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ELI5: Why doesn't the intensity of the urge to urinate directly corralate with the amount of urine?

There have been times when I felt my bladder was about to explode and only a squirt came out.

Think of a bag which is being filled with water. The amount of water in it directly determines the amount of pressure on the walls of the bag. This is what you expect from your bladder as well, right? Well, you are far more complex than just a bag. For example, psychological stress is also directly correlated to the "urge to pee" regardless of how much pee their actually is in your bladder. This means: Besides the amount of pee in your bladder, there are many factors influencing your urge to pee, nearly all of them are of a psychological nature.

ELI5: Why are medical gowns for patients open on the back?

Why are they made so your butt shows?

I think they are made this way because it provides several useful features: \- can be easily and quickly taken off/put on a person who is lying down (in terms of both routine care and emergencies); if you had to put them on like a normal shirt and tie at the front it would involve a lot of turning and moving \- they provide full coverage for people who are lying down or sitting down (as most patients do most of the time) \- if they closed in the front there would be a lot of potential for them to open for patients who are not fully capable

What is Zizek all about (idealogy-wise)

I want to delve into him one day, but I’m curious as to where to start / what kind of arguments he is making

Slavoj Žižek's work in philosophy intersects Hegelianism, psychoanalysis and Marxism. For an accessible introduction to his views on ideology, you can check out the 2012 documentary *The Pervert's Guide to Ideology*.

Can fire occur from a non-oxygenated reaction?

Combustion is the reaction of a material with oxygen, right? But the fire is a result of the energy being released from the exothermic reaction. So does that mean that other exothermic reactions can create fire? Or is it just oxygen, and why?

It probably depends who you talk to as to how specifically they'd define it. But certainly there are other chemicals that burn exothermically - for example anything that can burn with oxygen can burn with fluorine. Even after it's been burned with oxygen.

ELI5: How do aircraft/fighter jets know that they are being locked on by an anti aircraft system or by another fighter jet?

So there are radio receivers on different parts of the plane. These can detect when radar hits them. Different radar systems do things differently so it can also tell the difference between different radar systems. It can tell when the aircraft has been locked on rather than just pinged by radar because a radar lock on is an intense beam of radar energy that continuously tracks the aircraft. So it's constant and high powered. A radar lock does this so it can feed very accurate positional data to the weapon system. Normal radar, which will be sending out a wider beam and so less intense for anything it's hitting on gives more general direction and range. However, this doesn't tell you anything if the system locking onto you using infrared (Heat Seeker) because that's a passive system so nothing from that is hitting the plane. It's just looking at the plane and detecting the plane's heat.

CMV: Hunting is disturbing and being happy you killed something is disturbing

Hey y'all. I'm really honestly looking for someone to shed some light on this for me. My boyfriend has recently gotten into hunting and it bothers me a lot. I've been an animal lover my entire life (yes I eat meat though) and could never imagine harming something myself. Hunting deer and geese seem to make my boyfriend really happy and I WANT to be supportive of him and happy for him when he gets a kill. But I cannot help feeling internal anger, disgust, and hurt. I understand hunting for food is natural and has been a thing since the beginning of time, but it just freaks me out and makes me feel weird seeing people pose with animals they killed. Please can someone give me some perspective and ways to deal with it so I can be both an animal lover AND be supportive of my bf's new hobby. Thanks so much :) EDIT: I’d like to thank everyone that has commented respectfully and I plan to work on my perspective with a lot of your comments in mind. I really appreciate the constructive criticism and new ways to look at things. To those downvoting my comments (because you don’t agree with me or are offended I assume), I posted this with the most genuine interest in having my views changed and having thoughtful conversation. I didn’t mean to target anyone. But still, go fuck yourselves. :)

Hunting can help the environment. Too many deer in one area can overgraze it and cause habitat loss. In Yellowstone wolves have been introduced and the environment for many species has improved. It worked in Yellowstone, but introducing wolves won't work everywhere. Too many geese can destroy a field of winter wheat. If they are not hunted for food, they will be shot as vermin and left to rot where they lie. Hunting is more than just getting an animal in your sights and squeezing the trigger. It's about understanding the animal and it's habits. There have been many cases where hunters have raised the alarm over a ecological issue. For them keeping the environment balanced is very important. The disappearance of a species which isn't their target tells them something is changing. The ecosystem is a complex web and hunters are our free eyes and ears of the system.

Passionate about learning but...

Hello, I've recently been trying to learn to program in python but I’ve been experiencing this overwhelming feeling of a desire to understand the underlying structure behind everything I’m doing. I want to be able to understand how computers work from the ground up, how hardware and software relate to one another, how all these languages that build on top of each other all rely on the same fundamentals and what those fundamentals are. Only then do I think I’ll feel comfortable and satisfied learning and working on a more superficial abstraction which I consider python to be. Can any of you recommend a path I should take in order to satisfy this need? Whether that be a particular order of learning certain topics or more specifically any book, video, course that you might consider appropriate given my situation. Thank you, Mango164

Look at Nand2tetris course on Coursera, exactly what you need. You build a whole computer program that is written in your own made language, compiled and translated by your own made compiler and translators running on your own operating system. You go from literally 010110110 type instructions to full blown program with everything build by you.

CMV: The United States government does not owe African-Americans financial reparations.

This has been an ongoing topic of debate in this election cycle in the US. To be clear, this post is not to say that I condone what white people have done to African-Americans (and other races) over many years. I just don’t see how reparations could ever work economically or socially. If the federal government were to authorize reparations, there would certainly be unrest in other ethnic communities. For example, Japanese-Americans that were kept in internment camps under FDR would likely wonder why they are not getting the same or similar treatment. Furthermore, reparations are not the best allocation of taxpayer dollars. It does not seem logical for innocent citizens to have to financially subsidize the wrongdoings of their ancestors. The federal government’s funds and energy would be better spent on addressing and repairing the wage gap between ethnic groups.

> For example, Japanese-Americans that were kept in internment camps under FDR would likely wonder why they are not getting the same or similar treatment. They did get similar treatment. In the 1980s they got 20k each. Adjusted for inflation, that's about 40 thousand dollars today.

ELI5: Why do our faces look so weird and tired when we wake up?

Why do our faces look bloated and eyes all puffy when we first wake up? What's taking place in its tissues to cause this and is there a way to speed up recovery?

More concentrated blood In different locations. All day you are standing up and walking around, and our body is built for that. Our veins have tiny one way valves that let blood go up but not back down to reach the head. When we sleep, that blood needs much less effort to go to the head. So there's more blood, think of it like completely harmless swelling. Just standing up and walking around will get everything back to normal.

ELI5: The difference between 1st, 2nd, and 3rd degree murder and manslaughter

How are they any different, and why?

1st degree: A murder which is intentional and planned in advance. 2nd degree: Still intentional, but not planned in advance. 3rd degree: Usually referred to as manslaughter. Manslaughter can also be divided into multiple categories. Voluntary manslaughter: Intentionally killing someone, but in a circumstance where the perpetrator had, for lack of a better term, a good reason for being upset with the victim. Involuntary manslaughter: Intentionally doing something stupid that accidentally results in someone else's death. The reason for these categorizations is that they carry different punishments. Someone who committed 1st degree murder made a choice to kill someone, whereas someone who committed manslaughter could very well be a sane person who just made a bad, split-second decision. Needless to say, someone who deliberately kills others deserves the harshest penalty.

eli5. How do table saws with an auto stop tell the difference between wood and a finger?

The safety feature detects an electric signal. Human bodies are electrical conductors, so when we touch the blade, we create an electrical circuit. The machine detects this electrical difference, and initiates the blade jammer when it does. A piece of wood is not conductive, and so it does not create a circuit with the blade. It's similar to those lamps or even your smart phone screen. You operated them by making contact with your skin. They detect the electrical impulse of your skin. If you tried to active these with a thick glove, it would detect no signal and not turn on.

CMV: Credit limits serve no purpose to college students

EDIT: I wasn't clear initially, so I will explain. What I meant by "necessary classes" included classes that aren't directly in your field of study (such as communications or technical writing, for example). These courses have value for obvious reasons. I was instead referring to the situation where even after all of the necessary classes are attained, you still must take random classes around the university to reach the 120 credit limit. Original Post: What I'm talking about here are limits like "you need 120 credit hours to graduate". Obviously you need to complete the necessary classes to get your degree, but this 120 limit often extends past what is needed to complete degree requirements. Students pay exorbitant amounts of money in tuition, and that amount has only been increasing. So, college for most students is an investment. Why should we have to spend extra time just getting to that arbitrary number when we already know what we need to get our degree? In my opinion, this is a scam to keep students on campus longer, and to waste more of their money.

>but this 120 limit often extends past what is needed to complete degree requirements. If the 120 credit limit is required for you to graduate, then it is _part_ of the degree requirements. It doesn't "extend past" them.

ELI5: What exactly happens when fighter jets "intercept" foreign aircraft approaching their airspace?

* long range radar detects an unknown aircraft heading towards US airspace * A couple aircraft are sent out to indentify and make contact with the aircraft * The intercepting aircraft attempt to contact the incoming aircraft on international frequencies, usually on 121.5mhz IIRC * If communications fail, 1 of the intercepting aircraft will break away and head towards the incoming aircraft to visually identify it * They will try again to make radio contact * If radio contact fails again, they will attempt to redirect the incoming aircraft away from the airspace, either by flying by it, and trying to get it to turn, or by showing off their weapons in an attempt to "scare" them away * If that fails, they threaten to shoot down the aircraft via the radio * If there's no response, they shoot down the aircraft

Can someone explain space velocity?

Imagine the universe was completely empty except for one planet, if we launched a cannonball from our imaginary planet at its escape velocity, wouldn't it eventually come back because you can never really escape the pull of gravity, it just gets weaker? So wouldn't it eventually slow down the cannonball and make it change directions and come back? Edit: I meant escape velocity in the title. Oops

This question is trivially answered if you understand gravitational potential energy. If you don't, you can think of it like this: The force from gravity gets weaker the further away you get from earth. Gravity takes time to slow an object down at any speed(since F=ma, the change in velocity from a given force is proportional to time it is applied.) If you are moving fast enough, the force of gravity gets weaker faster than your velocity decreases, so the force of gravity never pulls you back. Escape velocity is the velocity at which you cross over from the regime where you will eventually fall back and the regime where you keep flying away at some (approximately, after a long travel time away) constant speed forever. At escape velocity, your speed will continually decrease towards zero, but never quite reach it.

[ELI5] Why do big things move slowly? (Ex: Giant robots or dinosaurs in movies)

I always see movies where big animals or creatures are moving slowly and my first thought is always: why aren't they moving as quickly as anything my size would? Does being big automatically make it slow??? Or is this just a common misconception/trope that we've perpetuated?

The amount of force it takes to accelerate something scales with the mass...if it's big, it's heavy, and if it's heavy you need more force to move it at the same speed. You \*can\* overcome this by just using a lot more force, but then something called the square-cube law kicks in...the amount of force your muscles can apply scales with the cross-section of the muscles (which is roughly the width squared) but the mass of the thing scales with the volume (which is roughly the width cubed). So the larger you get, the harder it is to maintain big enough muscles to keep the acceleration constant. In practice, you don't maintain acceleration, you see something in the middle...moving somewhat slower, but also gettting much more muscle-y. This is why elephants have way fatter (relatively) legs than horses or humans.

[Harry Potter] Why does the greatest wizard of all time work at a secondary school?

Dumbledore, and several other prominent magical figures work at what is essentially a secondary school (Hogwarts). Why does a school have such a central role in the wizarding world?

Presumably they like their job and it allows them to pass their skills onto the next generation in case they're needed in the future. A lot of people work places you may not expect them to because they enjoy the work they do and prefer that than moving into a role others would say they've earned or should do.

Can plants be "fat"?

