title list | over_18 list | post_content stringlengths 0 9.37k ⌀ | C1 list | C2 list | C3 list |
|---|---|---|---|---|---|
[
"AskScience AMA Series: We are Jeff Galvin and Dr. David Pauza (long time lurkers, first time posters) here to talk about “treating the untreatable, curing the incurable” -- the future of genetic medicine. How it works. What it can do. Ask us ANYTHING!"
] | [
false
] | Who are we? I’m Jeff Galvin, son of an MIT Electrical Engineer and inventor who pioneered advanced portable radar and analog signal processing. I’m an entrepreneur, Silicon Valley startup guy and former Apple International Product Marketing Manager in the 80’s; where I traveled the world introducing the original Macint... | [
"Do you regard ageing as a disease? Any indications whether genetics will help us break the 120 years 'lifespan limit' in large numbers?",
"Will genetic work help us achieve older humans who feel good and are mentally sound through a larger percentage of their lives? "
] | [
"Where do you believe the line should be drawn (if it should be drawn at all) between treating diseases via gene therapy and fundamental genetic modification? ",
"In other words: once these processes become established ways to treat previously untreatable diseases, do you think options should be made available fo... | [
"Hello guys. Glad you are doing this, hope all is well. ",
"What kind of timeline are we looking at, where this treatment will be easily accessible to all and become the norm? "
] |
[
"If the pancreas is the organ that produces insulin, why aren't pancreas transplants used as method to cure diabetes?"
] | [
false
] | null | [
"They are",
". Pancreas transplantation has been done since 1966, and to date, over 28,000 pancreas transplants have been performed in the US alone.",
"Another option is to transplant only the ",
"pancreatic islets",
", which contain the insulin-producing beta-cells."
] | [
"It's worth noting that pancreas transplants are very sensitive, and even with islet therapy you have to be on immunosuppressants for as long as you want to be free of the diabetes, and the side effects of being on those is arguably worse than the diabetes itself."
] | [
"As with all other types of organs that can be transplanted, there is huge shortfall. And since you can't live without your pancreas, you need a deceased donor. AFAIK, pancreas are most often transplanted with the small intestine, which further narrows the number of available organs."
] |
[
"Why do we die (so quickly) due to lack of oxygen? Can all our cells not respire anaerobically like our muscles can?"
] | [
false
] | If our cells can respire anaerobically, why do we die (so quickly) when suffocated? Wouldn't the cells just start respiring anaerobically until oxygen was re-supplied so the lactic acid could be broken down? I'm assuming here that all cells can respire anaerobically like muscle cells can. | [
"I think this is the best answer so far. The point is that not all of your cells die quickly without oxygen. In surgeries they cut off blood supplies for up to hours and tissues don't die.",
"Your brain is really what needs the oxygen. It has a huge metabolic requirement, and it needs a constant supply of oxyg... | [
"I think this is the best answer so far. The point is that not all of your cells die quickly without oxygen. In surgeries they cut off blood supplies for up to hours and tissues don't die.",
"Your brain is really what needs the oxygen. It has a huge metabolic requirement, and it needs a constant supply of oxyg... | [
"Neurons, probably more than any other cell type, really rely on the concentration gradient of sodium and potassium to be maintained. It's crucial for their activation of other cells.",
"Action potentials are caused by the influx of ions, and that causes the release of neurotransmitters. ATP-requiring pumps pus... |
[
"Why do some wind turbines have textured edges ?(image in text below)"
] | [
false
] | I noticed on the blade of a wind turbine in from Jeff Bezos's Instagram. What are they for? | [
"They're vortex generators. ",
"https://www.youtube.com/watch?v=FGQkjT9tJg4",
"Basically as air flows over a curved surface (like an airfoil), the boundary layer slows due to friction and may not have the energy to go around the curve, which causes the air to separate from the airfoil creating drag or even cau... | [
"Obligatory “that’s why golf balls are bumpy.” In their case, the turbulent flow is induced just to reduce drag, not to help create lift, but the reason and method for keeping flow attached to the rounded body is the same."
] | [
"Imagine a rowing or dragon boat paddle going through the water. A static head of non- moving air is built up on the face. Basically a wedge of dead air, which diverts the water and reduces resistance and power in drive. Now imagine a new paddle with properly sized HOLES on the face of the paddle, turbulance is cr... |
[
"Is it possible to lengthen or shorten the wavelength of light through a (meta)material?"
] | [
false
] | Is it possible with a passive material? If not, how about with an active one? With what kind of materials? Can you permanently effect the wavelength, meaning that the output wavelength is different after the light exists the material? I mean, I do know that eg. light shortens the wavelength IN the glass, but as soon as... | [
"Normal light is circularly polarized, ",
"'normal\" light is ",
" polarized, not ",
" polarized. Remember, polarization simply refers to the direction the electric field vector points. We often describe polarization as being the result of adding two electric field vectors together: an electric field in th... | [
"Yes. There is a whole field of study that deals with this. It is called \"",
"Nonlinear Optics",
"\". Since this is a very general question, I can't give a more specific answer than this. You can submit follow-up questions about more specifics."
] | [
"1) Ambient light is typically unpolarized (i.e. randomly polarized). Circular polarization is not a mixture, it is a single polarization state where the E field direction oscillates instead of its magnitude. ",
"2) A magnetic field does not effect light in vacuum. A magnetic field can alter the behavior of elect... |
[
"How would accelerometers/tilt sensors in smartphones work in space?"
] | [
false
] | I was watching my cousin play a game on her mom's smartphone yesterday that involved tilting the smartphone to roll a marble through a maze. I'm wondering how the game would react if for example, a person on the ISS was playing with their phone. Or maybe, if they're browsing reddit on the AlienBlue app for iphone, and ... | [
"They wouldn't work. Tilt sensors in smartphones use an accelerometer, occasionally combined with a magnetometer. Accelerometers measure ",
", or acceleration of free fall; that is, they measure the acceleration of the device with respect to an inertial frame. This is why an accelerometer set still upon an horizo... | [
"Yes, this is correct. I wasn't sure if the devices could detect a constant rotational motion from tilting even in the absence of a 1G field. But my contact tells me that none of it works. The ISS crews lock the screen orientation of their iPads and change it manually if an application requires it. "
] | [
"Oh, cool. I find it interesting to learn these little details that make life in space different from most people's. Thanks for the follow-up!"
] |
[
"What Happens to Light Absorbed by a Black Hole?"
] | [
false
] | As I understand it, black holes are not actual holes, but rather super dense objects which light cannot escape from. But what happens to this light that is trapped in a black hole's gravitational pull? | [
"It adds to the mass of the black hole."
] | [
"No, you're right (and IMO the most accurate of the comments at this level)."
] | [
"No, you're right (and IMO the most accurate of the comments at this level)."
] |
[
"How do tectonic plate shifts effect the pipes and sewers underground? How do we deal with/ prevent it?"
] | [
false
] | [deleted] | [
"A good example of this is the Alaskan Pipeline. This pipeline was built mostly above ground due to high seismic activity in the Ring of Fire region, along with permafrost and a few other factors. The pipeline itself sits on two “I” beams with a piece connecting the two beams and the pipe rests on that piece. So wh... | [
"What was your career path from geo graduate to pipeline analyst? "
] | [
"In depth answer\n2009 B.Sc Geology (College of Charleston)\n2010-2012 Wiser LLC (Military Mapping)\n2012-2015 Williams Gas (Petroleum)\n2015-2016 NX Utilities (Fiber Optics)\n2016-2107 Cartographer (Can’t tell anymore still work for em)"
] |
[
"Did the recent eruption at Sakurajima give any indication about the high volcanic pressures at Mt. Fuji? Is Mt. Fuji still safe to climb?"
] | [
false
] | Thanks ahead of time for the replies. | [
"Fuji and Sakurajima are not connected in the way you are thinking. Climb! ",
"A Volcano erupts because of pressure built up in its magma chamber. It is very unusual and mechanically difficult for volcanoes that are separated by a good distance to cause the other to erupt (it's possible under extremely unusual an... | [
"Fuji and Sakurajima are separated y several hundred kilometers. There is no way they share a plumbing system, and so they have no more in common with each other than they do any other volcano on the Pacific ring of fire.",
"Climbing an active volcano is always a calculated risk. Would I want to climb fuji at the... | [
"Find me this article."
] |
[
"Can You Help Me Choose Between Two Fields to Pursue?"
] | [
false
] | null | [
"You might want to try ",
"r/AskAcademia",
", you'll probably get more responses there, but anyway, I'll add my two cents.",
"If you are talking about pursuing this fields with the goal of obtaining a PhD (which I assume you are based on the fields you've listed), I hate to break it to you, but in none of the... | [
"Thank you so much. That actually really helped haha. And it's not that I don't have the desire, I can't decide which one I like more!"
] | [
"You're welcome! Trust me, you're going to have lots of time to decide what you're really interested in, and you might end up loving something you didn't even know existed. In my second year of undergrad, I told my friends I would never work in a certain field (it was too \"boring\"). I'm currently working in that ... |
[
"Are there any animal species whose gender ratio isn't close to balanced? If so, why?"
] | [
false
] | null | [
"A colony of honey bees are made up of about 90% all females. They're all worker bees except the queen bee, and the males are all basically her reverse harem. The males just lounge about and eat honey all day until it's their turn to do the business."
] | [
"They are also killed at the end of the summer if they're still hanging around. None of them overwinter.",
"Cool fact - ",
"Drones are produced from unfertilized eggs, so they only carry the genes of the queen, and they only have a single copy of their genes."
] | [
"Any species that’s able to reproduce by parthenogenesis (i.e the females are able to produce young on their own without genetic input from a male), so some aphids and a couple of reptile species. Hive insects like bees and ants tend to be mostly female too."
] |
[
"Would we know if another animal on our planet reached a state of sentience/sapience to the level of reason?"
] | [
false
] | [deleted] | [
"It all depends on how you define sentience:",
"Elephants are known to ",
"grieve and bury their dead.",
"Apes are known to ",
"wage war on each other,",
" (I've seen actual footage of an attack in a forest but can't find it now) ",
"make tools,",
" and even ",
"weapons",
"Chimps are commonly used... | [
"I'd query that killing for sport/fun has anything to do with sentience rather than fulfilling fixed action patterns. Cats and dogs often kill without purpose, and so do several types of birds not known for any particular cognitive ability (noisy miners: shitheads of the bird world)."
