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

[User]
CMV: GoFundMe and similar services are the internet equivalent of panhandling and should be actively discouraged and socially unacceptable.

It seems like nearly every day I'm seeing a new post on my facebook feed asking me to donate to someone's friend. I see Today I Fucked Up posts on reddit with comments suggesting that they set up gofundme pages and ask for donations.

No one would ever suggest these people go hold a sign up on the side of the road, but posting a request for donations online is totally acceptable.

When did it become socially acceptable to ask friends and strangers to fix your financial mistakes? Do these people feel no shame in telling the world that they have poor plannings skills, can't provide for themselves, don't know how to manage money or make sound decisions, or do we just not care about that anymore?

I'm not against charity or welfare. I'm a huge proponent of the social safety net and associated programs. But that's not what's being asked for here. I've got people asking for money to cover their move into a new apartment. Someone posted that their water heater broke and they need 5 grand to fix it - that sucks, but you won't die if you have to ask a family member to use their shower for a few days while you secure a loan. Today someone posted about stupidly giving $27k in cash to a friend to pay for a funeral and getting ripped off - that's terrible, but there are other solutions to that problem that don't require begging for money.

What's worse is that in all these situations, they just want a handout. I'd be at least a little more understanding if gofundme offered a method of arranging microloans. At least there would be some semblance of responsibility and intent to return the money.

[Assistant]
> When did it become socially acceptable to ask friends and strangers to fix your financial mistakes?

There is an entire industry centered around credit counseling, bankruptcy, lending, financial advice, etc. It's always been there.

> What's worse is that in all these situations, they just want a handout.

So what? That's the entire idea behind charity. You can either give to a large organization that eventually trickles down to people, or you can give directly to people. Everybody knows what the deal is, and they do it willingly. Sometimes you just want to help someone. What's the problem with handing things out?


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

[User] [MCU] If Ronan was on Ego's planet and hit the ground with his Warhammer and power stone, would it kill Ego or just surface wipe everything he created?

[Assistant] Peter Quill and the Guardians were able to overcome Ronan when he held the Stone.  Ego is more than twice as powerful as Peter due to his vast experience.  Ronan would be a quick kill for Ego, even with the Power Stone.


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

[User] What are we smelling when we open a fresh can of tennis balls?

[Assistant]
Plasticizer! Some plastics and rubbers have chemicals called plasticizers that enhance the material's flexibility. One of the characteristics of plasticizers is that they're volatile, meaning they naturally want to evaporate. The smell you get from a fresh can of tennis balls is the evaporated plasticizer that has built up in the canister.

Plasticizer evaporation is also the reason that extremely old tennis balls become brittle.


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

[User] [Star Wars]Could either (light side) Anakin or Mace Windu individually have defeated Palpatine?

[Assistant] Mace Windu did best Palpatine in a dual. He did bring in other Jedi to arrest him but they were killed rather quickly, both in the movie and novel. If Anakin hadn't showed up when he did then RotS would have ended much differently.


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

[User]
How can water be heavier than the respective elements that make it up?

So I understand basically that electrolysis of water splits water into its base elements of Hydrogen and Oxygen, but how can combining them create something that is heavier than the sum of it's parts? How can both Hydrogen and Oxygen be lighter than water if they make up water?

Edit; Wow, this has been really eye opening to how little I understand chemistry. Thanks everyone that replied and I'll definitely be trying to learn more.

[Assistant] Water actually weighs very slightly less than its constituent parts. Bound states are lower energy than unbounded states and this is manifested as a slight defect in mass. This is why you must put energy into the system to break it apart.


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

[User] [Fantasy] What are the general abilities of a newly minted Paladin?

[Assistant] After being formally inducted into their order, the first thing a paladin will learn, barring basic combat skills, is the ability to channel holy forces from their god of choice, light, the sun itself, etc. The major tenants of any paladin usually revolve around healing, protection, and smite. Focusing on spells (if their universe calls them spells) that aid their allies, protects them, and burns their foes in holy flame. Usually they follow a set code of ethics that help enable these abilities.


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

[User]
[X-Men] Are Mutants allowed to exploit their powers in gambling? If they arent, how are they spotted by casinos.

My question is referring to scenarios such as if someone with the power of Domino decided to make money playing blackjack or a telepath like Xavier took advantage of their power during a game of poker to see the other players hands.

Can mutants do that legally? And if they cant, how do the casinos spot cheating mutants like that?

[Assistant]
Mutants of their own who detect other mutants, read minds, can do insane math on the fly to calculate odds of that person winning like that and notice unusual patterns.

A smart mutant isn't going to try and gamble vs the house but approach them demonstrate the threat and get a job.


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

[User]
Why does a photon move non-stop in space and where does it get "energy" to do so?

Why does a photon move non-stop in space and what is giving the photon energy to move? Does this energy come from the photon itself, from space, or from something found in space?

[Assistant]
Motion does not require a continuous supply of energy to keep moving. The reason a car must always be powered to retain its speed is that friction from the air and road and internal frictions of the car "steal" energy away from motion (which heats the tires, moves the air etc...), so your engine provides power to replace that energy.

In vacuum however, nothing stops you once you're moving, both photons and baseballs travel forever in space never having to replenish their kinetic energy. This is Newton's 1st law. They retain the energy they are given and do not change their energy unless they interact with something. In this way, Newton's 1st law is a consequence of the conservation of energy.


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

[User] [Star Wars] Does an oncoming blaster bolt have measurable surface area, and if so, what would happen if the shot clipped something? Would it get split up into a smaller shot that keeps traveling?

[Assistant]
A blaster bolt is not a laser. It is a streamlined blob of super heated plasma that is contained in a powerful magnetic field. As such, it does indeed have a surface area that is variable depending on the blaster and it's power.

Now when a blaster bolt hits a physical object, the magnetic field collapses, and the plasma disperses. This causes concussive damage from the momentum of the bolt, burning damage from heat of the plasma, and ionic/electronic damage from the collapse of the magnetic field. So in a sense the shot does break up and keep traveling, however because it is plasma, and not a solid shot, it disperses in a short distance losing its potential damage.

Now the exception is when such a bolt hits another strong magnetic field such as a lightsaber blade or a magnetically sealed object. Because of the opposing magnetic field the bolt is deflected but the magnetic sheath of the bolt still remains intact, so it ricochets until it hits a non magnetic field and disperses. Since the fields required to do all this are so powerful and efficient, there is only a small loss of momentum from the Bolt.


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

[User]
ELI5: Why aren't we taking advantage of the Earth's magnetic field to generate electricity?

Assume that I have exactly enough information to get terminology, and not much else.

[Assistant]
Because you can't get energy from a static magnetic field.  Either you have to move wires through a magnetic field, or you have to move a magnetic field past stationary wires.

And since we have to have motion, and since the Earth's magnetic field is so weak (compared to the magnets used in generators), we get better results simply using electric generators.


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

[User]
Which is more efficient, keeping my house at a constant temperature even when I'm gone, or repeatedly cooling and heating it?

Some people tell me that I save energy by turning down the heat when I'm not here. Others say those savings are lost when I try to warm the house back up later. What should I do reddit? Constant temp or constant flux?

[Assistant]
it is more efficient to turn down the heat.

think of it like a leaky bucket.  the leak is worse when there's a lot of water in the bucket (the pressure of the water causes the leak to run faster; similarly the higher temperature difference causes heat to be lost more quickly).

one thing that can be confusing is to worry about the heat used to "warm things back up".  but in the end what matters is the heat that escapes to the "outside".  in mathematical terms, the heating/cooling of internal structures is irrelevant to the loss through the external boundary. i wish i could explain this point better in words, but basically, your only losses are to the "outside".  another way of seeing this: you are continually "re-warming" your walls as they lose heat; so heating them up once after cooling down is no worse than doing the same in a "continuous" way throughout the day.

the above is based only on the physics of heat loss.  there may be arguments based on the efficiency of the heating mechanisms that say it is better to keep things at a constant temperature (but even then, it's hard to think how such an argument world work as long as the heater is inside your house - the most likely exceptions are for external furnaces).


