there instead."
] | [
"Is there a way for me to move it there without making a new post?"
] | [
"Unfortunately no."
] |
[
"Why might UTIs (urinary tract infections) have a drastic affect on mental health? What is the link?"
] | [
false
] | [deleted] | [
"I must strongly disagree with most of the comments in this thread. Generally the idea that UTI can affect mentation and cause altered mental status comes from the geriatric literature, where infection is one of the many causes of AMS, delirium, or encephalopathy, three words which are synonyms and mean “disordered... | [
"This is the only response here even remotely close to correct, and it's spot on.",
"Other common causes of delirium which are often present alongside bacturia are dehydration, other infections, med interactions or improper dosing especially of chronic steroids, and lack of social or mental health support, among ... | [
"UTIs can impair kidney and liver function and reduce their effectiveness in removing toxins from the blood which can build up in the brain. This can cause cognitive issues."
] |
[
"How can something like graphene aerogel be lighter than air if it's composed of matter and air? If it's already made of air and then extra matter is added into it to give it a solid body, how could it be even lighter than the preexisting air?"
] | [
false
] | null | [
"The term \"lighter-than-air\" when used in the context of solids means that the mass of the material that it consists occupies a volume such that the quotient (i.e. the density) is smaller than that of air. It does not account for air that would fill the cavities within.",
"If the aerogel is truly lighter-than-a... | [
"So what that term basically means is less dense than air?"
] | [
"Specifically, it means that the ",
" is less dense than air."
] |
[
"Is there a viable way to shape sound waves?"
] | [
false
] | I only mean in the sense of sound not going past a certain point. The basis for this question started for me when I read . I remember reading the part where Ender was first introduced to the Giant's Game by another character. I can't remember the exact quote, but it was something along the lines of: Ender saw (xyz character) playing a different game on his computer. It was interesting because he had never seen it before. He could see the player talking to a giant, but he could not hear what the giant was saying because the sound was shaped towards (xyz character). My question in short, is this. Is there a viable way to shape sound waves so that only a small contained area can "hear" the sound? | [
"Yes. Sound is a wave, so with a correctly shaped reflector the sound can be focused on a narrow area. This type of setup often used in museum exhibits to limit the audible narration to a small area. Narrowly focused sound can also make a non-lethal weapon. See ",
"parabolic loudspeaker ",
" and ",
"LRAD",
... | [
"Also you can use ultrasound as carrier waves to focus sound like a laser."
] | [
"There's a huge problem with that, there was a post here ",
"If two frequencies, one or both of which is by itself OUT of the audible range, have a beat frequency that is IN the audible range, might someone perceive the beat frequency?",
"Turns out that no, you can't easily. As in, if we assume the linear model... |
[
"Why do different substances have different specific heats?"
] | [
false
] | The amount of thermal energy in a substance is how much kinetic energy the molecules have, and the temperature is related to the average speed of the molecules (right?). So why is the relationship between the two so inconsistent? I imagine it's some mix of inter-molecular forces and different molecular masses, but I'd appreciate a more thorough explanation. | [
"Energy can be stored in translational, rotational, and vibrational modes inside a molecule. ",
"It can get even more complicated in solids."
] | [
"Motion you can't predict",
" counts toward the temperature. The laws of thermodynamics are ",
"surprisingly agent-based",
"."
] | [
"Why is water so good at holding heat? Is it because it does all three of these energy storage forms well?"
] |
[
"Are very active individuals who retire from their active lifestyles as they age at greater risk of obesity than their consistently inactive peers because they maintain the dietary habits needed to perform maintain their active lifestyle?"
] | [
false
] | null | [
"Unfortunately, there are so many variables at play here that it'd be impossible to deduce. There's a plethora of genetic and environmental variables. Being that we're speaking of those of retirement age there are even epigenetic variables, and the science of epigenetics is so young its still in the womb, so to spe... | [
"This is a great question. The fact that people can rapidly gain weight after ceasing exercise is pretty well known. The question is do they gain more than they would have if they hadn't exercised in the first place. I don't know the answer in people, but here is the answer in hamsters:",
"http://ajcn.nutrition.o... | [
"Thanks for the reply.",
"The explanation is that the retired hamsters have a delay in feeding and metabolic adaptation to decreased energy expenditure. In people, exercise seems to promote weight-loss maintenance by more closely matching food intake to energy expenditure. You can imagine that if someone with lar... |
[
"Is there an easily achievable pressure, either + or - standard atmospheric pressure, that would significantly reduce the growth of most foodborne pathogens?"
] | [
false
] | My thoughts are for humble food storage containers. Of course, refrigeration increases the time before spoilage, and a perfect vacuum would have an effect. But is there any sweet spot above a perfect vacuum where all or most growth of pathogens gets slowed to a crawl? Or perhaps a higher pressure that's not in danger of exploding? | [
"I don't see how a perfect vacuum changes much. From my impression vacuum sealing prevents infectious agents from entering mostly from the \"sealing\" aspect. The vacuum part prevents ice crystals from forming on the surface and \"freezer burning\". But if you took some meat and had it exposed to some bacteria or s... | [
"I don't think so because of experiments like this ...",
"http://www.popsci.com/technology/article/2010-08/bacteria-survive-553-day-exposure-exterior-iss"
] | [
"May be check out this google search ...",
"http://scholar.google.com/scholar?start=0&q=vacuum+packaged+bacterial+growth&hl=en&as_sdt=0,48&as_ylo=1992&as_vis=1"
] |
[
"Are we past the tipping point for the insect population decline?"
] | [
false
] | null | [
"Not likely. Insects as a group are exceptionally diverse and most reproduce quickly with large numbers of offspring. It will vary strongly from group to group, with heat-loving generalists doing well and specialists (e.g. obligate parasites with rare hosts) hurting the most.",
"Additionally, some are very suscep... | [
"My background is in ant ecology, but I have had general entomology training. I can find some references for you in a few hours.",
"Edit for more compelling evidence:",
"a famous example of rapid evolution",
" though, variation must exist for selection to act upon, so small populations are at greater risk giv... | [
"I believe ",
"this",
" is the article you are referring to. It has gotten a lot of publicity and is good for raising awareness.",
"However, ",
"this",
" article explains that the main patterns affecting insect ",
" (not ",
" diversity) and in the discussion explains why the long-term study above may ... |
[
"What would be the effects of a baby being conceived and being born on a larger or smaller planet?"
] | [
false
] | im curious how this would effect the biology of a human's growth. | [
"This article",
" reviews research on the effects of gravity on cell signaling in the immune system. The research suggests cell signaling is ",
", susceptible to gravity or absence thereof. Development relies heavily on cell signaling, I know for certain neural migration is majorly dependent on cell signaling t... | [
"would a person born on mars be taller than somebody from earth then?"
] | [
"Honesty im not positive, with the weaker gravity field pulling on them I figure they would grow taller but I would guess its more based in genetics "
] |
[
"Did the old english language contribute to modern french or did old french contribute to modern english?"
] | [
false
] | null | [
"There was probably some exchange both ways, but more the latter. England was conquered by Normans in 1066, and the class divide between French-speaking nobles and Anglo-Saxon peasantry shaped much of English's early development. For example, many terms for animals are germanic, coming from farmers, while many term... | [
"I'm a little late to the conversation, but wanted to reply anyways as you're quite wrong on this, and anyone reading later on might be confused. French is a Romance language, not a Germanic one. Is there a chance you are confusing \"Germanic\" with \"Indo-European\"? Slavic, Romance, Celtic, Hellenic etc. language... | [
"I'm a little late to the conversation, but wanted to reply anyways as you're quite wrong on this, and anyone reading later on might be confused. French is a Romance language, not a Germanic one. Is there a chance you are confusing \"Germanic\" with \"Indo-European\"? Slavic, Romance, Celtic, Hellenic etc. language... |
[
"Evolutionary Biologists: What Is the Rationale for Having two Genders?"
] | [
false
] | [deleted] | [
"It's not certain, but having two sexes (gender includes mental state) allows for more variations in mutations in offspring. This allows us to keep up with more short-lived (and more mutation heavy) competitors like parasites. This is called the ",
"Red Queen Hypothesis"
] | [
"To allow for sex. Sex facilitates genotype recombination, which is really valuable in organism with high investment in few progeny. ",
"http://en.wikipedia.org/wiki/R/K_selection_theory",
". In the absence of two genders, there would be frequent self-fertilization of the gametes (eg 'spegg' or 'overm'). If... | [
"I'm Familiar with RQH, i'm afraid i phrased my question badly. What i was interested in knowing is What is the advantage of placing such a high physiological burden on one gender and not the other. I should Probably put that in the question."
] |
[
"Is it possible to quicken a planet's rotation?"
] | [
false
] | null | [
"Yes. As an example of what will happen, look at Phobos' eventual fate (",
"http://en.wikipedia.org/wiki/Phobos_(moon)",
" ). It will draw closer to Mars' surface and eventually hit it. Phobos might break up into a ring first, but that doesn't matter for our purposes. Either way, as Phobos' orbital altitude dec... | [
"Interesting. Is it possible to calculate the length of a day once the Moon has left the Earth-Moon system (or by the inverse square law has an insignificant influence)? How long would until this happens?"
] | [
"Specifically, if a moon is in a lower orbit than the (geo)synchronous altitude for its planet, tidal perturbations will tend to lower its orbit and speed up the rotation of the planet. If it's in a higher orbit, the perturbations will raise its orbit and slow down the planet.",
"For the Earth this critical alti... |
[
"Is Earth's centre of gravity at its geometric centre?"
] | [
false
] | Not entirely sure if this question makes sense. Thanks! | [
"Ok..i'm going to try to break this down as I go. Center of gravity from the point of what you looking for is actually the scientific term center of mass where all the accumulative mass from all outside forces = 0. If you wanted to measure this I would try to simplify a few things that I already know, the earth is ... | [
"No.",
"The gravitational field of the Earth is very complex and depends on local and non-local differences in density. Because it's so complex it's very hard to define a \"centre of mass\".",
"We have detailed maps of the Earth's gravitational field, e.g. ",
"measured by the GRACE spacecraft",
" "
] | [
"A large majority of the earth is solid, the only liquid portion that would make a significant contribution would be the outer core."