] | [
"I think we would know. As mentioned, any animal which shows signs of being particularly bright gets studied very intensely for signs of intelligence. Apes and some other animals are more sentient/sapient than other animals, although I think there's quite a gap between them and humanity. ",
"But to more direct... |
[
"Were the first pathogens able to infect organisms with nothing to stop them or did \"immune systems\" predate multicellular life?"
] | [
false
] | Sorry if it's a badly worded question. Basically, was there a period of time where there were pathogens but no immune systems? Surely if immune systems are a counter to infection, there must have been a brief period where this countermeasure wasn't yet evolved. This could be completely false I'm just curious. | [
"Well, for starters, single cell organisms also employ strategies we describe as being immune responses. In fact, is it this exact type of biochemical response that is behind CRISPR gene editing! Bacteria have an ability to recognize some pathogenic genes, and it cuts them up to protect the cell from the invading g... | [
"Multicellular organisms emerged ",
"around 1.7 billion years ago",
". Bacteriophages (viruses that infect bacteria) emerged ",
"more than 3 billion years ago",
". Bacteria have adaptive immunity to bacteriophages through ",
"a number of mechanisms",
", most notably through CRISPR/cas genetic modificati... | [
"I could imagine the the basis for CISPR evolving from archaic RNA/DNA proof reading mechanisms later adapted for immune response."
] |
[
"Can people experience synesthesia with senses outside the five aristotelian senses?"
] | [
false
] | For example can we experience a proprioceptive synesthesia? | [
"There's time-space synesthesia where people report seeing time arranged spatially. For example, many such people report seeing the calendar months arranged as a circle around their bodies with the current month directly in front of them. "
] | [
"I don't know if there is a default orientation if they don't know the day. It is not limited to days of the week. Some experience hours this way. Others years. ",
"Here",
" are descriptions of a few such people / experiments. You can find more examples with a google search."
] | [
"Thats interesting, though the example feels unsatisfying to me. What would happen to such a person if they entered a cave for an unknown number of days and then came out not knowing the date. The example doesn't seem tied so much to our sense of time as it is to our social construct of time. It seems to me that we... |
[
"Do bionic eyes need a blind spot?"
] | [
false
] | With human eyes having a blind spot in the centre, would there be any adverse effects if bionic eyes didn't have it, or would the brain just adapt? | [
"No. We have a blind spot because our retinas are \"backwards\". The photoreceptors are at the back while lots of other cells (e.g. ganglion cells) are in front (closer to the front of the eye). Your optic tract is made up of projections from the ganglion cells -- they need to exit the eye somehow, but since there ... | [
"Why are our retinas backwards?"
] | [
"OP meant something else.",
"If we were designing the retina we would put the top of it (the one exposed to light first) to be the light sensitive elements and their support structure under them (blood vessels, etc.)",
"The eye is backwards to ",
".",
"Namely, the support structure is above the light sensit... |
[
"Why do pigeons never seem to fly in straight lines?"
] | [
false
] | They have the gift of flight but they never travel in straight lines or seem to migrate? Why do you never see a flack of pigeons? I grew up in Saudi Arabia and they would circulate minarets. My mom called it “praying” but what is it they are doing? | [
"If by flack, you mean flock, it's virtually the only way you see them in the UK.",
"Try walking through ",
"London",
"Where I live in the UK, pigeons are kept for sport exactly because they do flock. People keep a roost for them to sleep in and shelter. They are allowed to come and go as they please (they ... | [
"They follow landmarks.",
"Seriously.",
"There's a BBC documentary that shows them following a road. It turns right at the crossroads."
] | [
"They're ALL drunk. Seriously, those birds party like Mo-fos."
] |
[
"A matter of taste."
] | [
false
] | null | [
"We don't yet know. We're trying to find out."
] | [
"Since matter and antimatter annihilate each other when they encounter each other this would be really bad for us. From astronomy we have not seen signs of large quantities of antimatter out there, so we are pretty sure the universe consists of mostly normal matter (and some dark stuff which we can ignore in this d... | [
"My understanding is that it started out with energy. As the universe began to expand this energy formed matter particles and anti-matter particles, but for whatever reason ",
" matter production. Most of the matter and anti-matter annihilates and goes back into radiation energy (photons). But after some brief pe... |
[
"Could allergic reactions be trained to attack cancers?"
] | [
false
] | null | [
"Thank you for your submission! Unfortunately, your submission has been removed for the following reason:",
"We do not debunk or vet theories or offer peer review on ",
"/r/AskScience",
".",
"For more information regarding this and similar issues, please see our ",
"guidelines",
".",
"If you disagree ... | [
"Thank you for your submission! Unfortunately, your submission has been removed for the following reason:",
"We do not debunk or vet theories or offer peer review on ",
"/r/AskScience",
".",
"For more information regarding this and similar issues, please see our ",
"guidelines",
".",
"If you disagree ... | [
"Questions based on discussion, speculation, or opinion are better suited for ",
"r/asksciencediscussion",
"."
] |
[
"Is there an unit/formula for measuring corrosion of metals?"
] | [
false
] | My science fair is due in a couple weeks and I am going crazy looking for a formula/unit for measuring corrosion of metals. Would it be possible to measure corrosion by weight or density? | [
"There are ratings system generally targeting percentage coverage (as well as quality - e.g. bubbling, scaling) of a surface and depth if a way to determine it is available.",
"The only equation I can think of is that sidewalk concrete will degrade inwards at 1mm per year which can be indicated with Phenolphthale... | [
"It sounds like for your purposes, you could quantify the amount of corrosion by percent change in mass of your samples. As long as you had samples similar in size, composition, and surface area, this would indicate relative amounts of corrosion.",
"This would not work if you were comparing different materials o... | [
"I am using 5 different kinds of metals, but my independent variable is are the liquids. What should I do?"
] |
[
"If two neutrons were suspended in an otherwise empty universe, would gravity or the strong force (or something else) be most significant in pulling them together?"
] | [
false
] | null | [
"Gravity. Gravitational force falls off as 1/d",
" where d is the distance between them, but the intranuclear force decays faster than exponentially with distance. Any magnetic attraction would be 1/d",
" or higher. However, due to the weak interaction a neutron will decay into a proton after an average of abou... | [
"That's interesting that a neutron would decay into a proton much more rapidly than I would expect. What special conditions must be present for rapid neutron->proton decay to take place?"
] | [
"No special conditions, it happens because a proton is less massive. In a nucleus you have to consider the mass of the daughter nucleus compared to the mother nucleus, so sometimes the opposite process can occur."
] |
[
"At the neuronal level, how do we encode memory?"
] | [
false
] | null | [
"I can't remember.",
"Jokes aside: if you knew this, you'd win a Nobel prize. This is one of the hardest questions in neuroscience. There's a lot of speculation: long term potentiation, synapse formation and degradation, hippocampal neurogenesis, basal ganglia and cerebellar motor learning (learning is applied me... | [
"This is a very deep question that can't possibly be answered satisfactorily here. Though a good high level description is that memories are thought to be encoded by the topology of the network between an ensemble of functionally connected neurons.",
"More specifically, when the brain assimilates a new piece of i... | [
"Instead of posting something cryptic and implying that the poster is blind, maybe you could provide some source elaborating on your statement?"
] |
[
"How does Herpes work? Why are there so many forms? Why can't it be cured?"
] | [
false
] | [deleted] | [
"Herpes viruses have a latent phase and an active phase. As double stranded DNA viruses they incubate (can't think of a better word) in the host cell nucleus, particularly the nerve cells. As these cells stay alive for your entire life, once you get the virus in them it's very hard to get rid of and is out of view ... | [
"They don't destroy the nerve cells, but rather use neural ganglia as a hiding place. For obvious reasons, the immune system is trained to leave the nervous system alone, which is why many autoimmune diseases in which the body attacks itself result in neurological damage. By laying dormant (and not attacking the ne... | [
"So every time they become activate and replicate they destroy our nervous cells? Wouldn't that mean they'd have like long effects (considering the nervous cells don't regen)?"
] |
[
"What are the difficulties of predicting the shape of DNA or proteins solely from DNA sequence?"
] | [
false
] | [deleted] | [
"The field you are looking for is \"computational structural biology.\"",
"You may be able to find more information here: ",
"http://zhanglab.ccmb.med.umich.edu/I-TASSER/",
"I-Tasser is the state-of-the-art when it comes to protein structure prediction algorithms. ",
"The main challenge is that although the... | [
"No. There is not enough known. Examples include the regulation of genes and protein-protein interactome. Systems biology is the field of trying to tie together all the complex aspects of a cell/organism. When you have an appreciation of how much we don't yet know about cellular processes, it makes the notion of tr... | [
"Your professor may have been talking about predictable secondary structures for nucleic acids such as ",
"hairpins and loops",
" which have serious implications on stability and transciption/translation. We can predict those structures.",
"For proteins we can predict simple secondary structures such as helic... |
[
"Why is the potential energy of the electron in the field of the nucleus proportional to Z/r?"
] | [
false
] | "The potential energy of an electron in the field of a nucleus is spherically symmetric (it is proportional to Z/r)." When r is decreased, the electron is nearer to the nucleus. Wouldn't that make its potential energy lower? Just like an object on earth has lower potential energy than if it were in space? | [
"If the nucleus has charge Ze and the electron has charge -e, the potential energy is",
"U(r) = -Ze",
"/r",
"The ",
" is Ze/r, which is potential per unit charge. Both are called the potential usually. As r decreases, so does U(r)."
] | [
"Yes, that's right. What is your objection exactly?"
] | [
"I thought that if r decreases potential energy should decrease also, according to the same way gravity is like. But what is stated in the statement above is the opposite."
] |
[
"How do we know what happened a fraction of a second after the big bang?"
] | [
false
] | I was reading about the chronology of the universe, and it described in great detail what happened one millionth of a billionth of a billionth of a second after the big bang. How do we know that in such a precise measurement of time? | [
"I'll start with a sentence from the ",
"Tabular summary",
" on that wikipedia page, where for the photon epoch it states:",
"The universe consists of a plasma of nuclei, electrons and photons; temperatures remain too high for the binding of electrons to nuclei.",
"In our model of cosmology and how the Univ... | [
"Thank you for your very detailed answer. I'm consistently amazed at the way our understanding of physics can be used to predict these things."