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

[User]
How is a mirror both silver AND able to reflect everything at the same time?

I don't understand. Is it actually not silver and there's some crazy cultural mind trick convincing me to think it's silver when there's actually no silver there in the first place?

[Assistant]
I believe your question is asking how can a mirror be colored silver, and at the same time show a reflection.

The way vision works is that light hits an object, bounces off, and then hits our eyes. When this happens some of the colors of light get absorbed, and what is left gets reflected. A green leaf will absorb every color except for green, which then bounces off for us to see.

A mirror is a very very smoothly polished surface, so that light bouncing off does not go in random directions. Instead all of the light rays bounce in the same way, so the light we see is almost exactly the same as what originally bounced off the object. A mirror also does not absorb very much light, so most of it bounces off unchanged.

If the silver part of a mirror was roughed up it would start to appear more "silver" because the light would be bouncing around randomly instead of all reflecting the same way.

TLDR Mirrors don't absorb colors of light, so their color is whatever hits them.


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

[User]
[Pirates of the Caribbean] why did the crew of the black pearl mutiny?

Im assuming barbosa did it because he wanted to be in charge but how did he convince the rest?

[Assistant] Iirc Jack didn't want to go after the cursed gold despite rumors and legends it was worth more than London.  He was more interested in smaller piracy and was having a hard time scraping by since he wouldn't attack every ship that passed by.  Eventually the crew grew tired of barely scraping by and wanted to go where the untold riches were that barbossa promised.


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

[User]
What's the physics behind shooting a plastic bottle cap?

Hey everyone, hope you're having a good day!
I very much like this subreddit because of the wide variety of questions that are asked here, from really theoretical questions to daily applications of science.

The thing I woud like to talk about belongs in the second category of daily applications of science in shooting plastic bottle caps. I am sure that a lot of you have tried this at some point, but let me explain what I mean exactly: If you take an empty plastic bottle (for example a water bottle or a soda bottle) and try to crunch it as much as you can with the cap still on it, you will be able to build up a lot of air pressure inside the bottle. If you then quickly unscrew the cap while the air is compressed, the cap will shoot off!

I do not know a lot of physics myself, but most of the fluid dynamics that I have heard of revolved around incompressible fluids and not gases, so I was wondering if there were any formulas or calculations one could make to figure out things like the **compressibility of the air** inside a plastic bottle, the built up **potential energy** in compressing the bottle and the conversion from potential to **kinetic energy** when you shoot the cap.
I hope you guys will enjoy this topic!

[Assistant]
Well you have:

P1*V1 = P2*V2

Basically as volume decreases from the initial state, the pressure will have to increase. When you scrunch the bottle down, you are decreasing the volume and causing an increase in pressure.

Pressure can be expressed as:

P = Force/Area

Since the area of the bottle cap doesn't change, as pressure goes up, so does the force on the cap.

Force is defined as:

F = mass * acceleration

Since the mass of the bottle cap doesn't change, then acceleration has to. Increase in force causes an increase in acceleration.

In conclusion, decreasing the volume causes an increase in pressure which increases the force on the bottle cap. The higher forces give the bottle cap a higher acceleration and send it flying.


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

[User]
[Marvel]Why don't the Avengers try to help mutants?

The Avengers are supposed to be Earth's primary protectors, but they seem to look the other way about the government mass murdering, incarcerating, and generally oppressing mutants. Why don't they try to do something about that, such as destroying Sentinels, taking out anti-mutant groups, or even something as simple as making public statements saying that what's happening to mutants is not acceptable?

[Assistant]
Currently? Because mutants are hostile to humanity as a whole and grow more and more cult\~ish by the day.

Previously - they really tried. Cap formed team of mixed avengers/X-men and X-men like Wolverine and Beast were on Avengers for long time even before that.


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

[User]
Why are so many fruits bright colors?

I was thinking about it today and I realized that a lot of the time in nature, bright colors are defense mechanisms that animals use to keep predators from eating them, but a lot of fruits are brightly colored.  Don't a lot of fruits need to be eaten to spread their seeds around?  Does the whole "bright-colors" thing not apply to fruit?

[Assistant] Bright colors are simply one of many ways to get attention, not  necessarily to warn away predators. In the case of poisonous animals, the bright colors are warnings, their predators have learned/evolved to associate them with poison. In the case of fruit, the colors attract attention as well, but for the opposite reason. Their eaters have associated them with sweetness or otherwise good taste. Sometimes it's *both*, as with peppers. Mammals find peppers spicy and painful, but birds don't taste capsacin, and will eat them. Either way, the animals which encounter the colors associate the colors with different properties.


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

[User]
ELI5: WHY is markup different from profit

ELI5:

I have been tasked with helping my boss understand the difference between GROSS PROFIT  and MARKUP on items we sell (YEA, I KNOW). I know they are different; I know a 25% markup only produces a 20% gross profit but I don't understand WHY they are different or "where the other 5% goes".

If I buy a carrot for $1.00 and sell it for $1.30, WHY/HOW do I only make 23% rather than 30%? Where does the other 7% go?

[Assistant]
Once you increase by a percentage, then the next time you use a percentage it's applied to the new number, not the original number.
 Example:  Start with $1, then increase by 50% - now you have $1.50.  Now reduce by 50% - you have $0.75, not the $1 you started with.

So:

* Start with a $1 carrot.
* Mark it up by 30%:  $1 \* 30% = $0.30, so the marked up price is $1.30.
* Sell that carrot for $1.30.  Your profit was $0.30.  What percentage is that?  0.3 / 1.30 = .23, so 23% profit.
* $.30 might have been 30% of $1, but it's only 23% of $1.30.


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

[User]
ELI5: Why does the change in weather bother your throat and sinuses so much?

Every single year around this time everyone is sick, right? At least in my area of the US. Usually flu or the common cold.
Currently have sore throat, had culture swab, was negative for flu, mono, covid etc. Doc said its the change in the weather and honestly couldnt really explain to me why it happens. Shouldnt our bodies recognize this routine and adapt at some point?

[Assistant]
When the temperature and humidity drop suddenly, your mucosal membranes in the nose and throat dry out and become irritated more easily. You body does adapt, but it takes a few days.

Second, there are literally hundreds of different viruses that can cause a sore throat. You cant test for every disease known to man every time you have a cold.


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

[User]
ELI5: Why does 'turn it off and back on' work for so many electronic devices?

Why does something so simple work on such a variety of things.

[Assistant] The active state of any software being run on an electronic device is stored in RAM. RAM depends on a constant power supply, if the power is cut, the contents of RAM disappear, and the device will restart all programs from their default beginning states. This will resolve any issues involving a program which had reached an inappropriate state in RAM (infinite loop, memory leak, unresponsive script, etc.)


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

[User]
What happens if you mix two immiscible liquids of equal density?

I thought of this as I was about to pick up a 20L of toluene today and was trying to judge how heavy it would be since one of my hands is a little busted. The answer that popped into my head was that it would make a suspension or an emulsion, however I usually associate these phenomena with the normal sort of polarity/hydrogen bonding/van Der Waals type interactions, and not with density.
For the sake of simplicity, imagine I had both liquids in a seperatory funnel, and shook it up. How, or would they seperate?

[Assistant]
They would separate, eventually. This isn't driven by the differences in density, but by the fact that the surface tension is minimized if the droplets coalesce. The difference is that the droplets won't rise or fall because of the difference in density, so they'll have to find each other through random brownian motion instead.

The two phases would end up over-and-under or side-by-side or some combination that minimizes the surface tension.


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

[User]
CMV: Fish barely qualify as pets.

Fish in a home aquarium are more like high-maintenance decorations. You feed them, clean up after them, look at them, and...well, thats about it. As far as I know, you cant cuddle them or train them to do tricks.

I dont have anything against fish or fish owners. If you like watching them swim around enough to bother with the mess and expense of having them, go for it. I just dont understand how people can develop an emotional attachment to them. To me, bonding with a pet requires more interaction than just staring at it and scrubbing algae off the glass walls of its home.

[Assistant]
I think it depends on the fish.  They can definitely show personality. Ive had fish that were more attention seeking or who were more stubborn.

