[System] Given the following post, respond as if you're commenting on Reddit:

[User] Can metals be transparent? If not what quality do substances like glass have that allow them to be transparent?

[Assistant]
Well, it depends how you want to define metals.

Can metals in compounds be transparent? Yes. Corundum (ruby, sapphire) for example contains aluminum and is transparent, or coloured transparent depending on impurities which are other metals. Gypsum (when not more of a powder) is transparent and contains calcium. Countless other metals in the form of salts/rocks/gemstones are transparent/translucent.

Are pure metals transparent? No, ,not in any meaningful thickness. Metals have electrons in a very open energy band under normal conditions, which means electrons are free to move. This gives metals most of their notable properties, electrical conductivity, thermal conductivity, malleability, reflectivity, and opaqueness. Light is an electromagnetic wave, which mean it has oscillating electric fields. Metals contain free electrons which respond to the electrical field in such a way to generate an opposing field and expel the electric field, which means light has little penetration (opaque) and a lot of reflection (silver colour). All metals electrons have a maximum light frequency which the electrons can no longer move fast enough to respond, typically happening in the UV region. Some metals have this occur in the visible region in the blue end, meaning the absorb rather than reflect blue making them gold/copper coloured rather than silver. So for the most part, all metals are very opaque and a highly reflective silver or sometime gold colour.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
[Marvel] If Charles Xavier decided to team up with Magneto, would non-mutant humanity be screwed?

If Prof. X were to suddenly decide his old friend was right and mutants should inherit the earth.  Would humanity be totally screwed or would there be enough human-aligned mutants to stop that power duo?

[Assistant] Can't Charles use Cerebro to simultaneously shut down the brain of every human on earth?  If he and Mags built a secret hidden Cerebro there isn't much anyone can do in the couple minutes it would take him to exterminate everyone.


[System] Given the following post, respond as if you're commenting on Reddit:

[User] ELI5: Is there an equivalent of 'Frames per second' in terms of audio recordings?

[Assistant]
There is a "sample rate" with digital audio.  A typical CD is about 44.1khz, or 44,100 samples per second.  The human ear can't detect any difference in rates higher than 50-60khz and professional recordings are often taken at 96khz because certain types of editing and processing can effect quality.

Basically when you're listening to a CD you're listening to 44,100 little blips of sound every second.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
Linguistics question: if a person lived in isolation, would they develop their own language?

My wife and I were having a discussion about this recently. She has a linguistics degree, and the topic came up of a person living by themselves with no prior language (hypothetically speaking, of course). She said there'd be no reason for this person to develop any language.  I thought that they would come up with words and names for things, if for no other reason than personal reference (e.g., cave drawings, maps, notations, etc).

So how much language, if any, would a person develop if they lived with no human interaction? What *would* develop? Thanks everyone.

[Assistant] You might be interested to read about feral children.  They're not very common, but they generally share similar symptoms, among which is a lack of language.  It's also not easy to teach them language skills after they're removed from their situation.


[System] Given the following post, respond as if you're commenting on Reddit:

[User] Eli5: Why do they say not to use your phone while gas is being filled in the car?

[Assistant]
Static charge and electromagnetic radiation (radio waves) *can* cause fuel to ignite. But your phone is not putting out a very high amount of energy at all, and the fuel pump systems these days are very well protected, so the chances of that happening are probably worse than the chances of winning the lottery.

This idea is much more serious at military bases where high-power radar poses a hazard to certain types of jet fuel.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
ELI5: Brute force attacks on passwords

Why can I lock myself out of an online account knowing the password but doing it wrong three times but a hacker can brute force possibly millions of attempts?

[Assistant]
The 3 wrong passwords=lockout function is a protection against brute-force attacks, and it's been a long time since hackers have been doing those attacks on login forms.  Instead, they are sometimes able to steal a list of *unsalted password hashes* from sites with poor security practices.  They are then able to run a brute force attack against that entire list, entirely on their own computer, and determine what passwords produce hashes that match the list.

> **hash**: For security, companies do not (well, should not) store your actual password.  Instead, they use a mathematical algorithm to mutilate your password in such a way that it can't be reversed.  The resulting value is the hash.  Then, when you log in, they mutilate the password in the same way and see if it matches.

> **salt**: For additional security, when you set the password, the system generates an additional random value and adds it to your password before it is hashed.  This value is saved and used whenever you input your password.  This makes it so that if someone steals a list of hashes, he has to re-hash each password for each account, instead of checking each password against the whole list at once.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
[Star Trek (alternate reality)] Pike: You could be an officer in four years, have your own ship in eight...

Just how exceptional did Pike think Kirk was?  An officer in four doesn't seem that out of hand, but surely the Captain track typically takes a little longer.  There's a little baiting a bravado there, but how much of that process did Pike expect Kirk to shortcut?

[Assistant]
Starfleet (or at least alternate Starfleet) appears to be a bit less rigorous than we'd expect when it comes to climbing the ranking ladder.  If you show you're good enough, if you demonstrate exceptional competence, then you'll be promoted accordingly. The best example of this is Kirk getting officially promoted to Captain of the Enterprise right after the incident with Nero, leapfrogging a whole bunch of more senior and higher-ranking officers in the process.

So, to answer your question, Pike likely thought Kirk was extremely exceptional. He recognized Kirk's intelligence, tenacity, and natural leadership qualities, and understood that Starfleet's meritocratic system would likely lead to Kirk getting promoted very quickly.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
cmv: I don't think the "n word" should be prohibited ENTIRELY from the speech of non-black people, provided they say it under the appropriate circumstances; that is, in historical discussions, in reading a book, etc.

Now, I should preface this by saying that I, myself, am a black person. This should provide the sturdiest defense in any accusations levied against me labelling me as a "racist" or a person who engages in such practices (this is satire. i am british. excuse me).

I guess my main issue is the fact that I simply can't conceive of an adequate defense against the prohibition of the n-word without appealing entirely to the feelings of black people.

Now, this isn't to imply that this argument alone doesn't carry merit; the pejorative obviously carries
tremendous, predominantly negative, historical baggage, in that it was a word used to dehumanize, subjugate and marginalize an entire race of peoples. Therefore, I agree that non-black people shouldn't really adopt this word in their everyday vernacular (in referring to their friends as "niggas", etc), considering the possibility of a black person to be offended at being called the word (and rightfully so). However, provided that the said person or persons were comfortable in being called such a word, I don't really see the issue...

This being said, I don't deem the word's usage in more formal settings (reading a book, quoting someone, historical discussions) morally unlawful. What I have gathered from my many perusals through the discursive minefield that is Twitter is that what determines the moral permissibility of the usage of the n-word is the extent to which it harms black people. But I question whether the offence being taken on the part of the black people is morally lawful...

I might be completely wrong on this, I confess. But lately it just seems more and more of a somewhat insufficient argument to make.

[Assistant]
Well, you are in luck, the n-word is not prohibited. There are no laws against using it and you can feel free to use it as often as you like in whatever company you deem fit.

Issue is that not a lot of decent company will see you as fit to be around and you may find your future to be lonelier.


[System] Given the following post, respond as if you're commenting on Reddit:

[User] [Star Wars] What's your favorite thing about the Star Wars Universe?

[Assistant] The insane depth of it all, there's so many damn alien species, planets, star systems, characters, weapons, technology and more. It's like Middle Earth level in how much just stuff there is in the fictional universe.


[System] Given the following post, respond as if you're commenting on Reddit:

[User] [Harry Potter] Can Voldemort magically detect when his name is being used? Or do people just not say it because his name brings bad memories.

[Assistant] Yes, he can detect it. After taking over the Ministry of Magic he instated a taboo curse, a powerful spell that automatically tracks anyone using a specific word and breaks weak passive protections and magical wards at the same time.


[System] Given the following post, respond as if you're commenting on Reddit:

[User] ELI5: Why does a piece of chicken or even french fries take 15 minutes to cook in a 350 degree oven but only 3-5 minutes in a 350 degree fryer?

[Assistant] Oil is a better conductor of heat than air, so the oil cooks it faster. Thats also why you can stick your hand in an over thats warmed up to pull food out and stuff quickly without getting burned. The air doesnt conduct heat very quickly so it wont burn you right away unless you touch something metal, since metal is a good heat conductor and will burn you right away. Whereas you cant stick your hand in the oil of a fryer at all.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
ELI5: How do U-Bend pipes work?

I was doing the dishes and draining some stuff when I decided to look where the water goes and looking underneath the pipe that the water goes into goes down, then curves back in on itself before going horizontal.

I was wondering why its this shape and how the water even moves if it curves back in and wouldnt it be better to keep it shaped so its always on a downward slope?

[Assistant] Thats a p-trap. It is designed to hold water in the low part to prevent stinky and dangerous sewer gasses from coming up through the drain. So, yes, a straight pipe *would* drain better but the curved pipe drains well enough *and* it doesnt stink.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
I always catch myself assuming that something involves me when it doesn't. What is this called and what is the reason for it?

I think it's related to my anxiety...Basically I always catch myself thinking that something involves me when it doesn't. For example I'm walking around and I hear someone yell, in the back of my mind, just for a second, I assume they must be addressing me. Is this a form of narcissism?