Edit: Oh guys, this is amazing. Thank you all

I think there are a few ways this question can be answered. The short answer is "no" but the long answer is "not exactly." Chloroplasts are plant organelles that can undergo dramatic changes as they develop from proplastids. When developed in the dark, proplastids develop into amyloplasts: chloroplast derivatives that stockpile starches in huge quantities. These amyloplasts are abundant in starchy roots known as *tubers* (think potatoes) which are (in simple terms) swollen roots that store energy. This is roughly analogous to fat reserves on an animal. Very well-fertilized and watered plants have more succulent tissues than plants grown under more limited conditions. In gardens and fields, this can result in plants that are more susceptible to pathogens, as their tissue is rich in nutrients and water. This is roughly analogous to the propensity of the obese to suffer from health complications. TL:DR: plants will not get "fat" but there are some aspects of plant physiology that could be considered similar to obesity/fat storage.

[Marvel] Why doesn't everyone learn both science and magic like Doctor Doom? How does learning both benefit Doom, like what can he do with one that he can't do with the other?

the same reason you dont have a phd in medicine, art, history, chemistry and physics, both of them require a lot of dedication and knowledge, so there are very few that are capable of putting in that time and discipline for two widely different fields

ELI5: Why is continuum mechanics researched mostly by engineers and mathematicians rather than physicists?

Traditionally it was in physics but the parts of physics associated with it simply drifted into engineering territory. The benefits of fluid flow, turbulence, etc modelling is absolutely priceless for basically all machinery, vehicles, medical equipment and implants, etc. It’s basically as relevant to every day life (and government interests…) as improvements in electronics. So a lot of research and development is done or contracted by engineering corporations (including big fat national defense budgets). Continuum mechanics does have some relevance for space. In fact it’s a critical puzzle piece in how our specific solar system even formed from spinning gas and dust. Recently there was discussion about whether the solar system has a shock wave, as the vacuum of space itself constitutes a weak continuum over that length scale. But of course theorising about space is less applicable to every day life (and big sticks) and more just cool stuff for research entities to look at. And that’s kind of where physics is drifting towards… researching cool but more obscure stuff

Light has waves, and certain types of matter do not interact with certain wavelengths -for instance, glass is transparent. Since gravity has waves, are there types of matter that would not interact with certain gravitational frequencies?

Basically, could we make something "invisible" to gravity?

Light waves are electromagnetic waves. As such, they interact with atoms by interacting with the electrically-charged or magnetic parts of atoms (such as the electrons). Since those parts vary in their properties, light interacts differently with them. For example the configuration of the electrons alters how atoms interact with light. Gravity, however, interacts with mass. For the most part, mass is mass. So gravity interacts with all mass basically the same. There is no equivalent of, say "configuration of electrons" in mass that would allow gravity to interact substantially differently with different particles.

ELI5: How do fish in fish tanks keep each other entertained?

Do they not go insane from being confined?

It's important to keep fish in the correct size tank, and with the correct number of fish (the rule of thumb is 1" of fish for each gallon of tank). It's also important to give them something to be active *with* - plants and decorations are good for that (plants are also vital for filtration - which is *another* thing that *all* fish need). If you don't do that, the fish *will* be stressed. They won't so much be *bored*, or appear bored - but they'll *not* be happy or have a good life! So all those goldfish in bowls? Terrible. All those betas living in a cup? That's just horrific. They might not look it but they *are* suffering. Fish - even betas or goldfish need at *least* 5 gallons, *and* filtration, *and* entertainment, *and* their water replaced regularly, *and* their tank cleaned, *and* temperature control.

ELI5:Why is there a 'Bee' in 'Spelling Bee Competition'?

We could simply call it Spelling Competition.

Historically the word bee has been used to describe a get-together where a specific action is being carried out, like a husking bee, a quilting bee, or an apple bee. Its etymology is unclear but possibly derived from the Old English word bēn, meaning prayer.

Eli5: What is an allergy exactly (how does it work) and what determines if you get one or not?

Edit: i probably should explain that i have no allergies and because of that i never had a talk with a doctor about it. Edit2: spelling

An allergic response is a separate department of the immune response. We have antibodies called IgE that don't directly fight an infection, but will alert the body that something foreign that shouldn't be there is inside. They respond to chemicals and "allergens" like pollen and, depending on your make up, either don't respond to the foreign material at all, or respond negatively, or respond catastrophically where your body goes into shock and die. IgE sound awful in this perspective, but the antibody is quite important when you have foreign invaders with an agenda to wreck havoc in your body. You can take a neat test at a clinic to see if you're allergic to anything. They'll give your skin a small taste of the chemical or allergen, and any redness, heat, or bumps is a sign that you respond negatively to it.

How far can an ant be removed from the anthill and still find its way home?

Driving away from a parking spot in a park, I see an ant walking across my windshield. I stop and let it off, but I've already driven 30 feet. Is that ant doomed to death? (I thought most ants leave trails behind them to find their way back home. Since the trail is now broken, how will it find its way?)

This has been asked a lot before so if you want deeper answers you can look them up. Basically if an ant doesn't know where it's trail home is it will start wandering around in random(ish) directions trying to find it. IIRC, they also have a good ability to remember landmarks, so that can help too. If they are really far away and can't find their home then yes, then they may wander until they die. They may find another colony that they can assimilate into, but more than likely they ants their won't accept the foreigner and will attack and kill it (even if it's the same species possibly.) So to answer your question of how far away, it depends. If they are a really long ways away, but get lucky in their random search they can find their way back. In general, I've seen estimates hover closer to 100 or less meters. It's actually a neat direct application of some of the algorithms in computer science if you want a more rigorous way to think of it.

CMV: using partial bleep censoring/grawlixes, e.g. "sh*t" instead of "shit", where the audience knows the censored word is pointless

I'm surprised by how often I see "sh\*t" for "shit" and similar substitutions in contexts where essentially 100% of the audience will be adults (or near enough) and familiar with the word in question. A reader familiar with the word will still understand the full meaning. I can see some value in a form of it where the audience includes young children and the writer does not want to teach them a word that their parents might not want them to know, though in that case I think far more of the word should be censored, e.g. "s***". I've deliberately picked a word that most people on reddit won't find very offensive, but this applies to racial slurs and such as well, which many here find extremely offensive. If the word is too offensive to use, it makes more sense to me to avoid referencing it directly at all, e.g. "Joe was fired for referring to a coworker by a racial slur". If it's necessary to quote it for precision or emotional impact, it may as well be quoted in full. I've seen it done for words describing traumatic experiences too. I'd be surprised if anyone's PTSD is less triggered by seeing a word related to their experience with a single letter obscured than by seeing the full word, but please do surprise me if you have personal or professional experience, or research that contradicts this.

The idea is to signal an intent not to offend and to demonstrate understanding of the taboo associated with the word. It's like saying the f-word, pretty much everyone knows the word you mean in context but are more fine with it because it signals a lack of intent to use the word offensively often talking about the word in meta.

There is no possible world in which the world does not exist. Does that mean that the world necessarily exists?

If we follow Lewis' conception of necessity and possiblity, then something similar to what you are talking about does follow. According to Lewis, we analyze "Necessarily x" as "In all possible worlds, x". That means we would have to understand "The world necessarily exists" as "In all possible worlds, the world (that world?) exists", which would obviously come out as true. But let's not get carried away with the result, which does not establish anything very interesting by itself. It does not, for example, establish that *this* world necessarily exists, or (generalized) that any particular world existst necessarily. Likewise, it does not establish that there are no empty worlds. Since in Lewis' framework, worlds are described in terms of sets, they don't "disappear" if they are empty. But Metaphysics has moved on quite a bit since Lewis. While his account is still a useful way to analyze necessity and possibility, philosophers have become more sceptical that it's all there is to say about modality. Kit Fine, for example, introduced the notion of a non-worldly necessity in his paper "Necessity and Non-Existence" (2004). According to Fine, there are certain facts that are true regardless of the world at which they are evaluated, like your statement of "The world existst.", but there are also statements that do not need a world context to be meaningfully evaluated, like "2+2=4". You can see that, while "The world existst" is true in all world contexts, and thus necessarily true, it is not true regardless of there being a world context, and thus not (what Fine calls) transcendentally true. There is good reason to think that there is more to modality than possible worlds, and you should not therefor put too much weight on your result. But it is a correct result, given Lewis' account.

ELI5: How does a back draft happen/work in a house fire?

I was reading a great web comic by Oatmeal ( http://theoatmeal.com/comics/house ) and came to the startling realization that i really didn't understand how a back draft works / happens. At this point all i do know is that a back draft means "Boom! Scary Fireball!!!". So I was wondering if one of you beautiful people could explain it to me.

Fire needs three things in order to burn: heat, fuel, and oxygen. On a normal day your home contains fuel (things that could burn) and oxygen in the air, so you prevent fires by never letting it get hot enough - not starting a fire. Meanwhile if your house does catch fire and nobody does anything, it'll burn until there's nothing left that can burn - at the end there's heat and oxygen, but no fuel. What can happen when a fire gets developed in a house is that it can burn until there's barely any oxygen left in a room. There's heat and fuel, but without that last ingredient the fire grinds to a halt. Now you open a door to that room (or a window breaks) and a whole rush of oxygen-rich air goes flooding in. All those hot flammable items catch fire in an instant, creating a fireball that can blast out of the open door or window. So, if you're ever unlucky enough to find yourself in a fire, touch each door and door handle *before* you open it. If it's hot, your salvation is not on the other side, so leave that door closed - and watch out for being above the window of a room that's on fire. The heat's going to shatter the glass at some point, and when it does you don't want to be above it.

ELI5: How does exercise actually reduce the risk of diabetes? And how does too much sugar in a diet cause a person with no diabetes to get the disease?

Type two diabetes is effectively caused by having a higher than normal blood glucose level for a prolonged period of time. When you eat, most carbohydrates are transformed into glucose and absorbed into the bloodstream. Simple sugars are digested and absorbed into the blood very quickly, causing large spikes in blood sugar. Insulin is released by the body to control blood glucose levels, and to enable cells to absorb and use glucose. Higher than normal glucose levels needs more insulin to control it. This ends up causing insulin ineffectiveness/resistance, which means tat your insulin is less able to control blood glucose levels. In response, the pancreas creates and releases higher and higher levels of insulin. This effectively makes the cells that produce glucose run out. Simple sugar is one if the things that causes this. Exersize does two beneficial things. Firstly, it reduces your blood glucose. It helps you control it without relying on insulin. This reduces the strain on your insulin and can prevent insulin resistance and diabetes. Secondly, exersize makes your insulin more effective. Combined, this reduces the chances of getting diabetes.

Why can't a country continously run on deficits in the balance of payment?

Please please help me out with this.This is one of my questions from an assessment and im having a hard time understanding why its possible in theory but not practically.

It is possible in practice. Australia typically runs a current account deficit (although weve hit a surplus recently). A CAD just means we imported more than we exported that year. It means we have a capital surplus, so we are funding those exports using foreign debt or equity. We need to repay that debt or equity at some point. Thats why it can be difficult in practice to run continuous CADs. But Australia can afford it because our economy grows faster than these debts.

When healing from a cut or gash (may or may not require stitches), what happens to the damaged blood vessels? Do they reconnect perfectly, are new ones formed, or do damaged veins and capillaries just have a dead end now?

Small blood vessels (capillaries) will be stimulated t grow back into hypoxic tissue by growth factor proteins that the hypoxic cells send out. This is called angiogenesis, and it happens all the time. For a skin cut, that's about it. Large blood vessels are more complicated. This is called vasculogenesis, and it takes a long time, and often doesn't happen at all, leaving you with an ischemic (hypoxic) limb that hurts.