They can be trained to do things if they are the right kind of fish. You can train them to go through hoops or swim in circles.

But if you just have a beta fish in a jar, that isn't good for you or for the fish.


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

[User] ELI5: why is glass transparent but other things are not? As in, why can you see through glass but not say a wall?

[Assistant]
Light is not reduced to the light we, humans, can see. As a matter of fact X-rays, Ultraviolet, Infrared, Microwaves, Radio waves, Wifi are all different types of light and Visible light is just a portion of the whole spectrum. Transparency is not reduced to visible light. Your cells are transparent to X-rays but not your skeleton and that's how doctors can examine your bones. Walls are transparent to radio waves and wifi so that's why you can listen to radio without needing an antenna outside your home and connect to the wifi from any room of your house. It happens that glass is transparent to visible light so we can see through.
Now, the reason why glass is transparent to visible light and walls are transparent to radio waves has to do with their atomic structure. It is kind of complicated for an Eli5 but it is a matter of interaction between atoms and light: if the atoms interact with a specific kind of light, it can't get through unscathed so it is not transparent to that particular kind of light. If there is no interaction then the light just goes through and the result is transparency.


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

[User] Why can we consume raw seafood and undercooked beef but not raw chicken?

[Assistant]
The short version: you *can* eat raw chicken without getting sick.

However, you *shouldn't* eat raw chicken, because you have a much higher *chance* of getting sick.

It's not a property of the meat itself, but the frequency and commonality of microbial presence on the meat. Chicken, by the nature of their diet, immune systems, and habits, have a higher occurrence of significant amounts of salmonella being present in their meat than do fish.

There are plenty of meats you shouldn't eat raw. Even beef and seafood are not *always* safe to eat undercooked. They're just *less likely* to make you sick than chicken is because they're less commonly infected with things that will make you sick.

*Just* raw chicken meat can be digested just fine by the human digestive system. The problem comes from all the non-sterile bacteria etc. that potentially exist along with the raw meat.


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

[User]
Is deriving symetric?

Usually derivation is explained like how the function changed when the variable changed. The way we do it is comparing the current point with a close previous one.
(f(x)-f(x-h))/h with small h
My question here is, can we compare the current point with the close next one? Like doing a mirror at x
(f(x+h)-f(x))/h with small h
I did a few tries with simple functions and it's working and makes sense but I don't know if it's something general or not.

[Assistant]
You are describing taking the limit from the left (x-h is left of x on the number line) compared to taking the limit from the right (x+h is right of x on the number line).  THE limit is defined to exist when the limits from the left and right are equal, and there is no limit when the two directional limits disagree.  So if there is a limit to something, you can use either method to computer it.

Consider f(x)=|x|/x as x->0.  The limit from the right goes to +1, while the limit from the left goes to -1, so there is no limit.  Compare that to g(x)=(|x|/x)^2, where both directional limits go to 1, so here the limit exists and you are free to computer it from either direction.

Edit:  If you're doing "standard" math stuff like in high school, you might have to think hard to come up with many cases where the limits disagree, so you are usually safe to use either method.


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

[User] ELI5: What is the difference between the National Debt and the Federal Deficit?

[Assistant]
Deficit is an annual number.  Every year the amount we spend minus revenue is the deficit, unless revenue is MORE than spending, then we have a surplus.

The debt is the current cumulative sum of the past deficits, plus interest.


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

[User] What causes "legs" - the droplets on the side of wine or whiskey glasses - and why do they form with some alcoholic drinks but not others?

[Assistant]
Alcoholic beverages are mostly ethanol and water, sometimes with some other things like added color and flavor. Legs, sometimes called tears, have to do with the surprisingly complicated interaction between the water and the ethanol molecules. The difference in surface tension between water and ethanol results in something called theMarangoni effect. Essentially, each water moleculeis attracted more strongly to the other water molecules than to the ethanol molecules. In the bottle, water and ethanol are mixed more or less homogeneously, henceno Marangoni effect, but in aglass, which is open to the air, evaporation happens.Since ethanol evaporates faster than water, the thin layer of liquid on the sides of a swirled glass has a higher concentration of water than the body of the drink in the glass. The Marangoni effect means thatwater molecules from the bulk of the liquid creep up the sides of the glass, since they want to stick to the other water molecules. The water accumulates until gravity eventually causes it to drip down in little watery rivulets that we call legs.

Generally they form in drinks with higher alcohol and/or sugar content. There's a lot of conventional wisdom out there about what these legs tell you about the drink, but really they don't mean anything. You can't analyze a drink by it's legs, and the don't indicate whether a drink will be "good" or high quality.


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

[User] [Zelda: Breath of the Wild] How does Zelda stay alive for 100 years while fighting Ganon in Hyrule Castle without aging?

[Assistant]
Once her true abilities were unlocked, Zelda had strength that was comparable (but not quite equal) to Ganon.

There's a singular pattern in nature that has repeated zillions of times since the world began: a Power rises, which is then held in check by  Wisdom; finally, Courage is found and restores balance.

Zelda's father wasn't pushing her to unlock her ability just to be a hardass: he knew that she was one of the only things that could slow or even stop Calamity Ganon.  She wasn't just a person, or a princess, or a daughter, or a warrior: she was Wisdom incarnate.  When she finally understood this truth, she was able to overcome her mortal boundaries and block Power's way until Courage was ready (and able) to truly stand at her side.


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

[User] What is it that makes bulletproof glass so strong?

[Assistant]
Bulletproof glass is made up of polycarbonate layered between glass. The polycarbonate distributes the force evenly across the glass which helps break up the force at the same time. These layers form a laminate.

When a bullet strikes bulletproof glass, its energy spreads out sideways through the layers. Because the energy is divided between a number of different pieces of glass and plastic, and spread over a large area, it is quickly absorbed. The bullet slows down so much that it no longer has enough energy to pierce throughor to do much damage if it does so. Although the glass panes do break, the plastic layers stop them flying apart. Think of bulletproof glass as "energy\-absorbing" glass and you'll have a good idea how it works.


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

[User]
[Fallout] If you gave a supermutant a great deal of mentants, could restor intellgence?

Need halp now.

[Assistant]
It should work,  though it would take a much larger dose and would wear off quite quickly.

Of course, if you were a *west* coast super mutant, you'd already have enhanced intelligence, and so wouldn't need the chems.


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

[User] [Star Wars]A terminally ill rebel asks his commander if he can suicide bomb himself denouncing the empire in public knowing he would be captured. Would the rebels approve of this tactic if empoyed by fatalistic and terminally ill rebels?

[Assistant] Saw Gerrera caused the Rebellion enough trouble with his tactics, Alliance Command would never authorize this. But in actual military operations Alliance Command was usually far from the front and hierarchy sometimes broke down, so it depends on who's in charge.


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

[User] ELI5: Why do we get that temporary pleasure sensation when we stretch?

[Assistant]
Putting you arms ups and stretching when you wake up is actually just contracting or using your muscles to get your joints to the end of their range of motion.

This exaggerated contracting of the muscles increases blood flow and releases endorphins similar to a mini workout.

If you mean stretching like static stretching when muscles are stretched they tense up and generate a slight pain response to prevent you from injuring them.

The tensing muscles release endorphins again and increase blood flow.

Also, after you stop static stretching the slight pain response is replaced by absence of pain response, which feels good and the muscles that tensed to prevent injury also relax more. Because of homeostasis, the body tends to swing back and forth for a short period of time: Contract muscles then stop, then the body will relax more than before the contraction, for a short time at least. It's like a pendulum overcompensating less and less with each swing.


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

[User] ELI5: Why is the Independent Commission Against Corruption in Hong Kong so successful?

[Assistant]
There are a multitude of reasons, so I'll try to ELI5 a few.

1) Hong Kong is small

Hong Kong is a self-governing city (and will remain so, fingers crossed, for the foreseeable future), so the government doesn't have to deal with different counties, states, or long distances. This makes effective communication and investigation much easier, since you're never going to have to travel far to look into something.