] | [
"Of course! And trust me, you and me both :)"
] |
[
"What kind of calculations are quantum computers good at?"
] | [
false
] | [deleted] | [
"First, you should know that it is an open question whether functional, practical quantum computers can be built. Not everyone is optimistic that it is possible.",
"There are certain problems for which we have found quantum algorithms that are much faster than any known classical algorithm. The two most promine... | [
"It's my understanding that many people are pretty skeptical about D-Wave and whether or not their products are \"real\" quantum computing. Wikipedia link: ",
"https://en.wikipedia.org/wiki/D-Wave_Systems#Reception"
] | [
"Well, a quantum computer is a quantum system. So if a quantum computer is better at anything, it will also, by defintion, be better at simulating quantum systems. "
] |
[
"Can dogs be dwarfs?"
] | [
false
] | Maybe this is the wrong sub to ask this but not sure where else to ask. Dwarfism we know from humans, can that occur in dogs (or other animals)? Can purebred great dane for example be a dwarf? | [
"Runt of the litter and small breeds are not the same as dwarfism or birth defects. "
] | [
"Runt of the litter and small breeds are not the same as dwarfism or birth defects. "
] | [
"Yes, they can. Some popular dog breeds body shapes are due to achondroplasia, one of the most common causes of dwarfism in humans (although by means of a different mechanism), or other types of dwarfism (you can see some types of dog dwarfism and the breeds that suffer them in the table 1 of ",
"this paper",
"... |
[
"I smoked two packs of cigarettes per day for 4 years. I haven't smoked in a year and plan to never smoke again. What is the statistical probability of me contracting some kind of cancer in my lifetime versus the general non smoking population?"
] | [
false
] | [deleted] | [
"The closest statistically I can get to answer your question is this. If you continued to smoke cigarettes by age 75 you would have a cumulative risk of 15.9% of developing lung cancer. (I realise you asked about all cancers but this is all the info I have.) Once you have stopped smoking the cumulative risk gets lo... | [
"Great! Thank you. This is exactly the information I was interested in :)",
"So smoking for 4 years (from age 16-20) means I'll always be at a higher risk for cancer? :( "
] | [
"The risk is greatest for ",
"COPD",
". This is what kills most smokers in the world today, not lung cancer. If you never smoke again, your risks should subside but ",
"second hand smoke can contribute to COPD",
". Don't hang out with smokers."
] |
[
"What is the range of the electromagnetic spectrum that a digital camera can detect?"
] | [
false
] | Visible spectrum? Invisible spectrum? Infrared? What is the range of wavelength values that can be detected? | [
"The technological basis of a digital camera is a charge coupled device (CCD), which has a material whose electrons are dislocated when light hits, then uses a voltage to run those electrons into a circuit (a simplication). CCDs can be used up to the ",
"x-ray range",
", and down to the ",
"microwave level",
... | [
"note, however, that your optics may filter out unwanted spectra. Glass is opaque to IR, for instance. And you may have some UV filtering on your camera as well. ",
"And individual pixels likely have some form of filtering only allowing some portion of the visible spectrum to hit the sensor itself."
] | [
"A lot of low-end/amateur cameras don't block infrared light, which means the color array of filters over the sensor lets infrared pass as a mix of red, green and blue. Usually, this ends up looking like a ",
"purple color",
" (that is a picture of a hot plate inside a valve). Try taking a picture of glowing ho... |
[
"Why are humans so much less likely to bear multiple children than certain other mammals?"
] | [
false
] | I feel like you almost never hear of certain mammals (dogs/cats/etc) only bearing one child, yet with humans it seems to be the total opposite. Why is this? | [
"All species have a typical \"litter size\" for when they successfully breed. It depends greatly on the amount of care the offspring require (this includes the energy put into the eggs). There is a trade-off between how many offspring you can make and the quality of those offspring ",
"(Source)",
"For example, ... | [
"I believe that mammals have twice the number of breasts than the average litter size. Which is why dogs have so many nipples and humans typically have two. Now imagine humans typically having 3 kids per pregnancy, and a woman with 6 boobs. "
] | [
"Former Evolutionary Anthropologist here. The \"natural\" interbirth interval in humans is thought to be about 4 years, so 3 under 5 would've been unusual for most of our human history. Breastfeeding, lack of calories, and carting the child around makes more than 2 under 5 very difficult. "
] |
[
"Why Pictures in ultrasonografy is shown in sort of triangle, sort of part of circle way and not square?"
] | [
false
] | If you don’t understand google ultrasonography pictures, you will understand me. | [
"Not all ultrasound photos are shown in a triangular image. It depends on the type of transducer (the object moved across the body) used to gather the information. The type of transducer used by the technologist depends on what depth of penetration is needed. A curvilinear probe will produce a triangular image that... | [
"What's the best part and worst about being a sonographer?"
] | [
"Basically because, while they are phased arrays that can beam form to interrogate a wide swath of angles, their transducer face is still typically small (some linears are pretty big) so those beams all originate from a small area to sweep a larger one, hence triangles."
] |
[
"Radio as a from of energy?"
] | [
false
] | null | [
"A radio signal is a way to transmit or \"radiate\" energy. A standard AM radio station transmits with around 100kW of power. In order to hear your favorite song play, you only need to receive tiny amounts of that power, nanoWatts or less. Your radio receiver picks up those nanoWatts and amplifies with some other p... | [
"A ",
"crystal radio",
" is an example of using the power in radio waves to do something useful. "
] | [
"It is basically a non-amplified radio receiver. Because of this, you need to be much closer to the radio source to get enough power to drive the speaker to an audible power level. Definitely an interesting piece of kit."
] |
[
"How does thermal imaging work?"
] | [
false
] | A more in-depth explanation would be appreciated. | [
"There are more wavelengths (colors) of light than the eye can see. Bigger wavelengths are \"redder\" and shorter wavelengths are \"bluer.\" ",
"Thermal imaging uses detectors that can \"see\" colors that are \"redder\" than what your eye can see.",
"So what does this have to do with heat? Everything with te... | [
"/u/bhtidalforces",
" explained why hot objects give off infrared light, but there’s still the question of how the camera works.",
"Most inexpensive thermal cameras use “microbolometry” to form an image. A grid of tiny resistors is placed under an infrared-transparent lens. The infrared light is focused on th... | [
"Awesome. Thanks."
] |
[
"The combustion of butane yields only CO2 and H2O, so why does my lighter flame make soot?"
] | [
false
] | I thought that my bic lighter uses pure butate, so what's happening? does it use a mixture for fuel? If so, what else is in there? Does the CO2 somehow become soot? | [
"It has to do with the mixture of oxygen and butane to form these products you mentioned. Sometimes the ratio of oxygen to butane is low and yields less water and carbon dioxide with the side products being carbon monoxide and carbon soot. In other words carbon dioxide and water will be the only products if the oxy... | [
"Let's talk about what's going on here in general.",
"You may notice that butane flames have both yellow and blue parts, and that if you twiddle the knob on a Bunsen burner then ",
"the flames will change color",
".",
"The equation you saw pretends there's exactly enough oxygen. If there is a massive flood ... | [
"While I agree that the soot will be flammable, in the video you linked the demonstration lights paraffin smoke, and not soot. The smoke looks darker because of the light angle. I would imagine getting soot-rich black smoke to light would be a bit different."
] |
[
"How exact does the energy of a photon need to be to excite an electron?"
] | [
false
] | A quick wikipedia search says that to excite a hydrogen electron from ground state to its first energy level, the photon's wavelength must be 121.6 nm. But 121.6...what? How precise does that wavelength have to really be, and why? | [
"The energies of unstable excited states are not infinitely precise.",
"You are often taught in introductory courses that they are like ",
"delta functions",
", infinitely precise at some particular value.",
"But that's not true. In reality their lineshapes are not delta functions, but instead ",
"Breit-W... | [
"So if that's the error/width, does the incoming photon have to be within one standard deviation of the error, or can it graze the outskirts of acceptability and still excite the electron, or am I misunderstanding what that error and width really means?",
"Γ is the FWHM of the Breit-Wigner distribution (it actual... | [
"Ok, this is along the order of what I was thinking... overlapping wave functions and such. ",
"It's been a long time since I've looked at that Schrodinger equation, and here's a follow up:",
"It says that the line width is then on the order of 10",
" So if that's the error/width, does the incoming photon hav... |
[
"How does the quantization of a field really work?"
] | [
false
] | Let's say I turn on a radio transmitter. Using Maxwell's equations I can predict the shape of the electric and magnetic fields. But how does it relate to photons? Are the photons the same "shape" of the established electromagnetic field with just a part of its total energy? Or are they just tiny particles that make up ... | [
"Imagine the simplest case of a reflecting cavity filled with a standing wave with light of just one frequency (i.e. no overtones). Now a standing wave can actually be decomposed into two traveling waves, traveling at the speed of light, moving in opposite directions.",
"This waveform only has one frequency and t... | [
"The field produced by radio transmitter is a coherent state of a large, indeterminate number of photons (distributed according to a Poisson distribution)."
] | [
"Thank you! That was exactly what I was looking for"
] |
[
"If hair is evolutionarily there to keep your head cool from the sun, why do Africans, Arabs, and South Anericans have black hair, while Europeans have blond hair? Wouldn't people in hotter regions need to evolve lighter colored hair?"
] | [
false
] | Lighter to absorb less of the suns heat | [
"The advantage is that lighter skin can more effectively produce vitamin D, which is harder to do the further north you go. Even non-blacks commonly had Vit-D deficiencies until they started fortifying a lot of foods with it (milk, cereal etc)"
] | [
"You have the right idea. Darker hair/skin (both determined by ",
"melanocyte activity",
") was helpful in protecting the body from UV damage. As humans migrated northward, this protection was less important, so the strong selection pressure towards darker pigmentation was lost.",
"The available studies do ... | [
"Why, then, as humanity spread northwards, did people ",
" dark skin? Sure, the advantage was no longer present, but why wouldn't it still be omnipresent, like the appendix?"
] |
[
"How can you determine the age of a cluster using a CMD?"