] |
[
"Why do we still drink milk?"
] | [
false
] | Are we the only species out there who still consumes milk way after we are done nursing? I don't want this question to come off silly, but there are many other better sources of vitamins, protein, and calcium. Also how much casein should we be consuming as adults, and why is drinking liquid out of an udder appealing to us? | [
"there are many other better sources of vitamins, protein, and calcium.",
"Uh, really? Name some.",
"Also how much casein should we be consuming as adults",
"Recent studies have correlated certain polymorphisms of casein in the cow population with lower rates of cardiovascular disease and diabetes, so as far ... | [
"Yeah, a lot of those foods are, individually, great sources for what they offer. The main appeal of milk is that it provides a lot of the nutrients and vitamins you need in one package. "
] | [
"Yea convenience is real nice especially if it comes with a handle lol"
] |
[
"Is a black hole a physical thing such as a planet? What exactly is it?"
] | [
false
] | null | [
"This answer isn't quite accurate. Not trying to play the internet cop, but forum rules clearly say that you shouldn't speculate.",
"a black hole is a collection of mass so heavy it collapses everything around it, including light.",
"Mass is a property, so how can there be a a collection of it? Either you are t... | [
"Black holes certainly do have physical properties, but making sense of them mathematically push the boundaries of our normal understanding of those properties. For instance, in the simplest case, when calculating the surface area of a black hole, we find it to be proportional to its mass. Normally, mass and volume... | [
"The earth creates gravity, pulling you towards it, the bigger the object the bigger the gravity, this is why the moon has less gravity then earth.",
"Isn't that not necessarily true? For example, white dwarfs?"
] |
[
"How is the total weight of the earth calculated?"
] | [
false
] | null | [
"We know that the acceleration due to gravity is equal to a constant (G) times the mass of the object (M) divided by the square of the distance to the object. We can measure the acceleration due to gravity either on the Earth's surface (9.8 m/s",
" ) or by looking at the moon (one rotation in ~29 days). This al... | [
"The word weight has multiple meanings. Only in science and engineering does it have the meaning specific to the earth's pull by gravity. Anywhere else it means the same thing as mass."
] | [
"Just put a scale upside down and weigh the Earth! Of course this is the weight of the Earth in your gravity field. "
] |
[
"A (probably ridiculous) question about bees posed by my six year old"
] | [
false
] | I was reading The Magic School Bus book about bees tonight to 6 yr old, and got to a bit that showed when 'girl' bee-larvae get fed Royal Jelly, they become Queens, otherwise they simply become workers. 6 yr old the asked if boy bees are fed Royal Jelly, do they become Kings? I explained that it there was no such thing as a King bee, and it probably never happened that a 'boy' bee was fed Royal Jelly, but he insisted I 'ask the internet people', so here I am. Has anyone ever tested feeding a 'boy' larval bee Royal Jelly? If so what was the result? | [
"In honeybees, the males are haploid and have only 16 chromosomes. Their genome is entirely derived from the queen. Drones produce sperm cells that contain their entire genome, so the sperm are all genetically identical (except for mutations). The genetic makeup of the female bees is half from the mother and half f... | [
"What is the mechanism by which larvae are chosen to become Queens?"
] | [
"No. DNA methylation is an epigenetic modification that doesn't alter the coding sequence. Instead, it adds \"markers\" to the backbone that can affect gene expression. In some cases, methylation patterns can be passed on to offspring, but methylation can be added and removed without affecting the underlying gen... |
[
"why do different pigments have different absorption spectra?"
] | [
false
] | why does the photopigment in blue cones, for instance, absorb light wavelengths that are mostly 430nm, while photopigment in red cones absorbs lights that's mostly 570nm? the difference in absorption spectra of chlorophyll molecules is due to variations in hydrocarbon tail length and side chain type. is there a method to the madness, though? like some kind of simple pattern that i can wrap my mind around, like more side chains = long wavelength absorption? or does the spacing of molecular components directly correspond to the wavelength? what's going on here? (i'm not looking for an explanation of the whole phototransduction cascade) | [
"Absorption relations fundamentally come from the interactions between electromagnetic waves and molecules; you can compute, using elementary quantum mechanics and advanced classical electrodynamics, the ways light should interact with a particular molecule, but there is no easy \"trick\" or correlation, mainly bec... | [
"Basically the absorption of light is due to energy transitions in the molecule. Visible light tends to be electron transitions (an electron moving from a lower energy orbital to a higher energy orbital). ",
"Putting it simply, electrons like to be spread out over larger volumes, and a molecule that can do this b... | [
"I wanted to add to your question: Despite \"different color\" cones using the same molecule for photon absorption, the proteins that envelope the molecule are different for red and blue cones, and interact differently enough with the molecule to change its absorption wavelength."
] |
[
"Is rain totally pure, clean water?"
] | [
false
] | I have heard that it is 100% pure H20 due to the evaporation process, but somebody else told me that rain molecules form around dirt/dust particle during condensation. Plus acid rain makes it more confusing | [
"rain water is not pure H20. Pure H20 is not typically found in nature, only in analytic chemical laboratories and some factories. Carbon Dioxide from the atmosphere is absorbed by water molecules and and turns into carbonic acid, which is found in all rainwater. It is slightly acidic, but typically not harmful t... | [
"Rain is not pure, clean water. Yes, water molecules need a nucleation point to condense into a water droplet (it's something I remember from a Bill Nye episode back when I was younger). This dust particle or impurity is usually known as a ",
"Cloud Condensation Nuclei",
". ",
"The thing I want to point out i... | [
"As the water evaporates it is pure water. When the water vapor returns back as rain it has picked up impurities of the air it has moved through. \nYes the impurities can act as a seed crystal which water vapor would adhere too",
"Acid rain is when some gasses mix with the water to combine a difference compound. ... |
[
"Does pouring boiling hot water on a toothbrush sterilize it?"
] | [
false
] | null | [
"At standard pressure, boiling water won't kill everything. And you'd have to keep your tooth brush in the boiling water for about 20 minutes or so to mostly sterilize it. The instant you bring it out of the boiling water though, technically it wouldn't even be mostly sterile any more, as what floats in the air w... | [
"However this would likely lead to a melted toothbrush as most are made from Polypropylene with a melting point of 130–171 °C. "
] | [
"It might kill a few things, but if you ",
" want to sterilize something, you'd need an autoclave, which uses hot pressurized steam to disinfect surfaces. Twenty minutes in an autoclave at 120-170 C and there will be practically nothing left alive."
] |
[
"If the extinction event of the dinosaurs never happened, how long would they have likely survived?"
] | [
false
] | null | [
"Dinosaurs are still living today, so to speak.",
"It was quite a shock at first (this scientific discovery happened within the past couple decades I believe), but ",
"birds are descendants of dinosaurs",
".",
"Check out the ",
"wikipedia page",
" if you'd like to read more.",
"Edit: And I realize thi... | [
"The discovery, or at least initial idea, that modern birds are descendants of dinosaurs is actually pretty old, going back to the late 19th Century. ",
"Archaeopteryx",
" was discovered in 1861 and showed a mix of bird and theropod dinosaur traits that got the ball rolling for many scientists. Thomas Henry Hux... | [
"For one thing, the way dinosaurs are depicted by artists has changed quite a bit as we study them more, so many pictures you may have grown up with could have been based on incorrect interpretations. T. rex ",
"used",
" to be a scaly, upright-walking dinosaur dragging his tail. ",
"Now",
" we know a bit mo... |
[
"What is actually an electromagnetic field?"
] | [
false
] | We know what a gravitational field is: the curvature of space-time. However whenever I look for information of electromagnetic fields, the conclusion I get is that a charged particle can make other particles to move without touching them. I know that the answer for this is "the particles do touch each other because their magnetic fields touch" however, this always seemed to me an explanation as magical as the "invisible force working at distance" that Newton described to explain how gravity works. Einstein in the other hand, explained that there is not a force working at distance, but that gravitational fields are nothing but the curvature of space-time. Is there an explanation like this for electromagnetic fields? I mean, do we know what is actually happening to the space between the particles interacting through their electromagnetic fields? | [
"The explanation is really not that different from gravity. The electromagnetic field is a \"thing\" that exists everywhere, charge objects can \"deform\" it, and charged objects are in term accelerated when in the presence of a deformed field. We are perhaps more familiar with \"spacetime\" as a thing that exists ... | [
"I don't think that's quite correct. Gravity is special because every particle feels the same effect in the same gravitational field, that's ",
" it's possible to have a picture of gravity in terms of curvature of spacetime. Although I think there are more geometric treatments of gauge theories (involving things ... | [
"every gauge theory has a geometrical formulation. The difference between something like QED and gravity is that in the one case the geometry is linked to an internal space and the other case the geometrical space is spacetime itself.",
"I think maldacena talked about this in one of his public lectures on a level... |
[
"Two humans are pushed off a building, one with enough helium filled balloons attached to him to make him weigh 1 kilogram, what is the difference between the force of impact on both people?"
] | [
false
] | Assuming that the difference between air resistance of the people falling is negligible. Would they both die? Also assuming that this is decently sized building that would kill the other human. | [
"Let's disregard air resistance and disregard the change of the buoyant force with height. So we basically have Dude A being pulled down by the Earth; and Dude B being pulled down by the Earth ",
" by a rope with a constant force. ",
"They're each 100kg, g=10m/s2. The force of the rope is 990N upward. This mean... | [
"Wouldn't they fall the same speed if there''s no air resistance? Like the feather and brick thing?"
] | [
"Dude B is slowed down by the buoyant force, not air resistance. I almost made that mistake as well."
] |
[
"What makes Chernobyl so much more lasting in radioactive impact than Hiroshima and Nagasaki?"
] | [
false
] | (*Hiroshima, Nagasaki or any other detonation location). Is it mostly about volume of material? Or are reactors that much more powerful than bombs in terms of thermal output? | [
"Mass of material, delivery mechanism, it's basically apples and oranges. ",
"A nuclear detonation annihilates fissile material to produce a massive emission of energy in a short period of time. A nuclear reactor produces electricity from fissile material generating steam when connected to a thermal exchange syst... | [
"The nuclear devices dropped on Japan used kilograms of nuclear material most of which was used up in the blast itself. What remained was spread over a large area very quickly.",
"The first atomic weapons were remarkably inefficient. It's estimated that only about 1% of the uranium used in the Hiroshima bomb fiss... | [
"The nuclear devices dropped on Japan used kilograms of nuclear material most of which was used up in the blast itself. What remained was spread over a large area very quickly.",
"The first atomic weapons were remarkably inefficient. It's estimated that only about 1% of the uranium used in the Hiroshima bomb fiss... |
[
"My teacher says all molecules that have benzine rings are bad for you. Am I right in saying this is false? If so, help me support my argument with her."