Being a very dense city, each jurisdiction has a large population. This means that there are a fewer number of jurisdictions overall compared to if the city was more spread out, which necessarily means the total number of civil servants is lower than you would expect for a region with a population of seven million. Fewer civil servants means it's much easier to weed out corruption.

LI5: if you all live in the same house, and there's not very many of you, it's a lot easier to find out who's been stealing from the cookie jar than if there were a lot of you and you all lived in houses far away.

2) The ICAC has a reputation

While Hong Kong was under colonial rule, the ICAC was answerable only to the governor. When it was founded in 1974, it replaced a police branch that had notably failed to curb corruption in the past, and so it had an incentive to be rather . . . harsh.

For example, a mass purge took place in early 1978, where it was announced that 119 officers, including several high-profile or high-ranking ones, were asked to leave under the provisions of Colonial Regulation 55. Colonial Regulation 55 essentially says that the governor can do what he wants; i.e. no trials necessary. Purging all these officers at once made a huge splash in the public consciousness, more so than a trickle-in of convictions would have. Even though the ICAC doesn't have this capability anymore, it still stands as a testament to its investigatory power.

The ICAC is also purported to have somewhat intense interrogation procedure. Take that as you will.

LI5: If you find out your friends are stealing from the cookie jar, they might threaten to not be your friend anymore or bribe you with some of the cookies if you don't tell. That's why the ICAC isn't friends with anybody, so it can be mean to people who steal from the cookie jar. This makes it difficult for people who steal from the cookie jar to get away with things.

3) Much corruption in Hong Kong is/was market-based

Off-course betting on horse races was a huge source of bribery and corruption, because gambling was and remains a large market that the general population (and therefore, police officers) participate in. Hong Kong made off-course betting legal, eradicating the problem.

LI5: Turns out, many people were stealing from the cookie jar because they wanted oatmeal raisin cookies. Now oatmeal raisin cookies are just on the counter so nobody has to steal from the cookie jar anymore to get them.

4) The ICAC focuses on education and prevention

The ICAC doesn't just investigate after corruption has occurred. It takes an active stance towards reducing corruption in the first place through education and prevention.

The ICAC makes clear that bribes and kickbacks are not to be an expected or normal part of everyday life, and reassures citizens that they're on their side and should they find themselves on the receiving end of any corrupt threat that they can turn to it to investigate.

The ICAC furthermore offers advice and practical help to enable companies and organisations to introduce systems and procedures that are resistant to corruption, making it more difficult for it to occur in the first place.

LI5: the ICAC doesn't just look to see who is stealing from the cookie jar, it also puts locks on it and teaches people what a cookie jar cookie looks like so that if they're offered one they can report who did it.

Hope this helps!


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

[User]
Cleaning Products that kill 99.9% of germs: are these not simply leaving the strongest 0.1% to survive and repopulate?

We see this in antibiotics (MRSA followed Methicillin by ~5 years, I read). Why does something similar not seem to happen in our households/environment? And if it *does* happen, are we not better off using soap and water, or just bleach?

[Assistant]
Most of those cleaning products use alcohol or something similar, and germs cant evolve a resistance to that in the same way that they can adapt to antibiotics.

The germs that survive antibiotics have a mutation that makes them more resistant, but the 1% that survive those cleaning products dont do so because of a mutation, they only survive because there will almost always be some small surface area that isnt fully exposed to the cleaner. So we arent really leaving the strongest germs behind, just the luckiest, and thats not an adaptation they can pass on.


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

[User]
Can you tell the / is there a the difference between redshifted EM radiation and EM radiation of a longer wavelength?

If you were to generate a photon from a relatively stationary point on a planet and observe it, it has a certain wavelength.  If you were to do the same thing on a ship that is traveling at a constant velocity apparently near lightspeed from your stationary point, the photon on the ship would appear to have a certain wavelength, which would be shorter than the wavelength would appear if we observed it from the planet.

My question is, if we were to generate a photon on Earth that was the same wavelength as the photon we detect from the ship, is there any way we could tell that the one from the ship was emitted from something moving away from us?

For instance, when we see red-shifted stars, we know they are traveling away from us because we know what wavelength we expect the light to be, and we see that it is longer.  But if we didn't know that, if we just saw some light without context, would we have any way of telling whether the light was red-shifted or if it was the same wavelength as it was in a frame stationary relative to the emitter?

[Assistant]
No. There is no difference. Photons in the exact same state are indistinguishable. This concept is actually true of all fundamental particles.

At the heart of your question is the fundamental nature of relativity: there are no preferred or special reference frames. All reference frames are equally valid and "real". A photon that is redshifted is really just a photon that is being observed from a different reference frame. Since all reference frames are equally valid, observing a photon from a certain reference frame does not make it different or special aside from the effects of the frame switch itself.

With respect to astronomy, the reason we can tell the light is red-shifted is because the spectral pattern for a certain element in a star is the same as the spectral pattern of the same element as measured on Earth, except it is shifted to the red. We can't tell that the light is red-shifted just by looking at individual photons and seeing them as somehow different.


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

[User]
ELI5: Why we don't paint on our airplanes like we did during WWII

I recently saw some WWII planes and I saw the unique, pin up, and fighter style designs. What changed from when that was okay do to, and now it doesn't?

EDIT: I realized I used "us" to refer to the Americans, I forgot that Reddit is a global website, my apologizes.

[Assistant] For one thing, some modern combat aircraft are designed for reduced radar cross section (i.e. stealth) and part of that is specific paint.  It would kind of suck if the hot pinup girl on your F-22 doubled its radar cross section.


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

[User] Why is it that when we fall asleep on our own, our time asleep feels longer than when we are put under anesthesia and the time passes what seems instantaneous?

[Assistant]
Because neurologically, being asleep and being unconscious are two different things.

When you're sleeping, you're not unconscious, you're in a *different state of consciousness*. You're still responsive and somewhat aware of your surroundings. It's why a loud noise or being shaken can wake you up, or how sounds around you can make their way into your dreams. While you may not be aware of it, while you're asleep you're still processing sensory input.

When you're anesthetized for surgery, you're not in an altered state of consciousness, you're fully unconscious. Your brain isn't processing sensory input or recording memories.

Essentially, when you're asleep, you just remember the time you spent asleep differently. When you're unconscious, you don't remember the time at all.


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

[User]
[A: TLA] How was Iroh such a high ranking member of the White Lotus?

"*The White Lotus has always been about philosophy and beauty and truth.*"

Given the nature of the White Lotus, how did Iroh, a former fire nation general, a man who led a (failed) seige on Ba Sing Se, become Grand Lotus?  That seems like an act that would be so against what the White Lotus stands for, that they wouldn't allow him to raise to a high rank (even if he was truly remorseful of his former self).  I understand the White Lotus transcends the division of the nations, but there's a difference between being born Fire Nation, and actively trying to progress the war effort in their favor.

I always assumed he wouldn't have joined until sometime after BSS, but everything I'm finding online estimates that takes place about ten years before Aang's return.  So how did he make his way to Grand Lotus in only ten years, surpassing the other members who must have been White Lotus members for far longer?

[Assistant]
First, Iroh isn't *the* Grand Lotus, he is *a* Grand Lotus. There are several working at any one time.

Secondly, He's scholarly, wise, philosophical, and a Master of his particular art. He meets all the requisites.

Thirdly, nobody cares. The organization was never an anti-Fire Nation society. They were a pro-Avatar society. While they would work against the fire-nation to help advise, direct, or lead the Avatar in his duties, they really dont care who wins what battle, or who conquers what city.

If Iroh, or whoever was commanding, wanted to sack a city, and burn their libraries, and put their wisemen to the flame; sure, they'd intervene. But Iroh never would have allowed that if he had won at Ba Sing Se. Even his opponents respected him.


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

[User]
Glass kept on shattering after breaking. Why?

Today we broke our second skillet lid in a week. My niece, who did the breaking (complete accident!) noticed that after it fell on the floor it "kept on popping, going pop-pop-pop". I rushed in there to rescue her and her bare feet from the glass and observed that she was quite correct - shattered glass all over the floor, and little bits of it kept jumping up and breaking again into smaller bits.