[Assistant] I suspect you are probably on to something when you say it might be related to anxiety! When we are anxious, our brain is on the look out for danger or a problem that needs solving. It's like being on high alert - you end up with a lot of false alarms! Assuming someone might be addressing you falls very well into that category of danger/problem: for example, you might be anxious about getting into a fight (danger), or anxious about making a social error so you try to figure out if you need to respond (problem to solve), etc.


[System] Given the following post, respond as if you're commenting on Reddit:

[User] [The Evil Dead] Why does it sometimes take full dismemberment to put a Deadite down, and sometimes they go down to several shotgun blasts?

[Assistant] In ash vs the evil dead, the hot evil woman said something among the lines of "magic/evil doesn't follow conventional logic" so, it probably means that different deadites, different ways to kill, just like how they posses others in different ways.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
[Star Wars] Let's say I am a much less ethical Obi Wan. If I decide to clone Anakin after I discover the Kaminoan cloning operation, would that give me thousands of clones at the same level of force sensitivity?

 What if I just made one clone?  Would they be the same level of force sensitivity? Luke is also force sensitive, a giant like his father, and we are told in episode one that it's all because of the midichlorian count in a person's bloodstream.

[Assistant]
It seems like The Force tends to not like people interfering with it's design/will.

If Obi-Wan were to attempt to clone Anakin, it's more likely than not one of two things would happen.

1. The clones would not be Force-Sensitive. Like the earlier poster said, Rey's father was a Palpatine clone, but wasn't Force Sensitive.

2. The clones would be Force-Sensitive, but become horribly deformed and not make it to a viable stage in their development.

The Force would likely engineer a pushback on what Obi-Wan was trying to do as well.

We also see that beings don't take well to being infused with The Force via high-midichlorian count blood. All of the experiments the Imperial Scientist was attempting ended with failure.

It seems like Force Sensitivity is controlled by the Will of the Force itself, and the midichlorians are simply organelles that facilitate the communication with The Force, instead of being the thing that grants Force Sensitivity.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
Does social policy in modern democratic societies reflect the will of the people?

Specifically, within the UK and the USA, what theory or research is there that discusses this issue in more detail?

I'm interested in finding out about why policy in the UK and USA (as modern democratic examples) is a reflection of "the will of the people". Is it at all?

Are people in general too misinformed and ignorant about politics to understand the necessity and/or consequences of certain policies? And are certain policy areas more reflective of the 'will of the people' than others?

If anyone has any further insight into this issue, or could point me in the direction of further research, I'd really appreciate it.

[Assistant]
Bruce Bueno de Mesquita talks about this in his theory about the "selectorate" in *The Logic of Political Survival*. He basically says that all we can really expect from people in power is that they want to keep their jobs. To keep their jobs, they have to please a certain amount (the winning coalition) of the people who get any sort of say in the matter (the selectorate). In an authoritarian government, the winning coalition is very small. In a democracy, the winning coalition is large.

The theory helps to explain why the quality of life in democracies is usually higher than in similar-sized authoritarian countries. An authoritarian leader can maintain the support of his small winning coalition by providing private goods (money, goods, political or economic positions, etc).

A democratic leader, though, needs to maintain a much larger winning coalition--for example, the hypothetical winning coalition of the president of a direct democracy would be more than half of the voting population. Getting the support of that many people by providing them with private goods is next to impossible, so instead they provide public goods: roads, medical care, public services, etc. Basically, things everybody gets to enjoy. A politician who wants to keep his job will listen to the demands of his selectorate and try to pass social policy that will get enough support to form a winning coalition.

Of course, things are lots of "buts" when you look at how things play out in real life as opposed to in theory. For a US politician, for example, is the support of one millionaire more valuable than the support of one guy making minimum wage? How much more valuable? How many votes from minimum wage laborers are worth the number of votes that the influence of one millionaire can bring in? Do 100 millionaires contribute more to a politician's winning coalition than 100 factory workers? How about 1,000 factory workers? 10,000?

So, to answer your question, it's not so much that modern democracies elevate the will of the people and translate it into social policy, but more that modern democracies make politicians more beholden to their constituents. Politicians don't necessarily have to *listen* to the people, but they do have to make them happy.

Or at least that's what Bueno de Mesquita argues.


[System] Given the following post, respond as if you're commenting on Reddit:

[User] [Star Wars] Does the average citizen living on say, Coruscant think that Anakin Skywalker was a Jedi hero who was killed during the clone wars, and a separate person named Darth Vader is an enforcer for the Emperor who was killed during the Battle of Endor?

[Assistant]
Yes, precisely.

It is not until the events of the novel *Bloodline*, set in 28 ABY (24 years after Jedi, 6 years before The Force Awakens) that the galaxy learns Vader was Skywalker and that Luke and Leia were his children. Beforehand, it was thought that Skywalker died somehow at the end of the Clone Wars and that Padm Amidala died suddenly around the same time. Leia, who is well known around the galaxy as a politician, was thought to be an average war orphan whose biological parents died and who was adopted by the Organa family. Eventually, the real events surrounding Vader's history and the birth of Luke and Leia are revealed. Leia is initially persecuted for this given the horrible reputation Vader still has decades after his death.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
ELI5: How is a degree from a place like Harvard or Yale any different from a degree in the same subject from somewhere else?

Also, is it any different in the UK with universities like Oxford and Cambridge compared to lower ranked uni's?

[Assistant]
For starters, many of these places have good reputations because they have cutting edge research and the best academics who are at the forefront of their respective fields. It should be noted that this doesn't always translate to the best *teaching*, but that might well be beside the point.

Some economic theories of the value of education are that it is a signalling mechanism - that by getting a degree you can prove your competency/commitment to a potential employer (as opposed to actually making you a more valuable employee). With that in mind, a degree from a prestigious university indicates that you achieved their stringent entry requirements and put in the required work.

EDIT: people pointing out the importance of making good connections - definitely should not be underestimated.  But the fact is that this is both a cause and an effect of the University's prestigious status.  They feed into each other.


[System] Given the following post, respond as if you're commenting on Reddit:

[User] [ATLA] In season 2 , when Aang is trying to go into the Avatar state at will, he sees a giant black/dark version of himself holding a sphere. What is that sphere? Can Aang do the Kamehameha?

[Assistant]
Remember that this is a metaphysical soul journey. The symbolism of the impassive shape with the whole world in its hands vs the very mundane and real sound of Kataara screaming is what's important here.

The sphere is the Avatar's full power, a mass of energy that makes one impartial to the world. It's not a real sphere. It's a symbol for what choice aang must make.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
Why is the value of e, e?

I am talking about the natural constant. I am wondering why e shows up everywhere. Why is it that very different things resemble e? For example, continuous interest has e in its equation while the amount of electrons in a capacitor has a natural logarithm (log base e). Why is this so? I assume e is just a number just like pi is pi because it is.

[Assistant]
Quick and fairly easy answer: it comes up everywhere because it has the unique property that d e^x /dx = e^x.  The numerical value is an approximation to the limit that defines e, e^x = (1+x/n)^n, as n -> inf.  You can derive that definition if you solve the differential equation dy/dx = y by assuming y can be written as a power series Sum_i (c_i x^i), computing the coefficients recursively and showing that the series converges.

Expanding on the above, it comes up everywhere because it's the solution to a whole range of differential equations.  Simple examples: e^ax solves y' = ay, y'' = a^2 y, y''' = a^3 y etc.  More complicated cases are, let's say, riffs on this basic idea--that the derivatives of y depends somehow on y itself.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
[Futurama] Difference between murderology and murderonomy?

During the professors what-if machine simulations, Dr. Zoidberg states that he has mail order degrees in murderology AND murderonomy. What differentiates these two fields of study?

[Assistant]
"The suffix -logy means a branch of learning, or study of a particular subject. The suffix -nomy means a system of rules or laws, or body of knowledge of a particular subject."

I assume that means Murderology is the branch that covers the theory of murder as a social construct, while Murderonomy studies the practical effects around how it has affected society (and what society has done to 'solve' it).

Alternatively, Zoidberg got ripped off by the online school that tried to sell him two separate degrees that were actually the same thing.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
ELI5: How does headphone impedance work? Are harder to drive headphones objectively better?

A lot of premium headphones require a lot of amplification to be heard, and I don't get why that's the case when many other headphones sound great even though they have low impedance and can be driven by something like a phone.

[Assistant] High impedance headphones were designed for recording studios where a bunch of people would have their headphones plugged into one source.  The headphones were designed with high impedance so it wouldn't overload the amplifiers.  Because they were designed for recording studios they were by nature higher quality.  Audiophiles started using them for home use because they were higher quality.  There really isn't any reason why low impedance headphones can't match the quality of a high impedance headphone.


[System] Given the following post, respond as if you're commenting on Reddit:

[User] [Star Wars] "You want to go home & rethink your life" - does this Jedi Mind Trick have an inherently positive outcome regardless of the target's life/circumstances or could it lead to a more negative/evil outcome?

[Assistant]
It likely didn't have any outcome at all.  The mind trick isn't a long-term method of control, and it doesn't fundamentally change a person's personality.
The person in question likely exited the bar with an intent to go home and do some introspection, but by the time he got there he'd be back to his usual thought patterns, and any rethinking of his life and what directions it should take would be entirely of his own accord.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
[Dune] Were the Harkonnens always evil? Or was Vladimir just a bad apple?