ELI5: Why is it it legal for a P.I. to do their job (follow, take photos, rummage through trash etc

They are regulated by a branch of the state government. The process and requirements vary by state, usually requires relevant experience but not always, usually involves a testing process, always involves paperwork and fees paid. Not cops by any stretch, but licensed and given specific powers, with penalties if they abuse them. They are more tightly controlled than bounty hunters.

How far below the surface of the water does a hurricane disturb the natural state?

Waves have a decaying effect and are essentially noise level at tens of meters depth. The rain changes the composition of the water and that diffuses through the area but even a meter of rain over a kilometer-deep ocean is going to be a negligible change for a short time. The change in bulk current and the flow of storm surge on littoral areas would be the biggest effects. When an entire bay gets sucked out to sea, that's 100%. Or when it gets pushed a km inland, or cuts through a barrier island, or creates one...

Is there a certain altitude where CO2 is concentrated?

The lowest ~100 km are very well mixed, so the concentration of most gases (including CO2) doesn't change that much with altitude, you can find it everywhere. Above that heavier gases, including CO2, drop in their concentration.

[Fullmetal Alchemist] If they're literally rearranging atoms to make new things, can't you just make anything out of thin air because there's always oxygen handy?

Alchemy isn't a random piece of magic that lets you convert anything from anything, but is a collection of techniques developed using applied chemistry and physics via powers that may or may not originate from a supernatural entity. In particular, alchemists are limited by the Law of Equivalent Exchange, which states that masses must be converted one-to-one *and* that the two substances must share similar physical properties. Lead can be converted into gold because they are both heavy and malleable, but oxygen cannot be converted into lead or gold because it is a light gas. On the other hand, you can convert nitrogen into oxygen and set it on fire. But that's only possible because oxygen and nitrogen have 'similar' properties.

[Harry Potter] What level of sentience do moving pictures have? Why can some talk and others not?

Also is there a difference between portraits and photographs?

Portraits take time to create, and because of the care and attention involved, magic infuses with the paint, giving it a semblance of sentience. Some portraits, however - such as a Hogwarts headmaster portrait that the castle automatically creates, are completely sentient.

Is a "luxury" high rise building being built across the street good for my properties value?

Ok, so I own a shitty condo in a middle class neighborhood. Couple of weeks ago a developer announced they were making a very nice building in front of my apartment, were there used to be a vacant lot. It feels like this would have positive externalities on my propertys value, but doesn't this also increase the supply for living space, lowering my propertys value?

There are too many factors to consider to adequately answer your question. It's quite possible that, in the long run, it'll be good for your condo because the area generally improving will make your unit inherently more attractive to buyers. (More money coming in, more businesses, etc.) But it's also possible, if there is enough undeveloped land, that more and more new condos are developed which would make it harder for you to sell unless you did major renovations to compete with what's being offered. So, it's too tough to say. There are a ton of factors that go into real estate speculation. As a very general guess... If you live in a really dense area, then I'd bet you're value will go up. If you live in a sparse area, then I'd bet your value would go down.

Why isn't Hegel included among the names most associated with phenomenology, such as Husserl and Merleau-Ponty among others? Is his Phenomenology of Spirit something completely different from the phenomenology elaborated by those we typically call phenomenologists?

There are people much more qualified to answer this on here but I'll take shot: In a sense, both Hegel and the 20th century phenomenologists have the same aim: To develop a philosophy that can ground "science" (*Wissenschaft*). The basic difference is that Hegel is trying to "ascend" from particular sensuous experience ("sense certainty") to abstract conceptual *"absolute knowing"*, whereas 20th century phenomenology is trying to "descend" back to particular sensuous experience (*"back to the things"*). Context is key here, Hegel was writing in a time when Kant had just blown philosophy wide open and possibilities seemed endless, the question was one of building the right *system* on top of Kant. So in a sense he was "building" philosophy from particular experience to the abstract universal to achieve a grounding of philosophy. Husserl was writing in a time when those systems established in the 19th century were crumbling - philosophy not only seemed to have been made obsolete by the natural sciences but the sciences were in a *crisis* as well (*"foundational crisis of Mathematics"*). His play to rescue philosophy was to *reduce* philosophy from the abstract universal to particular experience to achieve a grounding.

ELI5:There's supposedly safety in numbers. But fish swimming in schools allows predators to just gobble them up easily as they're all concentrated in a tight ball. Wouldn't it be easier for a them to carefully swim the ocean alone, instead of getting corralled and targeted in a feeding frenzy?

This has always bugged me, and since I've been watching a lot of Planet Earth recently, I figured I'd ask since it seems so obviously counter-intuitive to me. Isn't [something like this](https://youtu.be/_B8qiqeDrI0?t=103) just asking for a ridiculous number of casualties?

Shoaling is more complicated than that really. Some of the advantages of shoaling include: * It's easier to find a mate. The sea is a big place and if you move in a group, reproduction becomes a lot easier. * Foraging efficiency, instead of each fish trying to find a meal, a large shoal finds large food sources and feeds the entire group (and in return become a large food source for predators) * And yes defence. * Visually it's very difficult for a predator to pick a target in a mass of milling fish. The mass of milling fish is both confusing to the predator's eyes and the predator's lateral senses (most fish have a sense organ running the length of their body that senses movements in the water) * When shoaling is done successfully, the fish in the shoal adeptly move out of the predators way, opening before him, closing behind him. Making it really difficult to grab an individual. * Every fish in a shoal likes to be at the center of a shoal. There really is safety in trying to make sure that if a predator does grab a fish, he'll grab someone other than you. * Social comfort, shoaling fish tend to derive a lot of comfort from the factors above. When taken out of the shoal and kept in a fish tank for instance, they tend to languish. Of course for every defence, some predators develop a good counter strategy. When you see a giant spherical shoal of fish near the surface, it's called a bait ball. When you see a bait ball, things have already gone wrong. Bait balls happen when predators manage to scare a shoal of fish into moving up towards the surface by attacking from below. This seriously limits the shoals available degrees of movement (can't go up because of the surface, can't go down because of the predator). The shoal panics and instead of efficiently confusing a predator with a billowing cloud of fish, the fish all try to move to the center, forming an almost perfect sphere that doesn't try to dodge predators. Even worse, forming a bait ball is a huge warning sign that tells other predators easy pickings are about to happen. Usually bait balls don't last for more than a few minutes before either the bait ball is mostly consumed or the shoal finds a way to escape away from the surface. It's mostly whales and dolphins that are intelligent enough to use their size, direction and even bubble curtains to herd shoals into bait balls.

What does mean sea level mean if you're thousands of miles from the sea?

As I understand it, Mean Sea Level is defined by taking the time-averaged effective gravitational potential of the water-air boundary averaged over the world's oceans. Since sea levels are rising globally, we choose some datum and stick to that. This seems reasonably unambiguous. If the summit of Everest is 8848m above MSL, does that mean it's 8848m directly above a point within the crust on that same equipotential, or does it mean it's on the equipotential defined by the average of all points 8848m directly above the sea? Or does it mean something else? How much difference would there be? *To rephrase the question: if you hollowed out Everest and made tunnels (sealed against groundwater) connecting that cavity to the oceans, would the water find a time-averaged level 8848m directly below the summit?*

Sea level is affected by gravity/mass (hence the moon causing tides and so on...). Therefore mountains affect the sea level. Currently, sea level is calculated by assuming the entire earth is covered in water, but the mass from the mountains is still there (hard to imagine, i know). Then the water "bulges" in some places where there is a lot of mass (also tectonic plates and such play a role), in these places sea level is "higher". To answer your rephrased question: yes (assuming that the tunnels do not measurably change the mass of Mt. Everest).

If we manage to confine air in a space with no perturbation (wind, sudden temperature changes, etc), will the heavier molecules sink to the bottom?

Just wondering. Also, if brownian motion keeps the system homogeneous, would a decrease in the temperature of the system decrease it enough to achieve a seperation of gases? Not sure if it's an adequate question. Couldn't find much online (or maybe I suck at looking it up).

A gas in a uniform gravitational field and uniform temperature will have a density profile proportional to exp[-mgz/kT], where m is the molecular mass of the gas, g is the gravitational field strength, z is the altitude, k is Boltzmann's constant, and T is the absolute temperature. mgz is typically small compared to kT, so the gas is approximately uniform (for example, in your room). However for very large systems, like the atmosphere, it's important. The density of the air that makes up the atmosphere of the Earth is obviously not the same at different altitudes.

Why do many laymen roll their eyes at philosophy?

It seems much of the public see it as an intellectual wank. A pretentious exercise using word games and manipulating language to make grand pronouncements about nature. Why do so many imagine philosophers pondering "is reality real?" and other such nonsense?

The technical side of philosophy takes a lot of effort to learn and the nontechnical side of philosophy is usually presented to a lay audience as asking them questions and getting their opinion on things like 'is there a soul?', 'what is the right thing to do?', and 'what is the meaning of life?' That leads to them thinking its all about opinions because they're not exposed to the rigour, and the fact that the questions are broad and they're not given an adequate basis for how to think about the questions leads them to think we're just sitting here thinking about nothing. Everybody has had to do a hard math problem and gotten the right answer, very few people have worked through the point/counterpoint of a philosophical conversation and been left with a clearer view of the issues involved. That amount of immersion is hard to give to lay people. TL;DR: People think we philosophize the same way they philosophize: wandering and wondering aimlessly through 'deep' questions.

ELI5: What happens in our brains when we get sleepy from doing something boring to us versus doing something interesting that will keep us awake for several more hours?

Directed attention fatigue (DAF) is a neurological phenomenon that results from overuse of the brain’s inhibitory attention mechanisms, which handle incoming distractions while maintaining focus on a specific task. The greatest threat to a given focus of attention is competition from other stimuli that can cause a shift in focus. This is because one maintains focus on a particular thought by inhibiting all potential distractions and not by strengthening that central mental activity. Directed attention fatigue occurs when a particular part of the brain’s global inhibitory system is overworked due to the suppression of increasing numbers of stimuli. This temporary condition is not a clinical illness or a personality disorder. It is rather a temporary fatigue of the inhibitory mechanisms in the brain. Essentially, you're working your brain more when you're trying to focus on something boring while on the other hand the job wouldn't be as hard if you were doing something interesting. Because of that mental exertion, you may feel sleepier and more exhausted. Signs of Directed Attention Fatigue include temporarily feeling unusually distractible, impatient, forgetful, or cranky when there is no associated illness. In more severe forms, it can lead to bad judgment, apathy, or accidents, and can contribute to increased stress levels.