Why would it do that? I tried googling for it, but all I got was results on breaking glass with your voice.

Edit: You guys are all extremely helpful, thank you! I now think I have a firm enough grasp that I can explain it to Eva :) I'd reply to you individually, but I dunno, our internet is on the fritz.

[Assistant]
Skillet lids are usually made from some kind of tempered glass.  Generally, this means that some sort of heat treatment has been performed so that the glass has solidified with its outer surfaces in compression and its inner layer in tension.

If you break the glass into large pieces, then this balance is shattered, and the tension (or compression - whichever locally dominates) will break the glass into smaller pieces.


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

[User] Apple claims their Apple Silicon is much more efficient than Intel's CPUs. Is that because ARM is an inheritly better architecture or because Apple is better at chip design than Intel?

[Assistant]
ARM is a totally different architecture, and it is a better architecture, than x86/64.

X86/64 is supporting 50 years of cruft and backwards compatibility.  ARM isn't.  ARM is a simple ISA, x86 isn't.  ARM is a RISC ISA, x86/64 is a CISC ISA, which Intel translates on die to a RISC ISA that they run on their hardware.  ARM doesn't have to do that.

There's a lot of deeper things to go into with it, but that's it in a nutshell.


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

[User]
[Red Dead Redemption] Once Ross has got his sights on John, is his fate sealed or could he have played things better?

We know Ross and the FBI weren't letting Marston and the Van Der Linde gang off the hook when accolades were on the line, but was John always going to bite the bullet when all other loose ends were cut? Or if John had been (uncharacteristically) polite, brown-nosing and devoted to the government cause, would he have gained any favour with Ross?

Besides fleeing the country, did John have any chance to die an old age as he claimed he wanted to Reyes?

[Assistant]
While it's not impossible to imagine a scenario where Ross lets John live, it's almost a certainty that he was going to kill him. Accolades and public opinion were too important, and Ross wanted his career to end on the highest note possible. If he let John go, he would forever be remembered as the FBI agent who ALMOST brought the entire Van Der Linde gang to justice. They were one of the last symbols of the wild west, and a constant reminder of the justice system's failure to properly police the country.

Hell, John was already supposed to be dead by a hangman's noose ten years before, but was broken out of prison by the very same gang. So if anything, Ross was going to enact a legal punishment denied to the government by the actions of Arthur and the other gang members.


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

[User]
Is there an upper limit on size for gecko wall-climbing?

My roommate was wondering if there is an upper limit on size/weight for gecko's footpads' ability to climb walls.  I figured this was as good a place as any to ask.

[Assistant] the amount of weight they are able to hold up is directly correlated to the amount of septulae (tiny bristles) on their feet. Given large enough feet (pedantry: its actually the amount of septulae but bigger gecko feet would generally have more septulae) any weight can be supported. However the surface they are attempting to attach to also plays a role in their ability to stick as they are only keeping themselves attached via Van Der Waal's interactions created between the molecules on the surface and the septulae on the gecko's feet. Based on the surface the gecko is trying to stick to these interactions will vary in strength and, thus, have great effect on how well the gecko "sticks".


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

[User]
Duty to country is not worth dying for because family obligations trump nationalism. CMV

Perhaps I'm a bad "patriot" or not much of a patriot at all, but I don't think there is anything inherently "good and proper" about dying for your country. First of all, nobody should be forced to fight and die for anything--it should always be a choice. Secondly, is one's country really a "cause", and a just one at that? What if your country were Nazi Germany? And who are you truly serving in dying for your country? Your family, friends and neighbors? Your government officials? Big oil companies?

Duty to country, in my opinion, a sort of dumb. It is blind, nationalistic idea installed into the minds of the population in order to maintain a large military. Pop culture is full of Romanticized images, songs, and commercials about military fervor--"There's strong, and then there's ARMY strong." Joining the American military has become (or perhaps always was) something glorious and good. But how much thought does the common soldier put into what he is really fighting for? In my opinion, family obligations, or love in general, are far superior to devoting yourself to a war machine whose purposes you may not even agree with.

[Assistant] Your family is in your country, so doesn't anything that serves your nation also indirectly serve your family?  In the case of the modern army, it is not expected that the majority of members actually give their life (as Patton said "The object of war is not to die for your country but to make the other bastard die for his."), and the pay and experience they get from the steady work directly benefits their family.


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

[User]
[Iain M. Banks' 'The Culture' series] What is the explanation for the abundance of human species seemingly arising independently throughout the galaxy?

There's human species everywhere, at varying stages of development, but no explanation I can find.

[Assistant]
Please remember that the Culture series of books are translations from the original Marin. The Culture is an amalgamation of many humanoid species.  With advanced gene-engineering the Culture has improved the biology of its citizens and incorporated many advances.  These advances include body modification and alterations that can be made at will.  This means that Culture "humans" could be considered mutts because of so many traits they all share with the original founding species.  So instead of getting bogged down in minutia, the novels just refer to Culture citizens as human.

As to the remaining civilizations in the Galaxy.  The Minds in charge of Contact have only released 10 books (and sadly no more) to the earth in preparation for further interactions.  They specifically chose these stories so that we could relate to the Culture.  They took our natural prejudices (that they do not have but are allowing us to keep for now) into account for these novels. We see lots of humanoids because it makes it easier for us.


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

[User] [Mr. Ed] What's the deal with Mr. Ed? Is he an alien? A secret government project? The result of atomic testing? Why did he choose Wilbur?

[Assistant]
When Wilbur and his wife bought the house, Ed was already there, so it's pretty clear that Ed is the ghost of the previous owner. He was murdered in the stable by his wife. At the instant of death, his soul migrated to the nearest creature. That creature happened to be his beloved Palomino stallion, Taffy.

This was all revealed in the show's final episode, where Wilbur goes to the city archive and finds an old newspaper article about the scandal surrounding the death of the house's owner... Edward J. Eddings.


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

[User] ELI5: Why does an aux cable connected to a speaker/amp buzz when a finger touches it?

[Assistant] The buzz is the sound of the radio waves created by the electricity all around you. When you touch the cable, you become a big antenna and gather some of those radio waves and pass them into the input.


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

[User] ELI5: how do scientists determine the density of something like a planet or moon?

[Assistant] Density is the amount of mass in relation to the volume of the object. They can tell the volume of the object by looking at it ("you can tell by the way it is"), and the mass can be deduced by looking at the orbital distance and speed, and how it impacts other objects of better known mass.


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

[User] ELI5: After waking from a coma or a serious head injury, how do people forget their native language and suddenly speak a new one? Do they need previous experience in that new language?

[Assistant] Some people might change to another language if the part of their brain which controls the processing of their native language is damaged. Of course they must know the other language before they can speak it; brain damage isn't going to magically teach you another previously unknown language.


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

[User]
ELI5: Why are green eyes so rare?

They seem pretty low in percentage (2-3%) compared to other eye colours. Aren't blue eyes a mutation? Why aren't they nearly as rare?

[Assistant]
When you make blue eyes you only need a light (lacking in melanin) top part (stroma) and a dark (containing melanin) bottom part (epithelium), so that some colors of light bounce all around in the top layer and look colorful (Rayleigh scattering in the stroma- same thing that makes the sky blue) while others "stick" to the under layer (are absorbed by the darker epithelium).

Green eyes require a more careful pairing of colors (more specific and greater concentration of melanin in the stroma) in order for some of the pretty brown light to bounce around with the pretty blue light instead of all just sticking to the bottom layer. It's like when you mix blue and yellow play dough, except with bits of light. If you look carefully (but not too close), some people's eyes look like they change color when you see them at a different angle; that's because of the different ways that the light bounces out of their eyes and into yours.


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

[User]
[Warhammer 40k] Do Orks have a favorite faction to fight? And is it the Guard? Please tell me it's the Guard.

NGL I'm only asking this because I ship a unhealthy and 1 sided friendship between the two and the Orks genuinely enjoying their scraps with the humans. But as like a healthy rivalry. And some of them have to think the 'umies have to be having a blast too! After all they have so much in common! The humans field loads of smaller boys with lots of shootas and big daka, but the big ones are clearly the knobs and war bosses. They even have their own gretchen(conscripts?)! They're even kind enough to lend them their tanks! Why wouldn't the humans be having fun too?