] | [
false
] | [deleted] | [
"If you need some specific examples:",
"Phenylalanine - An essential amino acid",
"Tryptophan - An essential amino acid",
"Tyrosine - An amino acid",
"Not only are they ",
" bad for you, they are essential to life."
] | [
"The phenyl ring (benzene ring) features in many pharmecutics, including aspirin and paracetomol. Further more, the compounds that make up our dna base pairs also have benzene rings! Benzene itself is toxic due to, in part, the metabolites, including (i understand) epoxides. It is an electron-rich compound, meaning... | [
"If you like; you may like to reference the structures of aspirin and paracetomol (and any others!) from a book or some scientific papers. Do a google search for molecule of the month, i think its an oxford uni website, thats a good source of interesting, benzene containing compounds that are important pharmecutics... |
[
"Why do you see a sort of “motion blur” in real life?"
] | [
false
] | Sounds kinda stupid but I couldn’t find an answer on google as “motion blur” will always turn up something about photography. Basically, what I’m curious about is the phenomenon when there’s a dim source of light in a dark setting (like using a phone in a dark room), any fast movement always translates to a weird trail of light behind the source. Is the light being momentarily burnt into your retina or is something else happening? | [
"That is in fact correct! The more technical term is persistence of vision, and it is caused by the photosensitive receptors in your eyes not reacting quickly enough.",
"It's also how most dimmable lights work, instead of lowering voltage and reducing efficiency, one can flicker the lights thousands of times a se... | [
"Your eyes receive light just fine (we can see strobes after all), but it takes a little time and some replacement chemicals for your retina to ",
" telling your brain there were photons."
] | [
"PWM always has the side effects of pulsating output, albeit not significant in some cases. In other cases like LED lighting where there's no momentum (i.e. the lights can turn on and off really quickly unlike incandescents) then you will see flickering"
] |
[
"How does the momentum of a parent particle affect its decay products?"
] | [
false
] | My understanding of this field is very limited, but I'm looking for an answer for the following thought experiment: A hypothetical unstable particle is accelerated into empty space where it will not interact with anything. Within its own timeframe, it is bound to decay into less energetic and more stable particles within a fraction of a second. But since it is accelerated to near c, we'll assume that it will take it one second in the observer's timeframe to decay. After one second in the observer's timeframe, the parent particle decays into two daughter particles. Do those two new particles keep traveling in the same "direction" as the parent particle did, or will the event of decaying cause them to change their trajectory? | [
"In the rest frame of the particle, the daughter products will have some moment that adds up to zero. If that rest frame is moving very fast relative to some other frame, in that other frame the daughter products will have momenta such that the center of mass is still moving really fast in the same direction."
] | [
"The net momentum of the particles will be zero, as long as the fission also emits gamma rays carrying the extra humph. From a spectators standpoint, both particles would move in such a way that the center of mass is travelling in the same direction as the \"mother\" particle.",
"I'm only commenting to stress the... | [
"Why would you need gamma rays for that? If a particle decays into two daughter particles, they just go back-to-back in the rest frame of the parent."
] |
[
"Why can electomagnetic waves travel in void, while acoustic waves can't?"
] | [
false
] | null | [
"Acoustic waves are oscillations in some sort of material medium like air or water. Without the material medium to oscillate, there can be no sound. Electromagnetic waves are oscillating electric and magnetic fields, so EM waves can travel through any region of space that contains these fields. The nice thing about... | [
"But if EM waves can travel through any region of space that contains EM field, can it travel through a perfect void?"
] | [
"If there is a perfect void, the EM wave will travel through it because it will create its own oscillating electric and magnetic fields in the void. ",
"Maybe try thinking of a situation in which you are trying to cross a deep ravine. If there is a bridge already built across the ravine, then you just have to wal... |
[
"When calculating thermal expansion, do you multiply the thermal expansion of oxides by their mass percentage or molar mass percentage in a glaze?"
] | [
false
] | I’m a ceramicist and I’m making a calculator for glaze analysis. I want my calculator to output the co-efficient of thermal expansion of the fired glaze as calculated by the expansion of the various oxides that make up the glaze, but I don’t know (and haven’t been able to find out) if I should be calculating from the mass or molar mass percentage of the oxides. Let me know if I didn’t explain anything well enough! | [
"Ok, I'm out of my tree here, so far that the squirrels are sending out search parties. But as a general note, the coefficient of expansion is 1/V dV/dT. So for a first order approximation, you want the relative volumes, not the masses. So, I'd go by the absolute mass for every oxide in the mixture divided by its d... | [
"Not exactly sure what you are aiming at. Do you want to derive the coefficient of expansion for a mixed oxide from the coefficients of the individual oxides in the mixture? I'm not a solid state guy, but that doesn't seem quite straightforward to me, since you'd have to take the interactions between the individual... | [
"That sounds like what I’m going for and yes it’s not totally straightforward or completely accurate, but it’s the common way of doing things and it gives a workable ballpark figure. ",
"I’ll try and give some more background. Mix raw materials together to make glaze, pour glaze on pottery, fire to 2,360.F, carbo... |
[
"Why are astronomers obsessed with finding water on extrasolar planets?"
] | [
false
] | [deleted] | [
"If you want to buy food, do you go to the grocery store, or do you just wander into the nearest retail outlet? Sure, there ",
" be food in the clothing store, or the furniture outlet, or the hardware store. But since you ",
" the grocery store can have food, and lots of it, you head straight for that. Looki... | [
"Well, life is built out of super-complex chemistry. Most of the complex chemistry we know about needs water to work. Any sort of chemistry based life needs some sort of solvent, just because otherwise chemicals can't float around and bump into each other. There's also a question of prevalence. Liquid water is ... | [
"Ah. This makes sense. However, is there nothing that precludes the possibility of life existing outside an aqueous medium?"
] |
[
"'Permanent' Storms. Would it be possible for them to persist on Earth?"
] | [
false
] | [deleted] | [
"Doe the ",
"Catacumbo lightning",
" count?"
] | [
"Best I've got on Earth is 31 days for Hurricane John in '94. ",
"I couldn't tell you if longer were possible from a technical perspective. "
] | [
"nearly, i'm wondering more about a giant weather system than a smaller local phenomenon.. still this is really interesting thanks for the link."
] |
[
"A weird question: could a giant pitcher plant dissolve humans?"
] | [
false
] | Presume that there is one of those carnivorous pitcher plants, but it was scaled up. Ignoring issues of base fragility and other scaling problems, suppose a human being were trapped in there. Would the fluids inside be able to dissolve them, or would it not be able to decompose our skin like it does insects? | [
"Assuming that the person was incapable of moving, and the plant was scaled up enough that it could a) contain a person b) drown said person (which is how it kills its prey) c) secrete enough enzymes to dissolve the person, yes it could eat a human. It has been known to ",
"eat small rats, mice, lizards and even ... | [
"Does the animal/human need to be dead and rotting before it will digest them?",
"No, the enzymes are working from the start. However, if the animal isn't dead it will continue to thrash about which could severely damage the plant. IF someone was trapped inside and was still living but could not get out, and didn... | [
"Good question. Reading ",
"this nice historic overview",
", it seems there's still quite a bit we don't know about how ",
" digests its victims. It's apparently known that it secretes an acid protease, i.e. a protein-digesting enzyme that only works in very acidic conditions. So it clearly does some digestin... |
[
"What's the most accepted hypothesis (or theory) for the cause (not pathology) of autoimmune diseases?"
] | [
false
] | null | [
"As many people have mentioned, there is no one 'most accepted' hypothesis (or factor, let's say) that is thought to be the primary ccause of autoimmune diseases. However, people haven't given a lot of details on some of the current popular hypotheses, including ones that relate to things you've brought up in comme... | [
"Thank you! Very informative."
] | [
"Yes of course anything can be spontaneous, but there's an epidemiology to think about, we see those diseases more in women, more in 1st world countries, more if there's a family history... etc.",
"So there must be some factors that are much more important than chance."
] |
[
"Why are our brains so high up in our bodies?"
] | [
false
] | Since blood is heavily influenced by gravity, and the brain requires a lot of oxygen to function properly, why do we have our brains in the highest part of our body, as it takes a lot of energy for great amounts of blood to be pumped all the way up there? | [
"This is due to the evolutionary trend in early chordates (more specifically the ",
"craniates",
") for ",
"cephalization.",
" Sensory organs and nerve bundles gravitated towards one end of the body to eventually form the head with the brain, eyes and nose in the same general region. This general blueprint ... | [
"It is possible to expand on this a bit. sensory organs tend to cluster around mouth-like orifices. Which makes some sense as organisms want to be able to find food and then put it in their mouths. This sets up an early axis of asymmetry where one end tends to have both sensory organs and mouths.",
"When adding ... | [
"To build off this even further...for the reasons you both mention, the brain starts off in the \"head\" region of vertebrates. These were fishlike creatures, so OP's blood-pressure issue wasn't an issue...the head was at the front, it was no higher than any other part of the body. This horizontal body plan conti... |
[
"Why do astronomers think themselves immune to the uncertainty principle?"
] | [
false
] | null | [
"Astronomers aren't \"immune\", really, any more than baseball pitchers are. First let's get straight what the uncertainty principle actually is. There are many uncertainty principles, but the one you are referencing is the classic ∆x∆p ≥ ℏ/2, where ∆x is uncertainty in the position, ∆p is the uncertainty in the mo... | [
"Whether space is open, closed, or flat doesn't affect it. The quantum effect is just too small to notice at classical, much less cosmological, scales. The uncertainty principle isn't proportional. It's an absolute size minimum on the uncertainties. When the values measured are very large, those size minimums are s... | [
"Just to be clear, whether space is open or closed or flat DOES affect exactly how distance and velocity are related (so far it's indistinguishable from flat). It just doesn't affect whether the uncertainty principle is important in those measurements."