CMV: Trans sports bans are a solution in search of a problem

Various states across the US are pushing new legislation aiming at banning trans kids from participating in sports in schools and colleges. The details of the bills vary, but most of them target the participation of trans kids in one way or another. I'll be focusing on Mississippi SB 2536, but it is, to my knowledge, very similar to the bills being introduced in more than 20 other states. An excerpt from Mississippi SB 2536: >> SECTION 3. Designation of athletic teams. (1) Interscholastic or intramural athletic teams or sports that are sponsored by a public primary or secondary school or any school that is a member of the Mississippi High School Activities Association or public institution of higher education or any higher education institution that is a member of the NCAA, NAIA or NJCCA shall be expressly designated as one of the following based on biological sex: >> (a) "Males," "men" or "boys;" >> (b) "Females," "women" or "girls;" or >> (c) "Coed" or "mixed." >> (2) Athletic teams or sports designated for "females," "women" or "girls" shall not be open to students of the male sex. This is a common thread through these laws. The law also specifies its reason for this: >> (e) The biological differences between females and males, especially as it relates to natural levels of testosterone, explain the male and female secondary sex characteristics which develop during puberty and have lifelong effects, including those most important for success in sport: categorically different strength, speed and endurance. The purpose of this bill, according to the state legislature, is to ensure that sports remain fair. Because if trans women competed with women, it would be unfair, because they have an inherent advantage. That said, is "trans athletes dominating women's sports" actually an issue that Mississippi has? The associated press reached out to Lawmakers in Mississippi and numerous other states, [and found](https://apnews.com/article/lawmakers-unable-to-cite-local-trans-girls-sports-914a982545e943ecc1e265e8c41042e7): >> Legislators in more than 20 states have introduced bills this year that would ban transgender girls from competing on girls’ sports teams in public high schools. **Yet in almost every case, sponsors cannot cite a single instance in their own state or region where such participation has caused problems.** The article is fascinating, and worth a read. Another excerpt: >> There’s no authoritative count of how many trans athletes have competed recently in high school or college sports. Neither the NCAA nor most state high school athletic associations collect that data; in the states that do collect it, the numbers are minimal: No more than five students currently in Kansas, nine in Ohio over five years. The lawmakers proposing these bills are not doing so because they see a problem that desperately needs solving. Because that "problem" _doesn't exist_. Just like with the infamous "bathroom bills", the threat is, at best, completely hypothetical. (It is possibly worth noting at this point that the bathroom bills were pushed by a group who [knew they were making it up](https://www.intomore.com/impact/anti-lgbtq-activist-admits-bathroom-predator-myth-was-concocted-as-cover-for-transphobic-hate/).) Trans women are not dominating women's sports. This seriously calls into question the claim in the bill itself, that trans women have significant advantages over cis women, which is its primary justification for existing. And the fact that the people proposing these laws most commonly cannot name a single trans athlete in their state that they would consider mentioning as justification for this bill indicates to me that they _know_ that there isn't a problem worth solving, and are moving forward with these bills anyways. These bills exist not to combat any actual problem, but rather to further marginalize trans people for the sake of marginalizing trans people. Change my view.

Is the fact of those officials being unable to name cases of transgender advantages in top tier physical competition in their state because trans athletes don’t have advantages, or because trans athletes in top tier physical competition are incredibly rare if not virtually nonexistent in many states? If it is the latter, that doesn’t seem like compelling reasoning to make the positive assertion that mtf transition does not maintain significant extra muscle mass for however long of a time period after or during transition. Most lawmakers also could not name a single case of top tier athletes dominating competition by wearing rocket boots either. This does not mean rocket boots wouldn’t be an advantage in the hundred meter dash. The thing about serious competition is that it’s not a purely social issue. It’s also about the livelihoods of people who have dedicated quite literally their entire lives into honing one specific skillset. As we only have studies trying to predict how much muscle mass mtf athletes retain, and rather limited solid practical data in practice for now, it’s hard to say whether a ban is justified or not. It is, however, definitely incorrect to attribute wariness of said potential issues purely to some sort of social maliciousness.

CMV: We need to acknowledge fanatical maskers in the same way we acknowledge antimaskers

The other day I’m at work and the head woman told me someone complained about me wearing my mask under my nose...alone...in the office...which is closed off to the main building by not only a glass window, but a plastic barrier in front of that glass window. Another time there’s a guy sitting on the far side of the room, by himself facing the wall. The guy closest to me comes and knocks on my window and says “that guys not wearing his mask”. Now this is a giant open room with high ceilings, ventilation, filters and the only people in it were these 2 guys over 20ft away from each other. Lastly I overheard a lady shouting “Get back to your area! You need to have a mask out here! If you don’t have one you need to leave right now.” This went on for about 3 minutes and I was wondering why grown people were sitting there taking that until I heard a little voice say “I’m sorry. My mask is in my pocket”. This lady was yelling and berating a 7-8 year old who was alone in the hallway getting a snack from the vending machine. There are people with legitimate reasons they can’t/won’t get vaccinated and those with fanatical reasons. we acknowledge those people and there’s an entire sub dedicated to making fun of them when they die (which is disgusting). But for some reason fanatical vaxxers/maskers go unaddressed and can be dangerous. For one I feel there are people who look to assert their power over other, Karen’s. It gives them a reason to harass or discriminate against people. I had a boss who did this and he himself was antivax. He used this to ban minorities from the business Another is it promotes a different type misinformation, albeit one that errs on the side of safety, but misinformation none the less. They usually exaggerate the science behind the precautions and this can lead to paranoia especially to vulnerable people. So I wouldnt say mask/vax fanatics are as dangerous as antivxxers but I do think they are very problematic Edit: wouldn’t

Lets say you have a safety inspector on the job. They are a real pain in the ass because they are on a power trip. Do you really think even though they are a dick their message is irrelevant or more dangerous than someone who says 'safety, who needs safety, safety is only for wimps' so while there is an element of dont shoot the messenger, you have to take into context that the messages from the messengers are different.

Why do some helicopters have 2 blades whilst others have 4 or 5?

The greater number of blades in a helicopter enables it to produce more lift, hence heavier helicopters, such as Sikorsky CH-53 has more blades. However, there will be trade offs from having more blades. The helicopter blades produce a wake of turbulence behind them, reducing the efficiency of the subsequent ones, resulting in a need to space them out sufficiently to prevent the turbulent wake from affecting the performance of the other blades to much. Furthermore, a greater number of blades will also complicate the hub, and overall increasing the cost. Hence it is not effective to increase the number of blades in small helicopters. In order to further increase lift, the blades can be rotated at higher velocity. Then why can't heavier helicopters just rotate their blades faster? This is due to the tip of the blades limited to subsonic speeds, as supersonic blade tips will create extremely large amounts of drag and turbulence, greatly reducing efficiency. Furthermore, even before the blades reach supersonic speeds, there would be formation of local pockets of supersonic airflow, which also creates a large amount of drag. Hence, due to turbulence created by the blades, and the inefficiency of supersonic tips, there is a need for more blades in heavier helicopters. Small helicopters are better off with lesser blades to reduce the need for a complicated hub, as well as to save cost.

CMV: In light of the recent Supreme Court ruling, the most logical extension of this policy is the eventual legalization of Polygamy and other non-standard marriage arrangements, which will have a negative effect on society as a whole due to the difficulty of defining "marriage" or a "family".

To be clear, I support the Supreme Court in their decision to legalize same-sex marriage, and I'm happy that rights that have been granted to heterosexual couples are now going to apply to everyone in society. I am, however, mildly concerned or at least intrigued as to where this debate or issue ends. The reason it's troubling for me is that the most common arguments used to support gay marriage are that "love is love" and "loving who you choose is your right". What these arguments implicitly say is that the necessary criteria to be allowed to marry is that you love that which you are marrying. Now I won't delve into the typical response of "Next thing you know, it'll be legal to marry your pets!" because I find that particularly hyperbolic and non-productive to the discussion. But I do feel that this open mindset of the definition of marriage will definitely lead to a future debate about what "marriage" is. I believe that the next group to demand legal marriage rights will be polygamists, and that the same arguments of "love is love" will still apply. My fear is that despite this good ruling today, we have opened up the door to extremely loose and liberal interpretations of the meaning of "marriage" to include anything we want it to under the law. ~~Further, I believe that polygamy is harmful to society and that raising children in a polygamous is harmful to their growth. I believe that polygamy is not a natural arrangement for humans, and that no matter what, it will be emotionally damaging to at least one person in this "relationship"~~. But then as I type those words, I realize that the exact same things were said about gay marriage in recent history. So, Reddit, CMV that this supreme court ruling isn't going to evolve into a culture of people being able to marry whoever (or whatever) or however many people they want. Edit: Let's avoid the moral implications of Polygamy for now. I shouldn't have typed out my personal views on the matter because it's really not what I'm interested in arguing (whether it's right or wrong). I'm interested in hearing legally, why this SC ruling will not lead to a case law precedent used to affirm Polygamy rights in the future. I ask this because all through this debate, most advocates for gay marriage rights said that comparisons of the movement to polygamy were ridiculous. _____ > *Hello, users of CMV! This is a footnote from your moderators. We'd just like to remind you of a couple of things. Firstly, please remember to* ***[read through our rules](http://www.reddit.com/r/changemyview/wiki/rules)***. *If you see a comment that has broken one, it is more effective to report it than downvote it. Speaking of which,* ***[downvotes don't change views](http://www.reddit.com/r/changemyview/wiki/guidelines#wiki_upvoting.2Fdownvoting)****! If you are thinking about submitting a CMV yourself, please have a look through our* ***[popular topics wiki](http://www.reddit.com/r/changemyview/wiki/populartopics)*** *first. Any questions or concerns? Feel free to* ***[message us](http://www.reddit.com/message/compose?to=/r/changemyview)***. *Happy CMVing!*

The basis of the Supreme Court's decision was the equal protection clause. The reason why the Court ruled the way that it did, was because the definition of marriage excluded an entire category of people. Not every legal categorization is given heightened scrutiny by the courts. For instance, legal discrimination on the basis of age is typically legal. When the court asks whether a legal classification is "suspect" under the Equal Protection clause, they ask whether the subject class is: * The group has historically been discriminated against, and/or have been subject to prejudice, hostility, and/or stigma, perhaps due, at least in part, to stereotypes. * possesses an immutable and/or highly visible trait. Lyng v. Castillo. * are powerless to protect themselves via the political process. U.S. v. Carolene Products. * The group's distinguishing characteristic does not inhibit it from contributing meaningfully to society. Frontiero v. Richardson. So today's decision wasn't arbitrary. And these factors probably don't apply to polygamists. There are guidelines for this sort of stuff.

How exactly does CRISPR-CAS9 insert new genes?

I understand the very basics of how CAS9 enzyme cuts off a gene with a guide RNA to help it locate,, but what's still unclear to me is what we do with the DNA breaks • If we let the cells repair it by themselves, will they not just remake the segment we just cut off? • If we insert a new gene, how exactly do we deliver it? Does it come with the CAS9 and guide RNA complex? Or do we use another enzyme to deliver it separately? I've just started learning about this topic so I'm sorry if my question seems very basic. I've tried searching online it but so far I've only gotten things like, "We insert the gene..." "We deliver the new gene..." or "The new DNA segment is delivered" without specifying *how* it was delivered

When you insert the enzyme and guide RNA, you also add a bunch of copies of short DNA sequences that match the region being cut, but that include the change you want to make. Then when the cell repairs the break, it's likely to grab one of these synthetic sequences to serve as the repair template, and boom. Change made.

CMV: There shouldn't be anything other than the metric system.

Posting this because I'm genuinely curious about Imperial systems advocates' POV. The metric system is much more precise, and the breakdown of units makes much more sense. Distance for example: there are 10 millimetres in a centimetre, 100 centimetres in a metre, and 1000 metres in a kilometre. Versus the imperial system: There are 12 inches in a foot, 3 feet in a yard, and 1760 yards in a mile....what? And if you want to go smaller than an inch, or between yards and miles, then you need to bring in fractions. The benefits of being precise far outweigh the benefits of less precise units of measurement, which I only see as being able to generalize (which you can do using the metric system as well). If we phased the Imperial System out everywhere, we would have no use for teaching it, and we would have little need of it in society.

Benefit of the imperial system (and base 12 system in general): They are divisible by more numbers. 10 is only divisible by 2 and 5. However, 12, is divisible by 2,3,4, and 6. This is helpful in areas like construction as now you have more options for scale. EDIT: As other's have pointed out, yes this is only relevant for feet/inches. However, people come across ft/inches conversions frequently enough to warrant a conversation about its benefit.

Why is Internet priced by speed, but cell phone priced by amount of data?

Illuminati? I dunno. Someone tell me.

Different infrastructures. Cell companies incur a lot of costs from power required to pump signals to your equipment. Less data usage, less signal needed, less money spent. Cable companies incur costs from trunk line maintenance, the faster the speed, the more trunks needed, the more costs incurred.

Why does gravity make planets and stars spherical but galaxies thin disks?

Also, is there a standard shape to super clusters of galaxies?