[Assistant] Those that have had experience with them tend to most enjoy fighting Chaos. The Warboss Tuska Daemon-Killa enjoyed fighting Warp entities so much that he led a Waugh into the Eye of Terror. He and his boyz are currently fighting an eternal battle outside of Khornes Brass Citadel, and for them it is Orkish Valhalla.


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

[User]
Does the expansion of space apply at all scales?

As in, if space itself is increasing the distance between galaxies, is there also a very small increase in the distance between atoms, subatomic particles, quarks, etc.?

[Assistant] No, the distance between atoms is not increasing because of the expansion of the universe. In fact, no two objects on the scale smaller than a gravitationally bound group of galaxies are increasing in distance because of the expansion of the universe. Expansion only happens between galaxy groups. This may seem weird, but it is the nature of spacetime. Expansion can be thought of as an inherent property of spacetime when not much mass is around. Some sources like to say that gravity inside a galaxy group overpowers metric expansion, but this is a little misleading. Gravity is just a description of how spacetime acts near masses, and metric expansion is a description of how spacetime acts far from masses. Therefore, traditional attractive gravity and metric expansion are really both versions of the same thing: spacetime. So a better way to say it would be that spacetime in a galaxy group acts in the traditional attractive way because there is enough mass around, but outside galaxy groups, spacetime acts according to metric expansion.


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

[User] ELI5: Why does a familiar word sound unfamiliar after you overly repeat it?

[Assistant]
It is a phenomenon called semantic satiation.

When you hear a word, your brain isn't really paying attention to the sounds, it is translating those sounds into an idea, and is primed to put it together with other words to form a more complex idea.

When you repeat a word over and over, your brain stops recognizing it as a word, and it breaks down into sounds that really have nothing to do with what the word means.


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

[User]
Eli5: What is that 'furry teeth' feeling that comes from sugary drinks?

What's that all about!?

[Assistant]
That is plaque that has rapidly built up. The proper name for it is a biofilm meaning a layer of bacteria that are able to feed on the sugar and other nutrients in your mouth allowing them to reproduce and thicken the layer. It also contains various polymers and secretions. These bacteria release acid which begins to decay your teeth. Equally the acid in the drink also dissolves your enamel.

If not brushed away those polymers attach to calcium ions and harden causing tartar/calculus which you usually find in the backs of your lower incisors.

Tl:dr when dentists say fizzy drinks are bad were not just spoiling your fun.

However the good news is if you drink them with meals its not as big of a problem as there is more saliva which neutralises the acid, still not great though


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

[User]
ELI5: How do multiple layers of skin retain the same fingerprint?

I can have my outer layer of skin peel and retain the same fingerprint below it, what keeps it so consistent?

[Assistant]
Imagine a printer creating copies of a sheet of paper. All of the copies that come out look more or less the same, since they were all created by the machine copying the same object.

Now, imagine your DNA is that printer. It's not copying your fingerprint, it has instructions to create that *specific* fingerprint over and over.


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

[User] [antman] what happens when antman takes off his suit after he shrinks ?

[Assistant]
Pym particles effect both the suit and Pym/Lang if he loses the suit he just loses the ability to control the particles at will. Therefore he would stay small without the suit.

After long term exposure to Pym particles the body will eventually produce their own. This allows the change without the use of a suit. Pym and Janet both produce their own due to this phenomenon.


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

[User] [Star Wars] How does BB-8 generate traction?

[Assistant]
?

Are you asking how he moves forwards?

Either anti grav like the speeder in ANH or how the toy BB8s do it - a weight at the 'front' on a gyro that makes sure the weight is always in the direction he wants to move. A sphere with an imbalanced centre of gravity will move to make the weight go to the bottom.

If you can then keep shifting that weight, it will keep moving  forward.

Think of a hampster in a hampster ball.


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

[User]
CMV: The United States will never have mandated paid time off like other Western Nations in our lifetime

I feel that it's something most Americans probably want but feel it's not practical for most to protest for.  Most countries in Europe get 4 to 6 weeks paid vacation plus around 10 paid holidays.  In the United States, employers are required to provide zero paid days off.  It seems most Americans are more worried about gay marriage, abortion, immigration, and other trivial matters that less directly affect them than getting paid time off work.

I'd imagine if the issue is ever brought up in legislation, conservatives and lobbyists would scream socialism and tie mandated vacation as a full fledged support of communism.  The average worker would probably then be outraged at the idea of guarantee paid vacation as unpatriotic and Un-American.  I just can't see this changing anytime in my life, hopefully someone can prove me wrong.

[Assistant]
It is not that unlikely.
Just a while ago, 15$ dollar minimum wage was considered fantasy and yet it happened in multiple states.  Some firms already offer paid time off, as well.
US has deep capitalist roots and therefore more engaged in the social, but especially now in a period of extended low unemployment, firms will compete with better working conditions and that includes things such as this. From there, lobbying for state-wide paid time off is just a step away.
Mind you, it is not just employees that would lobby for this; its in the interest of companies - both those willing to attract more employees and those willing to keep them and compete with other firms on equal footing.


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

[User]
ELI5 why the light on my Dell AC Adapter doesn't go out immediately after unplugging it.

Sometimes electricity "goes away" the instant I unplug whatever it is that was being powered.  Other times, it appears to hang around for a few seconds.

For example, when I unplug my television or vacuum, it turns off instantly.  When I unplug my dell laptop AC Adapter, yes, the computer stops being powered instantly, but there is still some small amount of power that keeps the light on at the tip of the plug illuminated for about 5 seconds or so.  Why?

[Assistant]
Let's imagine that you have a small water mill and a glass. If you use the glass directly on the water mill, the water mill will not turn regularly because you need to refill your glass with water.
Now, let's use a funnel between your glass and your mill. You are now able to run your mill. (Most of sand mill toys are designed with this funnel!)
When you stop filling your funnel, it takes some seconds for the funnel to empty.
The glass is more or less your AC power, the funnel is a capacitor, the stream of water is DC power, and the mill is your led.


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

[User] Why does wood not decay/rot and stay strong, when other natural plant/animal matter rapidly decays?

[Assistant]
Wood can decay and weaken, depending on the environmental conditions.

One thing that ruins wood quickly is constant humidity and temperature changes.  Ever seen an old fence or deck that's all warped and cracked?  In many cases, that's because the constant inflow and outflow of water is ruining the cell walls.  The waterlogging of the wood causes structural changes, followed by the collapse of the material when the water leaves.  This is why conservation is so vital for waterlogged wood from an archaeological site.

Keep wood in good environmental conditions, and it can last for a very long time, as you've noticed.

Other organics can survive as well, if given the right conditions.  Leather and bone can both survive in good shape for centuries, if proper conditions are met.  Organics (of many kinds, including textiles) are frequently found on shipwrecks, especially where they've been buried in mud.  This is because they reach an equilibrium with their environment, and because no microorganisms are eating them (the mud prevents oxygen from reaching the artifact).

When *not* in the right conditions, organics are frequently eaten by animals or microorganisms, in addition to the physical weathering processes.


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

[User]
ELI5:How does Anti-cheat systems like PunkBuster or VAC work?

Just wondering how it works and how it can be improved?

[Assistant]
tl;dr: Similar to antiviruses. Match memory with database, block anything found.

---

In ELI5 terms:

Imagine you're going to cheat on a test. Some guy gives you a cheat sheet, tells you these are the answers to the test. You put the cheat sheet in your pocket and use it to pass the test. Now, suddenly, everybody starts passing the tests. So teachers hunt down your friend and after investigating him, they notice that he's giving people cheat sheets.

Now, in an attempt to stop this, teachers start patting down students taking tests looking for "cheat sheet". Soon as a matching cheat sheet is found, the student is banned from taking the test.

So your friend ups his game and now starts sending text messages to students with the cheats. Teachers notice that something's weird when students start passing all tests. They investigate your friend, notice he's sending texts, and now teachers start searching students for "cheat sheet" and "mobile phone".