] | [
false
] | I know if the turn-off point has a B-V value of x you can estimate the age but is there a solid equation that links the two? | [
"The main sequence lifetime does go roughly as 1/M",
", though only for part of the main sequence. At the brighter end of the main sequence the exponent is closer to 1.5 or 2, and at the lower end the exponent is closer to 3.5. This is because the relationship between mass and luminosity changes as you go to diff... | [
"Forgive me, this is not my specialty, but I'll do my best to describe the calculation.",
"\nA \"solid equation\", not really. An approximate one sure, this is how it goes, roughly.",
"\nIn a cluster, stars formed at roughly the same time, this allows an astronomer to say,",
"\n\"If I don't see Main Sequence ... | [
"Thanks, that is all really helpful, but thats the stuff I understand. I've read somewhere that main sequence lifetime is equal to 1/M",
" where M is solar mass due to following the relationship of the suns luminosity, mass and MS lifetime. I can't verify this anywhere (but an ohio state lecture pdf). It was some... |
[
"Why rockets don't go completely vertical?"
] | [
false
] | [deleted] | [
"Good question.",
"The reason why is because if you were to shoot a rocket straight up, it would simply fall back down to the launch site (unless it reached escape velocity of Earth).",
"Most of the time, we want to place a certain payload into orbit around out planet, either into low-Earth-orbit (LEO), or some... | [
"Thanks, now it makes more sense to go on an angle rather than go completely vertical :)"
] | [
"A rocket that goes straight up still goes into orbit, it's orbit just happens to intersect the Earth. Orbits that intersect the planet aren't very productive, however."
] |
[
"Trying to understand how crystals form. Particularly what makes them the shape they are."
] | [
false
] | I have no real science education and do not know exactly where to start looking for my answers. Any links or explanations are much appreciated. Apologies in advance for lack of correct terminology and vagueness. I want to understand how a molecule is arranged to make a crystal. There are a few parts to this that I want... | [
"There is a lot to talk about here but it sounds like you're on the right track. Let's start by covering your questions:",
"1) Yes a pure crystal in the context of chemistry or physics is when a single element or molecule forms into an infinitely repeating pattern. Because of this geometry, this is why pure cryst... | [
"Also wasn't sure whether this belonged under 'chemistry' or any other particular category. I can categorize it if someone lets me know.",
" seems this was done for me, cheers."
] | [
"Thank you for the thorough and awesome post!",
"I'm having a hard time trying to absorb all the information but am trying and may post back with some more questions for clarification."
] |
[
"My audio software can slow sounds down without changing the pitch. How does it do this? Was this even possible before the \"age of digital\"?"
] | [
false
] | null | [
"One quick and dirty way to do this, which is ultimately fairly similar to what your audio software does is: chop up the audio into 50 pieces per second, and play each piece twice consecutively. There's some fancy stuff you can do with Fourier transforms to smooth the transitions more gracefully.",
"When thinking... | [
"It does it by stretching out the samples and then interleaving the gaps with data created by the computer. To the best of my knowledge it wasn't possible before 'digital', it was certainly a revelation when I first saw it on Soundforge."
] | [
"True, but that is an embellished response to what I said - which was a simplified response to someone who was curious and, perhaps, not familiar with the nitty-gritty of complex electronics.",
"In the context of the original question, I was closely involved with music production when digital electronics was nasc... |
[
"Do viruses ever combine their genes, similar to sexual reproduction?"
] | [
false
] | null | [
"It's called ",
"\"antigenic shift\"",
", and influenza is notorious for this. In the case of influenza, the virus has 8 strings of RNA, each of which codes one or more proteins. When the virus reproduces, multiple copies of all of these RNA strings are packaged into fresh virions and extruded from the host c... | [
"Do the viruses have to be pretty similar for the antigenic shift to work? "
] | [
"Antigenic drift consists of normal mutations - primarily errors in the machinery that copies RNA, resulting in nucleotide substitutions, deletions, insertions, etc. This may result in a slow drift in the nature of the influenza moving through a population, as it slowly changes over time with the gradual accumulat... |
[
"Why is it so difficult to find a unifying theory in physics and why is it necessary? Can't it all work separately?"
] | [
false
] | null | [
"Why is it so difficult",
"I could go into details of examples of current difficulties but that would just lead us astray from the real answer, which is: why should it be easy? ",
"Can't it all work separately?",
"Often it can in practice. For example you could have a theory that works well for slow speeds bu... | [
"Thanks for the elaborate answer m8. It's more clear to me now what the issue really is. +1. "
] | [
"Good explanation.",
"Aside from the practical aspect, the reason people don't want to say \"It all works separately\" is that this would translate to \"The laws of physics just change sometimes and there's no explanation for it.\"",
"If the laws do seem to change, the explanation of that change ",
" the unif... |
[
"What is the most recent R0 (R-naught) value of covid?"
] | [
false
] | All things being equal, how contagious is this virus? I haven't heard an update I several months. Furthermore.... if someone wears a mask, how much lower does the R0 factor drop? And how much does social distancing drop it? If this thing is going to get beaten, information like this will go a long way in convincing pe... | [
"The replication index (R) is different in different corners of the world. In Europe it is dropping, in India it is currently sky high and rising further. In Australia it is more or less 0.",
"\nMind you, R is a theoretical number of how many people a single, positive patient infects. That number isn't just depen... | [
"as I understood, the R0 is the initial theoretical number how many people would get infected when an infected person gets in a group of (non immune?) people. The R number is a more realistic number of the current situation.",
"However, R is still a theoretical number, as it does not give information of the spe... | [
"The R0 figure I'm hoping to know is its similarity to other viruses (like small pox, etc). This would imply no one is vaccinated and everyone was \"acting\" normally... attending pre-pandemic events like weddings, sporting events, concerts.",
"The hope is to gauge just \"how bad\" this virus is so that steps li... |
[
"Can gravitational lensing bend a light ray enough to make a complete U-turn?"
] | [
false
] | Can gravitational lensing bend a light ray enough for it to make a complete U-turn and return to the source (similar to a spacecraft being slingshot by a planet)? If yes, how heavy should the blackhole (or whatever mass causing the lensing) be in order to achieve the effect? | [
"The size of the black hole wouldn't matter, remember, if you can observe a black hole, it has a horizon where light orbits and cannot escape, anything below that gets 'sucked in'.",
"Any point above where light would orbit is already having an extreme change in direction. At first it would be close to a 360° cha... | [
"Light can escape the photon sphere. It just has to be moving perpendicular to it. Or at least, not tangent to it. The further down you go the higher an angle the light has to move, until you reach the event horizon where even if it's completely perpendicular it will just stay put."
] | [
"Light orbits on the ",
"photon sphere",
", which is at 1.5 times the radius of the event horizon. So you can actually get light to orbit without quite being a black hole."
] |
[
"How do we know it takes plastic 1k yrs to decompose if we used plastic for only 100 yrs?"
] | [
false
] | [deleted] | [
"Accelerated aging tests. For example they can calculate based on how long it takes a certain amount of UV to degrade a sample of a given weight. Or similarly calculate based on microbial consumption and then extrapolate. I think the 1,000 years is more of a general “anti-plastic” position. There are lots of materi... | [
"They can also look at rates. I’d need to actually do the math but you could see 5% breakdown in 10 years would yield a full breakdown in x years.",
".95",
" = .01 (99% decomposed) log both sides. x = log(0.01)/log(0.95) = 90 years. Change % decomposed and observation years and you have a different lifetime."
] | [
"It’s kinda like how they say (or used to!) that a watch would lose one second in 300 years - when the watch was only in production for a year. Did they wait 300 years? No. They just saw the watch lose a few milliseconds in a few days and just extrapolated from there to a nice consumer friendly number. ",
"Instea... |
[
"Ice or heat to alleviate swelling?"
] | [
false
] | [deleted] | [
"What did your Dentist say?? You need to check with him(or her) as to what he needs to do.",
"Scientific part is: Ice reduces swelling, heat can increase blood flow, which would increase swelling if done too much. ",
"TL;DR: Ask your dentist. Not reddit."
] | [
"Ice at first to reduce swelling, then heat to aid in circulation/blood-flow to aid in healing."
] | [
"Ice. It's always ice for swelling.",
"Heat can be used after the site is no longer swollen, or in chronic injuries."
] |
[
"Why doesn't sand stick to players during Olympic Beach Volleyball?"
] | [
false
] | I was reading a yahoo article and they had posed this question. Their "answer" was that the sand was made in a way that makes it not stick to the players... Their answer esentially rephrased the question. I was wondering if anyone knew how the Olympic sand is made/ why it doesn't stick. Is their some sort of chemical r... | [
"It's engineered sand.",
"\"",
"\""
] | [
"Uniform grain size and similarly shaped grains...",
"It's practically a pool of tiny silica marbles. With a relatively uniform surface, each grain has no pocket to hold moisture."
] | [
"FIVB sand specifications.",
"Wet sand sticks together because of the surface tension of the water in between each grain of sand. Dry sand sticks to your damp skin because the surface tension of the water on your skin holds the grain of sand to your skin. ",
"The smaller the particle of sand, the more of them t... |
[
"If diamonds are the hardest material on Earth, why are they possible to break in a hydraulic press?"
] | [
false
] | Hydraulic press channel just posted this video on Youtube , where he claims to break a diamond with his hydraulic press. I thought that diamonds were unbreakable, is this simply not true? | [
"Hardness is a separate property to Strength and Toughness.",
"Hardness is the measure of how resistant solid matter is to permanent shape change when force is applied.",
"Strength is a measure of the extent of a materials elastic/plastic ranges.",
"Toughness of a material is the maximum amount of energy it c... | [
"Unlike hardness, which denotes only resistance to scratching, diamond's toughness or tenacity is only fair to good. Toughness relates to the ability to resist breakage from falls or impacts. Because of diamond's perfect and easy cleavage, it is vulnerable to breakage. A diamond will shatter if hit with an ordinary... | [
"A better example is gorilla glass vs bulletproof glass. ",
"Gorilla glass is hard. Cell phone companies advertise their resistance to scratches. But drop the damn phone, and it will Crack. ",
"Bulletproof glass is the opposite "
] |
[
"Why were so many people in the 19th century inventing things at the same time?"