Hydrostatic equilibrium. Stars and planets are supported (prevented from collapsing) by the physical pressure of the solids or fluids that make them up. Galaxies, on the other hand, are prevented from collapsing by the velocity of their component stars-- each star is on an orbit around the galaxy. Disk galaxies form out of collapsing clouds of gas (just like solar systems do), which always form disks, because disks are the only stable way to have collisional gas orbiting a central object over many orbits. Otherwise the gas streams will just run into each other and trade angular momentum until they've equilibrated to coplanar orbits. Superclusters do not have a standard shape. This is essentially because the time it would take for them to undergo many dynamical timescales (the time for galaxies to complete an orbit around the center) and thus become regular in shape is longer than the age of the universe. Galaxy clusters often do have a somewhat regular shape, at least in the sense that they have a large cD elliptical galaxy sitting at the middle and a spheroidal distribution of galaxies around it, with a gradually decreasing density of galaxies as you get farther away from the center. But even so, they are much less regular than the shapes of most galaxies, because they take much longer to smooth out the irregularities, and there are more galaxies falling into the cluster all the time.

ELI5: How do planes/subs know when missiles have a 'lock'?

Or have I been watching too many movies

Missile systems generally consists of a radar to detect where the target is and send commands to the missile to tell it where to go. The radars have several modes which have their different use cases and a target can detect the signals from the radar to see what mode it is in. A radar might start out using low frequency and large sweeping scans to detect the rough placement of all planes in the sky. However this does not give accurate enough and frequent enough updates to be able to hit anything. So they change to a higher frequency radar with a more narrow sweep. This means they can only detect the airplane in the direction they aim the radar but they will be more accurate. This change of mode can be detected in the target airplane but still have to be interpreted correctly. A lot of radars had different modes of operation in peace and war so that the enemy would not be able to analyze their signals before the war.

ELI5: Why is the inside of the palms always white regardless the skin color or tan?

Melanin which colours the skin is in the lower layers of the skin, the skin on the soles of the feet and the palms of the hands needs to be substantially thicker to protect from wear and damage so there is no melanin close enough to the surface to darken those areas.

ELI5 why can a person's weight change +/- 5-10 pounds a day when they definitely aren't eating 5-10 pounds of food/water a day. Where does this extra mass/wight come from?

Don't underestimate the weight of food and especially water. A half gallon of water (the standard-even-if-derided recommended daily amount) weighs over 4 pounds. A hearty meal can weigh 1-2 pounds on top of that. Not all of this material stays in the body long-term because we expel it as waste, but our body's capacity for storing water especially goes beyond the size of our bladders. Our cells literally get dehydrated overnight and will swell up with water over the course of the day.

I believe that those arguing against national income disparity without supporting international redistribution are somewhat hypocritical. CMV.

To summarize before I begin, I believe the arguments applied by first world inhabitants arguing against high income disparity (i.e. the 1%, etc.) can be applied to advocating that their tax dollars be siphoned to aiding third world countries, where the average income is far lower. Supporting redistributive measures in the states seems unjustifiable to me without supporting redistributive measures internationally. I'm not making any claims about the validity of either redistributive claim, nationally or internationally, merely stating that I believe that one can't hold without the other. Take this as a TLDR. I'll go into more detail in the following. Consider that the average personal disposable income in China, normalized for purchasing power parity, is around 3000 USD. The same figure in the states is 23000 USD [\(source\)](http://en.wikipedia.org/wiki/List_of_countries_by_per_capita_personal_income). Just for the sake of an upper threshold, since the "1 person" phrase is so popular, we'll go with that figure as a benchmark, which [is around 370000 USD in the states](http://money.cnn.com/2012/11/20/news/economy/top-1-percent/index.html). This translates into 16 times higher than the average personal disposable income, assuming the entirety of the 370000 is disposable (a good enough estimate). Using this same scale, anyone who has 48000 or more in disposable income makes 16 times more than the average Chinese citizen. [This is around half the nation as of 2009](https://en.wikipedia.org/wiki/Household_income_in_the_United_States#Distribution). So now that the numbers are out of the way, a couple of points. First, the arguments that we are all Americans (or whatever nationality), and therefore are not responsible for the wellbeing of the Chinese I don't believe hold. You can draw classes or groups among people wherever you want to and create categories. Rich people could be one category - the one percent, in fact, could be such a category. Chinese and American are such categories. There is also the geographic argument, but again, rich people tend to be segregated from the poor geographically, at least from what I know about the states. Second, I believe the dependence argument, saying that the one percent, or whatever rich percentage, works no harder than the rest of the country yet reaps the benefits of those he steps on, is also mirror in the China/America comparison. Our consumer economy depends on cheap labor from China, and those of us making a the aforementioned 48k a year definitely enjoy a higher quality of life because of those folks in China. Further, I argue that they work just as hard, or perhaps even harder, than a lot of us in that income bracket. I'd like to think that I've given this topic quite a bit of thought - a bit of personal background - I used to strongly believe in a higher minimum wage, but then ran into this moral dilemma. If we were to look on the international level - we are all humans on the world scale, after all - and create a poverty level based off of PPI and the same percentile the minimum wage level is in the states currently, a vast majority of those even under the minimum wage level would in fact be paying out, and not receiving aid [\(source\)](http://www.bbc.co.uk/news/magazine-17312819). Why should those of us without as much claim that the incredibly rich should have to redistribute their wealth when we would consider it absurd to redistribute our wealth internationally (I'm sure this is a view that some have, but it isn't common from what I've observed). To finish - I'd like to just reiterate one of my first points. My view isn't that we should be redistributing international or nationally. It's simply that both views ought to be taken together - either both true or both false. The validity of either is a topic for another day.

One question: how? You can actually do meaningful levels of redistribution within a single nation. We have one nation, one economy, and one currency. Money taxed from the upper echelons of society and given to the poor still remains within the same economy. The money will be spent largely on goods and services from American companies. These companies are largely owned by the very people you're taxing from. As such, the overall net impact of taxing is greatly reduced. The money will create American jobs and employ many of the people that would otherwise require government aid. Now, how would you send hundreds of billions, perhaps trillions in aid needed to bring third world up to parity? More importantly, how do you do it without collapsing their economies? Let's say we send stuff. We send boatloads of grain, millions of automobiles, clothing, consumer electronics, etc. We manufacture it all and just ship it wherever it's needed. Well what happens to their economies? Their agricultural sectors collapse. Their factories can't sell finished goods. How do you compete with free? The economies collapse as workers are laid off by the millions. The country has plenty of whatever goods we choose to send them, but they are too poor to afford anything else. These nations become completely dependent on the large-scale aid. As you send more aid, more domestic industries collapse, resulting in a greater need for aid. You thus have to send even more aid, until the entire country is subsisting off of first world handouts. Let's say we send dollars. We send pallets full of cash to third world countries. Let's assume we can magically do this without most of the money ending up in the hands of various warlords and corrupt government officials. Let's assume the money actually gets to the poor folks who actually need it. Well what are they going to do with those dollars? They can trade them for the local currency, but then the local currency broker has to do something with them. In the end, the money has to find its way back to the American economy. The money has to eventually be used to purchase American goods and services. If the American dollars don't come back to the US to purchase American stuff, a glut will exist in the poor nation's dollar supply, and the dollars we send over there will be worthless. So, ultimately, American dollars will result in the purchase of American goods to be imported into the foreign country. Their economy is thus again flooded by cheap/free American goods, and the same economic collapse occurs. International aid can be used to effectively address highly specific problems. Vaccinating against disease? Providing emergency food during a famine? Sure, you can provide aid for these things without negatively affecting the poorer countries' economies. But the moment you start talking about massive international wealth distribution, macroeconomics comes back to bite you in the ass and ruin your great plans.

[40K]In the opening cinematic of Space Marine, who is having the text conversation?

OK, when xenos invade this valuable Imperial forge world, we see [two people texting about it.](https://www.youtube.com/watch?v=w9asMbft0QU) It must be someone very powerful, since they're making super high-level strategic decisions. But the dialogue is very clipped, all business, almost like two AIs talking (which I understand they're not). There's no ritual language, no invocations of the Emperor or other quasi-religious phrases. I find it difficult to imagine a couple of uber-powerful Imperial officials sitting down at their computer terminals, deciding these matters with a few brief, unceremonious texts. "Calling Smurfs, BRB." Who is actually writing these lines?

Long-range communications are somewhat unreliable, therefore messages are often short, brisk, and clear as possible. The people talking are either Inquisitors, Space Marine Chapter Masters, Lord High Admirals, or Lord Commanders, as they are the only ones that can order an exterminatus.

ELI5 why a picture that I take with my smart phone or even a decent point-and-shoot camera looks NOTHING like what I see with my naked eye.

Generally, I don't get nearly as much content in the photo as I'm trying to capture, which I understand is a limitation of the lenses. But why do the pictures always seem to come out so much darker than it actually is? I can see just fine, why can't the camera? And why is it so hard to capture accurate colors? I've tried to take pictures of various colors in clouds and other sources to use as a reference for other projects later, but the colors seem to come out extremely muted and much less subtle and varied than what I can see with my eye. What's going on?

Regarding the light issues: Your eye has a much larger dynamic range than a camera sensor, meaning it can differentiate a much larger range of brightness. Think of it when you walk into a dark room, you can't see anything, the eyes' dynamic range cannot differentiate objects with so little light. Same goes for when you walk out to sunny outdoors. The difference is that our eyes can adapt, shifting to the range of what we see. Cameras do that too, but to a more limited extent, with a smaller range, so when something bright and dark is in the same scene, it makes a decision on what it wants to differentiate. 'Better' cameras have a wider range. If you were 10: We actually use similar mechanisms to do so- the iris of the human eye functions as an aperture, opening wider under dark conditions, and smaller when there is a lot of light. This relates to the 'f-stop' on a camera.

Why does fire change colour with certain chemicals inside it?

The color represents electron transitions between orbitals on the vaporized material (i.e., the fuel, the combustion byproduct etc.) Different materials have different energy levels for their electrons. The transition between these levels produces unique wavelengths of light. Taken in aggregate, these are the colors you see in the flame.

What effect does reccesions have on black markets? illegal drugs, ect

Anyone know?

Overall the black market suffers, but it could also have varying effects depends upon from which side you look. From Sellers POV, as there is no fixed price, at a time fo reduced demand they will increase the prices so that they are able to cover up the shortfall in revenues. This leads to an increase in prices, but an addict or one who is hooked will try his/her level best to meet the prices, either borrow or sell assets or even indulge in crime, like theft and burglary with an aim to find resources. From Buyers POV, for normal goods, the demand falls with income, so it depends on what preferences the buyer has. If you look at those who have high financial debt or use it as a coping mechanism they will need it at all costs so they will definitely buy and they will too hunt for resources either through crime or other means, as their incomes fall in recession. There will also be varying effects in districts that are hit the most, that is, that have high unemployment.

Professors experienced in teaching both grad and undergrad students, what are the salient differences? I'm teaching undergrads for the first time in 15 years, have any tips?

It depends on your institution. Mine is not very selective. There is more variance among undergrads. Some don't even know how to take notes, how to start an assignment, etc. Others are ready and may be as good or better than grad students. Grad students (I teach MBAs) are more focused and career-oriented. They may not want an A in every course but they do want to learn and do a decent job.