---

Something like PunkBuster reads the player's computer's memory for matching signatures existing in the database. Every software you run exists in your memory as it runs and has a particular footprint. The developers of PunkBuster study these bots, find out what they look like in memory, and put it in a database. PunkBuster then scans your memory and if anything fits the signatures in the database, it blocks you.

---

PunkBuster has a bunch of other functions to make it more efficient. But this is the core.


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

[User] Eli5: What's the sound we hear when we yawn or stretch?

[Assistant] It's the tympanic membrane of our inner ear vibrating due to stimulation of the muscles that control it. Certain muscle actions of the face can cause those muscles in the ear to flutter, resulting in the whooshing noise we hear.


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

[User]
Why don't hockey teams use extremely large men as goalies?

There are some very athletic huge men out there, think sumo wrestlers or linemen in American Football. So why don't teams use a gigantor to guard  the goal?

[Assistant]
The rules limit how big a goalie's pads can be, so they don't show up with giant pads that block the goal.

So a fat guy might take up a lot of space, but much of his body will be unprotected from 150+ km/h slap shots.  He might block the first few, but he'll be leaving the ice on a stretcher before the game is over.


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

[User] ELI5: Why do American high schools put so much emphasis on extra curricular activities?

[Assistant]
Because getting into colleges -- especially if you're looking at specific programs, really prestigious schools -- is a competitive progress.

Let's take Harvard, for example.  You're this massive ivy league school with endless in applicants.  Let's say 10,000 of them have 4.0 GPAs (the highest grade you can get without honors classes/weighted GPAs).  Well, you can't accept 10,000 students as an incoming class of freshmen.  So how do you differentiate the students?  By the stuff they did outside of school.  Do they show motivation and interest in succeeding outside of the classroom?  What of your character can you see but what they've been doing?  Who has already proven to some extent that they can be successful out in the real world?


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

[User] What is the need of n-dimensional geometry in mathematics, with n greater than 3 ?

[Assistant]
Sometimes in a system you can have more than 3 degrees of freedom. In dynamics, a solid body can translate (linear motion) in all three directions, it can also spin on 3 different axis, this would be n=6.

You can start relating bodies together and get much higher degrees of freedom. These aren't more dimensions as in x,y,z coordinates, they are dimensional information needed to describe an entire system's state or behavior.


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

[User] ELI5: How does a plane become "invisible" to radar?

[Assistant]
1. Coated in a radar-absorbing paint mixture.
2. Shaped in a way that bounces radar waves off in a different direction than their source, which works because most radar devices have the transmitter and receiver in the same place.


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

[User]
Can anyone explain to me why the CRISPR/Cas system is supposed to be a huge leap forward in gene editing? Why is it better than using viruses to insert genes?

I think transgenics is a cool field and I'm trying to add to my knowledge, what do you guys think?

[Assistant]
CRISPR/Cas9 is indeed a giant leap forward in gene editing technology. It should be noted that it isn't "better" than using viruses, in fact, we often use viruses to deliver the CRISPR system to our cells of interest.

CRISPR is amazing for a number of reasons. The Cas9 enzyme makes double stranded DNA breaks in a targeted fashion: you can supply the enzyme with a short guide RNA (sgRNA) that directs Cas9 to a specific site in the genome, where it does it's thing. In the simplest use of CRISPR/Cas, this alone can break your gene of interest. Most of the time, homologous recombination will repair the break just fine, but this means the the sgRNA target sequence is still present, so Cas9 will hit it again. At some point, the DSB will be repaired by non-homologus end joining, the gene will likely be broken, and the sgRNA target sequence will be gone, so this is a stable end point.

For more nuanced genome editing, you do the same thing as above, but you supply an alternate repair template, with a particular mutation of interest included. At some frequency, now your DSBs will be repaired off of your mutant template, and in this manner, you can quickly introduce just about any mutation that you want, at nearly any location in the genome. Critically, we've had genome editing capabilities for a long time, but CRISPR/Cas make it **much much** more efficient. It used to take up to a year or more to design and make a targeting construct, get it into cells of interest, and select for targeted events. This was generally reserved for making targeted mutations in ES cells that would go on to become transgenic mice. With CRISPR/Cas, because it's so much easier and quicker, now people are editing all sorts of cancer cell lines, and are able to ask questions that we previously had been unable to answer.


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

[User]
[MCU] So what exactly IS Yggdrasil?

In Norse mythology it's a literal tree with some magica-mystica to it, and in the comics there's some elements of that. But in the movies, we never hear anything about it except from a brief description in Thor 1. By Ragnarok, Hela's description of the Nine Realms is just that "Odin stopped at 9 because reasons," which would indicate that the "World Tree" is just a poetic description of things. But in The Dark World the Convergence indicates that there *is* something significant about those 9 in particular, because it's *their* alignment that causes those gravity anomalies and that Malekith can use to destroy them. So there's got to be some fact behind this "World Tree" idea, but what is the reality of it?

[Assistant]
From the right dimension it actually looks as a tree. Our minds cant comprehend what it is so we get an interpretation.

Kind of the same how galactus looks different to each alien race.

That tree actually stands for a complicated interdimensional connection system. Its not just about getting from realm to realm. There needs to be a balance between the realms. If the balance is tipped too far. All suffer causing the connections to deteriorate and eventually break down. And that would spell doom for all.


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

[User]
ELI5: Why can't we eat other people?

I get the moral implications, but I've heard that if you eat human flesh you can get very ill, even though we're all made of the same stuff. How does that work?

[Assistant] Any pathogen (whether viral, bacterial, protozoan, prion, or whatever) in your meal is going to be something that's already perfectly adapted to living in human beings. This isn't really the case with, say, fish.  That's the main problem.  Your risk isn't terribly high, but somewhat higher than it would be eating something else.


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

[User] [The Omen] So, why does Damien kill his adoptive parents? The father is going to become President of the United States. Damien could use that position to further his interests.

[Assistant] Contrary to popular belief, Damien is not being possessed by a pre-existing demonic spirit. Rather, he is a brand new evil entity, and is not yet mature enough to control his impulses and plan for the long term.


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

[User]
ELI5: Syriza won the Greek general election. What does this mean for Greece and Europe in general?

Is the fact that they're "anti-austerity" actually good? Did most people just vote for them because of that keyword? With this win, does it mean that Greece is closer to getting out of the EU? I tend to pay attention to current events, mainly those in Europe since it's where I live, but the whole greek situation has kinda slipped by me so i just know the basics. Would like to get filled in on the details (albeit "5yo" details).

[Assistant]
It means a game of chicken is now going to be played.

The Greeks have 7 billion euro of debt that must be paid this summer.  They do not have 7 billion euro to pay it.  The plan is that they will borrow that money from other governments and central banks.  That plan is contingent on Greece following through on various commitments it has made to cut expenses and raise revenues.

Syriza says it will not make those cuts or raise those revenues.

If the EU blinks, they'll refinance that debt and let the Greeks operate outside their commitments.

If Syriza blinks, they'll honor the deal made by the previous government.

If neither side blinks, the Greeks will not be able to roll over that 7 billion euro debt and they will default.  After they default, the pressure to expel them from the eurozone, and then to expel them from the EU will be overwhelming, and they'll probably be forced out.

Then they'll re-institute the old Greek currency, the Drachma, which will immediately inflate because it is worth less than the euro, and Greece will have to operate with a balanced budget because for a few years at least nobody will lend it any money - which means it will make deeper cuts, and raise more revenue than it would have had to do if it had honored its commitments in the first place.

The logic is nonsense.  People in Greece are voting because they're angry and tired and hating the fact that they have nobody to blame but themselves for their economic problems.


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

[User]
Is it possible to have steam hot enough to start a fire?

As in igniting f.ex. paper.

[Assistant]
The answer is YES!

But not without special treatment. The trick is to HEAT THE STEAM ITSELF!