] |
[
"What part of honey is antimicrobial?"
] | [
false
] | I've often heard that honey is antimicrobial, and it does seem to have an incredible shelf life for something that's mostly sugar and water. What is in honey that keeps it from going bad? | [
"Oddly enough, it's the sugar. Honey is so concentrated that it exerts tremendous osmotic pressure, essentially meaning that it sucks the water right out of micro-organisms. In addition, it's fairly acidic, and contains some hydrogen peroxide. You do have to keep honey sealed, or it will absorb moisture and eventua... | [
"And this is known as the ",
"water activity",
" of something. If you add enough sugar there isn't really any living thing that can hold water, and without water there is no life.",
"In fact low water activity is the main preservative in MANY foods. It's the reason syrups don't really spoil (honey, maple syru... | [
"Strictly speaking honey is \"bacteriostatic.\" meaning that it inhibits the growth of microorganisms but doesn't kill them reliably.",
"This is mostly due to it's low water activity and high sugar content, it tends to dehydrate cells exposed to it. ",
"Honey which has been heavily diluted with water is used to... |
[
"If I take half a dose of a drug, does it last half as long, or is it half as effective, or is it a mix of both?"
] | [
false
] | For example, if I drink half of a Five Hour Energy, do I have lots of energy for 2.5 hours, or some energy for 5 hours? Or is it somewhere in between? Also, is it different for different drugs, like tylenol or adderall? | [
"It would come down to the ",
"dose-response curve",
" of the drug. It may be that the drug works but for a shorter time or it may not work at all. You need to overcome a minimal effective concentration or ",
"minimal inhibitory concentration",
" and enter a therapeutic range for many drugs. This would be... | [
"It depends on the mechanism of action. Seroquel 50mg = sleeping pill/anti-histamine; 100mg = antidepressant; 200mg = mood stabilizer; >300mg = antipsychotic. Same molecule.",
"This three-part series (parts ",
"one",
", ",
"two",
" and ",
"three",
") should give you an idea of how deep the rabbit hole... | [
"My personal knowledge about drug delivery (specifically, dissolution, some basics about drug kinetics, and that really boring pharmacy class I took 2 years ago) concur."
] |
[
"Does the moon cause tides in the mantle of the Earth similar to the tides it causes in the ocean?"
] | [
false
] | null | [
"Actually, it is estimated that the earth internal heat was 3% the effect of the friction caused by the moon pulling the mantle over the years. This has caused the moon to lose it's orbital height slightly and you can make some estimates of the early times of the moon based on model and calculation of the earth int... | [
"The moon does warp the shape of the Earth, but it is only a very slight difference since the mantle is ~99% solid and far more rigid than the oceans. Other planet-moon pairs where there are much larger masses involved (Like Jupiter and Io) can distort the moon's shape enough to cause significant friction and heati... | [
"Well, it's observable by instrumentation - not observable on a scale normal human senses could pick up. Practical effects are a slight increase in temperature inside the planet, but that is about it. Other factors influence volcanism much, much more. ",
"It undoubtedly has ",
" small impact on many different t... |
[
"Muscle memory and brain injuries"
] | [
false
] | Does muscle memory remain after any brain injury/trauma where there is memory loss? For example, a weight lifter ends up with a brain injury and is not able to train for a few months, and also ends up with some memory loss that might or might not be about his weight lifting. Does the muscle memory still remain or will the lifter have to start from scratch? | [
"Muscle memory is actually stored in both the basal ganglia and the cerebellum, the cerebellum is a part of the brain dedicated to motor control. The basal ganglia is a much deeper structure in the brain and is responsible for a lot more then movement; including cognition and emotion. ",
"Losing the ability you t... | [
"Muscle memory is formed and stored in the basal ganglia. A brain injury that spares these parts will not impact muscle memory. This is where you get those stories of people getting brain injuries and losing memories but they can still do things like tie shoes or perform repetitive motions that they did before the... | [
"There exists more than one type of memory, so the answer to your question depends on the specific injury. A good example for your question is ",
"patient H.M.",
". He had surgery on both hemispheres of his brain in an attempt to treat an intractable seizure disorder. Unfortunately, he was left with an inabilit... |
[
"Charon is being considered as a dwarf planet because its orbit makes Pluto wobble. Why?"
] | [
false
] | [deleted] | [
"It's because their common centre of gravity (the point about which they orbit or 'wobble' in the case of the larger mass) is entirely outside the surface of Pluto."
] | [
"Huh, didn't realize that Jupiter was massive enough to have a barycentre with the sun outside of the suns radius.",
"I'd think it gets even more complicated to work out the solar system barycentre,or rather the centre point around which all the bodies effectively orbit once you take all the other gas giants into... | [
"Which is fine, but the other day I read that jupiter and the sun do the same thing! Now obviously we aren't going to call the solar system a binary system, but that puts it in a different category to the planets. "
] |
[
"If the earth rotated on a horizontal axis like Uranus would it make much difference to life on earth?"
] | [
false
] | null | [
"Edit: For anyone who doesn't know about the rotational axis of Uranus and what this question is about, see ",
"this",
".",
"The seasons would be very extreme. Basically the polar circles would be at the equator, and all seasonal effects now only happening at polar regions would affect the whole globe to some... | [
"This is assuming that the geographical and geological features of the Earth would be the same as they are now. But since with a different rotation the shape of the Earth would be different can we actually assume that the way the continents panned out would be same?"
] | [
"Yes true. I just figured it was easier to refer to different latitudes like that. When I said Europe and United States I really meant anything beyond about 30 degrees northern or southern latitude, whatever continents might be there.",
"I have no idea how the continental movement would be affected but I guess it... |
[
"What makes things soluble?"
] | [
false
] | [deleted] | [
"Alright, I'm going to cite heavily from ",
"Intermolecular and Surface Forces",
" here. I'm going to assume you're talking about a solid salt dissolving in water, but the same general framework is true for anything, with modifications.",
" The solubility of a solid in a liquid depends on whether the individu... | [
"Dissolving happens when dipoles react to ionic bonds. When charges on the ions attract dissolving substance, the dipoles manage to 'screen' charge of ions for each other so the force holding them together weakens."
] | [
"Like dissolves like. Things that dissolve in water are called hydrophilic or ionic/polar. The hydrogens in water are slightly positively charge (not a full ionic charge like Na+) and oxygen has a slightly negative charge. This happens because in a molecule, the atoms share electrons, but unequally. Oxygen nuclei h... |
[
"Could or do steam power plants close to coastlines double as desalination plants?"
] | [
false
] | null | [
"They can't use salt water in the boilers or turbines. Regular tap water is not even good enough. Steam power plants use incredibly pure water (the contaminants are measured in the low ppm). This water is heated in excess of 600 Degrees and many of the contaminants found in un-purified water would react with and co... | [
"There are already power plants that do this. Theres an actual word for what you are talking about.",
"Cogeneration: The use of excess heat from power production to accomplish another task.",
"They have plants all over the world that use this system to desalinate sea water."
] | [
"You are right that drinking ultrapure water can be dangerous, but this is only the case when drinking it on a regular basis. So yes it would be unsuitable as a drinking water supply, but its not going to burn your mouth or anything. The main issue is that the water leaves you body with more minerals than it enter... |
[
"Is there a name for this/am I just imagining this? (Genetics)"
] | [
false
] | [deleted] | [
"There is a phenomenon called ",
"chimerism",
", where the zygotes of fraternal twins merge into a single embryo, resulting in one organism whose DNA varies throughout their bodies.",
"I'm not sure if it expresses in the way you describe. As always, seek advice from a medical professional on such matters."
] | [
"Sounds like a normal degree of variation that occurs in the development of all symmetrical animals; when symmetry is dependent upon a complex series of gene expressions within spatial perimeters defined by protein gradients—themselves the product of previous gene expressions and their interactions—then variable am... | [
"Apparently you can check."
] |
[
"Statistically speaking, is there any Isaac Newton in my bowl of porridge?"
] | [
false
] | Was pondering this thought with a colleague. Is there any chance any of his molecules are in my breakfast? | [
" There will be about 10 million atoms of Isaac Newton in every ounce of your soup. The same is true for any other person who ever lived. ",
" You are what you eat. I mean that in a very literal sense too; your body uses the food you eat to build tissue and it uses the water you drink to subsist. By this logic, N... | [
"The water didnt necessarily just pass right through him. Your body uses water in everything, so a good portion of those 10 million atoms will have been his sweat blood and tears ( and everything else). ",
"What Im trying to say is that Newton spit in your food :/"
] | [
"Does that take into consideration that he'd likely be using particles previously part of him? Surely there's diminishing returns in a method difficult to caluckate"
] |
[
"If a predator had an endless supply of prey, would they get fat?"
] | [
false
] | So theoretically speaking, if a predator has access to an unlimited supply of prey, which take minimal effort to catch and eat, would that predator typically just continue eating as much of that prey as possible and subsequently get fatter, or would there be a reason for the predator to regulate its hunting/ eating as to not get fat? | [
"It depends on the predator. Some animals will stop eating when they are full. Most large animals will consume enough food today that they can go tomorrow without food. There is a limit to how many days food they are willing to store. Some predators are also prey and they have to maintain the ability to run. I... | [
"It's not just what tastes good, which is definitely a large part of it.",
"Changes in portion sizes, in the US at least, have played a large role in obesity.",
"If you look at nutritional guidelines and prepare a meal at home, then have that same dish at an American restaurant, I suspect you'll find that the r... | [
"Bears will always choose to get as fat as possible. They don't need to run from anything and they are adapted to save up for hibernation. A few years ago one in NC got access to a pig farm and turned himself into a blimp."
] |
[
"When integrating a linear reciprocal function that can be factorised, should you factorise the function before integrating?"