] | [
false
] | [deleted] | [
"One of the reasons you don't hear about 'person X discoverd phenomenon Y yesterday' is because the nature of discovery is changing. Al lot of the easily picked fruit has been picked in the 19th century. Discoveries are now made in teams of scientists (CERN employs almost 8000 scientists, for example). But we haven... | [
"I think Facebook is a bad analogy. A better analogy is that it took about 40 years from the first computers to general American access to personal computing. "
] | [
"The 19th century saw huge advancements in the way that information was disseminated. Mechanization through steam power made printing easier, so books could be printed and distributed faster and sold cheaper than before. Steam-powered ships and trains allowed people to travel faster and in greater comfort, so sudde... |
[
"Some questions about the big bang I have always wanted to know."
] | [
true
] | [deleted] | [
"If you want to explore the theories behind this more, I highly recommend \"Through the Wormhole\" series, specifically the first few episodes of Season 1.",
"This is discussed at length in one of the episodes but I don't remember which one.",
"For example, they discuss the theory that \"the big bang\" was para... | [
"Ah thank you for these explanations!",
"One followup question if you may:",
"Space itself has expanded (and continues to do so)",
"How exactly is space expanding? From what I've gathered, there is a theoretical infinite number of galaxies spread relatively evenly across the universe (which is also infinite)... | [
"The size of the universe is not infinite, it is finite, as are the number of galaxies in it. And yes over time the distance between galaxies will grow.",
"Imagine taking a marker pen and making dots on a not-blown-up balloon. Now blow the balloon up. As the balloon expands the distance between the dots increases... |
[
"What's the benefit of icing your knees during and after working out?"
] | [
false
] | [deleted] | [
"1) an analgesic effect. Places which are cooled by ice reduce the sensation of pain, so the ice makes your knees hurt less.",
"2) anti-inflammatory benefit. The most recent evidence on this is somewhat mixed, but the traditional line of thought is that cryotherapy reduces inflammation. The most recent data su... | [
"Is there not some kind of pump action that increases blood flow to the area when tissue is cooled and warmed cyclically? "
] | [
"No evidence for it, but you'll see it repeated all day long.",
"Basically, the duration and severity of temperature difference you'd have to introduce to penetrate past the cutaneous layer makes it wildly impractical. We're talking 110 degree for 2-3 hours, followed by 50 degrees or so for 2-3 hours. "
] |
[
"How does hypnosis work?"
] | [
false
] | I never really understood how it works, and honestly, I only saw it in movies which are obviously full of it. Always wanted to find out the real deal about it though. I was too scared to actually get hypnotized though because I didn't want to end up doing stupid things. How does it work? Is it true that you can ask peo... | [
"There's plenty of ",
"similar questions",
", specifically ",
"this one with the same title",
" has a lot of discussion, and ",
"this one even more",
" and seems a bit more sciencey"
] | [
"Hmm being downvoted for trying to help.\nYou are beginning to piss me off reddit. "
] | [
"I believe the short answer is that you need to be willing to be influenced. I would elaborate at length but I'm relying on second hand opinions which aren't really valid in this subreddit, but the gist as I understand it is that states of mind exist and techniques to change between them are considered hypnotism e.... |
[
"I don’t understand how AC electricity can make an arc. If AC electricity if just electrons oscillating, how are they jumping a gap? And where would they go to anyway if it just jump to a wire?"
] | [
false
] | Woah that’s a lot of upvotes. | [
"Imagine the electrons as a bunch of marbles (or ball-bearings) in a tube all touching each other.",
"You push one end, the other end moves almost instantly. You push them back, they all move back instantly. You're causing work to happen on everything that those marbles rub against. That \"work\"/\"friction\" ... | [
"While this is a great response, to go into slightly more detail, air doesn't conduct in the same way that metals conduct electricity. In conductors, electrons are free to move around in an applied electric field (voltage). Once voltages exceed the dielectric strength of air, 3 x 10",
" V/m, air becomes partially... | [
"An 'electrical arc' by definition requires a gas to ionize. We don't call cathode ray tubes and electron guns 'arcs.'"
] |
[
"In ketosis, does the decomposition of fat into ketones release energy? If yes, where does it go and how does it affect the body's energy expenditure?"
] | [
false
] | [deleted] | [
"In addition to acetyl-CoA, beta-oxidation also ",
"produces NADH and FADH",
". Also, alot of fatty acids are stored in triglycerides. Glycerol (a component of triglycerides) can widely be used in the gluconeogenic pathway which could account for some of the difference in energy densities as well."
] | [
"Fatty acids contain a significant density of energy by molecular weight, which is why they are so beneficial. During ketogenesis, acetyl-CoA is converted to a ketone body which requires a small, but still considerable, amount of energy (in the form of reducing equivalents, NADH+ for the reaction and NADPH to later... | [
"Ketone production is an outcome of a rescue metabolic strategy when carbs are in short supply and cells must oxidize fatty acids. A key metabolic intermediary in fat oxidation becomes rate-limiting and so ketones are formed to free it up. Ketones can be oxidized in muscle but is toxic and must be eliminated in the... |
[
"Is it true that marijuana can cause (activate?) schizophrenia in people predisposed to it?"
] | [
false
] | Is it true that marijuana can cause (activate?) schizophrenia in people predisposed to it? I was told as much in my drug awareness class years ago and would like to know if it's true. | [
"There is definitely correlation. Causation is up for debate.\n",
"http://www.psmag.com/health/the-cannabis-and-schizophrenia-conundrum-10218/",
"\nThis article tends to lean towards at least partial causation. But you'll find a lot of people argue the other side."
] | [
"Yes. ",
"Here is a past thread",
" which I (while obviously biased) think sums up the scientific thinking pretty well."
] | [
"I'm the author of the post I linked. My bias is in describing it as well written."
] |
[
"Can we dig channels to dried lakes, like Ahnet or Chad, so that when ice melts water will fill them up and prevent flooding of the coastlines?"
] | [
false
] | null | [
"This is one of those questions where simple calculations can be useful, but the critical thing to consider is that the ocean is huge so that the seemingly small rate of sea level rise implies a massive volume of water. The average rate of sea level rise at present is ",
"3.3 mm/yr",
". If we apply this to the ... | [
"Thanks for your time."
] | [
"Yes thank you both the asker and the answerer; that's wild."
] |
[
"How can protons and neutrons always have the same mass, when during beta+/- decay nucleons still have the same mass as nucleons that haven’t undergone beta decay?"
] | [
false
] | null | [
"‘Physics’"
] | [
"‘Physics’"
] | [
"When you consider beta decay of a nucleus, you can't think of it as a free nucleon decaying. It's the entire nucleus which is decaying, and the constraint that comes from conservation of energy is on the difference in the masses of the entire parent and daughter nuclei."
] |
[
"Scientists: How did you get to where you are?"
] | [
false
] | Inspired by a post on about scientists posting pictures of their labs, I decided I wanted to make a post about how scientists came to be scientists. Any sort of background about where you studied, what you studied, what degrees you earned, any jobs you held early on, etc. would be really interesting and helpful for so... | [
"BS Physics, BS Mathematics, MS Applied Physics, MS Applied Mathematics, working on Ph.D. Astrobiology (technically, Multi-Disciplinary Science).",
"I chose to go in-state for undergrad and work hard to stand out. Then I chose the area I wanted to study in. Found the person who is the most well known and most res... | [
"BS in biology. One month away from a PhD in genetics. ",
"I've done little in the way of useful work so far. 5 summers at a plant nursery doing physical labor and 3 months at a grocery store stocking shelves aren't very applicable. ",
"I did summer research in undergrad and I recommend any other potential ... | [
"I drove here."
] |
[
"When the antibodies are created against coronavirus, or any other similar special diseases, do they stay in body for lifetime? Or would they get destroyed when not in use?"
] | [
false
] | null | [
"Antibody titres will eventually decrease. However, the cells that produce them (B-cells) should persist in your body for much of your life. They will slow down antibody production over time, but will reactivate, and proliferate should they detect a similar infection."
] | [
"So remember that antibodies are just proteins produced by a certain type of white blood cell--if you want to use a war analogy, think of them more like miniature mines left by the immune system that catch onto passing pathogens. They have a half-life of about one month (depending on the type), meaning after that t... | [
"Is there any limit to how many viruses can be remembered? Do lymph nodes have data caps?"
] |
[
"Are there drugs based on the pathogenic mechanism of Corynebacterium Diphtheriae?"
] | [
false
] | I'm currently learning about C. Diphtheriae and it's pathology, and I was wondering if it was possible to replicate the molecular mechanism to use as an anti-cancer drug. It produces a toxin which inhibits protein synthesis through deactivation of Elongation Factor 2 (EF-2). Would it be hypothetically beneficial to inj... | [
"One of the problems I see is we vaccinate against the DT. So our own immune system could respond to the toxin perhaps making it ineffective. "
] | [
"Surely the vaccination is against the antigens displayed on the surface of ",
" rather than the toxin itself? So the immune system responds to the organism rather than the toxin"
] | [
"The DTaP vaccine is against the toxins not against the bacteria. Actually C. diptheriae can colonize the upper respiratory track without any issues, especially for those who've been vaccinated as for some reason the bacteria doesn't tend to produce the toxin at that point. "
] |
[
"What are candidate susceptibility genes?"
] | [
false
] | [deleted] | [
"I think it will make more sense to you if you separate \"candidate\" from \"susceptibility genes.\" [Searching for the whole phrase is unlikely to yield useful results simply because it's not an exact phrase that we use.] ",
"As NSBTawney said, susceptibility genes are genes which have been linked somehow to s... | [
"Just to go a little further, genome-wide association studies (GWAS) can be a common source of lists of candidate genes that correlate with susceptibility to a common disease. GWAS tend to get a lot of media attention so maybe this is where you heard this term?"
] | [
"The term is generally used when referring to the cause of a disorder. The gene that they are talking about is a candidate to be a susceptibility gene, which means that the gene in question may be the cause or one of the causes of the disease."
] |
[
"Shampoo/Conditioners: How do they work, if at all?"