I understand that 1) the Atreides and the Harkonnens have been feuding for generations, and 2) Vladimir Harkonnen is an especially cruel and treacherous man.

But even if there was a legitimate cause for multigenerational bad blood between two families, I don't see that requiring that one side is particularly evil. It just means that there was a grievance or some kind of inciting incident back in the day.

Were the prior heads of House Harkonnen as depraved as Baron Vladimir is now? And if the Harkonnens have actually been that heinous for generations, why are the Atreides the only house that seems to have a vendetta with them? Wouldn't they have made more enemies in the past?

[Assistant]
Evil is often in the eyes of the beholder, but the Harkonnen for generations were a House that prioritized their own interests as nobles, well above that of their people. Indeed, the people served to promote the lifestyle of the Harkonnen. If the average citizens got wealthy under that system, so be it. It just means more taxes for the House. *Everything* in their society was arranged to benefit the people at the top because that was their literally divine right as Nobles.

Meanwhile the Atredies, for generations felt that Nobility's main job was to provide a stable environment for the people to prosper. Now that meant the Nobility had to live life a certain way to maintain their readiness to fight and protect the people, and it also meant the people had a duty to support the House in a accordance to those needs, but it all comes down to allowing the people who serve House Atredies to be able to live their lives are freely as possible (as constrained by moral law) and to grow and prosper.

The end result is that both houses taxed their people, used those taxes to live a life of relative comfort and luxury, and to make war (or at least scheme) on other Houses. Both built large militaries, drafted troops, and engaged in conflict (with other Houses as well as each other, and sometimes their own cadet branches that decide to rebel). While it is fair to say that neither house has hands entirely clean of blood or oppression, the Harkonnen were bloodier by light years as that basic conceit of "All for One" meant taking every last bit of excess to fuel their lives, while the Artedies's belief on "One for All" meant protecting those weaker (admittedly, for a price).


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
Regression Toward the Mean versus Gambler's Fallacy: seriously, why don't these two conflict?

I understand both concepts very well, yet somehow I don't understand how they don't contradict one another. My understanding of the Gambler's Fallacy is that it has *nothing* to do with perspective-- just because you happen to see a coin land heads 20 times in a row doesn't impact how it will land the 21rst time.

Yet when we talk about statistical issues that come up through regression to the mean, it really seems like we are literally applying this Gambler's Fallacy. We saw a bottom or top skew on a normal distribution is likely in part due to random chance and we expect it to move toward the mean on subsequent measurements-- how is this not the same as saying we just got heads four times in a row and it's reasonable to expect that it will be more likely that we will get tails on the fifth attempt?

Somebody please help me out understanding where the difference is, my brain is going in circles.

[Assistant]
They both say that nothing special is happening.

If you have a fair coin, and you flip twenty heads in a row then the Gambler's Fallacy assumes that something special is happening and we're "storing" tails and so we become "due" for a tails. This is not the case as a tails is 50% likely during the next toss, as it has been and as it always will be.  If you have a fair coin and you flip twenty heads, then regression towards the mean says that because nothing special is happening that we can expect the next twenty flips to look more like what we should expect. Since getting 20 heads is very unlikely, we can expect that the next twenty will not be heads.

There are some subtle difference here. One is in which way these two things talk about overcompensating. The Gambler's Fallacy says that because of the past, the distribution itself has changed in order to balance itself out. Which is ridiculous. Regression towards the mean tells us not to overcompensate in the opposite direction. If we know that the coin is fair, then a string of twenty heads does not mean that the fair coin is just cursed to always going to pop out heads, but we should expect the next twenty to not be extreme.

The other main difference between these is the random variable in question. For the Gambler's Fallacy, we're looking at what happens with a single coin flip. For Regressions towards the Mean, in this situation, the random variable in question is the result we get from twenty flips. Twenty heads in a row means nothing for the Gambler's Fallacy, because we're just looking at each coin flip in isolation and so nothing actually changes. Since Regression towards the mean looks at twenty flips at a time, twenty heads in a row  is a very, very outlying instance and so we can just expect that the next twenty flips will be less extreme because the probability of it being less extreme than an extreme case is pretty big.


[System] Given the following post, respond as if you're commenting on Reddit:

[User] ELi5: When building tolerance to a substance, does your body get more efficient at removing it (reducing its affect) or do you subconsciously get better at managing the affects?

[Assistant] Depends on the drug. What happens with opioids, for example, is that your body will start reducing the number of dopamine receptors in your brain. When you take an opioid, it causes your brain to release more dopamine. With the increase of dopamine, your brain says "whoa! Sensory overload!" and starts to reduce the number of dopamine receptors that are available. So, in order to get the same effect, you need to take higher doses because you now have fewer dopamine receptors to stimulate, so you need to stimulate them more often. This is what we call "tolerance." Generally, tolerance is not due to increased removal of drug or increased enzyme production.


[System] Given the following post, respond as if you're commenting on Reddit:

[User] [Marvel] Why did the collector trade any part of the Infinity Gauntlet away? What could he possibly uptrade for?

[Assistant] The Collector has been known to trade things away to get other things...in *Thanos Quest*, the prequel that led in to *The Infinity Gauntlet* series in the comics, he traded his Infinity Gem (which, as far as he could tell, didn't do anything) in exchange for The Runner, a fellow Elder of the Universe who had been reduced to a baby by Thanos' use of the Time Gem. In this case, the Collector did screw up - but as Thanos demonstrated, it's because the gem he held was the Reality Gem, and you need a degree of imagination to use it.


[System] Given the following post, respond as if you're commenting on Reddit:

[User] ELI5: Why are tight rings so much harder to take off than they are to put on?

[Assistant] Lots of wrong answers here. Its because of your skin and the shape of your joints. Putting on a ring you are basically pulling your skin tight against your fingertip and pushing it up over the cleft of the joint.  It cant go very far so it doesnt form folds easily. Pulling off a ring your basically pulling on a lot more skin with no hard anchors nearby and it drops off over the cleft of your knuckle so it folds there and jams under the ring.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
ELI5: Why isn't there any skin colored tattoo ink that can be used to cover up bad tattoos?

Recently saw a picture of a woman who got a tattoo covered up by just getting a big black square tattoo over it. Why couldn't they do the same thing, but instead of using black ink, they use ink that matches her skin color?

[Assistant]
Tattoo artist here.  Tattoo ink isn't actually "ink", it's pigment in a carrier (usually sterilized water and alcohol), which means that when it goes into the skin, it's staining the skin at a depth where the skin heals (anything above that dies and falls off during the scabbing process).  Have you ever stained white fabric black?  Now try staining that black with a lighter colour... doesn't really work.  Mostly because the darker colour will still show up through the lighter colour.

*Edit*scabbing, not scanning.


[System] Given the following post, respond as if you're commenting on Reddit:

[User] [Star Wars/Ghostbusters] What would happen if the Ghostbusters tried to capture a Force Ghost? Would containment, even for a brief time be possible for them?

[Assistant] Probably.  Force Ghosts are just echoes in the Force left behind by powerful users.  We know that the Ghostbusters' equipment traps and contains beings composed of psychokinetic energy.  But what is "The Force" other than a "psychokinetic energy field" by another name?  The Ghostbusters' PKE meters should also read Force activity and detect Force Ghosts the same way they detect psychokinetic energy usage and entities.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
I think private schools should be abolished. CMV.

I live in the UK and would prefer a British perspective on this, if possible - I'm not familiar with the details of the US education system.

My problem with private, fee-charging schools is that they help to sustain inequality. As they charge fees they have more money per pupil, which should mean that the quality of the education provided is better. However, a child who goes to a private school and benefits from this education has not done a great deal to earn or deserve it - although they may have passed the entrance exam, their parents also need to be able to afford the fees. So children of the rich have a head start in life that allows them to get even richer, which they have done little to deserve. This makes society less meritocratic and decreases social mobility.

In addition, if rich and powerful people have an alternative to state schools, they do not have so much of an incentive to work towards improving these schools.

[Assistant]
Do you also believe that private microwaves, cell phones, food, cars should also be abolished, since they all cost money and richer people get better ones, thus increasing inequality?

Private schools are actually different from the above because they have more financial aid that public schools, so they actually allow some really strong social mobility.

Since when do children have to "deserve" something to be given it by their parents?

Whenever you even say "inequality" its unclear if you want to improve conditions of poor people (sounds good to me) or just bring rich people down (has never done any good in the history of the world).

Assuming you want to improve education of poor people: At the end of the day your narrative is that public schools don't improve or even change because  somebody doesn't have incentives. False. Public schools don't improve just because they are public. If they educate people better, it's not like a teacher is going to get a bonus. If they educate people poorly, the teacher will not get fired. There are no processes for improvements and looking for scapegoats never fixed anything either.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
[Starcraft,wh40k] How come the zerg swarm dont starve, like the nids do?

So, normal zerg get substance from creep, i get that. But how come the swarm as a whole can bunker down a planet, cover it in creep and buildings and living zerg, and not starve? One of the nids few weaknesses is that they are always starving, how come this is not a problem for the zerg? Sure, they eat from the creep, but what do the creep eat of?

[Assistant]
The Zerg don't starve, because they don't Consume, they Assimilate. When the Zerg take a planet, they convert it into a Zerg biosphere. There are Zerg Organism-Structures which go through photosynthesis to produce metabolic energy which sustains the Swarm, and a Zerg world like Char can sustain the Zerg indefinately, as the raw materials are just kept in constant circulation, sustained by the photosynthetic spires and Geothermal conversion.