Learning academic research skills by yourself? (not satisfied with skills I acquired in psychology)

I am nearly finished my degree in psychology. The skills I have acquired relate almost entirely to empirical research - competence in statistics, evaluating the strength of a study based on methodology, conducting my own scientific research. It's a good foundation to learn independently but I'm haunted by what I may have missed had I studied something without scientific dogma. I am more interested in subjects such as philosophy, sociology and political history - and I imagine the academic skills involved in researching these areas is very different from what I already know. I want to be competent in independently investigating questions across humanities, and fear I might be incompetent or fall through amateur pitfalls in areas outside of psychology. I notice how starkly misinformed people outside of psychology are of psychological approaches - and I'd like to take the right approach for whatever I look into. I'm sick of formal education and, once I graduate, I want to go forward as an autodidact. But I'd love to be able to chase down answers to philosophical/political problems in the same way an academic does, if that doesn't too ridiculous of an undertaking. Maybe somebody here has insider-info on psychology AND a non-empirical discipline? Maybe its all just a matter of actively reading whatever is relevant to your scope of enquiry and if I have something worth adding then I just write it? (I got slammed by philosophy crowd for assuming this was the case)

Academic research is in service of the academy and the organized principles of various disciplines. If you’re just interest in being an autodidact for your own purposes then you’re not interested in academic work and none of us can be any help. Honestly I’m not really sure what you’re asking.

When a corporation makes a profit, where does that money go?

My understanding of "profit" is what income is left over after all expenses are accounted for including all operational costs, legal/service fees, and paying every single employee, so who gets the profit? Also, if corporations are legally people, why don't people post profits as well?

Some profits may go into the bank (or investments), to be used later. Some profits may go into expanding the business over the next fiscal period (thus going to pay for future expenses). Some profits may go into repurchasing shares. Some profits may go directly to shareholders as dividends.

[X-Men] why don't mutant inhibitor collars remove physical mutations. Eg. Since Nightcrawlers odd appearance and his teleporting are caused by the x-gene, then why is the collar that nullifies the x-gene only change the teleporting?

Why doesn't the collar also make him look human as well as stop him from BAMFing if it was the x-gene causing both the inhuman appearence and the teleportation powers

The genes that built any given mutant’s body have already done their job by the time collars are applied. Keep it on for a number of years and you may start to see complications for certain mutants like Nightcrawler, Beast, or Glob Herman, because the body is constantly regenerating itself. What those complications may be can range from an otherwise healthy entirely human appearance to death, depending on the exact type of collar used and the individual mutant’s unique physiology.

How a non-academic can support someone in the academia, relationship-wise?

Hey, I've recently started dating a 33/M who has PhD in Astrophysics and works as a researcher at the university. I (33/F) have no degree (dropped out of four(!) degrees due to previously undiagnosed ADHD), but I haven't ruled out getting one (or finishing one of the previous ones) in the future. Currently I'm working in IT with a permanent full-time position and life is stable in that way. He is currently under lot of stress due to applying for research grants, reviewing papers and preparing a talk at a seminar, all having deadlines next week. This has now resulted in that we haven't had time to meet in a week (live in the same city), and probably won't have time to meet until the end of next week. Have been pretty much been contact via WhatsApp only. As I have other academic friends as well, I understand the pressure and haven't pushed for a meeting. The question is: How could I best provide support for him? I show regular interest towards his work and research to the best of my abilities, though I know absolutely nothing about physics (other than what I've read from Wikipedia - funnily enough, we ended up talking about Hawking radiation at the first date!) I guess I have to just back off now, for the time being, considering if he's so busy there's no time for setting up a date - but how could I show support and interest in the best way in the future? What are the things you appreciate in (non-)academic partner's behaviour during stressful times?

Being understanding and flexible is the most important kind of support. You show interest the same way you do about anyone's career. Ask how things are going, let them talk and listen. You don't have to become an expert in their subject. That said, a lot of other comments here mention cleaning up and cooking and doing other household tasks. While this is certainly a very nice gesture, you should think long and hard about the role you want to take on in the relationship as it develops. A lot of academics have partners who do everything for them, because it is a stressful and demanding career. Is that a role you want to take on? Or will you want your own demanding career, or even just to devote time your own interests and hobbies? The patterns you set early in the relationship will effect expectations down the line. Don't act like this guys' mother/maid unless you are prepared to accept that jobs(s). I really wonder if you were a guy writing this, whether you'd be getting that same kind of advice.

Eli5: Why do some soldiers wear digital camo, is it actually useful for camouflage or is it just for aesthetic reasons?

Scale variance and insomulance. In 2001 the Canadian Armed Forces developed Canadian Disruptive Pattern (CANPAT) which uses an innovative digital pattern. This pattern was intended to replace the standard "woodland" pattern in use in the late 20th century and claimed to have the advantage of "scale variance." If you consider a soldier hiding in vegetation, he will come to look more and more like a soldier in recognizable camouflage the closer you get to him/her because the "blotches" will seem unnaturally large compared to the color diversity surrounding him/her. Digital camouflage provides natural looking patterns at a greater variety of distances than the Woodland pattern that proceeded it. MARPAT was adopted by the US Marine Corps modeled on the Canadian design in 2002. The rest of the US Armed Forces adopted the Universal Camouflage Pattern (UCP) in 2005. In each case the tactical advantage of scale variance was stated as the principle reason for the change. However in 2015 the US Armed Forces began transitioning its units to a new Operational Camouflage Pattern (OCP) this will fully replace UCP by the end of 2019. The OCP is based on the multicam pattern which was originally developed in 2002 but lost out to UCP. In 2010 it came to be deployed as a field uniform in the Wars in Afghanistan and Iraq and has caught on with lots of other militaries involved in uneven warfare. The purported advantage of multicam and the transition to UCP is that it addresses the problem of insomulance. This is a fancy word that means that at a distance all the colors blur together and become gray. That is because the digitization works like pointillism. The UCP provides computer randomized color variation that still addresses scale variance without creating insomulance. If there's one thing we can guarantee, its that military uniforms will change. Militaries are always looking for a tactical advantage. Even the perception of a tactical advantage can do wonders for morale and bravery. As the US completes its transition out of digital uniforms you can expect to see surplus digital uniforms used by other countries for a time, but ultimately the digital pattern will look like the Iraq War period just as Olive Drab looks like WWII.

Eli5: How can higher labor costs increase profits? How did Henry Ford's $5 wage per day increase the profitability of Ford's motor company?

People who feel valued (not exclusively in terms of money!) tend to be more motivated and willing to "go the extra mile", which increases throughput and decreases errors. If someone feels exploited, why would they do more than the bare minimum to not get fired?

Eli5: What happens to a child’s schoolwork when they have to go to juvie, rehab, mental hospital, etc.?

Most schools will send your school work to you and you will do it at the hospital/facility. But if you are incapable of even doing that then you will have to repeat the school year once you are capable.

ELI5: how computers are able to read programing languages

They usually don't. ##Assembly A long time ago, programming was done entirely in Assembly, which is a very low-level programming language. Generally, each assembly command is the same as a single instruction that the computer's Central Processing Unit (which does most of the computer's logic) will process. For example, an assembly command might look like add $1, $2, $3 which adds values in numbered registers 2 and 3, storing the result in register 1. ##High-level languages CPUs have a limited number of registers, which can temporarily store data. However, dealing with a limited number of registers, along with the multitude of other severe limitations of the Assembly language (one of the largest being the fact that you generally end up having to write far more assembly to do the same thing in a higher level language), is one of the reasons why we created high level languages (like C++). That same statement in C++ would look like variable1 = variable2 + variable3; but that does even more than just what the assembly line did. Not only did it add three variables (data stored in the computer's memory), but it also had to load the value of variable 2 and 3 from memory into a register (some methods of CPU design allow directly working with values in memory, too). After adding the values together, variable1 must be saved into memory. These kinds of tasks get very repetitive when coding in assembly. But with a higher language like C++, the compiler does all this work for you. ##The compiler The sole job of the compiler is to transform the higher language into assembly, which is unique to a family of processors. The ability to create compilers for different types of processors makes higher languages more portable (meaning they can be used on a larger variety of machines). ##The assembler But even the compiler doesn't do enough for the processor to run a program. Processors are complex devices that consist of many very simple devices. To keep things simple, they work in binary, which means there's only two possibilities: 0 or 1, which can be easily represented as a high voltage versus a low voltage. The assembler converts the assembly code into binary machine code. For example, the add line above might look like `000000 00001 00010 00011 100000` (which is indeed valid machine code for a MIPS 32 processor). The processor knows how to handle this. It can split the binary value up into portions that it knows how to deal with. For example, with the previous machine code line, the processor would probably note that the first 6 characters are all 0, which is the operation code. This code tells the CPU what to do with the instruction. In this case, an opcode of 0 denotes an operation on three registers. The next three space delimited binary numbers are register numbers, in binary. For example, `00001` is simply the number 1 in binary, while `00010` is 2 in binary. The last 6 binary numbers tell the processor what to do with the registers. In this case, `100000` denotes addition. The processor now knows it has to add the values in registers 2 (`00010`) and 3 (`00011`) and store the value in register 1 (`00001`). ##But that's not all In addition to the compiler and assembler, large programs often use what's called a linker. The linker can combine machine code "objects" together. This is useful for large programs because we could, for example, compile (and assemble) each file into machine code, then link them all together. If we make changes to a single file, we only have to recompile that one file and re-link, instead of recompiling everything (which can take a long time for large programs). There's also dynamic linking, which links libraries of code (a library can be thought of as a list of things that code can execute) at the time that you run the program. On Windows, you'll often see dynamic linking in the form of DLL files (which stands for "dynamic link library"). In Linux and related OSes, `.so` (shared object) and `.a` (archive) files do essentially the same thing as DLLs. The advantage of dynamic linking is that programs can load this dynamic library into memory once and allow it to be used by multiple programs. Other advantages include being able to use other programs as dependencies and ease of updating a program. ##Interpretted languages You may have heard of languages that don't need to be converted into machine code. These are referred to as Interpretted languages, and include languages such as Python and JavaScript. They are not the same as a high level language as C++ in that they are not directly executed by the processor. These programs are interpret by another program (which is in machine code), which executes appropriate machine code instructions to "run" the scripting language. This has the downside of being much slower. ##Java is weird Java can be interpret like a scripting language, running in what's called a virtual machine, which emulates a processor (also like a scripting language). This does make Java a bit slower than a compiled language like C++. However, Java also can do something called "Just in time compilation" (JIT). This means portions of code are compiled into native machine code on the fly. This machine code is able to run faster than code that the Java virtual machine interprets. In general, Java would still be slower than compiled languages like C++, although sports advantages such as being able to run on any operating system that the Java virtual machine supports (which is quite a few). There also exists special programs that convert Java programs into native machine code (which in a way defeat the purpose of the Java language in exchange for speed). **TL;DR: A *compiler* converts a high level language (like C++) into assembly code, which an *assembler* converts into machine language, essentially the only thing a processor can understand.** ^(Edit: Changed "scripted languages" to "interpreted languages", courtesy of /u/MathPolice)

ELI5:Does making eye contact go against your biological instincts (in cases where you're not trying to be threatening)?

Throughout the animal kingdom, eye contact is considered a form of aggression. Many human cultures also do not consider eye contact to be an appropriate behavior. However, Western cultures generally expect eye contact and attribute a variety of negative traits to those who don't maintain it (most of the time). This could indicate that in humans, eye contact is related to culture. But even many Westerners have trouble maintaining eye contact, which would indicate that Western culture is only masking biology.

I think in Western Culture it is seen as a sign of respect because you are looking at the person who is speaking and visually paying attention to the speaker. This is different from starring someone down, or "shooting daggers". This is also different from the don't fuck with me stare. All of them involve looking at the subject the difference is facial expressions. Squinting pinching tensing of your facial muscles tells much more than your eye movement.

ELI5: If disorders like depression and anxiety are chemical imbalances, why are non-chemical treatments like talk therapy effective?

Let's say that the chemical imbalance the person is suffering from is a lack of a brain chemical called X. If the problem is that your brain is not creating enough X, there are two solutions: * Supply additional X artificially (e.g. by taking a pill) * Get your brain to create more X If you can get your brain to create more X by talking with a therapist, playing music, going for walks, cuddling a puppy, or balancing a spoon on your nose, those are all legitimate treatment options.