] | [
false
] | I've been told that shampoos and conditioners perform contradictory functions. The shampoo washes oils/dirt out of your hair, and the conditioner puts specific oils in. This begs the question of 2-in-1 shampoo/conditioners. Do they work? If so, how? Wouldn't the shampoo half negate whatever the conditioner half do... | [
"Essentially, it is 2 ingredients added to a regular shampoo, a silicone and a suspending agent. The silicone is usually an ingredient called Dimethicone and it is what makes the formula conditioning. The suspending agent is Glycol Distearate and it is what keeps the silicone from separating out of the formula. The... | [
"Are you talking about the 2-in-1 formulas?"
] | [
"Yes. That's exactly what I'm talking about."
] |
[
"How do animals, like the chameleon \"see\" the world with eyes that move independently from each other?"
] | [
false
] | Do they see two images or switch between the two? The whole idea can seem really foreign and hard for me to understand since I've only seen the world one way with eyes that are both front facing. That brings up another similar question, what about animals that have eyes on either side of their head? | [
"Your retina has a bunch of individual nerve fibers that leave it in a bundle called the optic nerve. You have two of these bundles of nerve fibers that come together at the optic chiasm. In a human, two bundles leave the chiasm with some individual nerve fibers from each of your retinas. This is the first step in ... | [
"Years ago, an experiment was conducted giving subjects glasses that flipped everything upside down. Initially they had great trouble feeding themselves and moving around. But after just a few days their brains adapted and they functioned the same as they did prior, even to the point of insisting that everything lo... | [
"The example of comparing it to my arms actually really helped. I never really thought about how my arms move and send information to my brain independently."
] |
[
"Would the increased albedo of an ice age significantly impact a planet’s orbit over time? [physics]"
] | [
false
] | I was reading about the asteroid deflection technique of painting their surface white, using the solar radiation pressure to change the orbit enough to miss earth. The process was estimated to need 20+ years of exposure to have the desired impact. This got me thinking about ice and how reflective it is, and a quick go... | [
"Not really, earth is way to heavy. It only works for small objects that have a greater ratio of surface area to volume. That's because inertia/gravity is proportional to mass and therefore volume, but the radiation pressure acts on the surface area.",
"Let's do a simple calculation:",
"Sun's radiation hit the ... | [
"Brilliant answer. Not to say that there won't be some effect on the orbit, but you demonstrated exactly how small it will be. "
] | [
"To put it even more in perspective, the average force of saturn acting on earth is 1.1e17N, which is still 100,000,000 time stronger than the radiation pressure.",
"http://www.wolframalpha.com/input/?i=(mass+of+saturn)+*+(mass+of+earth)+*+(gravitational+constant)+%2F+(average+distance+of+saturn+and+earth)%5E2"
] |
[
"Is there tolerance differentiation between alcohol types?"
] | [
false
] | [deleted] | [
"I am pretty sure that all \"alcohol\" contains the same molecules that make you feel \"drunk\". The molecule is C2H5OH (ethanol) and all drinking alcohol contains this.",
"Now, during fermentation and distillation, some small quantities of other alcohols are produced, but generally everything is done to minimise... | [
"In addition to what Fluffeh said, there is such a thing as situational specificity of tolerance. See, your body tries to counteract the effect of alcohol in your system by producing chemicals to remove it quickly. Due to classical conditioning, your body can start to produce these chemicals even before the alcohol... | [
"Thank you for your reply!"
] |
[
"How can a consumer thermal camera measure temperatures lower than itself?"
] | [
false
] | In an article about James Webb Space Telescope, it was written that it is needs to be cooled down so it can measure lower temperatures, so the blackbody radiation of the mirrors doesn’t blind the sensor. How can a consumer thermal camera avoid getting blinded by the warm lenses and sensor when measuring below freezing ... | [
"the sensor when cooled is more sensitive. it does not have to be cold to work and detect photons (that’s the whole point of thermal cameras). the cooling just increases the sensitivity greatly. Consumer thermal cams do not need that level of sensitivity so they are not actively cooled."
] | [
"The micro bolometer array used in those cameras is not nearly as sensitive as JWST. To calibrate the array, every few seconds they use a solenoid to move a shutter over the array blocking all light. The temperature of the shutter is measured via a thermistor or thermocouple and the entire array is compensated. I'm... | [
"Uncooled consumer thermal cameras ",
" susceptible to thermal noise from their own components, even with careful selection of the lens material for high transparency in the infrared and careful sensor design. In turn, the lowest temperature they can usefully distinguish is far hotter than outer space, of course.... |
[
"A meteor hits the earth either on land or in the ocean. How are the effects different?"
] | [
false
] | Also side question...if a meteor hits the ocean at a point where the ocean depth is the deepest, does the meteor hit bottom? I understand the size and speed of the meteor has a lot to do with this as well but any insight into the matter would be interesting. Thanks. | [
"You might find this ",
"impact effects calculator",
" useful and fun to mess with. ",
"In short, it depends on how big a rock it is, and how deep the water is.",
"Consider ",
"this run",
" which is for an large, 500m rock hitting at 17km/s (average asteroid impact velocity), 45°, and in the Pacific Oce... | [
"Tsunami in the ocean affects coastal regions predominatly. ",
"Land based impact. Aside from property damage and mortality (death has possibility of being averted in tsunami), dust will be turned up, leading to a giant sun blocking cloud that will be comparable to a volcanic eruption of ash and smoke, which bl... | [
"I would take a very large meteor to kick up a significant tsunami. Like, absurdly large. Like, it would need to hit with an impact of a few gigatons to throw up even a noticeable tsunami. That's the sort of hit that would create a several kilometer crater if it hit dry land."
] |
[
"If I would to left a refrigerator open in a room, would the room temperature drop or rise? And why?"
] | [
false
] | I recently had a discussion with a man who is the chief Mechanic on a overseas freight ship and he was convincing me that the temperature would rise. But I can't get my head around this problem and I would like to know how big the room has to be to achieve a temperature drop and a temperature rise. Simple explanation ... | [
"A fridge is a ",
"heat pump",
". It takes heat from inside it and dumps it outside, into the room. But this effort generates heat over and above the amount of heat moved, regardless of size, type, power etc, so the room warms up."
] | [
"It's a machine that uses electricity to do something, hence it creates waste heat. That's about the simplest way you can look at it. Doesn't matter what goes on inside the machine, specifically in the cold compartment of the fridge.",
"In normal operation the waste heat is dumped outside of the fridge in the roo... | [
"And this is one consequence of the Second Law of Thermodynamics. In fact, it is more or less Clausius's formulation of this law."
] |
[
"Can a parasite change a human's genome?"
] | [
false
] | I'm writing a science-fiction novel, and I'm wondering if it would be possible for a parasite to take over a body and change it completely. I don't need to know whether or not a parasite exists that does this, but if, hypothetically, it's possible. And if it is possible, how would it go about changing human DNA? | [
"Can a parasite change a human's genome?",
"Yes, it happens all of the time by a number of mechanisms. The most common way is for some viruses to insert all or part of their genome into that of their host ... host being a human in this case. A large percentage of the human genome is made up of copies of ancient... | [
"For the most part, the large majority of our genome that is comprised of ancient viral genomes that have long integrated into us are from retroviruses. Just like any retrovirus, in order for it to replicate, it need to produce and integrate a DNA copy of its genome into ours. But over time, the proviral genome (th... | [
"Has the genome simply assimilated these portions so that they're \"compatible\" with the rest of the sequence or do they simply not inhabit a large enough part to effect anything?"
] |
[
"Are the smallest components of mass able to rotate?"
] | [
false
] | I know that the velocities of the smallest particles can change their direction, but I don't know if these particles themselves are able to rotate. My thought-process was this; when an object rotates, the object is made up of smaller components which are then sent moving in different directions. But the smallest partic... | [
"We can't exactly look at them and check. However, they ",
" they rotate. They have an intrinsic angular momentum that behaves just as we expect, can couple to other angular momenta, and the whole sum is conserved, etc."
] | [
"Since they are only made up of one part, and cannot have different parts to be sent in different directions, it seems to be that they are unable to rotate.",
"That's very true. In modern physics, a distinction is drawn between ",
", which relates to what you are talking about, and ",
", which has exactly the... | [
"This is called spin?",
"Yes, that's correct. The longer name is \"spin angular momentum,\" which when added to a system's \"orbital angular momentum,\" gives a \"total angular momentum\" figure which is conserved."
] |
[
"What is the scientific explanation behind taste in music?"
] | [
false
] | Why do people like only a certain genre of music and disregard others ? I know it doesn't (always) have to do with age since I know older people who listen to songs that you wouldn't normally think someone that age would listen to. Do you know of any such studies that delve deeper into the reasons? | [
"I didn't realize we had a panelist for this on here. ",
"This subreddit is impressive. "
] | [
"I didn't realize we had a panelist for this on here. ",
"This subreddit is impressive. "
] | [
"Thank you, you were very helpful."
] |
[
"Eclipse Frequency: How often do certain \"Blood Moon\" sequences occur?"
] | [
false
] | in the are making a psuedoscientific connection between the frequency of "blood moons" or lunar eclipses. Specifically, there seems to be some suggestion that four lunar eclipses in two years, with this round near Easter Sunday, are a predictor for the 'end times'. Question: How often does this occur naturally? Name... | [
"Eclipses are one of the most predictable natural phenomena known to man, so this is pretty easy to answer. ",
"Easter is always ",
"the Sunday after a full moon",
", so eclipses occur near Easter very commonly. ",
"Tetrad events",
" occur in roughly 600-year cycles, with alternating 300-year periods of f... | [
"So if tetrads are caused by the Moon/Earth pair lining up \"really well\" at the same time that the moon is full, that pattern, in itself, has a cycle. Most notably we've had 38 chances for this to happen beforehand (after the year 500), a fact ignored by the press, of course.",
"My follow up would be \"do ecli... | [
"Correct, over long enough time scales you would expect all days of the year to have an equal probability of an eclipse. But long-duration cycles like the Saros cycles mean that you have to take an average over a very long time to see this."
] |
[
"Why are Neanderthals (Homo neanderthalensis) a separate species from modern day humans (Homo Sapiens)?"