The Zerg drive for expansion isn't for sustenance, but perfection. The Swarm is unable to Evolve on its own, and has to consume other genetic material to change. They seek it out and assimilate new DNA in order to try to acheive Perfection, and become the Xel'Naga.

The Tyranids, however, consume. They have no internal regulation, no stability. When they come to a new world, it's not to assimilate and create a new Hive, it's to strip it bare and move on. They also are not entirely beholden to consuming the genetic traits of others, and CAN evolve on their own.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
Is coughing an evolutionary advantage? If so, why do we try to suppress it with cough syrup ?

Coughing is the way our body tries to get rid of foreign bodies out of our lungs. I wonder why we should prevent our body to cough, even if it allows us to get rid of some virus. I understand that it slows down the spreading of the disease, however I don't understand, from an evolutionary point of view, why this feature was kept. If it is so disadvantageous, why would this trait survive ? If it's advantageous, why do we suppress it ?

[Assistant]
Coughing does aid in clearing the airways of particulate debris and mucus. It is a reflex mediated in part by the vagus nerve (CN X). However, coughing is violent and forceful and too much can be detrimental.

In many respiratory viral illnesses, the skin lining the airways is a target and port of entry. These skin cells can slough off the airways and mix with mucus and get coughed out of the lungs. However, when the skin sloughs off, it can expose nerve endings called J-fibers. These J-fibers can stimulate more cough, leading to more skin cells sloughing off and more exposed J-fibers and the process builds on itself in a positive feedback loop.

Additionally, coughing can be so violent that a person can break ribs, dislocate joints, suffer a pneumothorax or pneumonediastinum, or any number of unintended consequences.

Suppressing cough is typically done for comfort, and to allow the skin lining to calm down and heal after a viral illness, and to prevent any unwanted sequelae from uncontrolled cough.

Cough suppression is not without risk however, and can put a person at risk for secondary bacterial pneumonia or any number of other lung diseases. The choice to treat cough is a risk vs benefit calculation.


[System] Given the following post, respond as if you're commenting on Reddit:

[User] ELI5: What is the motivation for these hacker groups to keep taking down the Xbox live and the Playstation network?

[Assistant]
As many hacker groups put it, they usually do it "for the lulz".

In other words, they get a kick out of (pleasure/enjoyment from) causing destruction, chaos, and/or inconvenience to many people.

It satisfies their need for attention and to feel important -- as though they have accomplished something great (not great as in good, but rather great in the sense that it has a significant impact on people).

It's a similar reason why some people develop viruses that provide no monetary benefit to the developer (ones which merely cause significant annoyance or inconvenience for users that have been infected).

Sometimes these attacks are targeted though in the sense that they are motivated by certain ideologies or political beliefs (e.g. maybe the hacker/group views Microsoft or Sony as the enemy because they are doing something [or have done something] the hacker/group doesn't agree with).


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
Which programming language do automated factories use?

I know they're not common right now, but it seems they will be in the coming decades. I think I should try and learn the language(s) that are used in them, so that i'm ready for the changes they bring.

[Assistant]
1) automated factories are quite common....almost every manufacturing process involves some amount of automation
2) the languages are specific to the manufacturer of a particular tool....many of them involve commands such as

> move tool to (3,7,1)
> spin drill
> wait 2 seconds
> stop drill

in short, there is no one language that is used, and most of them are proprietary, and not worth wasting your time learning until you are on a job that requires it.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
ELI5:Why are textbooks so expensive in the United States and why hasn't this been remedied?

I'm studying at university in the United Kingdom and have friends in the US who complain a lot about the textbooks they have to buy and the cost of them. The costs seem absurd.

I compare this against the UK where I haven't had to buy a single book for a three year course in Physics and Philosophy at a prestigious university. I'd estimate that 70% of my required reading for all my modules is available free online through my library membership and the other 30% can be borrowed from my library.

Do americans not use libraries (I doubt this is the case) or are they not available?

A few of my books say on them "For sale only in Europe, Africa, Australia and Asia" which leads me to believe that for some legal reason they can't be sold in North America. Why would this be the case?

[Assistant]
Price discrimination by the publishers. They can sell higher in the US, so they do. A budget for textbooks is included in any US university's financial aid packages, student loans, etc.

There is also an aspect of subsidy going on; textbooks can be sold internationally much more cheaply in part because they're being covered by the high revenue from the US.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
Why do males have two testicals as opposed to one?

Is there any benefit to having two? Why have we evolved to have two, and not just one?

[Assistant] Bilateral symmetry. Humans, at least, begin life as female in the womb. After a certain point of development, If you are meant to be male, you differentiate into a male. Labia fuse to form the scrotum, ovaries differentiate into testes, and the clitoris becomes a penis.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
[Dune] What were the Bene Gesserit planning to do with the Kwisatz Haderach?

They were working on their breeding program for ages (decades? Centuries? Millennia?) with the goal of producing the Kwisatz Haderach, a male Bene Gesserit. When it happened early, they failed to control him and even though they continued their breeding program, were very careful not to produce one again.

But what did they want him for, anyway? How were they going to use him? What kind of powers were they expecting him to have?

[Assistant] Had they been able to control him, they'd have used him to shape the world to what they considered ideal.  Really the only difference between their plan and the Golden Path was a difference of opinion as to goals.


[System] Given the following post, respond as if you're commenting on Reddit:

[User] ELI5: How is venom used in making anti-venom?

[Assistant] You inject venom into an animal like a horse, who is big enough and strong enough to survive the injection.  Their body produces antibodies to attack and destroy the venom.  You pull some blood, extract the antibodies, and then infect them into humans as needed.


[System] Given the following post, respond as if you're commenting on Reddit:

[User] [Marvel Cinematic Universe] In Thor 2 why did the Dark Elf soldiers have guns but the Asgardians use spears and shields? Especially as the guards for the royal palace.

[Assistant] Asgardians can easily shrug off fire from most guns.  It takes something much more powerful to even phase someone like Thor, a blast from the destroyer or a weapon powered by the tesseract for example.   So most of the time it takes Asgardian strenth to overcome Asgardian durability.  A significantly durable sword still works as a strength mutliplier if weilded by an Asgardian.


[System] Given the following post, respond as if you're commenting on Reddit:

[User] [Star Wars] Why did Vader sense Kenobi's presence, but not Luke's? Surely someone with that much potential with the force would cause a disturbance? Plus it was his son. Even though he didn't know that he had a son, wouldn't that disturbance be unique?

[Assistant] Vader knows what Obi Wans presence in the force feels like.  He was around it for most of his life.  Luke is someone pretty much unknown to him.  When Vader felt a large force presence on the Death Star he instantly recognised Obi Wan.  The addition force presence he probably just chalked up to Obi-wan having become more powerful and changing since the last time he saw him.


[System] Given the following post, respond as if you're commenting on Reddit:

[User] ELI5: Why is it ok to watch a sunrise/sunset but its not okay to look directly at the sun?

[Assistant] During the sunrise and sunset, less of the sun's rays are shining on your location, and they travel through more air to reach you. This causes the beams into change to a less harmful intensity, and allows you to look properly at the sun.


[System] Given the following post, respond as if you're commenting on Reddit:

[User] ELI5: Why in so many parts of the world are salt and pepper the ultimate and preferred condiment and seasoning?

[Assistant]
If you are curious about salt get the book Salt by Mark Kurlansky and prepare to have your mind blown.

Salt was not as abundant as it is today and it used to be much more valuable. Cities were built on the salt trade, people were paid in salt (ie the phrase "he is worth his salt", also the word salary is derived from the Latin sal meaning salt), you could not go to war without salt.

Salt is why Chinese brine extractors were drilling bore holes thousands of feet down 500 years before the first oil well in America was drilled at just 60ft.

People in England proudly lay waste to the landscape, pulling brine from underground untill sink holes started appearing, boiling it untill the skies were black from soot, in pursuit of the purest, whitest, finest salt.

Every fisherman was also a salt farmer. Months on end farming salt in the heat of the tropics, then sailing to far away seas near lands unknown where fish were so plentiful they could be scooped out by bucket.

Today things are the opposite. White salt is almost freely available where impure salt (eg. pink himalayan salt) is highly prized. Salt isn't needed for fishing anymore but fish are scarce.

Its really an interesting book and you won't look at the salt shaker in the same way again!

Dono about pepper.

Edit: to actually answer the question:
Firstly, salt intensifies the flavour of your food, so it makes sense to keep it where you eat.

Secondly, as mentioned salt used to be very valuable so keeping salt on the table was also a display of wealth. It was sometimes kept in ornate dishes and handled with special customs.

Some cultures do not have salt at the table or even use it directly in cooking. Much of Asia uses salty sauces such as Soy sauce or fish sauce.

Dono about pepper.

Edit 2: since this has ballooned - salt was so valuable for two reasons:

 1. If you didn't have a cold storage place or it wasn't winter, meats and vegetables had to be salted to stop them going rotten. Therefore a large portion of food had to be salted, especially for campaigning armies or navy ships where even fresh food was hard to access. Nowadays  we have much less demand for salt due to refrigeration and canning/packaging technology/freeze dry etc.