ELI5: Why does the beam of the flashlight fade out after a few meters typically, when the light travels much farther?

The beam gets wider as it gets farther from the flashlight, so you have the same amount of light being spread over a larger and larger area. Eventually it gets spread so thinly that your eyes can’t tell the difference.

ELI5: Instead of removing the testicles and ovaries and uterus, why do so many veterinarians not perform vasectomies and tubal ligations?

It's not only about preventing pregnancy, it's also about behavioral control, cleanliness, cancer prevention, and infection prevention. If a female dog's ovaries and uterus were still intact, she would still have heat cycles--which means owners will be cleaning up blood. Then as she ages, her chances of eventually developing a potentially fatal condition called pyometra (infection of the uterus) increase. Removing the uterus prevents all that. The increased estrogen levels from having her ovaries would also keep the potential of her developing mammary (breast) cancer up. For male dogs, a vasectomy will not eliminate the testosterone--making them more aggressive, more likely to "hump" or "mount" things/people, and also allows for testicular issues and prostate cancer. edit=typo

ELI5: Scientifically, what is the difference between color film and black/white film? What changed and allowed film to be in color?

What gives? I understand the basics of how film cameras work, but for the life of me I don't understand what changed.

Black and white film consists of a single layer of material that changes opacity based on the amplitude of light that flows through it, regardless of the color of that light. This produces a film 'negative'. The negative is then processed so that it doesn't change color anymore and is then used to expose another layer of film to produce a standard image that can be projected. In color film, the film may have three layers or three chemicals that change opacity to match hues of cyan, magenta, and yellow. This produces a color negative. When this negative is processed and exposed to another layer, you get the inverse of cyan (red), magenta (green), and yellow (blue), which can then be projected and matches the colors of the original photography subject. Negatives are usually preserved as much as possible, since they represent the highest quality version of the original image.

ELI5: What exactly is "processed" food?

And why is it bad for people?

"Processed" food means the food has undergone some mechanical or chemical manipulation or "processing" to reach that state it was that would/could not occur naturally. For example, Reddiwhip/Coolwhip are oil based whipped cream products that undergo processing to reach a state where they have the texture of whipped cream. The reason they may be bad for people is that a lot of the processing involves adding chemicals which are not necessarily optimal for human consumption as opposed to eating naturally occurring food items.

Can you build a program in C++ to compile any language?

I was reading up on how Node.js came about, which lead me to Google V8 and what it was. I know some Java, and not C++, and the "compiling Javascript to Native Machine Code" description, finally made me interested in the JVM, and made me look up some of the differences between Java and C++. So, is there something special about JavaScript that lets C++ make a program to compile it, or can it do with any language? And when you do something like that, how complicated of a task is it? It seems pretty complicated to build a program from another language, whose purpose is to understand another language and then compile that.

Yes, you can write a compiler for any language in C++. In fact, you can write a compiler for any language in any language, because all a compiler does is read your source code file and write another file that your operating system and CPU are able to interpret; that obviously requires knowledge of the OS and CPU your compiler targets. A program that has input and output is by definition "a program". Writing a fast virtual machine (like the JVM, or even VirtualBox/VMware/dotNet) however, does require a programming language that can direct the CPU to execute any code it wants directly. That's something that C++ and C can do, but there's no implementation of JavaScript or Java that can do that directly. (Oversimplification alert: you can write a very small unit of code that your Java VM will load via JNI that could do that... but that's not Java anymore).

[Halo/The Expanse] What is the tactical/strategic benefit to having large warships with frigates/destroyer hangar bays, (See MCRN Donnager and UNSC Infinity), as opposed to those smaller ships traveling with them?

A few reasons come to mind: - Large craft can have bigger powerplants, and on the whole, transport itself and attendant "child" ships more efficiently than they could themselves individually. The child ships can also be designed with a more combat-oriented focus, forgoing long range spaceflight capability for speed and weaponry, since they are hosted by the carrier. - "Child" ships can be docked, repaired, rearmed within the parent, making it a mobile shipyard. Damaged ships can be carried out of the conflict zone without any special service craft. - In the case of superluminal travel, a large ship with smaller ships inside it only has one jump to calculate, and there is much less risk of fleet elements being lost due to errors or accidents. - There is a tactical advantage to hiding the true amount of spacecraft ready for battle, even a handful of hidden destroyers/frigates can drastically change the fight. Edit: grammar fix

CMV: I am going for a degree based on how financially lucrative it is, Instead of chasing a passion.

A few more details. I am in my early 30s , never went to college and worked all kinds of jobs and eventually opened small businesses. I have done ok but now want to go for something more stable. I’ve been told for over a decade to go to school and chase a passion but honestly my only passion has been art, I am sure you know the value of an art degree. I am thinking tech because I actually do ok with math, and I don’t hate the field. I am comparing the financial value of different tech degrees and planning to go for which ever one makes the most money as long as I feel I can meet the demand of earning that degree. Every time I discuss this people immediately tell me to find something I am passionate about instead and that this is a bad plan, but I feel like if I have not found it by now I can’t really wait around forever and it be better to just get something that makes money so I’d at least have that going for me.

Most tech fields *require* passion as well. An engineering degree in itself is just a starter kit - they will teach you basics, and how to obtain more knowledge; what you learn at a university will not be enough for your job! No matter which area, technology evolves rapidly, and to keep relevant, you need to be genuinely interested in it and constantly educate yourself. It's not a job which you leave behind when you leave the workplace. So, "doing ok with math" and "not hating" is not enough. In a couple years in the industry, you will have a choice: Either force yourself to continuously learn new things which don't interest you, or fall out of the circulation.

When a photon enters an optically dense medium (n>1) does the photons energy decrease? If so where does it go?

When light enters a material, the frequency of the wave does not change. The energy of a photon is E=hf (where h is planck's constant and f is the frequency), so the energy also stays the same. What about wavelength? Well, the wavelength of an optical signal is related to the frequency and the speed of the wave : (wavelength)(frequency)=(speed of light in the material). In materials, the speed of light is slower than *c*. Since the frequency does not change, the wavelength must change accordingly. In fact, the change in wavelength is proportional to the refractive index: (wavelength in vacuum)=(wavelength in material)/(n, the refractive index)

ELI5: How do huge companies bank accounts work, are they literally like the bank accounts we have? also are the bank accounts with Normal banks or specialized banks?

For most businesses it is more or less just like a personal account. When you start getting into larger corporations they have dedicated employees that manage their money in investments, then many smaller accounts tied to different departments within the company. However it is usually easier to just have company credit cards where all the bills just go to one place. The biggest difference with most business accounts is there may need to be more than one person's approval to initiate any large transactions. And yes they are mostly the same banks dealing with businesses, in fact most of your everyday banks make more of their money off of businesses than personal accounts. They actually use the money from what are essentially long term savings accounts collectively to loan out to businesses (along with personal car/home loans) at a higher interest rate than they are paying you to keep your money at their bank, which is a large part of how they make their money. What most consumers think of when they think of a bank is just a place to hold their cash safely isn't primarily how the bank makes money. By offering free or low-fee checking and savings accounts the bank really just wants you to be a loyal customer when it comes time to take out a mortgage for your first house.

How much salt would I need to be able to float in my bathtub as if it were the Dead sea, would it work?

1. Can I use kitchen salt? 2. Why would it work? 3. Why wouldn't it work? 4. If the answer to #2 is no, why does it work in the Dead sea?

The general rule of thumb for salt water aquariums is 1/2 a cup of salt per gallon. The Dead Sea is 8 times saltier then that so 4 cups per gallon. The average bath tub holds 50 gallons so 200 cups of salt are need. 1 cup of salt weighs approx .6 pounds so you need about 120 pounds of salt. Mix well until all salt is dissolved. Lay back and enjoy your mini Dead Sea.

[Warhammer 40k] Since the Dark Mechanicus aren't stagnant like the Adeptus Mechanicus are, won't Chaos eventually win through technological superiority?

Any more than they already have, I mean - the Imperium today produces more than enough war, stagnancy, plotting and pleasure/suffering to feed Chaos.

You can't do much research when your laboratory decides what rules of physics it will adhere to at the moment. And it changes very often. Also, Chaos does not like other following chaos, they are just as likely to be killed by the Imperium as by other Chaos followers(if not even more so). Death tends to stop research really well.

Does the intellectual content/technological advancement in CS progress faster in industry, or academia?

It seems like companies are coming up with new things all the time, esp. in data science, machine learning, AI, machine vision, etc. Do these innovations etc. move quicker in industry or academia? If it's in industry, what purpose does academic research serve CS these days?

Few companies (Google, Deepmind, Microsoft among the most notable ones) come up with new breakthroughs, and that's mostly in ML. Most of the "intellectual advancement" (aka research) in CS happens in academia, though it often takes decades to be adopted in practice (by companies). CS is a massive field and the topics you mention are only a part of it.

Why is the unit "second" defined at 0 Kelvin?

According to [the official definition at page 95](http://www1.bipm.org/utils/en/pdf/si-brochure.pdf), the definition of the second is > the duration of 9 192 631 770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium 133 atom. I understand why this is the most practical definition ([as discussed before](http://www.reddit.com/r/askscience/comments/hq1xx/how_exactly_is_the_second_based_on_the_hyperfine/)), but not why we chose 0 Kelvin as a reference point (see the same page of the definition). Isn't that somewhat unachievable (disregarding some highly specific experiments) and impractical?

When a stationary atom emits a photon, the wavelength of light emitted depends on the energy an electron lost when it jumped down an energy level. However, if the atom is moving, the frequency of the optical wave will be doppler shifted either redder or bluer. Furthermore, the direction of the doppler shift (red or blue) will depend on the direction the photon is emitted compared to the direction the atom is moving. Since the definition of second depends on the number of cycles of an optical wave (its frequency), and the frequency of an optical wave depends on the motion of the source, saying the temperature must be 0K is simply a way of saying the emission source must be stationary.

ELI5 what do water towers do and how do they work?

Engineer here! Water systems are driven by pressure, through either pumps or gravity. In places where there are hills, a RESERVOIR near the top of a hill will spurs the pressure through a water conveyance system to the lowest locations of the water conveyance district. (NYC gets its water from the catskill mountains, about 100 miles north) In places without many hills, water is pumped to the top of a water tower that will feed the municipality with pressurized water (so it's an artificial hill that water will push down from to allow water to rise up to the second story bathroom of your house) Water flows through big pipes, then smaller pipes as it branches through the city or town you live in. The water mains in residential streets vary from 4" to 24", or larger. The pipes in the street tend have valves to isolate them, and at the end of each dead end is typically a fire hydrant, both to help put off fires and to drain the water line from stagnant water. To get to the house, two cocks (lol) are used; they are small valves that isolate your individual house from the main line. These are called curb stops and corporation stops. These can be opened or closed to allow water to flow into the house. Any other water or storm drain questions?

[Superman] I find a rock, paint it green, then spray it to make it glow. Could I use this to placebo effect Supes into giving up?

Or would he know the difference between green glowing rocks and kryptonite?

I think it would depend on your distance. IIRC he can feel kryptonite's effects from a couple feet away, so if you were in front of him with it, he'd be able to tell the difference. There's also his super vision, he might be able to see through the rock and know it's not kryptonite.

How do scientist determine bond angles and bond lengths in chemical compunds?

There are different ways, It depends alot on which scale you are working. Macromolecules like proteins are usually investigated with x-ray crystallography. The same method Is used for minerals and solid crystals. Smaller molecules are usually studied with rotovibrational spectroscopy if they are not too complex. EDIT: typos

[Superman] How exactly does Superman's x-ray vision work?

I hear Superman has x-ray vision (as if he didn't have enough powers am I right?) but how exactly does this work? Is he hitting me with radiation if I get x-rayed by him? Furthermore I even heard that he is able to actually see as if he was in the room while using his "x-ray vision" rather than the "seeing bones" scenario one would expect... Are there any theories on how he does this? I don't like the idea of him being able to see through my clothes even if he is protecting us...