] | [
false
] | This might be a stupid question, however I have noticed that when integrating a linear reciprocal function which can be factorised, you get different results depending on whether you factorise it or not. For example, if you integrate 1/(3x + 9) without factorising, you get 1/3ln(3x + 9) + C However, if you factorise 1/(3x + 9) first and integrate 1/(3(x + 3)), you get 1/3ln(x + 3) + C My question is, should you factorise a linear reciprocal fuction before integrating it? I thought that maybe the constant of integration would account for the difference, however I can't see how that would work for definite integrals. Sorry if I'm being an idiot. | [
"I thought that maybe the constant of integration would account for the difference,",
"This is correct. ln(3x + 9) = ln(3(x+3)) = ln(3) + ln(x+3), so the difference is the constant ln(3).",
"however I can't see how that would work for definite integrals",
"Constants of integration never affect definite integr... | [
"As it has been pointed out that it doesn't change the result in this case, but it's worth noting that factorizing is one way to solve more complicated integrals.",
"For instance, consider (x",
" + 3x +4)/(3(x",
" + x",
" + x +1)). This looks like a nasty thing to integrate, but once you realize that you ca... | [
"ln(x+3)/3 and ln(3x+9)/3 are the same up to a constant of integration."
] |
[
"Why is it bad if air bubbles get into your bloodstream?"
] | [
false
] | null | [
"The heart muscle contracts and pushes blood forward. The air will travel through your circulatory system until it gets to your heart. Because air can be compressed much more than liquids can, the heart squeezes the air but it just pushes the air molecules closer together instead of pushing the air forward, meaning... | [
"Short version: it takes up space that should be occupied by blood, screwing up circulation.",
"http://en.wikipedia.org/wiki/Air_embolism",
"A small one isn't likely to cause problems. A big one will kill you."
] | [
"Yup. I'm not sure how much air. If there are little bubbles (champagne bubbles) in IV tubing, we don't worry about it. 10ccs would probably do it. ",
"There's something called a central line- an IV where the tube in the blood vessel goes all the way to the heart. I've heard of a patient dying because someone ac... |
[
"I can keep my eyes active while closed, to a slideshow of 5 crazy morphing images/second. What's going on?"
] | [
false
] | null | [
"I can do this too! It's usually scary monster faces that merge and morph randomly every second or two. I thought I was the only one!"
] | [
"Do you do it to try to fall asleep, or can you do it any time? What do you do to start it?"
] | [
"I usually do it out of pure boredom. I would say mostly at night when im chillin or dozy. Sometimes my brain 'isn't in the mood' and it doesn't work, or it might take a while to snap into the mode.",
"Another variation I do is where i get cloth material or a jumper and but it over my eyes - the cloth has to be t... |
[
"How easy is it for electricity to arc in a vacuum?"
] | [
false
] | I'm doing a project that's going to involve running a bunch of electronics in a near vacuum. Unfortunately I have basically zero experience working in a vacuum. I've done my best to account for a lot of the factors that could affect the circuit based on what I've been reading, but my big concern is that I need a kill switch that will physically disconnect power from the circuit controlling a set of 12V motors while it's being pressed. I've found a number of normally closed buttons that would work under regular conditions, but my concern is that the voltage can just arc across the leads in the switch even if it's opened once it's in the vacuum. Realistically, is this something I will likely need to worry about, or is there an equation that can give me an idea of whether or not arcing is likely? If you need more info. The switch is going to be connecting a 12V battery to a circuit, and the physical action that's going to press the switch is at most an inch. I'll have electronic measures as a backup, but ideally I would like to be able to physically cut the power. | [
"In vacuum, there is no conductive material to allow current to flow through it."
] | [
"Arcing through air is easier than arcing through vacuum, because the air can be ionized and provide a conductive path for the current to flow through.",
"You can see a list of dielectric strengths of various media ",
"here",
"."
] | [
"I work with a small hydro-electric power system. Our main switchgear uses vacuum breakers. It's designed for 5kV at up to 100A.",
"Anyhow, the actual switching is a set of contacts inside a glass bottle. The bottle is under strong vacuum, and the contacts are moved via magnetic forces.",
"Anyhow, the long and ... |
[
"Does an interferometer add or multiply together signals? Is it either?"
] | [
false
] | I'm studying honours physics right now and have to get an understanding of interferometers, specifically in the context of astronomy and interferometer telescope arrays. However, I'm having some trouble as we only covered the basics of interferometers in undergrad. We went over stuff like the Michelson-Morley experiment and obviously did wave interference, but not as much in terms of modern application. It seems to me that devices where multiple light beams are sent to interfere directly, and then detected, are called interferometers. This makes sense to me as you are using the interference of the two signals to measure something or to filter noise. But, in the notes I have for my project, the basic example of an interferometer array made of two telescope dishes looking at some source has the signal correlation be a multiplication instead. I understand that this would also show you where the signals correlate, and would cancel out some random noise that is specific to one of the telescopes. But this doesn't really seem like it is interference. Or am I just doing wrong something really basic to do with interference? Thanks. | [
"There are a couple things that you could be referring to:",
"1) There are a number of trig identities that turn adding two trig functions into multiplying two trig functions. One that you may have seen in class is the beat frequency: Add two waves with similar frequencies, and it becomes one wave with the mean f... | [
"you may have seen in class is the beat frequency",
"To actually get the beat frequency, say 1000Hz & 1050Hz = 50Hz (actualy 50Hz & 2050Hz, the sum and differences), requires non-linear interactions. Otherwise adding the two merely ",
"linearly superimposes them",
", while the ",
" shows the beat. There is ... | [
"Two waves at a point in space: Y1=A*sin((w0+wb/2)t), Y2=A*sin((w0-wb/2)t)",
"Y1+Y2=A*[sin(w0t+wbt/2)+sin(w0t-wbt/2)]",
"sum of angle identity: sin(a+b)=sin(a)cos(b)+cos(a)sin(b)",
"Y1+Y2=A*[sin(w0t)cos(wbt/2)+cos(w0t)sin(wbt/2)+sin(w0t)cos(wbt/2)-cos(w0t)(sin(wbt/2)]",
"Y1+Y2=2Asin(w0t)cos(wbt/2)",
"",
... |
[
"AskScience AMA Series: I'm David Pogue, tech and science writer, and host of NOVA PBS' new series Beyond the Elements. AMA!"
] | [
false
] | A former weekly tech columnist from 2000 to 2013, I'm a five-time Emmy winner for my stories on , a bestselling author, a five-time TED speaker, and host of 20 science specials on PBS. My most recent special is a mini-series called " ," a sequel to my 2012 documentary " ," which has become a staple in science classrooms worldwide. The new show's three one-hour episodes take me on a worldwide quest for the key molecules and chemical reactions that make up human civilization, including concrete and fertilizer, plastic and rubber, fire and venom, explosives and hot peppers. I've written or cowritten more than 120 books, including dozens in the Missing Manual tech series, which I created in 1999; six books in the line (including , , , and ); two novels (one for middle-schoolers); my three bestselling books of tips and shortcuts (on , , and ); my how-to guides and ; and my 620-page magnum opus, . After graduating summa cum laude from Yale in 1985 with a distinction in music, I spent 10 years conducting and arranging Broadway musicals in New York. I won a Loeb Award for journalism, two Webby awards, and an honorary doctorate in music. I live in Connecticut and San Francisco with my wife Nicki and our blended brood of five spectacular children. For a complete list of my columns and videos, and to sign up to get them by email, visit . On Twitter, I'm ; on the web, I'm at . I welcome civil email exchanges at , and of course, AMA! I'll be on at noon (ET; 16 UT), AMA! Username: | [
"David Pogue! I used to love your tech reviews. Feels like a long time ago, when the internet was a different place. \nI see you continue to be insanely prolific. I'll check out some of these links. ",
"Question? What's your favourite element?"
] | [
"I used to love those tech reviews, too! :) ",
"Favorite element: Sodium, for a really personal reason. Of course, sodium explodes violently with water—but when we mix it with a lethal gas (chlorine), we get table salt (NaCl). This is nothing new--but one of the early NOVA shoots on \"Hunting the Elements\" invol... | [
"You've heard of most of them--self-driving cars, phasing out coal, etc. But here's one that's not on anyone's radar: SIT (sterile insect technique) for mosquitoes!",
"With climate change, mosquitoes are advancing northward incredibly fast, making more people sick in more places. Insecticide and genetic engineeri... |
[
"Are solar panels in hotter places more efficient than solar panels in other, cooler temperatures?"
] | [
false
] | By hotter places, I mean surface level temperature and the temperature you see on the weather Does it even make a difference ? If so by how much? | [
"The technically correct answer is that lower temperatures are more efficient, the thermal coefficient is about -0.4%/⁰K, see PV panel datasheet ",
"example (pdf)",
", however, that colder temperature usually means the sun is lower in the sky, losing energy due to ",
"air mass",
".",
"\nFind locations of ... | [
"I don’t believe it’s the temperature that matters",
"Solar panel efficiency decreases with increasing temperature",
"."
] | [
"What happens is that temperature shifts the bandgap of semiconductors. Very low or very high temperatures can have ",
"dramatic effects",
" on the color an LED emits, and on the colors that solar panels can efficiently absorb.",
"Almost all solar panels on the market use silicon as their semiconductor. Silic... |
[
"Reddit, my bedroom is directly above my kitchen. Every time someone switches on the microwave, my internet freezes for whatever the duration of the time set. Why is it doing this, and how can I stop this happening?"
] | [
false
] | null | [
"Interference. You can stop it by using a hard-wired connection instead of wireless. Failing that, reposition your wireless access point or your microwave. "
] | [
"I presume you mean your wireless internet. ",
"Get an 80211.n wireless instead of b/g. Different frequency. "
] | [
"You could also change the channel your router is signalling on, I'd suggest doing that as well."
] |
[
"Ask Anything Wednesday - Engineering, Mathematics, Computer Science"
] | [
false
] | Welcome to our weekly feature, Ask Anything Wednesday - this week we are focusing on Do you have a question within these topics you weren't sure was worth submitting? Is something a bit too speculative for a typical post? No question is too big or small for AAW. In this thread you can ask any science-related question! Things like: "What would happen if...", "How will the future...", "If all the rules for 'X' were different...", "Why does my...". Please post your question as a top-level response to this, and our team of panellists will be here to answer and discuss your questions. The other topic areas will appear in future Ask Anything Wednesdays, so if you have other questions not covered by this weeks theme please either hold on to it until those topics come around, or go and post over in our sister subreddit , where every day is Ask Anything Wednesday! Off-theme questions in this post will be removed to try and keep the thread a manageable size for both our readers and panellists. Please only answer a posted question if you are an expert in the field. . In short, this is a moderated subreddit, and responses which do not meet our quality guidelines will be removed. Remember, peer reviewed sources are always appreciated, and anecdotes are absolutely not appropriate. In general if your answer begins with 'I think', or 'I've heard', then it's not suitable for . If you would like to become a member of the AskScience panel, . Past AskAnythingWednesday posts . Ask away! | [
"In the future do we think they might be able to delete memories?",
"I’m thinking brain mapping technology. EMDR, neuroplasticity but using computers to actually reprogram us, rewire us. PTSD and survivors. ",
"Too sci-fi or an actual possibility?"