2. Salt is not easy to make or get to. Sea water is only 3.5% salt and evaporation take a long time. Boiling it takes a lot of fuel. Salt is corrosive and will damage your metal containers.

Satisfying the huge demand for salt with limited production capacity means it had high value. Supply and demand people!

Please stop asking about pepper.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
[GOT] "They are dragons, Khaleesi, they can never be tamed" But somehow they can be ridden?

Title pretty much says it all.

I'm just a show-watcher (grad student, no time for reading the books), and up until recently, been imagining Dany and her nuclear dinosaurs returning to Westeros and burning/eating certain vile assholes alive.

The problem I have: Ser Jorah keeps telling Dany that dragons can never be tamed, but we KNOW that Targaryans (sp?) used to ride them into battle AND keep them just chilling around the Red Keep, which sounds pretty tame to me. How do these two things reconcile with each other?

[Assistant]
They can be trained, but not tamed.  Like a lion or a wolf, you can teach it to follow commands but you can not truly know its heart.  It will never be a dependable companion like the family dog.

Also, Jorah Mormont may not know jack shit.  He's not really the most authoritative source on anything except for current events... Westeros Weekly sort of stuff.  He is highborn and educated, but he doesn't know any more about dragons than any other nobleman.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
(Independence Day) How did the governments of Earth rebuild their nations after the alien invasion?

and what did they do with all of those city sized motherships that crashed?

[Assistant]
Rebuilding a city from a big blast is not an insurmountable task - Japan's done it twice.

Many cities also mounted evacuations that saved a large number of citizens, and while the supply chain was certainly disrupted, the fact that the aliens attacked the cities with (seemingly) non-nuclear attacks means that there is no fallout, and that farms will still operate - so the refugees won't necessarily starve. (The bigger problem is that many cities attacked were port cities - it's easier to ship grain overseas than it is over rails.)

As far as the ships, the military forces would establish a security cordon and start investigations. The United States would have a leg-up, since the ship crashed in the middle of an inhospitable desert right next to an advanced research facility, and the only two living humans who are extremely familiar with the technology - a programmer and a pilot with direct hands-on experience. We can reasonably expect the USAF to have undisputed air superiority for decades to follow.

It remains to be seen whether there are going to be any biological consequences - ships of that size might have had members with the sniffles, and who knows how that's going to react with our biology. We're pretty different from the invaders, so their bacteria and viruses probably won't even notice us and vice versa, but the only people who know for sure are in Area 51.


[System] Given the following post, respond as if you're commenting on Reddit:

[User] [Game of Thrones] How do you beat dothraki on an open field ?

[Assistant] Unlimted numbers of raving undead that feel no pain and fight until utterly destroyed. Add in a flying undead dragon for air support and the ability to raise dead Dothraki to fight their former comrades.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
If I cloned a tortie, calico, or spotted cat, would the colors appear in the same place on the clone or would it be random?

PS I have a good background in cat coat genetics, but I don't exactly understand how the x-linked inactivation works.

[Assistant] I can oy answer about the calico. The spots from calico cats come from something called the Lyon hypothesis. What happens is that in every cell one of the X chromosomes is inactivated by bar bodies and a gene for hair color is on the x chromosome in cats. So in every cell there is basically a 50/50 chance of which X chromosome will be expressed. This is why only female cats are calicoes by the way. Hope this helps!


[System] Given the following post, respond as if you're commenting on Reddit:

[User] Are new galaxies still forming? If not does that mean there are only a finite number of galaxies that can form?

[Assistant]
New galaxies are not forming. Galaxy formation occurred in the first few billion years of the universe. During this phase, dark matter halos caused matter to collapse in them, forming galaxies. Each halo formed an associated galaxy (we think), and after some time the universe had expanded sufficiently so that expansion counteracted gravitational collapse.

However, most of the atoms in the universe are still out there in the intergalactic medium, having never fallen into gravitational potentials and thus never been able to form galaxies. So the limits on galaxy formation are due more to cosmological constraints (how fast the universe expands and thus how fast its density decreases) than to limits on how much matter there is to make galaxies.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
What makes pigeons bob their head so violently when they walk?

Is this an anatomical phenomenon (their head physically must bob for them to walk) or a conscious effort by the pigeon? It just looks so funny and I'm wondering why they evolved this way.

[Assistant] Their eyes don't correct for motion very well so they compensate for this by keeping their heads still for as long as they can, moving their heads forward and *then* their bodies so their eyesight is more stable.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
Rabies is a disease with (untreated) near-100% fatality and a prolonged transmissible period. How is it contained in the animal kingdom?

Rabies is near-universally fatal unless treated early, at least in humans. In animals such as canines, it also provokes aggression and attacking others, which helps spread the disease, over a prolonged period of time and with an easy infection vector.

Diseases are generally thought to fall on the mortality-transmissibility curve, where highly lethal diseases generally kill the host before many others are infected, while highly infectious diseases are usually less lethal, with both ends of the curve limiting the diseases' destructiveness at the species level. Rabies, however, seems to be strong in both categories. What stops it from completely decimating every species it targets?

[Assistant]
> with an easy infection vector.

It's actually not a very easy infection vector.  Spread by respiratory droplets or through contaminated water is an easy infection vector, requiring one animal to have to actually get physically bitten by another is actually a pretty difficult infection vector, since most animals will go out of their way to not get bitten.  Furthermore, in any aggressive alteraction there's a significant chance that either the rabid animal or the bitten animal will die outright of other causes, which reduces further spread.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
CMV: all drugs should be legalized, manufactured, and available for public use.

My view here stems from 2 ideals, a personal one and a logical one. The more succinct ideal is a personal view that it is not, nor should ever be up to the government to decide what I can or can't do to my body.
My logical (and more detailed) part of this view is on how society would benefit. Drugs are currently being used at a staggering rate. And yet these drugs are illegal. As prohibition of alcohol has shown us, making something illegal doesn't erase the market, but instead creates a black market for that product. With black markets come crime, corruption and violence which adds stress on our healthcare and justice systems. As well, overdose due to drugs cut with unknown and dangerous substances and the spread of diseases through sharing needles is an epidemic that is a further tax on our healthcare system. By manufacturing these drugs and having them available for public consumption we could eliminate the spread of diseases, and prevent overdoses by controlling the whole process of drug addiction. And by this extent we're able to even help people out of addiction, instead of letting them fend for themselves.

[Assistant]
Available how? Are we talking corner grocery stores and super markets?

Also, lets not say all drugs please. People do not need easier access to roofies, to fentanyl, to carfentanyl, and to untested and dangerous synthetics like K2 and smiley.


[System] Given the following post, respond as if you're commenting on Reddit:

[User] How did scientists think the sun worked before the discovery of nuclear fusion?

[Assistant]
In the 19th century, Lord Kelvin (the one the temperature's named after), thought the sun emitted light and heat through gravitational contraction. The sun's gravity would move all matter closer to the core, thereby decreasing their potential energy and releasing energy in some form.

Calculations based on this 'determined' that the sun was about a hundred million years old, and definitely no older than half a billion years, which was already disputable in his own time (geologists were much closer to the actual value in their conclusions).


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
ELI5: What happens when digital money is stolen? How is it moved to a different bank account? And more importantly why can't some hacker just "create" money instead of moving it?

As asked by someone, by "digital money" I mean the financial report kept in a bank, not cryptocurrencies.

[Assistant]
Creating money is much easier to spot if the banks are running their systems properly. Banks don't just create money (disclaimer; sometimes they kind of do) - so whenever they have money going into an account it must have come out of an account somewhere.

Even if you are paying in physical cash to a bank, the total cash brought in can be compared to the total 'digital' money added to make sure they are the same.

So if you have created money there will be an error somewhere when the bank 'reconciles' its records. Which means the bank knows quite quickly that something has gone wrong and may look into it.

It it much easier to create fake payments, so move money from one account to another account. That way the bank doesn't know anything wrong happened - the only person who can tell is the other account holder, and it is on them to prove they didn't authorise the payment.

---------------

As to where it goes [disclaimer; not a bank thief]; yes, you'd move it into a different bank account. Ideally then into another bank account, maybe at another bank, maybe move it through joint accounts or mixed with other money, trying to 'launder' it as much as possible, and hopefully get it to a bank that is in a different jurisdiction to the original one and has strict rules on privacy (the classic "offshore bank accounts" or "numbered accounts" where not even the bank has records of who owns the account).

The idea is to get the money either somewhere it can't be 'traced' (either practically or legally) or get it out of the banking system before anyone spots that it has been stolen.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
ELI5 if we managed to clone a sheep 20 years ago, why has so little progress happened since then with?

Cloning seems like it has the potential to cure disabilities and diseases, and also make farming easier. With so many potential uses why is it that nothing major has happened since Dolly the sheep?

[Assistant]
First off, in terms of farming, plants are cloned all the time. It's amazingly easy, just take a cutting and keep it alive and it'll will grow roots and become a new plant which is a clone of the original.