We humans are already able to build machines that can read all manner of different types of energy and convert them into visual aids, for example thermal imaging, electromagnetic spectrum and so on. If used in the right manner these allow us to look through seemingly solid matter. It seems incredible, but it's just making good use of physics. Superman merely (merely, hah!) has this ability on a biological level, greatly refined.

What is the significance of the successful energy modeling of an H2 molecule by a quantum computer?

This was announced recently by what seems like the gauntlet of universities at the cutting edge of technology, but as someone in chemistry who knows little to nothing about computing I feel as though I'm seriously underestimating the importance of this finding. What does this mean for quantum computing as a whole? Is this as momentous as it seems to a layman like myself?

The theory of quantum computers is well understood, because just like a normal computer, given enough time, a person could do all the maths by hand. The advantage of quantum computers is that they are really efficient at particular kinds of maths, like factorisation and stuff. They are also good at simulating quantum processes, as they *are* quantum processes. With a little trickery, you can build 'quantum circuits' - chains of 'quantum logic gates' which do well defined maths on four dimensional matrices (a fancy kind of number that is used to represent quantum states). With these 'quantum circuits' you can do things like simulate things like H2 molecules. This has been known for a long time. So why is it important? It turns out that circuits specially designed for working with matrices are widely available, and a regular computer can use these, or just work with them by themselves. So although we know that in theory we can simulate H2 with a quantum computer, we only know this because we have simulated quantum computers! Actually building a quantum computer is important, as it shows three things: 1 - quantum computers are possible 2 - quantum computers behave as we think they do 3 - quantum *physics* behaves as we think it does Successfully building a quantum computer to do various things show these three to be probably true.

Is there a way to establish a network?

Hi, I would like to know how do you start to establish a network with other researchers. I'm actually an Assistant professor at a top-3 university in Brazil, so I'm already in academia. However, I'm having too much difficulty in establishing a research group/network or any type of contact with other researchers to work together. I have a researchgate and academia.edu profile but I don't interact a lot there. Unfortunately, my colleagues from my department that share some common research interests with me are at another moment in life, with little focus to work and more to family. So, how do you started your research network?

A good place for me has been by attending conferences for professional associations and organizations. Those provide a good place to meet and talk with like-minded individuals and begin to build relationships that can turn into research collaborators and co-authors.

ELI5: Why do movie reviews have such a large influence for some movies, but are ignored on others?

There are movies that get bad reviews, but still make a sizable profit, such as many Adam Sandler movies. However, there are also movies like Baywatch that tank due to bad reviews. Why does this happen? Thank you in advance.

This is a complex topic, but it comes down to branding and preconceived notions. To use your example; Adam Sandler has a brand. Regardless of what movies he puts out, there are going to be Adam Sandler fans that will watch his movies. He has a specific brand of humor that does not sit right with a lot of people, but is very attractive to his fans, and his fans don't care much what the broader audience thinks. Bay Watch, while there are some fans of the original; everyone who likes an original is skeptical of a reboot. Those that aren't familiar with the original have no ties to the movie. So now most people's biggest piece of information regarding Bay Watch is going to be reviews. The more branding surrounding a movie, the less reviews matter. For example, the next Harry Potter movie, the next Star Wars movie, the next Avatar movie, etc...it doesn't matter what critics say, these will all generate a ton of revenue. A movie you've never heard of, like Get Out...its success depends solely on what critics have to say about it.

ELI5: how do bugs eyes work….specifically flies and dragonflies. Like what do they actually see and how does it work?

They have "compound eyes." Their eyes are made up of thousands of tiny lenses. The simplest way to explain how they see is each lens is a tiny portion of a larger picture sort of how many pixels make up an image on a screen. This way the insect has a very wide range of vision. The downside to insect compound eyes is that they can't control how much light enters their eyes, humans have pupils that can control how much light to let in. That means insects are extremely near-sighted. On average, they can only see a few yards away. The upside to compound eyes is that it's extremely good for differentiating movement. They can react to movement much more quickly.

[South Park] Kenny’s Powers

If Kenny’s mother were to die would Kenny cease to be immortal?

It’d depend on the nature of the enchantment. If the spell was originally cast on Kenny himself (or rather, his unborn form/soul,) then it’s likely that the next motherly figure for Kenny would likely be the next host (his dad’s new girlfriend or even possibly one of the other boy’s mom.) What’s more likely, considering the eldritch source of Kenny’s power, is that the enchantment grants his mom and dad both a form of immortality (or at least a greatly extended lifespan,) since Kenny is very much a product of both his mother and father. They probably aren’t unkillable, so the death of either spells the end for Kenny too. But it doesn’t benefit Cthulhu or his cult very much for the progenitors of one of his clearly most important agents to live and die in the blink of a Great Old One’s eye. Especially with the particularly unhealthy lifestyle that Kenny’s mom and dad have, and yet the two don’t seem any real worse for the wear.

ELI5: How do broken bones heal?

Bone healing occurs in three stages. The first is the inflammation stage, where clot forms between the fracture. The next is the repairing stage, where the clot is replaced with cartilaginous and fibrous tissues to stabilize the fracture, which are then gradually replaced by bony tissue to form an immature spongy bone mortar. The final stage is the remodeling stage, where the marginal spongy bone is replaced with the harder compact bone, leaving the bone basically as good as it was before fracture.

ELI5: Why do some drugs, like opiates, develop a tolerance in the user while other drugs, like Prozac, do not?

Just wondering why with some drugs the brain adjusts to the new balance of brain chemicals, whereas with SSRIs and such, it doesn't.

This is a tough question to ELI5, but drug tolerance is controlled by a complex series of counter-regulatory systems, and some systems are simply more responsive than others. Opiates are an interesting example because they act on multiple receptors, and only some of those receptors develop tolerance. The opioid receptors that reduce pain sensation and cause euphoria become much more tolerant over time, while the receptors in the GI tract and respiratory center of the brain do not develop tolerance. Because of this, people need increasing doses to relieve pain and/or get high, but they do not become resistant to the respiratory and GI side effects.

ELI5: Why is there depth in reflections?

This might be a dumb thing to ask (or a genius thing, idk) but it hit me and I've been thinking about this since. So lets Take [This image](https://i.imgur.com/CIGZw21.jpg) for example. There is quite a distance from the house and the pond. Why is the house' reflection in the pond also in focus?

Reflections preserve the angle of the light which strikes them. So as far as the light rays are concerned, they start diverging from the actual object, continue to diverge, strike the reflection remain diverged, and continue to diverge as they reach your eye/camera/etc. This means for the purposes of focusing, you can treat the reflective surface like a window, with the reflected object as far behind it as the reflection is from the object (e.g. House -100 feet-> puddle - 10 feet -> you = 110 foot distant object). This is unlike a photograph, where the camera has focused everything beforehand. So when you look at the picture, the light rays diverge from *the photo* (e.g house - 100 feet -> camera -> photo - 10 feet -> you = 10 foot distant object).

ELI5: How do stealth planes work and why can't radars detect them?

Radar works by shooting out invisible light waves in all directions. That light gets reflected back to the antenna which can detect it and based on any frequency/amplitude changes and signal lost it can determine the size of an object and its distance away. Stealth planes operate on the basic principle of making sure as little of the reflected light makes it back to the radar antenna to be detected. The first method was design of the craft. By situating the panels of the craft at specific angles you could ensure that only small bits ever reflected light in one direction at any given time. That's why the initial stealth craft, like the F-117 Nighthawk, looked weird with their triangular shape and sharp edges. The second method was material type. By making the shell of the craft out of special material it could absorb the radar light, rather than reflect it, making it invisible to radar. As technology improved they could rely more on the radar absorbing material and less on the design, which allowed them to go back to the more standard aircraft design as seen in the F-22 raptor.

Why do the water droplets that make up clouds, bunch together into clouds instead of being evenly distributed in the air?

Cloud droplets form in areas where air is cooling, causing water vapor (humidity) to condense into liquid. Usually, this happens because the air is rising: air cools as it rises into lower pressure. So the big puffy white clouds on a summer day are actually plumes of moist air rising up from the ground: the air between them is where dry air from higher up in the atmosphere is descending to the ground.

CMV: Plastic surgery shouldn’t be as stigmatized as it currently is in the US

As a Korean American, where the former (Korea) exists on the other end of the spectrum in terms of acceptance of cosmetic surgery in relation to the latter (America), I think that cosmetic enhancements serve society well in net satisfaction. People who suffer from crippling self-remorse or receive backlash from inevitable societal judgments should have the freedom to undergo treatments to improve their quality of life. Seeing as society will certainly continue to make judgments regarding physical appearance, it is only fair, or equitable, that people have access to cosmetic surgery to improve their chances at a better life to even the playing field, and it seems backwards to judge those who partake in these surgeries to fulfill society’s (and their own) standards. It is easier to uncover the ongoing popular phenomena in the United States of cosmetic surgery (often under the guise of new makeup techniques or weight loss programs) and change the societal perception of this just one self-enhancement mechanism as opposed to changing the social climate as a whole. It’s a lose-lose situation to judge those who don’t adhere to conventional beauty standards while also judging those who try to conform to these very same standards.

The problem is, that which becomes common becomes mandatory. Two generations ago no-one had braces, so people whose teeth were crooked were not stigmatized because they were most of the population. One generation ago, most people got braces, and those that didn't were stigmatized. Now, essentially everyone gets braces, even for very minor cosmetic flaws. We're in a cultural equilibrium where every child goes through ~1 year of painful mouth realignment, even though for most children it's not necessary for any medical reason.

Are there any good resources to study Foucault's Madness and Civilization?

Spark notes leaves out a good amount of content in each chapter and I find it generally lacking in the book. Are there any supplemental resources to hell make sense of what Foucault is saying?

There is a podcast called Philosophise This which covers Foucault extensively, as well as most other philosophy topics (it's a long going podcast). Things are looked at seriously, with quotes, explanations, counter arguments etc. You can find it on Google Podcasts and just look for the Foucault episodes.

Is it okay to create and name my own principles in my philosophy paper?

I was assigned a philosophy essay with a very traditional prompt. It's pretty open ended and has to be less than 2000 words. I kind of got carried away, becoming passionate about the question and I wrote what I think is a stellar paper. It's still less than 2k words, ready to be submitted, but I just feel like I was too pompous in a particular area. That's because I became proud of a main argument in my paper, so much so that I gave it a name like this: "Principle of *\[blank\]*". I even made an abbreviation for it so could reference it multiple times in my paper. I just feel like as an undergraduate student and someone who isn't even a philosophy major, I do not really have a place in putting that kind of material in the paper. Does anyone agree/disagree with this? Part of the reason I have all this doubt is because it seems rather similar to what Peter Singer wrote in one of his books. He revolutionized the "Principle of Equal Consideration" of equal interests (PEC) and referenced it all throughout *Practical Ethics*. I can see that Singer absolutely has the privileges of doing this in his great book, but not me with this measly 5-page paper.

This strikes me as a pretty tiny concern. Is the principle meaningfully defined? Does it avoid being unnecessarily duplicative of something in a source you were supposed to use? Is your use of it justified in the paper? Does it help you answer the assignment? Worry about the terms of the assignment, not some little technical move. Instructor sensibilities differ, but this would not phase me at all.

ELI5: So there are dominant and recessive genes. Why is the recessive gene recessive?

What makes the dominant gene dominant?

Say that the first version of the gene produces X protein, and the second version does not. If you have any copy of the first version, your body will have some X; the only way you can end up with no X is if you get two copies of the second version. Now, if your body has some process that doesn't care about how *much* X you have, but only whether or not X is present, the first version will be dominant and the second will be recessive.