] | [
false
] | I am reading a book that states what separates species is the ability to mate and have fertile offspring. How are Neanderthals and Homo sapiens separate species if we know that Homo sapiens have Neanderthal DNA? Wouldn’t the inheriting of DNA require the mating and production of fertile offspring? | [
"The species concept in general is pretty fuzzy. The Linnaean system is ultimately based in a pre-evolution mindset and is not fully compatible with our modern understanding. But, it's useful, so we keep it around.",
"To get a bit more to the science, while we do know that anatomically modern humans and neander... | [
"Depending on how you divide them up there are ~4-5 main species concepts. The idea of breeding and producing fertile offspring is really only present in one of them. ",
"The others more or less revolve around some form of isolation (time, space, reproductive selection) that prevents individuals from mating even ... | [
"Some people have suggested that Neanderthals are actually a subspecies of humans for this exact reason. (Humans would be classified as Homo Sapiens Sapiens and Neanderthals would be Homo Sapiens Neanderthalensis.) However, like the other commenter already mentioned, there's evidence that humans and neanderthals we... |
[
"What is the maximal distance possible between two single elements of matter ?"
] | [
false
] | [deleted] | [
"Objects don't have to be near each other to influence each other. Light and gravity can both travel for an unlimited distance through vacuum (although they start to be insignificant at large distances). Neither of them depends on the presence of matter to propagate.",
"We can see objects whose light has traveled... | [
"You seem to be confusing sound waves with electromagnetic waves.",
"I'm sure you have heard, that sound cannot travel through space, because there is no medium through which it could travel. The reason why this is true is, that sound is a pressure wave of matter. Thus, sound is an oscillation of particles, that ... | [
"I made an image to understand my question more easily :\n",
"http://imgur.com/10OoVDC",
"\nIf the sphere is empty of any other elements (in my understanding fields are not elements), is there a maximum distance between green and orange ?\nIs there no limits for the vaccum between them even if the sphere is the... |
[
"How do processes that change copper's surface color and appearance affect it?"
] | [
false
] | This is actually a collection of several questions related to copper I'm trying to get my head around, regarding patina and the gasoline-on-concrete look heated copper has. Patina Is patina a form of rust, or is rust specifically iron? If in a high corrosion environment, like a dock, would patina form faster, like iron... | [
"Copper is known as a transition metal. It is called this because its atom has a certain electron arrangement (the particles that surround an atom, and involved in reactions).",
"Transition metals have noticeable colours because these electrons take in light at different wavelengths. For example, Copper sulphate ... | [
"Is patina a form of rust, or is rust specifically iron?",
"Why not just let Wikipedia settle this?",
"Rust is an iron oxide, usually red oxide formed by the redox reaction of iron and oxygen in the presence of water or air moisture",
"So yes.",
"Can the oxidation colors be cleaned off easily?",
"Yes. ",
... | [
"Looking it up it appears that CuO(Copper(II) oxide) does form a monoclinic crystal, does that mean that it has more integrity than say patina?"
] |
[
"Where does the weight you lose go?"
] | [
false
] | [deleted] | [
"Almost all the weight you lose exits through your lungs. A 140 lbs person exhales about 1kg of CO2 per day through basal metabolism. The carbon comes from cell respiration as the cells burn sugars and fatty acids for energy. Since you're inhaling equal moles of O2, the total weight lost is about 270 grams per day,... | [
"O2 is transformed into CO2 at the lungs",
"That's not right. CO2 comes from cell respiration. Each cell in your body uses carbon-bearing molecules like glucose to produce ATP. The end products are CO2 and H2O. The CO2 is dissolved in the blood and released in the lungs. "
] | [
"The hydrogen goes out in H2O, like C6H12O6 +3O2 -> 6CO2 + 6H2O, so 1/6th of your weight loss goes out as hydrogen.",
"And you're right, most of it goes to making ATP. A maximum of 34 ATP can come from a single glucose."
] |
[
"Does the sun have any discernible features on its surface that make it look different than a big ball of fire?"
] | [
false
] | null | [
"It has sunspots."
] | [
"In addition to ",
"sunspots",
", there are also ",
"solar flares",
" and ",
"coronal mass ejections",
". There's a lot of cool stuff happening at the surface of the sun.",
"(I guess coronal mass ejections aren't at the surface, but they're still pretty interesting, and not really what you'd expect f... | [
"also has ",
"granule",
". the sun also ",
"pulses/oscillates"
] |
[
"Do insects evolve faster than most animals due to short life span?"
] | [
false
] | null | [
"Please post this in ",
"/r/asksciencediscussion"
] | [
"What's the difference? "
] | [
"Your question is very open ended which is not allowed in ",
"/r/askscience",
" so you should post it in ",
"/r/asksciencediscussion"
] |
[
"What would the surface of the moon look like during a Lunar eclipse from an astronauts perspective?"
] | [
false
] | null | [
"No, both sides would be dark... ",
"A lunar eclipse is when the earth blocks the sun from shining on the moon."
] | [
"The question is more about what you'd see in the sky: as the Earth's shadow blocks out the sun, you'd see a ring of sunset-red around the Earth, biased to the side closest to the Sun and burning more or less evenly around the world when the Sun and Earth are exactly aligned, as you see every sunrise and sunset sim... | [
"Would there be a total eclipse so you could see the aurora, or would earth's atmosphere refract enough sunlight to prevent that? Or, could you just place your thumb between you and the sun to eclipse since there's no atmosphere on the moon?"
] |
[
"Why when riding a bicycle do I not just fall over to the side?"
] | [
false
] | null | [
"Poke around ",
"these pages",
" from Andy Ruina's research group at Cornell. Bicycle dynamics turns out to be rather complicated. Simple explanations don't suffice."
] | [
"http://en.wikipedia.org/wiki/Bicycle_and_motorcycle_dynamics"
] | [
"Can you elaborate on this concept?"
] |
[
"AskScience AMA Series: We're infectious disease experts here to answer your questions about monkeypox. AUA!"
] | [
false
] | In early May, reports began circulating about confirmed cases of monkeypox, an orthopoxvirus similar to smallpox. As of mid-June, there were over 2100 reported cases of monkeypox in dozens of countries. While a great deal is already known about the science of the monkeypox virus, this outbreak has raised several new qu... | [
"Histopathology doctor here. What's the most useful information we could be providing in our reports to clinicians that query monkeypox, other than that the tissue features are/are not consistent with the clinical query?"
] | [
"How long does the virus survive on surfaces for i.e days, hours, etc?"
] | [
"Thanks for doing this AMA.",
"As far as I understand there is a smallpox vaccine that's also effective against monkeypox. If the outbreak keeps spreading, do you expect a large-scale production and vaccination program similar to what we had with COVID?"
] |
[
"What is the most fundamental 'perspective' to study Thermodynamics?"
] | [
false
] | null | [
"Yes, statistical mechanics. Landau and Lifshitz's book is very good."
] | [
"Which volume is the most adequate?"
] | [
"Volume 5."
] |
[
"How do two particles become entangled?"
] | [
false
] | [deleted] | [
"Here is a simple case, which is idealized but not too different from how it works in a lab.",
"Suppose a particle, at rest, with zero angular momentum, spontaneously decays into two back-to-back photons. (A neutral pion does this, for example, or the Higgs boson.) Each photon has one unit of angular momentum, an... | [
"There are ",
"quantum gates like CNOT",
" that can entangle or disentangle several qubits. It's basically an if-statement that flips bit B only if bit A is 1, which means the bits are now entangled because B depends on A (that is, if you start with a non-entangled state. For some specific entangled states it w... | [
"How would a quantum computer entangle qbits intentionally?"
] |
[
"What is the scientific explanation for the weird light phenomenon I saw today?"
] | [
false
] | null | [
"Did it look like ",
"this",
"? Your identification sounds correct. It sounds like you’re describing a ",
"glory",
" and a ",
"Brocken spectre",
". You can also see the from the top of tall buildings or mountains with clouds or fog below. ",
"It means you were directly opposite the sun, which was shin... | [
"Yes it looked exactly like that. Thank you!"
] | [
"I think you’ll be able to get better answers if you ask about what causes the atmospheric phenomenon known as a glory. It’s easier for folks to find the question that way. If you’d like to resubmit, let me know and I’ll make sure it gets released."
] |
[
"Can parallel evolution lead to a single trait in 2 species under totally different environmental pressures?"
] | [
false
] | Sorry for my clunky formulation here. My understanding is that evolution refers to the development of a single trait in organisms that share an ancestor, as a result of the same environmental pressure(s). Whereas evolution refers to a single trait showing up in two related species, but they diverge. In other words, the... | [
"In parallel evolution, the two species start with a similar characteristic, and evolve to have a different characteristic which is still similar to each others' characteristic. Example: Species A and Species B both have front legs used for walking, A and B both evolve, A and B's front legs evolve into wings.",
"... | [
"So then the two concepts (parallel/convergent) are ",
" distinguished on the basis of the original morphology (or whatever)? I don't understand why that's significant, though. Why does it matter where 2 species started out, given that they've ended up at (loosely speaking) the same place? After all, I assume the... | [
"Parallel, convergent, and divergent are just terms describing the comparison of evolution of (or away from) a particular feature between an arbitrary number of species. The terms don't denote that anything special happens other than evolution.",
"The majority of the ",
"wikipedia page on parallel evolution",
... |
[
"Toxicity of CO2?"
] | [
false
] | The general perception is that CO2 is not toxic, and it only is harmful as an asphyxiant agent, replacing oxygen. That's what my anorganic chemistry prof told me and what I found in some posts here when I was searching if it had been asked before. But in my fire department's SCBA course CO2 was described as an nerve ag... | [
"CO2 causes suffocation. It does by replacing oxygen in your red blood cells. Hemoglobin, the protein that makes up the majority of your red blood cells (giving them the red color because of the iron it contains) is charged with transporting oxygen throughout your body and collecting CO2. It preferentially binds CO... | [
"It's important to note that carbon dioxide does not bind in the same spot as oxygen. Rather, it binds in a prosthetic group away from the heme group where oxygen binds, and it's interaction with the protein and the resultant conformational change is what causes the lower affinity to oxygen in the presence of CO2."... | [
"Your body can sense how much CO2 and O2 are in your blood through what are called chemoreceptors; that's how your body determines whether you're getting enough oxygen or not. However, the chemoreceptors for CO2 are actually much more sensitive than the ones for O2, so CO2 is the primary controller of breathing. If... |
[
"If inflammation is the bodies natural reaction to heal itself/fight infection, then would any measures to counteract inflammation (medication, ice) interfere with the body's healing process?"