Cloning technology is alive and well, and making a positive therapeutic impact in modern medicine. We haven't gotten to the point of growing a new liver in the lab for transplant yet (we'll get there!), but one great example is an anticancer treatment called CAR T-cells. Killer T-cells are one of the immune defenses which kill invading pathogens. We can extract T-cells from a cancer patient, genetically modify them to enhance their ability to fight cancer, then clone the new T-cells and reintroduce them into the patient. These treatments are TREMENDOUSLY powerful, so much so that the primary side effects relate to them being TOO effective. These are most effective in blood cancers but researchers are working on making them effective against solid tumors as well. Many, many patients have been completely cured with what would have been a death sentence a few decades ago!


[System] Given the following post, respond as if you're commenting on Reddit:

[User] ELI5: Why does my phone screen not respond to pressing when my finger is wet?

[Assistant]
Phone touch screens work (well modern ones) based on capacitance. That is a build up of charge between two conductive materials with an insulator in between. So when you touch the glass with anything conductive (your finger and water included) a small amount of charge builds up on the object you touched it with and on a conductor on the other side of the glass where you are touching it. This is how the phone knows when and where you touch it.

When you have wet hands, you inevitably get other parts of the screen other than where you are touching wet. The phone doesn't know what is your finger and what is water. All it knows is it is being touched in multiple places. The results is kind of like you smashing your palm all over it, and you can imagine that doesn't work well.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
Is empathy a prerequisite to being a therapist?

Do good therapists exist that have low empathy?

[Assistant]
Speaking as a currently practicing mental health therapist, empathy is essential. If you cannot empathize with the position your clients find themselves in, your clients will notice. That will affect their ability to trust you, which in turn affects the working relationship.

That said, it is also essential to learn how to compartmentalize. Otherwise you're going to get burned out very quickly, and then you will also not be able to treat your clients effectively.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
[MCU] Could Tony have at least tried to survive his snap?

His armor was degrading rapidly protecting him from the stones' energy so they could handle it at least for a very short time. Would it have mattered if he put his helmet back on or used his energy shield in some way to block the radiation? I realize it's unlikely, but he is someone that leaves nothing to chance so why wouldn't he have taken every precaution to increase his chances for survival?

[Assistant]
Thanos was using a magical dwarven gauntlet specifically built to harness the power of the six stones, and he still went out with his left arm barely usable.

Tony did not have a special device and he was a mere human. The moment the six stones were connected he already was on a one way ticket to the afterlife.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
[Hitchhiker's Guide] How do I fix an Infinite Improbability Drive?

Ok so I'm kind of panicking right now, because I borrowed my semi-half-cousin's ship, which happens to have one of those fancy-shmancy new Infinite Improbability Drives in it, and took it out for a spin around Vogon territory. I guess they didn't like that very much, though, because they tried to blow me up. I escaped, but one of their shots blew a hole in the room with the Infinite Improbability Drive in it, and now the Drive won't work. Please help! How do I fix it?

[Assistant]
The thing about Improbability drives is that they're not actually that Improbable when you don't have them powered up. So, unfortunately, it's impossible to make repairs to it using improbable methods if the IID is non-functional.

However, it's very likely that your semi-half-cousin still has it on warranty!

So, really, you have three options. Option One: Explain to your cousin what happened and see if his insurance will take care of it if his warranty isn't active. You may be in for a long, chilly ride home, but it's more reliable than Option Two. However, if it doesn't work... Well, Option Two is going to be your best bet.

Option Two: Find someone else with an IID and convince them to activate it with your semi-half-cousin's ship around, working on the improbable outcome that your IID will repair itself. This can be a lot trickier, with some nastier possible side-effects on top of the difficulty of finding another IID-user willing to help you. If this doesn't work, you're basically stuck with the final possible option.

Option Three: Wait until the ship is repaired, then use it to go back in time and fulfill Option Two yourself.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
Why does CO2 only reflect heat back at the earth?

Shouldn't CO2 also reflect heat back at the sun, as well as back at the planet? Or is there something else?

[Assistant] The energy coming from the sun comes at frequencies that can pass through the atmosphere (visible light, UV, etc.). The earth re-emits the energy, but at a lower frequency (infrared). The lower frequency radiation is absorbed by the atmosphere.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
Steven Hawking once set up an experiment too disprove the idea of time travel becoming real by hosting a party, and only telling people the day after

What ways can this experiment be debunked?

[Assistant] Its not really an experiment that proves anything one way or another so theres nothing really to debunk. If time travelers had shown up then that would be proof that time travel is possible. But since nobody showed up we dont learn anything one way or another.


[System] Given the following post, respond as if you're commenting on Reddit:

[User] [Daredevil] There's blindfolded man screwing up business in Hell's Kitchen. Anyone know a blind guy in his 20s-30s, that had some fighting training, living in a 10 block radius?

[Assistant]
Pffft...the mask is *see through* you idiot. Which is easier to believe?

1. Dude has a see-through mask or
2. Dude is blind and somehow manages to fight like that?

C'mon man, pull your head out of your ass.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
[Masters of the Universe] So...what exactly is Skeletor?

I mean...is he just a guy in a skull mask? A demon? A possessed Halloween costume? He seems to like spandex to show off his muscle tone but I haven't the foggiest what he actually LOOKS like under that getup.

[Assistant] Skeletor was once Keldor, brother of King Randor, and Prince Adam's uncle. He wanted the power of Greyskull for himself, and rebelled against his brother's rule. His face was disfigured by a vial of corrosive liquid during an attack on the Hall of Wisdom. Keldor was brought to Hordak, an interdimensional demon, who agreed to save Keldor's life in return for a pledge of service. He does uphold his bargain, but burns all the flesh from Keldor's face and renames him Skeletor.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
What is the science behind the Gauss rifle?

Im learning about magnetic accelerators and a topic came up about their uses in the military and new-era tech. I understand how it works and builds but, what is the science behind such a design?

[Assistant]
A gauss rifle is also known as a coil gun, since it uses electromagnetic forces from a coil of wire to push or pull projectiles. There are two types, ferromagnetic and electrodynamic.

In a ferromagnetic coil gun, the coils pull on the projectile. A ferromagnetic circuit wants to minimize air gaps when there is a current flow, so the projectile experiences a force to be inside the coil. When the projectile is in the center of the coil, the coil is turned off and the projectile momentum carries it forward. The projectile must be made of a ferromagnetic material, like iron.

In an electrodynamic coil gun pushes a conductive projectile using the skin effect. Rapidly changing currents must slowly soak in to any conductor, which is why AC transmission lines cannot be arbitrarily thick and contain many parallel conductors. If a conductor is near a coil that has a rapidly changing current flow, it will be repelled. In this type of coil gun, the coil is located slightly behind the projectile, and pushes it away. The projectile must be conductive, and is commonly Aluminum or Copper.

Both types can contain multiple stages, where the projectile location in the barrel is measured, and the coils are fired in a useful sequence.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
[jaws] how did they know that this was the real shark?

when they left to get the shark, how did they know, what was the exact shark, among the thousands that exist, in the middle of all this ocean?

[Assistant]
It was the right size, and due to territoriality, the possibility of there being any other sharks even remotely of the right size anywhere even remotely close to Amity with *that* beast swimming around were vanishingly small.

IOW, they didn't actually have definitive proof, but it was a pretty damn good probability that they were right.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
[Star Wars]Where is Ahsoka during Episode 3?

I've watched some of Clone Wars, but never finished it.  How do they explain her absence in Ep 3?  She's not dead since she's in Rebels.  So what gives?

[Assistant]
Spoilers below, but it's the only way to answer your question.

In fact, her absense makes the descent into Darth Vader make even more sense. In Season 5, she is framed as a terrorist and all of the Jedi except for Anakin believe that she is a traitor, don't investigate it any further, vote her kicked out of the Jedi and are about to turn her over to be made an example of.  Anakin eventually proves her innocence, both both of them are resentful toward the Jedi for not even trying.  She is offered immediate promotion to full Jedi because of what she went through, but quits in disgust and want nothing more to do with Jedi after that.

This in turn causes Anakin to resent and distrust the Jedi, expecially the Jedi Council, which does play into Episode 3.


[System] Given the following post, respond as if you're commenting on Reddit:

[User] [WH40k] Does it realy make sense to give worlds a special task (Forgeworlds, Hiveworlds, etc.) instead of dumping everything on one planet?

[Assistant]
Yes, for various reasons. When you can't produce enough product in your workshop, you build a factory. When you can't produce enough product in a factory, you build an industrial park etc. You keep everything from the factory lines to the labourers in one place so nothing has to travel far and that way you maximise output.

At the scale where the imperium needs product, it makes sense to dedicate entire planets to industry or some other purpose.

To nuance it a little, no every planet is mono purpose. The imperium contains millions of inhabited worlds with an unimaginable diversity. Some are at a stone age level, others are virtual utopias and everything in between.

Some worlds however have such a unique character that it would be a waste to use them for anything else. Let's say there's a world that has a perfectly habitable atmosphere and it's wedged between suns at a distance that gives it a temperate climate an daylight almost around the clock.

Are you going to shove it full of cities or are you going to make the most of all that sunlight and grow 4 planet sized harvests a year?

If you find a planet that is almost entirely composed of minerals with no biomass whatsoever. Are you going to terraform it and go through tremendous effort and expense to turn it more 'earth like' or are you going going to capitalise on all those valuable minerals to make it a planet sized factory
line?

Hives are another good example. Hive worlds aren't build intentionally. It's just what you get after thousands of years of 40k style urban development. The cities keep getting bigger, the planet keeps getting more ruined. In the end you just have a planet with nothing more than massive urban centers in toxic wastelands.