] | [
"I've read that mobile communication like LTE is limited when moving fast, such as using it on a train or car. See ",
"here",
" for example.",
"What causes this limitation and why is this not an issue with internet on planes?"
] | [
"*Correct me if I'm wrong* But sending any kind of signal that needs satellites requires a steady place. Imagine you send your signal to the satellite in space and it needs to resend the feedback signal. So if you move faster the signal will have a harder time to hit your location as it is changing fast. Planes, on... |
[
"What if we could see more of the electromagnetic spectrum?"
] | [
false
] | [deleted] | [
"there is a condition known as ",
"Aphakia",
" where the lens of the eye is removed. The lens is a 'strong' UV absorber and after its removal some people are able to be able to see ultraviolet down to ~ 300 nm. They report seeing blue/white/violet light. "
] | [
"Well, the sky would look like ",
"this"
] | [
"This is kind of a fun experiment -- most phone cameras can see into the infrared frequencies. Next time you're watching TV turn on your camera and point it at the tip of your remote control where the little light is. When you press any button on the remote you'll see the flash of IR light through your camera but n... |
[
"Will the push to cloud services eventually lead to bandwidth saturation?"
] | [
false
] | I remember hearing a few years back that there was barely enough bandwidth to keep up with the mobile devices in existence, this was ~5 years ago. Of course, I believe it was offered as a defense against criticism of Comcast pricing, so take it for what its worth. But, reductum ad absurdum- will moore's law eventually be unable to keep up if we move ALL services, software, and data storage to the cloud? I think it will, thats why I'm sticking with my desktop, linux, and local music and move storage. I don't think the cloud is the future and everyone will eventually be back to the desktop. | [
"Mobile devices are subject to frequency limitations; there are only so many channels to transmit on and once they are in use you are at capacity. This can be combatted with shorter range coverage, which we already see in the use of WiFi. Many locations within the range of one cell tower can reuse the same WiFi cha... | [
"Thanks for the clarification. I'm not necessarily assuming infrastructure will stagnate, just wondering if development can keep up. "
] | [
"Thanks for the clarification. I'm not necessarily assuming infrastructure will stagnate, just wondering if development can keep up. "
] |
[
"What is it about copper that gives it anti-microbial properties? Why does bacteria die when it comes in contact with it?"
] | [
false
] | null | [
"Copper produces hydrogen peroxide and oxygen radicals via the Fenton reaction. Lipid peroxidation in the bacterial outer membrane ensues, eventually leading to a loss of membrane integrity and cell lysis. A recent ",
"paper",
" reported 10",
" cells being killed in less than 3 hrs. "
] | [
"Copper truly is the death metal."
] | [
"So if we make a similar knight's move down the periodic table, we find that shampoo should kill aliens."
] |
[
"A question on herbivores, protein and evolution."
] | [
false
] | Two questions, actually: 1) How do herbivores 'get' the necessary protein (and other dietary necessities for animals) without eating other animals? Have they evolved some method of coping with not eating meat in ways that humans and other omnivores have not? 2) What are the evolutionary advantages of having to hunt and kill your food? Why would any animals have evolved to be carnivores? Thanks! | [
"1) Plants have protein. Plenty of humans eat only plants and don't suffer from protein deficiencies. ",
"2) Other animals are the most dense source of food energy around, so if you can catch and eat another animal without spending too much energy in the process, it's a pretty good way to spend your time. Herb... | [
"I thought that only animals/dairy had protein",
"Everything that is alive has proteins, they are an essential component of life. This includes animals, plants, bacteria, and even viruses.",
"Proteins are made of amino acids. There are many amino acids, but only 22 are ",
"proteinogenic",
", that is, requir... | [
"Oh - I thought that only animals/dairy had protein, and that vegans (especially) were prone to protein (as well as other) deficiencies?"
] |
[
"What FOV do humans have (like in video games)? Can it very from person to person?"
] | [
false
] | null | [
"The field of view is close to 180 degrees. But the resolution are the extreme edges is very low, only able to detect motion. Most of our field of view has low resolution, a human eye only has around one megapixel. Nearly all of that is concentrated in a tiny area in the centre of our field of view, about the wi... | [
"honestly, yes, it's highly variable. there is fov, and then useful fov. it has to do with periphery vision. in this case, you should at least read this ",
"https://en.wikipedia.org/wiki/Vision_span",
" ",
"it's a pretty good explanation."
] | [
"Human field of view is around 210 degrees horizontally. Each eye has about 150 degrees, with about 110 degrees common to the two and 40 degrees visible only to that eye.",
"While I'm not sure, I'd guess there is a fairly narrow range of individual differences in FOV for humans with binocular vision. Differences ... |
[
"Is there any functional difference between a capacitor and a rechargeable battery?"
] | [
false
] | null | [
"The hell are you talking about?\nThat's not just crude, that is completely and utterly wrong, and is absolutely not a good way to visualize anything!",
"Capacitors absolutely don't create some \"pulsation\", although they are ",
" frequently used to ",
" pulsation coming from rectifiers."
] | [
"Yes. Batteries store small amounts of energy (relative to their mass) and release it over long periods of time, ideally in a mostly constant fashion. Capacitors store large amounts of energy and release it over short amounts of time in an exponential fashion. ",
"From a more theoretical perspective in circuit de... | [
"Wait what? You know that's EXACTLY how a camera flash works right? A capacitor is able to effectively dump it's entire charge in a fraction of a second. If you let the capacitor charge and then release you are not \"crudely\" defining pulsation, that's literally the definition of pulsation."
] |
[
"Since the event at CERN that proved the existence of Higgs bosons/Higgs field, can we now see this event happen regularly now we know ‘where’ to look?"
] | [
false
] | null | [
"It doesn't quite work that way. There never was a single event at CERN that proved the existence of the Higgs. What happened was, they announced a few years ago, and detailed in subsequent paper, a statistical analysis of the decay products detected after countless collision and deduced the existence of a subato... | [
"I'll give it a shot:",
"On the axis you can see the production cross-sections of gluon fusion (ggH) and vector boson fusion (VBF)... cross-sections can be interpreted as a measure of \"event frequency\". ggH and VBF are different ways the Higgs can be produced (the 2 most common)",
"The 2 \"blobs\" are 2 of th... | [
"can you elaborate what figure 4 in your link means?"
] |
[
"If magnetic pull between a magnet and a piece of metal operates under an inverse square law, is this then an inverse to the power of 4 when changing the distance between two magnets?"
] | [
false
] | null | [
"The field of a dipole goes like 1/r",
", so the ",
"force",
" goes like 1/r",
"."
] | [
"This is also true between a magnetic dipole and non-magnetized metal, right? Because the magnetic dipole induces a dipole in the non-magnetized metal?"
] | [
"The same would be true for either an induced dipole or a permanent dipole."
] |
[
"Which 'light' does photosynthesis use exactly? Ultraviolet?"
] | [
false
] | Been searching but most sources say it uses 'sunlight' or 'light energy'. I want to know exactly which kind of light it is. Can you technically shine a UV lamp onto a plant and promote photosynthesis? | [
"Chlorophyll a absorbs most strongly red light, while chlorophyll b absorbs blue light most strongly. The light that's left over is green light which is why plants look green.",
"Check this out for more detail:\n",
"http://hyperphysics.phy-astr.gsu.edu/hbase/biology/ligabs.html"
] | [
"Chlorophyll can absorb some UV light, but UV light is also absorbed by many other components of the cell, including DNA. UV light can damage DNA, and is generally detrimental to plant growth, so plants have evolved protective strategies, including producing \"sunscreen\" compounds that absorb UV light. ",
"Her... | [
"Well, just from noting the color of the light that the leaves reflect (green), you can tell the color they must absorb (red). ",
"Wikipedia",
" also says some plants absorb at a blue-violet wavelength as well so maybe they can use some UV light. "
] |
[
"How can extra dimensions be 'small' in string theory? And how do these additional dimensions enable string theory?"
] | [
false
] | null | [
"Think of a cylinder, the direction \"around\" is always at right angles to \"along\". Now imagine that the cylinder is very (or infinitely) long but has a small diameter"
] | [
"Only if you want it to be. Imagine something like an old arcade game where the left and right of the screen wrap around to each other, but up and down the screen is really long (and don't wrap around) that's a cylinder that is purely 2D, no need to put it in 3D.",
"The point is though, here is a simple example o... | [
"That's exactly it.",
"The second part of the question relies on stuff that's a lot more technical and I can't think of a good reason it \"should\" be true. The upshot is though that string theory is only even self-consistent when there are a specific number of dimensions, 9 of space and 1 of time (or 25 + 1 for ... |
[
"In terms of killing potentially harmful bacteria/viruses/etc., what is the most effective way of cooking food?"
] | [
false
] | Taste or evenness of heating notwithstanding, which method of cooking food would be the most effective in terms of making food safe for consumption? The idea for this question came from on the Lobsters/Crabs feel pain thread in . Would electrocuting your food before cooking it more traditionally (or hell, just cooking it via electrocution) have a more or less noticeable effect on germ populations? | [
"You might want to cite your sources on the nutrients claim there."
] | [
"As long as the internal temp reaches 160, it doesn't matter how you cook it. Digital thermometers are great for checking the temp."
] | [
"Which nutrients? And how are they \"killed?\""
] |
[
"Does biking uphill require more energy than running uphill?"