] | [
false
] | [deleted] | [
"Depends on the infection. Some infections deliberately* provoke an excessive immune response, because the damage that results either makes it more difficult to fight the infection, or because the damage introduces elements that the pathogen can utilize to its advantage. In such cases, depressing the immune respo... | [
"Sometimes, yes.",
"This is one of the reasons why doctors do not generally recommend anti-inflammatories like ibuprofen for small kids anymore in Australia. Sometimes the body needs to learn to fight and heal on its own, and to have a properly tuned immune system.",
"In some cases, slowing inflammation actuall... | [
"With broken bones, for instance, inflammation does help with the healing process. This is why if you break a bone, for pain Tyleonol (acetaminophen) is recommended over NSAIDs like Advil (ibuprofen) or Aleve (naproxen). "
] |
[
"A friend stated \"Tilt: Two charges of one Coulomb each separated by a meter would repel each other with a force of about a million tons.\" Is this statement true?"
] | [
false
] | null | [
"Yes, although the way it's worded is nonsense. 1 million tons is a unit of mass, not force**. However if we assume they mean the equivalent weight of 1 million tons on Earth then it's easy to check,",
"The force between two charged particles is",
"F = k q1q2/r^2 \n",
"k is a constant, k = 8.987*10",
" N m"... | [
"To add to this, the force ends up so huge because one Coulomb of charge is a huge amount of charge. It takes ten million trillion electrons (10",
" ) in order to get one Coulomb of charge. "
] | [
"He could be referring to one time as in 2000 lbs which is a unit of force"
] |
[
"In sending humans to Mars, what problems will need to be solved with respect to launching and returning astronauts from Mars' surface?"
] | [
false
] | Even with the lower Martian gravity, will returning launch platforms/vehicles need to be in place before humans step foot on Mars for the first time? Also, with respect to the amount of time to travel to Mars and the differences between a Martian orbit and and Earth orbit, what is the minimum amount of time such a tri... | [
"There are several problems to be solved.",
"You're quite right to point out the issue of the return vehicle. This is a safety issue since humans would inevitably die if they cannot return, so redundancy is needed. There are different mission concepts out there, some of them plan to land the launch vehicle before... | [
"Thank you for mentioning the ionizing radiation. I feel like the public has been sold a false bill of goods because this isn't discussed realistically.",
"The effects of interplanetary radiation on the human body are relatively unknown. Measuring radiation is tricky, because not all radiation is the same. A \"ra... | [
"I haven't seen any serious human on Mars missions that are only one way trips. Can you link to any?"
] |
[
"Why do Beavers build homes as dams not on land?"
] | [
false
] | [deleted] | [
"Beavers ",
" eat fish."
] | [
"Beavers do not always create dams, they only do so if they need to. Beavers live in \"lodges\" (a distinct structure from the dam) which are similar to burrows but have underwater entrances. They do this to evade predators since their aquatic adaptations give them an advantage in the water compared to larger carni... | [
"Not a biologist but I do love beavers. They don't live in their dams. ",
"Beavers are nature's engineers. They build dams to block of creeks and other small waterways in order to create a body of water that makes it easier to hunt fish and other prey. Dams can actually be extremely destructive to the local ecosy... |
[
"If a base liquid existed that could completely neutralize stomach acid, would I absorb fewer calories and nutrients from that food?"
] | [
false
] | [deleted] | [
"Such actually exist. Tums, Rolaids, Malox, etc all work by neutralizing stomach acid.",
"And while these WILL interfere with digestion to an extent, you will still absorb most of the calories from food. In fact, the base salts in the above mentioned products tend to act as a laxative, which as a more profound ef... | [
"I thought they were laxative for exactly the reason of then neutralizing the acid and thus interfering with the enzyme function, which is crucial for food absorbent. Thus no absorbent of food -> everything goes right through you -> laxative.",
"But defienntely not my area of expertise. "
] | [
"The acid in your stomach really plays a large part in digesting protein. The fats are broken up by bile, produced by the liver and released into the small intestine and starches and other saccharides are broken up by pancreatic amylases. The most calorie dense food (fat) and easiest to obtain energy (sugar) both d... |
[
"Why is the integral of the standard normal distribution function from negative infinity to positive infinity equal to 1?"
] | [
false
] | null | [
"It's 1 because the probability distribution is normalized (as all are). We ",
" its integral over the whole space to be equal to 1 so that we can interpret the thing as a probability distribution (probabilities must be real numbers on the interval [0,1]).",
"If the domain is infinite, wouldn't the area under t... | [
"So what you're saying is that for very large values of x in positive and negative directions, the area produced becomes so small that it approaches 1?",
"I haven't gone very in-depth with integral calculus so my understanding was that if a function had no closing (infinite domain) the area under the curve would ... | [
"So what you're saying is that for very large values of x in positive and negative directions, the area produced becomes so small that it approaches 1?",
"If f(x) is the standard normal distribution, I'm saying that for large values of |x|, f(x) becomes small enough that the integral of f(x) dx over the whole rea... |
[
"I'm on a small to mid-sized boat, far from any coast, and a tsunami is heading in my direction. What happens? Do I notice anything wrong?"
] | [
false
] | null | [
"Not much, except your elevation changes. ",
"Tsunami wavelengths are huge. If there’s no land around to make the wave break, it will just roll under you with no drama like a very long swell. You go up, then you go down. "
] | [
"You probably wouldn't notice it at all. The wavelength of a tsunami is so long that your rise and fall would be gradual. Out on the open ocean with no coastline to measure against, the tsunami acts more like a rapid tide change than a wave you might see at the beach."
] | [
"Over the course of a few minutes, the water would rise and fall a foot or two. You would be unable to feel it, especially since your boat will be rocked by the ordinary wind waves."
] |
[
"How did scientists calculate the amount of hydrogen left on the sun and thus calculated the age of the sun?"
] | [
false
] | null | [
"That isn't mass spectrometry, it's optical spectroscopy used to determine mass "
] | [
"That isn't mass spectrometry, it's optical spectroscopy used to determine mass "
] | [
"yep, you're correct. Mass spectrometry is when you fire an ionized particle through a magnetic field and measure its deflection. This yields the mass-to-charge ratio of the particle. "
] |
[
"What is the heaviest element created by the sun's fusion?"
] | [
false
] | As I understand it (and I'm open to being corrected), a star like the sun produces fusion energy in steps, from lighter elements to heavier ones. Smaller stars may only produce helium, while the supermassive stars are where heavier elements are produced. If this is the case, my question is, what is the heaviest element... | [
"I prepared a lecture on this during my masters in nuclear physics. There are many processes by which the heavier elements are created. Most people so far seem to be speaking of the processes by which the sun creates fusion energy. It is true that only the fusion of elements up to Iron produce more energy than is r... | [
"When the hydrogen is exhausted it will move on to helium, and when this is exhausted the sun will become a red giant star.",
"A process will then begin called shell burning, going through the spare hydrogen and helium not within the core itself. The sun will then fuse heavier elements together, until it reaches ... | [
"When the hydrogen is exhausted it will move on to helium, and when this is exhausted the sun will become a red giant star.",
"A process will then begin called shell burning, going through the spare hydrogen and helium not within the core itself. The sun will then fuse heavier elements together, until it reaches ... |
[
"what is the science behind soccer ball bending/curving ?"
] | [
false
] | examples: | [
"It's known as the ",
"Magnus effect",
"."
] | [
"Here is a video that explains it well. \nThe Physics Behind a Curveball - The Magnus Effect: ",
"http://youtu.be/YIPO3W081Hw"
] | [
" by Robert Adair is a great book which covers this and many other topics, and is very accessible to the layman."
] |
[
"How do we calculate the area of a country?"
] | [
false
] | For example, how did we figure out the exact land size of Russia? Seems very complicated. | [
"There are specific map projections of our planet, each has its own definition and mathematical characteristics. Computers are able to give you area of any shape. ",
"But how would I approach; If you imagine map in some of these projections with specific scale factor, you could put strip of given width from south... | [
"They had teams of cartographers go around and do measurements and position determinations all over the place, then, once you get enough points, you build a polygon on the surface of a sphere. From there you use maths (probably splitting the shape in triangles to approximate real shape) to calculate the area."
] | [
"Most rich countries did it themselves in 19th early or sometimes earlier. There's even a Jules Verne book with people working on this but I forgot its name. Today we have satellites."
] |
[
"What happens to all the lab rats that don't die after an experiment?"
] | [
false
] | null | [
"No, they get killed. ",
"I'm not sure how they kill rats but the most common ways to kill mice include cutting their head off with scissors or twisting their necks like chicken. You can also buy special guillotines to cut their heads off cleanly."
] | [
"The last biology lab I observed a few years back used a gassing chamber (CO2 I believe?) to kill/knock-out the rodents then confirmed the kill using a metal bar to break their necks."
] | [
"Well, even if the animal doesn't die due to the experiment, it is likely that there is a lot of extra information to be deduced from the study of its various organs. In several of the labs I worked at, the outcome by default involved sacrificing the rat.",
"A good ethical experiment is designed in a way that the... |
[
"In UV-Visible spectroscopy, why aren't the absorption bands infinitely thin, since the energy for each transition is very well-defined?"
] | [
false
] | What I mean is: why there are bands that cover a certain range in nanometers, instead of just the precise energy that is compatible with the related transition? I am aware that some transitions are affected by loss of degeneracy, like in complexes that are affected by Jahn-Teller distortion. But every absorption I see ... | [
"The energies of the states ",
" exactly discrete. The lineshape of the state is not quite a Dirac delta function, but rather a ",
"Breit-Wigner function",
" with some nonzero width. The width is inversely related to the lifetime of the state, so only states which live forever truly have definite energies.",
... | [
"There's also another major reason in the case of molecules. In the UV/Vis spectrum you are exciting more than just electrons. You can excite other modes such as vibrational modes in addition to electronic modes and since you naturally have a distribution of vibrational states in molecular systems it takes differe... | [
"The width is inversely related to the lifetime of the state, so only states which live forever truly have definite energies",
"And, just to clarify, this is because of the time/energy form of ",
"Heisenberg's uncertainty principle",
", which states that the fundamental uncertainty in the energy of a state (t... |
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