But yeah, in short it does make sense to have a smaller number of hugely productive industrial worlds with a massive product output than it does trying to collect a little bit of output from millions of worlds and redistributing that.

It's not like every 40k world is self sufficient. Even though plenty are (millions of worlds, staggering diversity remember).


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
ELI5:How did two different forms of genitalia evolve? What is the advantage of having males and females?

I've always wondered how two things so complicated were created to work together and what advantage there is to prevent the organism from mating with half the population?

[Assistant]
There are thought to be two main reasons why there are two genders, the first is the more commonly known reason, the sharing and mixing of genetic material. If two individuals combine their genetic material they can allow for more variation, and try more possibilities, making it easier and faster to adapt and evolve in the long term, where as if any two individuals can mate it promites inbreeding and less diversity, as the nearest viable mate is normally a relative. It's also a great advantage if there are two competing groups each with different, advantageous mutations - by mating, members othe two groups can give their offpsring *both* mutations, instead of the mutations having to compete, and one eventually dying out and being lost.

The main reason why there are only two genders in most (arguably all) animal species is likely that adding extra genders does not improve the efficiency of the process - it's a lot harder to gather together three individuals, all ready to mate and all of different genders, where are the increased genetic diversity it offers is very limited - you're adding 50% more new genetic material (less when you consider that the third individual probably shares a lot of genes with at least one of the others), but making the process drastically harder. It could have been possible to evolve multiple genders which each needed only one other gender to reproduce with, but this requires additional sexual organs, and would naturally tend to lead to asexual (reproducing without any help) or hermaphroditic (both genders at once, and able to mate with any other individual) species.

Another factor which probably played a large role is the difficulty of evolving a third gender - evolution works in tiny increments, and each change must be beneficial, or come with other beneficial changes, to be passed on often enough that it spreads through the population, meaning that it would be extremely difficult for extra genders to evolve in large, complex organisms that reproduce in the manner we do.

Finally, the other reason why we think there are two genders (and not more or none), is mitochonrial DNA, a type of genetic material found outside the nucleus of the cell,  in the mitochondria (thought to have been added to cells around 2 billion years ago by bacterial infections), which also produce energy for the cell. This genetic material has the ability to copy itself very rapidly. Mitochondrial DNA may in fact be responsible for making extra genders a disadvantage but at least two genders neccessary, as any mutation in the mitochondrial DNA can be passed on far more often than mutations in the nuclear DNA, meaning that if an individual picked up a very harmful trait it could rapidly destroy the whole species - male and female genders are thought to have evolved as a stopgap to prevent this, as mitochondrial DNA is only inherited from the mother and not the father (limiting how much of it is passed on), preventing it from spreading out of control and limiting the ability of the individual with the harmful mutation to flood their offspring with the same mutations.

It is worth noting however, that some scientists argue that some types of shrimp and ants have what can be viewed as extra genders, and funghi can have as many as 36,000 (interestingly, funghi do not exchange mitochondrial DNA, which may be why they are able to have so many genders without suffering disasterous effects).


[System] Given the following post, respond as if you're commenting on Reddit:

[User] ELI5:Why did our so call 'Western culture' suddenly stop eating insects after relying on them as a major source of nutrients for most of our species' evolutionary history?

[Assistant] Because keeping a flock of chickens and some wheat is a lot more convenient and tasty than tracking down a bunch of crickets. Europe also has fewer very large insect species than areas like southeast Asia, so it's harder to live off of bugs.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
ELI5 : how do we know what's under the crust?

How to we know what the layers of earth are? I've learnt in primary school that underneath the crust is the mantle, then the outer and inner core, but how can we prove this if we have never dug below the crust?

[Assistant]
By looking at the stuff that bubbles up through features like volcanoes.

We can also use data from seismic measurements around the world. As the energy produced by earthquakes moves it will deflect as it goes through areas of different density. By collecting data from all over the world we can get a pretty good idea of the depths of different layers.

We can also measure meteorites in our solar system older than the earth's crust to get an idea of the likely composition of the earth.


[System] Given the following post, respond as if you're commenting on Reddit:

[User] ELI5: What is the difference between socialism and Communism and why do we Americans fear it so much?

[Assistant]
Both Socialism and Communism at their core advocate one thing and that is the ownership of the means of production by large groups or "the people" instead of individuals. Where they differ is in severity.

Socialism advocates that profits from a business enterprise be redistributed among all the workers equally. The idea is that all the workers own the enterprise equally because everyone is equal. Taken to a greater level, at the level of the state, socialism advocates that everyone should have access to the basics such as food water and shelter. These should be provided for by large scale industries because they are in fact collective efforts from many different facets of society. Socialism can be applied to varying degrees. For example, many say programs like medicare, medicaid, social security, welfare, and other such safety nets are socialist programs. These programs are ones that apply the socialist concepts of trying to redistribute wealth. Socialism, unlike communism, can be used in conjunction with capitalism to create a society where individuals strive to make their own profits, but will be provided for in the even of the eventual economic downturns caused by capitalism.

Communism takes it farther and is kind of a theoretical end result of socialism over time. The theory is that over time a socialist society will lead to a state where social classes don't exist. There will be no concept of rich and poor or strong and weak. Every industry and all things produced in the state will be owned equally by everyone and profits from production will be redistributed equally among the populace. How this occurs is a point of contention among many different theorists. Just like democracy isn't the same everywhere, communism differs from country to country. True communism, the kind that the original guy Marx wrote about, requires a huge abundance in resources caused by an increase in the level of technology. He argued that with abundance comes equality. Russian communism called for a strong central government that forced equality to happen. Chinese communism also differed slightly in the sense that they organized people into distinct economic entities where everything produced by that one entity was shared causing equality among those groups, but not equality overall.

The reason why Americans are so scared of it is that it's a remnant from the cold war. Russia and the United States during the period between the 1950s-early 1990s were consistently in a state where war could break out at any point. Instead of all out war which would have been devastating for the rest of the world (nuclear war), Russia and the United States fought proxy wars with each other by trying to coerce other countries into accepting their ideologies. Russia was a communist country and the United States was a capitalist country. Countries that share the same economic/political ideology tended to be allies with one another. In a way, the cold war was about who could amass the most allies against the other. A bunch of propaganda was ran by the United States that depicted communists as evil or trying to end the way of life in the United States, so that has carried over all the way to today.

Americans are scared of socialism because of an entirely different reason. Most people who are scared of it don't actually know what it means. We already have many socialist programs in the United States and they work pretty well. Most people who are scared of it are scared by the word and the fear mongering that happens due to politicians, specifically in the republican party, demonizing the word as a weapon to be used against their opponents. In reality, there are many very successful societies that have incorporated socialist practices to larger degrees than the United States and seen large amounts of growth in the economy and the standard of living. Germany, The UK, Australia, New Zealand, France, Switzerland, and many more are far more socialist than the United States and have greater qualities of life than the U.S.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
ELI5 Why can't I use one credit card to pay off another?

If the balance was kept low and paid off every month, couldn't the money keep rebounding between the two?

[Assistant]
You can.  Credit card companies assess a fee for paying off other credit cards.  If the fee is less than your total savings from going from a higher-interest card to a lower-interest card, it might make sense to do this.

You cannot use one credit card to make the payment on another credit card, though.  That's called "robbing Peter to pay Paul."  Eventually, you'll hit your limits on both cards, and you'll be insolvent.

Edit: had to change a "to" to a "from"


[System] Given the following post, respond as if you're commenting on Reddit:

[User] ELI5: Why do spears for fishing typically have 3 prongs?

[Assistant]
Such as a trident?

Typically because fish are lateral and linear.  Three points broadly struck prevent the fish from gaining enough momentum to wiggle free.

1 or 2, and a fish coukd still.throw its weight back and forth.  3 stabilizes the fish, preventing this.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
ELI5: Why, in documentaries about drug users, do the people using drugs not get arrested once the police see the video?

It seems like video of the person doing the drug is ample evidence that they are doing it, right? Why can't the police just be like "oi! get in jail"

[Assistant]
Several reasons, including the fact that there's no way to prove conclusively what they're smoking, swallowing or injecting. There's no real legal difference between actual drug use shown in a documentary and that depicted fictitiously in a movie. There's no way to tell them apart.

There's also often uncertainty about when or where the use happened.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
[Marvel] How does Rocket know who Jackson Pollock is?

I mean... He's a friggin racoon.

[Assistant]
And he's not from Earth and probably never had been on Earth and possibly had never even **HEARD** of Earth.  Nor had any of the others who got the joke.

However, to facilitate better communications the universal translators they use also include cultural databases and can offer brief explanations (and comparisons to similar things/people/events/etc from the listener's culture) when needed.

So the people on the ship didn't hear a reference to Jackson Pollock, they heard a reference to an artist they were familiar with who did similar work. In fact, since none of the people hearing the joke shared a cultural background every one of them heard a different artist referenced.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
Its the current instability from the coronavirus a supply shock? If so, why is the fed cutting rates?

I thought cutting rates during a supply shock was inflationary and not effective. Thats why stagflation happened. Am I wrong?

[Assistant]
The coronavirus has elements of both an aggregate demand and an aggregate supply shock.

On the supply side, there are the blunt and direct effects of reduced supply of imports to the US from China and an associated rise in the relative price of imports.