] | [
false
] | null | [
"Naive analysis:",
"If we assume that the two modes of transportation have no energy losses, then we just compare the change in energy between the initial and final states. Assuming you are stationary at the start and end, the relevant energy is the gravitational potential energy E = mgh.\nWalking, you only have ... | [
"Note you probably will feel more tired cycling, because cycling probably goes up the hill more than twice as fast as walking, and therefore requires a higher power input. In this example a cyclist (16 km/h) has an average power input of ~ 1kW, while a walker (4 km/h) has an average power input of ~ 340 W.",
"See... | [
"on the bike you will only burn a percentage of the total energy required.",
"If by \"total energy required\" you mean the total gravitational potential energy gained by moving to the top of the hill, you've got some conservation of energy problems here. Mechanical advantage has nothing to do with it, since Work ... |
[
"How do planets lose their atmosphere?"
] | [
false
] | Can earth lose its atmosphere? How long would it take? | [
"To start you off see ",
"Wikipedia: Atmospheric Escape",
". Given that Earth is pretty massive and that the atmosphere is shielded by Earth's magnetosphere, the Earth doesn't undergo appreciable atmospheric escape and thus won't lose its atmosphere in the lifetime of the solar system."
] | [
"Earth atmosphere would most certainly be blown off by solar winds; however, earth's iron core generates a magnetosphere that protects it."
] | [
"While Earth's magnetosphere does shield the Earth and its atmosphere from the solar wind, it is not necessary to have a magnetosphere to keep an atmosphere. An example of this is Venus which has a very think atmosphere and no magnetosphere."
] |
[
"How did all the gases in the Earth develop if it formed out of gas clouds of hydrogen?"
] | [
false
] | I know that the Sun developed from nebula of hydrogen and helium and the planets formed out of gases that surrounded the Sun by accretion. I also know that before oxygen started liberating from the ocean there was an atmosphere of ammonia, water vapor, carbon dioxide etc. How did all these gases form? | [
"The earth itself didn’t form from hydrogen. First generation stars form out of the light elements first, burn bright and hot and relatively fast, making heavier elements in its core. When one goes nova, it spews out heavier elements like carbon and iron, from which second generation stars (like our sun) are form... | [
"So the earth, everything in it, and everything on it, including you and I, were formed in the crucible of a giant star’s core billions of years ago.",
"Except the hydrogen and a bit of the helium and lithium."
] | [
"This is mostly correct, though there are some elements created in the immediate aftermath of the big bang: ",
"https://en.wikipedia.org/wiki/Big_Bang_nucleosynthesis"
] |
[
"Why do mitochondria have their own separate 'mitochondrial DNA'?"
] | [
false
] | Do other cells or organelles have their own separate DNA? Is it some relic of the very distant past? | [
"It is in fact a relic of the past. Early in the history of life, we believe the eukaryotic ancestor enveloped an aerobic bacterium, but rather than digesting it, it lived within the cell. Eventually, the eukaryote and the bacterium would exchange genetic material, and the two would become interdependent on one ano... | [
"Is it some relic of the very distant past?",
"This is the theory, mitochondrial DNA looks a lot like bacterial DNA so a lot of people subscribe to ",
"endosymbiotic theory",
" for mitochondrial origin.",
"Essentially, the idea is that an early progenitor of multicellular organisms gobbled up a bacteria, an... | [
"They are referencing chloroplasts and possible secondary events of further endosymbiosis. Chloroplasts have three membranes (inner, outer, and thylakoid) and thus are predicted to have undergone a secondary pseudo-endosymbiotic event. Chloroplasts are very similar to mitochondria, but perform photosynthesis to gen... |
[
"The Classic Birds in a Box Question?"
] | [
false
] | [deleted] | [
"If the box is closed, then the weight of the box remains the same whether the birds are in flight or not.",
"If the top is open, then the weight of the box is a function of how high the birds are, as fluid movement can lead to weight transferred outside the box, especially for cases where the birds are near the ... | [
"No i don't think it would change for the birds.",
"The birds must push on the air molecules in the box to fly. The air molecules would then collide with the bottom of the box, which would impart a downward force to it. The magnitude of this force would be equal to that of gravity, because the bird needs to push ... | [
"Mythbusters did it."
] |
[
"Will antibiotics affect corona virus deaths?"
] | [
false
] | null | [
"Hi babamum 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 followi... | [
"Flair choice: medicine"
] | [
"Flair choice: 'Medicine'"
] |
[
"Noah's Ark Thread REMOVED"
] | [
false
] | null | [
"So is this an appropriate place to ask that this subreddit be removed from the default home page?",
"EDIT: Hey guys lets move the meta-discussion ",
"here",
" where it's more productive. Thanks"
] | [
"This is the shit we've had to deal with",
"Please, only answer if A. you actually know what you're talking about, B. the answer is based on scientific evidence or reasoning, C. it actually addresses the question being asked, and sometimes D. if you have a secondary question that adds to the original."
] | [
"I second this, with more vehemence than my clicking an upvote can muster. If we want /askscience to be without tripe and aggravation for mods - it ",
" to get off the default page.",
"Have reddit make a \"you might be interested in...\" interim step of some sort."
] |
[
"Why can a rocket fly straight up without wings and doesn't tip over?"
] | [
false
] | null | [
"Large commercial rockets are actively steered. Either the engines are 'gimbaled' (the angle is adjusted) constantly, or small sideways-pointed rockets are fired as needed, to push the rocket where the computer is programmed to send it.",
"Smaller rockets without adjustable engines or controls normally cause the ... | [
"More fundamentally, ",
"the center of gravity is ahead of the center of pressure",
". This creates a restoring force to counter any destabilizing force.",
"This is why hobby-grade model rockets built by 7-year-olds can launch vertically without active gimbals.",
"On the other hand, gimbals on a large rocke... | [
"The diagram describes rockets with fins. Almost all modern launch vehicles don't have any fins and are actively steered. "
] |
[
"What are the health risks of long term sleep deprivation?"
] | [
false
] | As a busy student this is very relevant to me (surely AskScience of all subs can sympathize). | [
"In a normal state of mind I'd probably be able to contribute something, but right now I am deep in a haze of sleep deprivation."
] | [
"How did you... This post is 13 days old. "
] | [
"Think I was lost somewhere in the CogSci sub-reddit and just kept clicking away. Turns out it's a bad idea for me to browse Reddit while in bed."
] |
[
"How much, if at all, does a human skull grow during adulthood?"
] | [
false
] | null | [
"Thank you for the rude response.",
"Also, please see the sidebar:",
"\"Please keep discussion:",
"Civil",
"On topic",
"Scientific (i.e. based on repeatable analysis published in a peer reviewed journal)\""
] | [
"Thank you for the rude response.",
"Also, please see the sidebar:",
"\"Please keep discussion:",
"Civil",
"On topic",
"Scientific (i.e. based on repeatable analysis published in a peer reviewed journal)\""
] | [
"After having searched and found only info that indicates no growth in adult skulls...",
"I am searching for information that discusses interpupilary growth or changes in adults and the acceptable tolerances for measurements among nationally recognized Opthamological organizations."
] |
[
"How does your immune system directly help with the digestion of food? Aren't enzymes specific to one purpose?"
] | [
false
] | I always thought that enzymes were made for one specific function and that certain enzymes were made to break down a certain kind of carbohydrate or fat or whatever you're digesting. Then I read and got all confused. A nutritionist recently told my father that by eating a bag of sun chips, given that it is not a natural food (natural carbs, fats etc), it is not broken down by the digestive system but by the immune system. The implication is that by involving the immune system and the digestive system it takes away some energy of the body when running. (He is a marathon runner). She also told him that milk is broken down by the immune system. Hence, milk is not a good food. Is this true at all? | [
"The idea of your digestive system appropriating enzymes from your immune system is completely false. Enzymes used by the immune system are produced and used in the cells that make them, they don't go to a central depository that gets shared out."
] | [
"Working on my PhD in nutritional immunology here, so I'll try to help; without more info about how exactly the nutritionist thought the immune system would be involved, it's hard to give a straight answer. ",
"IgA antibodies secreted by the immune cells in the gut can target antigens in the digesta, but their a... | [
"Okay, I'm just a high school bio teacher, so somebody will come along and correct my mistakes hopefully. There is a a distant fainting hint at something almost based on science here. Some proteins are more difficult to digest than others. Some peoples' bodies tag these proteins with immunoglobin, and the body c... |
[
"If babies breathe through the umbilical cord, how do chicks breathe in eggs ?"
] | [
false
] | [deleted] | [
"It's predominately diffusion across the eggshell.",
"...up to the time when internal pipping takes place, when pulmonary ventilation is initiated, about 20 liters (O2 + CO2 + water vapor) have passed through 10,000 pores of an 80 gm egg.",
"--Pores and gas exchange of avian eggs: a review. Rahn H, Paganelli CV... | [
"It is really cool that you are able to explain why, thank you"
] | [
"Great explanation. Is it worth making the distinction between breathing using lungs and being supplied with oxygen through the Allantois organ (effectively the umbilical). Same distinction with human babies. They do not ‘breathe’ using their own lungs until post birth. Prior to birth all oxygen is supplied by the ... |
[
"If alien observers detect the earth through the Transit Photometry method, would it be possible for them to realize earth is inhabited due to our artificial lights?"
] | [
false
] | null | [
"The limitations and capabilities of astronomic measurements are highly speculative? The signal-noise-ratio of transit detection is speculation? Light occlusion methods such as those already used to detect exoplanets(",
"http://www.eso.org/public/news/eso1024/",
") are speculative future tech of which no one kn... | [
"You're asking about the technology, including the sensitivity, of alien observers, which is highly speculative. So is future technology. Current technology is not, and yes, the level of technology definitely determines the limitations and S/N of a transit detection; Kepler has different photometric sensitivity tha... | [
"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."
] |
[
"How much heat does the moon redirect to earth?"
] | [
false
] | For an average distance between the moon and the earth. Is the amount of energy transfer phase dependent? Is it proportional to the level of light received? | [
"Doing the math",
" it's about 107 GW. That sounds like a lot, but that's for the whole Earth. For comparison, the Earth gets about ",
"174 PW",
" from the sun directly, which is about 1.6 million times more.",
"Also it does depend on the phase. What I just gave is average. During a full moon you'd get doub... | [
"Does the moon get heat up by the earth? I know there is no atmosphere, but do the surface rocks heat up from the earth radiating heat? If so, how is this affected by climate change/more greenhouse gases"
] | [
"Yes it is. It makes a bigger difference since the earth is larger than the moon, but it's still pretty tiny. Climate change doesn't do anything. The reason greenhouse gases cause the earth to heat up is that the reflect the infrared light back to the ground. This heats the earth up until it's hot enough that the l... |
[
"Yoga: Are the benefits of yoga scientifically proven? If yes, how did the inventors of yoga make up the asanas and know their benefits?"
] | [
false
] | null | [
"Penn and Teller did an episode of Bullshit on yoga. They claim that all of what is modernly known today as 'yoga' in America was invented very recently (I think the 60's) and just artificially tied to ancient stuff to give it credence.",
"Is stretching, strength training using your own body weight, and regular ... | [
"There's plenty of science related to the health and psychological benefits of exercise in general. Ignoring the meditational aspects of some varieties, yoga is a form of exercise, and as such is going to have benefits. ",
"A google search for \"",
"yoga scientific research",
"\" turns up plenty of specific... | [
"Humans are also romantic creatures, aesthetics is a testament to this. Logic and function is not always the most optimal way in doing this. Making the exercise fit your frame of mind through spiritual mumbo-jumbo enables the function of exercise.",
"So, what I'm trying to say is: It is magical and healing if you... |
[
"Historically how important have viruses been to our evolution?"
] | [
false
] | [deleted] | [
"Viruses have played a very important role in all evolution, including human evolution.",
"The figure you mention is likely referring to the large sections of DNA composed of retrovirus-derived repetitive sequences, or transposons. While human transposons have not been active for millennia, they were active in ou... | [
"I don’t think this is a question that we fully have the answer to yet. We do know of a handful of functional Human Endogenous Retroviruses (HERVs) in our genome. Most of them however are negative, being associated with cancer. It’s pretty well established that a handful of HERVs play vital roles in placenta functi... | [
"There is evidence that the mammalian ability to form a placenta comes from viral DNA ",
"https://whyy.org/segments/the-placenta-went-viral-and-protomammals-were-born/#:~:text=Now%2C%20we%20get%20this%20viral,but%20also%20keeps%20them%20separate",
"."
] |
[
"How can I classify mud?"
] | [
false
] | Hey I am trying to categorize mud so that what I am working on can meet certain requirements. I know there is a way to classify soil, USCS, but does that change with mud? | [
"What does \"Land-Sea Couplings\" research entail?"
] | [
"What does \"Land-Sea Couplings\" research entail?"
] | [
"thanks, but do you have any sort of official source for this or is it just how its done/personal experience type of thing?"
] |
[
"when you get sick and recover, is this like your immune system getting \"exercise?\" is it now stronger for the future?"
] | [
false
] | null | [
"So basically, vaccines are training simulations for your immune system."
] | [
"It's like this in a way, but the \"strength\" is only specific to the illness you just suffered from. For example, recovering from one strain of the flu isn't going to give you protection from all forms of the flu, or from illness in general, but it creates immunity (antibodies) against that particular form to pre... | [
"When you get sick your immune system designs antibodies that learn how to fight off the ailment. This is what a vaccine is for, a weakened version of something the immune system can learn to fight without risking being defeated.",
"In reality I wouldn't say it's exercise to get stronger as much as it's like a mi... |
[
"To what degree can we affect our genetics?"
] | [
false
] | [deleted] | [
"Epigenetics is defined by ",
" changes in gene expression that do not involve changes to/in the actual fundamental sequence of the DNA concerned. There are a number of known molecular mechanisms which govern such changes (e.g. methylation of DNA and various histone modifications). From my knowledge, environmenta... | [
"I think that you are confusing genotype (i.e., genetic makeup) with phenotype (expression of those genes). While you can modify your phenotype with diet and exercise, you can't (but, see below) modify your genetic predisposition for that body type in the same way. This is essentially Jean-Baptiste Lamark's theory ... | [
"A reminder here that your family being overweight does not mean you are genetically predisposed to being overweight. It might just be that those families have eating/cooking and (lack of) exercise habits that lead to them gaining weight (or it could be a combination of genetic and environmental factors). In the ... |
[
"A couple of questions about memory."
] | [
false
] | Why do I often recall completely insignificant memories? For instance, I have this memory of when I was a kid, going grocery shopping with my mom, and I happened to run into this other kid with whom I went to school and was only moderately friendly. It was a completely uneventful occurrence, yet it pops into my head a lot. That brings me to my second question: How does the brain decide what information should be stored as a short-term memory versus a long-term memory? Using my previous example, why is that any more important than remembering what I ate for dinner last Tuesday (which I can't)? | [
"Memory works by associations. It's really difficult to make any 100% definitive statements here, but this is most likely what happened:",
"Odds are you were surprised to see your neighbor. Surprise at seeing your neighbor (especially if you haven't seen other people you know at the grocery store often before) ... | [
"You might see a penny a hundred times but still not know what direction Lincoln faces. You might have your mom yell at you 30 years ago and still remember the look on her face with precise detail.",
"TIL that I have no clue what direction the presidents face on most coins."
] | [
"I wish I knew the answer to this. I can't remember Birthdays, Holidays (beyond Christmas), or any other important date. I can't remember plans for the weekend that my wife made 3 days ago.",
"However, I can quote damn near every movie I have ever enjoyed watching, and can recall almost every scene in detail. ... |
[
"Would spraying blood-spatter at a crime scene with ammonia (like in Boondock Saints) really ruin any DNA evidence?"
] | [
false
] | I've also heard the same mentioned about bleach; would that work as well? | [
"Given modern molecular techniques, I don't think the aforementioned Boondock Saints scene would be as accurate as it may have been back then. There are now DNA extraction kits that are specifically designed for old, contaminated, or mishandles samples. These \"forensic kits\" have several wash stages that remove c... | [
"This isn't correct. While the distinction between organic and inorganic can be somewhat arbitrary, the sugar backbone of DNA and the bases are certainly organic.",
"Also there are many inorganic molecules which are quite easily destroyed and likewise some very hardy organic compounds which can persist."
] | [
"So, does DNA ever \"expire\"? As in, does it ever naturally degrade and stop bearing usable genetic code?"
] |
[
"If sea turtles return to their birth beach, how do the species ever spread to new areas?"
] | [
false
] | Every article I can find on sea turtles shows that female sea turtles return to the beach where they were born to lay eggs, most likely through sensing location via the Earth's magnetic field. Yet sea turtles are found the world over, so how do some female turtles find new beaches? | [
"This review",
" gives a good overview of the genetic structure of populations of all 7 sea turtle species. Some key relevant points:",
"1) The natal hypothesis of female nest site choice is supported in populations which overlap in overall territory but not in nesting location or genetic markers (see figure 1)... | [
"A common misunderstanding of this and similar phenomena, such as migration, are that ",
" members of the species participate in it in exactly the same way. The majority of the individuals behave this way, but there are almost always some that don't. I'm fairly sure a careful analysis of a large sample of turtl... | [
"Thanks!"
] |
[
"Do the calories in fruit increase as they ripen?"
] | [
false
] | null | [
"No, not exactly. Fruits tend to taste sweeter as they ripen because ripening is a form of decomposition. The polysaccharides in fruit that represent the energy stored begin to break down into smaller molecules that are easier for our body to break down into glucose meaning less time is needed to digest the fruit. ... | [
"After I posted this I thought of something. If you place fruit together they ripen faster because of the gases they release. Is it possible that they actually loose calories due to the energy it takes to produce these gases? Do they heat up during this process? But it seems as though, if heat is actually generated... | [
"A loss in energy doesn't necessarily equate to a loss in calories. It could be decomposing into a more bioavailable form."
] |
[
"How do you prove that time is a dimension?"
] | [
false
] | One of my friends doesn't believe that time is the 4th dimension and I haven't been able to prove him wrong and need some help. | [
"Tell him there's a great party you'd like him to join you at, at your friend Bob's. When he asks you when the party is, respond by pointing out that if time isn't a dimension then that question is meaningless. "
] | [
"I don't think it can be ",
" that time is a dimension. Rather, depending on the model you are using, time either is or is not a dimension. Some models are more accurate than others.",
"Our best model of time is general relativity. In general relativity, it is taken as a postulate that there are 3 dimensions... | [
"The idea of a dimension is a construct that helps us solve problems. There is nothing to prove.."
] |
[
"Are fighter aircraft noticeably \"weighed-down\" by their armaments?"
] | [
false
] | Say a fighter pilot gets into a combat situation, and they end up dropping all their missiles/bombs/etc, how does that affect the performance of the aircraft? Can the jet fly faster or maneuver better without their loaded weaponry? Can a pilot actually "feel" a difference while flying? I guess I'm just interested in payload dynamics as it applies to fighter jets. | [
"It's a huge difference. The weight changes the stress on the airframe, and if external the ordnance produces lots of extra drag.",
"For example, a f/a 18 is rated for +7.5g and -3g maneuvers when light, but at full weight only +4.8g and -1.8g.",
"Here are some study cards for an f/a 18: ",
"https://quizlet.c... | [
"Also, what's a wingtip launcher rail?"
] | [
"Wing tip launcher rails are mini-pylons of sorts that are attached to the wingtips of an aircraft. Usually, they hold things like a short range Air to Air missile, like an AIM 9. ",
"Here's one on an F-16",
"As far as to why an F/A-18 can't fly without wingtip launcher rails, I believe they are a permanent att... |
[
"How does altitude (atmospheric pressure) influences our hearing?"
] | [
false
] | Does the difference in atmospheric pressure make a noticeable difference to how we perceive sounds? | [
"Assuming the back of your eardrum is the same pressure as the atmospheric pressure (ie, your ears don't need to be popped), then no, the pressure difference doesn't really have an effect on your hearing. This is, of course, assuming that you are at a reasonable pressure where the air is still breathable (not in th... | [
"Sound most definitely travels slower at high altitudes/low pressures.",
"Sound travels slower at higher altitudes because of the temperature difference. Sound speed is expressed as c=√(γP/ρ), where γ is the ratio of specific heats (a property of the gas), P is the ambient pressure, and ρ is the density. However,... | [
"Sound most definitely travels slower at high altitudes/low pressures. This means sound dissipates faster so hearing something at a distance is significantly harder"
] |
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