On the demand side, the coronavirus is causing people to cut back on current spending.

At minimum, the Fed would like to neutralize the adverse effects of the coronavirus on aggregate demand.  Once that's done, the Fed's response to the supply-side effect depends on whether the Fed is more concerned about output stability or price stability.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
Plants know which way to grow because of gravity , so what happens if we plant one in space ?

Do roots grow in all directions , or do they grow in a random direction which could make the plant grow in the ground , and the root going upward ( I consider upward is out of earth)

[Assistant]
Yes. There are many videos of botanical experiments on the ISS.

IIRV they look like a jumbled mess because the hormones that tell a plants parts to grow with or against gravity, like the roots and leaves, are not able to detect which direction they should be growing.


[System] Given the following post, respond as if you're commenting on Reddit:

[User] [James Cameron's Avatar Blue Cat People 2009 Movie Film] A high price generally means a tiny market. How big is the market for unobtanium if it costs $20 million per kilo?

[Assistant]
High price usually means that supply is far more limited than demand.  Likely, the mineral is able to make weapons, spaceship tech, energy production, and/or communications technology far better than anything we can mine or create on Earth.

Also, it probably costs that much because of the infrastructure (spaceship, marines, base, supply chain) required to acquire it on Pandora then ship it back to Earth.


[System] Given the following post, respond as if you're commenting on Reddit:

[User] [The Last Crusade] Did Elsa Schneider knowingly give Donovan the wrong cup?

[Assistant] I think she did - she's clearly got a hateful look in her eye when he's not looking after she offered up the wrong cup. She clearly doesn't like the Nazis, only working with them to get the grail so this was her stabbing him in the back.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
CMV: 5 is an honorary even number

I'm one of those people who feels weird whenever volume controls aren't left in even numbers. Increments of ten are the best, of course, but when either 10 is too low or 20 too high, any even numeral in between satisfies this mental itch. However, I have noticed that if I move it to 15, or any number ending in 5, it also satisfies this desire.

As I thought about it, it began to make sense. As I already stated, when volume is set to increments of ten, it's a delight. 5 is a beautiful number, too, because it is perfectly even between these increments of ten. Due to this half-perfect nature, I believe that 5 is essentially an honorary even number. Like an honorary doctorate, it's not really an even number, but can hang with that crowd if it wishes.

Edit: I appreciate the seriousness with which people are engaging in my tongue-and-cheek semi-shitpost. Thank you for the smiles. :)

[Assistant]
I dont think this has anything to do with being even. It has everything to do with being a multiple of 5

As an example, for volume between 10 and 20, even though 14 is an even number, 15 is superior. Same with 12, 16, and 18. Volume specifically is not based on even numbers at all.


[System] Given the following post, respond as if you're commenting on Reddit:

[User] ELI5: Why does the atmosphere not stratify itself by the molecular mass of its components, with the heaviest gasses at the bottom?

[Assistant] It does! Gravity just isn't strong enough to make this effect noticeable down at the surface. But at the edge of space, light gases are more concentrated than down here - that is how helium can move up, all the way into space, where it's blown away by solar winds.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
What are the low hanging fruits in philosohpy?

First I have to state that I have no formal education in philosohpy at all and no intention of getting one. That does not mean that I'm not interested in the subject but it means that I'm not prepared to struggle through any arcane books that I have very little prospect of understanding.

I learned about Hume and the problem of induction a few years ago and it has completely changed my outlook on life. I was brought up in a scientistic environment and have since become much more open to more 'obscure' ideas.

I am constantly looking for similar experiences but also a bit lazy and easily scared when it comes to complicated texts. So what are the easy pickings in philosophy? The concepts that might not be obvious but that are easy to grasp and have the potential to change one's life?

Edit: I must add that I'm a bit bored with the analytical tradition would like to understand continental philosophy. So far all my attempts have come to very little or nothing...

[Assistant] There are a couple of books, like The Pig that Wants to be Eaten, which are full of philosophical thought experiments and a are a great way for someone to get a taste of the kinds of things philosophers think about without being overwhelming.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
"You breath in a single atom of Julius Caesars final breath every breath you take." How far can this be extrapolated?

It is said that you breath in a single atom of Julius Caesars final breath every breath you take.

Given that there's nothing special about either Ceaser or which breath it was, can this be extrapolated to say we breath in an atom from every breath that any person who ever existed took? (Or maybe from before a certain date of death - I doubt I breath any atoms from the most recent breath of someone on the other side of the world to me, right?)

How far can this go? I presume it becomes unreasonable to say that if some oxygen breathing creatures existed on a different planet in a different solar system that any of their atoms would have made it to here?

[Assistant]
The extent of it depends on a thorough mixing of atoms, and is therefore limited by diffusion. Working out diffusion on a global scale is not easy at all, so it would become very difficult to pinpoint exactly where in the world at each point in history this holds for.

In terms of the question of other oxygen breathing species: If they required oxygen to breath as we do, It would have to mean that their planet had a sufficient mass to stop oxygen being able to exit the atmosphere, as we go here on earth. Therefore, the amount of oxygen being released by such a planet would be more or less nil. Added to this that the chance of even a single atom being able to travel from another solar system to ours make it so improbable that it is basically impossibile, even when you are playing with the number of atoms in a single atmosphere.

I got bored and decided to prove the idea of us breathing in Caesar's last breath, for anyone interested

Working with a breath being a full lung capacity (to maximise the amount of atoms Julius Caesar breathed) That gives us 6L of air to work with. Wolfram Aplha gives this as 7.65g. The mass of the Earth's atmosphere is usually given as 5.1*10^18 kg, so 5.1^10^21 g. Converting this to numbers of atoms gives 1.59*10^23 atoms in 1.06*10^44 atoms, so one atom in every 1.5*10^21 was part of Caesar's last breath. When we breath in, we take in about 500mL of air, or 1.33*10^22 atoms. That means that on average, we breath in 10 atoms that were a component of Julius Caesar's last lung capacity.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
Considering leaving academia so I can spend more time on research...

Recently I have been feeling that the biggest obstacle between me and the research I want to do is the university and academic system that is supposed to facilitate it.

I work on theoretical projects in physics requiring no significant resources other than time and mental effort. Teaching, grant applications, performance reviews, meetings and other requirements are a constant drain on my time and energy.

Looking ahead, it seems that career progression within academia will only lead me deeper into this administrative swamp and further from the research I actually want to do. When I look at the day to day lives of top professors in my field, I realise this is not a life I want. I don't want to teach, manage, or do any paperwork whatsoever. I just want to work on my research. It seems crazy to follow a career path (a very demanding and competitive one at that) where the end goal is a life I don't actually want.

I still want to do my research though, and all I need to do so is money. So I have been thinking more and more seriously about quitting academia and looking for part time work that pays well enough for me to spend half my time focused solely on the research I love. I have good relationships with people in my field and I doubt doing so would harm any of my collaborations.

Is this a crazy idea? Has anyone else followed this path? I would love to hear about your experiences if so.

[Assistant]
If you treat the non-research part of your current position as this hypothetical 'part time work' - do you think it currently takes up a greater percentage of your day-to-day than an entirely separate, independent job at some company would?

A part-time job also often comes with lots of additional overhead: scheduling, training, performance reviews, travelling, queries on work-phone, mental distraction by doing work totally unrelated to your research, and so on. For example on that last point, the admin of writing grant applications can certainly be beneficial time spent viewing and planning your research at a higher level.

Maybe you will find you've even less time to allocate to research?


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
ELI5: How are calories in food worked out and how accurate are they?

I was just at Subway ordering a 6inch Melt when it occurred to me; who the hell can say with such confidence that my sub had 392 kcals in it?

[Assistant]
They use a bomb calorimeter.

Basically they burn the food inside a sealed chamber surrounded by water, then measure how much the water is heated up.  That tells you the energy content of the food.

For your sub, they didn't measure it directly, they instead added up the caloric content of the ingredients.  This is scaled by the quantity of any given ingredient.

For hand made food such as sandwiches, it's not very accurate.  You can assume +/- 10%, easily.


[System] Given the following post, respond as if you're commenting on Reddit:

[User] ELI5: Why does our voice sound a lot different from what we can hear and what others can hear?

[Assistant]
It's because of the way we hear. Your inner ears work by picking up vibrations in the air on the tympanic membrane (ear drum) and transferring them into the cochlear duct, which is kinda like the sensor that your brain uses to pick up sound. Tiny hairlike fibers inside the cochlea vibrate and pass that information onto the nerves that go to the brain.

When you talk the cochlear duct picks up your voice vibrating the air around you like anyone else voice, but it also picks up the vibrations of your vocal chords as they pass through your skull. This would be kindof like listening to music while having your head inside of a tin can. You'll still hear it but there's echos and other distortion.


[System] Given the following post, respond as if you're commenting on Reddit:

[User]
How does refraction work?

I understand that light "slows down" in different mediums. How does the light interact with the different medium?

[Assistant] The electric field causes the electron clouds of the atoms inside to oscillate. Oscillating charges of course radiate with same frequency as the incident radiation. Inside the dielectric, when you sum over all the oscillating dipoles, the superimposed fields has the net effect of extinguishing the incident field at all points but leaves a remaining wave traveling with the reduced speed v=c/n, as per the extinction theorem.