Imagine a pot of water on the cook top.  Instead of the lid making a seal, make the lid have a single copper hose (maybe .5cm internal diameter) coming out into a tightly looped coil.  As the water in the pot boils, the vapors above the water (the steam) will expand and flow through the copper coil.  If you place a torch under the copper coil itself, you are now adding thermal energy to the steam!  It is not unreasonable to reach temperatures over 800C this way, PLENTY hot enough to ignite paper, cellulose, or any other common combustible.

Source:  10 years working on boilers in the Navy, work in combustion science now.


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

[User] ELI5: Why is store bought mayonnaise white, even though the ingredients are mostly yellow?

[Assistant] Mayonnaise is an emulsion. When it's created the ingredients are whipped together create it. This introduces a lot of air bubbles, which is why mayonnaise is rather fluffy and gelatinous. Aerated substances look white. Think of a cloud or a waterfall. Air bubbles reflect light, and thus lend a white color to mayonnaise.


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

[User]
Why are batteries different sizes? What is the difference between using four AAA vs. two D batteries?

Wondering after looking a some flashlights of mine. One uses a couple D batteries while some use AAAs and some use AAs. Do the size differences have to do with voltage, or amount of battery? Could you theoretically change something that runs off a D to run off two AAs?

[Assistant]
AAA, AA, C and D cells are all 1.2 to 1.5 V when new. The difference is the amount of current each can deliver, and for how long. Bigger cells can deliver higher current and can deliver more amp\-hours. Alkaline AA are roughly 3 Ah each, but D cells are roughly 15 Ah each.  So two AA \*in parallel\* may be able to power something designed for one D cell, but for around 40% as long. Five AA in parallel are equivalent to a single D cell.

Combining cells in series leads to voltage differences which most circuits are incapable of handling. That is, you can't put two or more AA in series to replace one D cell.


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

[User]
[Star Wars]Compared to other jedi since the inception of the order, how powerful of a jedi was Obi Wan?

Was he just average, especially compared with the likes of Nomi Sunrider or Lord Hoth?

[Assistant] He was above average, but he was nowhere near as powerful as Nomi Sunrider or Lord Hoth. He was certainly one of the most legendary Jedi in the use of Form III of lightsaber combat, but overall he wasn't exactly so powerful that he would have been able to stand up the the things Nomi, Hoth, or even Yoda could.


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

[User] How far off are we really from achieving artificial gravity?

[Assistant]
Well, we can simulate gravity reasonably well by spinning something at a constant velocity so that the centripetal acceleration is close to 1g., we just haven't been able to put anything big enough to do comfortably it into orbit. Or, if we had something that constantly accelerating at 1g, that would do it too.

As for artificial gravity like in movies, where everyone is floating around and someone presses a button and the 'artificial gravity' turns on and everybody falls to the floor? That's not really possible.


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

[User] ELI5: Why can human skin endure near frozen water for minutes without repercussions, but not endure boiling water without getting third degree burns?

[Assistant]
So let's consider magnitude here.

"Near frozen" water is around 0 degrees C (32 degrees F).  "Room temperature" for humans is around 20 degrees C (70 degrees F).  So our near frozen water is about 20 (38) degrees off from "comfortable".

Boiling water is 100 degrees C (212 degrees F).  By the same math it is around **80 degrees C (142 degrees F) different** from "comfortable".

So there you have it - boiling water is a lot hotter than frozen water is cold to humans.


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

[User]
Is there a response to people who say "it's all just semantics"?

Often in debate it seems people try to reduce everything to a matter of definition alone.  The idea seems to be that, nobody actually disagrees, but instead just define things differently and these definitions are the source of all dispute.

Has anyone written about this phenomenon?  I find it a tad annoying when I feel a debate has had real substance, but others deflate it to one of just definition.  Especially when people try to basically relativize definition, as though all definitions are equally good and there's no use trying to work out whether one might be preferred and why.

[Assistant] I think you're asking about two different things here. As for when someone alleges that a distinction is merely semantic, the relevant objection would be to point out a substantive difference concerning the matter at hand. As for when someone dismisses a matter on the grounds that it just depends what definition we adopt, usually what needs to be clarified is that the question of which definition we adopt is the substantive matter at hand, or significantly implicated in it.


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

[User]
[Stargate] Why are the gates almost never in defensible positions?

I'm only in season 3 of SG1, but have seen some episodes here and there throughout the rest of the different series. But one thing has been pretty common, it doesn't matter what planet they are on, if it's populated or controlled by Goa'uld, or even if they're surrounded by forest, the gate always seems to be in a completely open area.

I don't know what the ancients were dealing with when they put them in, but wouldn't it make sense to place them where they can be easily protected instead of being able to be ambushed upon arrival or during retreat?

Side question: I recently finished the episode where they find the people training with intar, specialized stun weapons used by Jaffa in training. Did the SGC ever reverse engineer these and mass produce them? They seem too useful to just pass up on.

[Assistant]
Just to reiterate, many of the original gate positions were determined long before any modern conflicts. The ancients wanted a convenient and accessible mode of travel, so it was reasonable to put them relatively out in the open.

But over the eons since they were created, many gates have been relocated. Goa'uld especially have moved them around, and sometimes use them as centerpieces for their religious temples and community centers. That way they could make grand shows of their entrances/exits and reinforce the illusion of their divinity to the unwitting masses they ruled over.

Also while some gates have been put in defensive positions by various goa'uld, it's also a tactical choice to leave them in the open. An invading force is instantly exposed, for example. And they provide the perfect choke points to corral pursuing enemies in the case of retreat.


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

[User]
[Home Improvement] Did people legitimately watch "Tool Time" for advice on construction?

If I was an audience member or television viewer, I would assume that *"Tool Time"* was a spoof of such shows and that all the accidents and one-liners were scripted. I would assume that Tim and Al were playing fictionalized versions of themselves, much like Stephen Colbert.

In fact, I think there's a scene where one of Randy's friends actually says that he assumed it was all an act.

Did people watch the show as a legitimate advice program, or was it enjoyed as a comedy program?

[Assistant] Tool Time was the best place in the 90s to get up to date information on the latest and greatest applications of Binford^TM tools! Sure, that Tim guy was probably a paid clown, but the real host Al always had great tips to compliment the act.


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

[User] ELI5: Why can I roll my eyes toward the top of my head but not the bottom?

[Assistant]
Your optical nerve attaches to the back of your eyeball at an upward angle just below your eyes midpoint. As you look down, it causes more tension as it tries to straiten the optical nerve, as opposed to when you look up, the tension is released on the nerve by laying it flat against the bottom of your eye socket.

Think of it like when you stretch a rope at an angle (like a slide), with a high point and a low point. Now take the high point and try to raise it whilst keeping the same point on a horizontal axis (looking down). You cant. Because the rope will want to try to reduce its angle on a vertical axis. Now take the rope's high point and lower it, whilst keeping the same point on a horizontal axis (looking up). Its much easier. Because as the high point lowers, it gives the rope more slack, just like the optical nerve when you look up.


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

[User]
CMV: Western music has missed out on a ton of creative possibilities by restricting itself to a 12 tone system.

The major and minor scales have a thorough basis in harmonics: the major scale is composed of the first and second harmonics of the fundamental tone (i, v, iii), the dominant (v, ii, vii), and the subdominant (iv, vii, i). The minor scale is just an inverted major scale, and so it may be similarly constructed (Schoenberg describes this beautifully in *The Theory of Harmony*). Thus, the major and minor scale have a foundation in physical phenomena, so it is reasonable that they should appear throughout a large portion of music.

On the other hand, the twelve-tone system we see in Western music does not come (at least not canonically) from a physical phenomenon; instead, it comes from a numerical coincidence, namely that 2^(19) is approximately equal to 3^(12). Thanks to this coincidence, a 12-tone system allows us to play a good approximation to a major and minor scale in any key. This was a revolutionary discovery as prior to this realization, an instrument would have to be tuned to a particular key, but now, instruments could be tuned (within a small margin of error) to all keys simultaneously. Bach's *Well-Tempered Clavier*, a series of fugues that go through all 24 major and minor keys, famously demonstrates the power of this 12-tone system. Ever since this discovery, the vast majority of Western music has been composed in 12-tone equal temperament.

But there are alternatives that have been ignored almost entirely. For instance, a 19-tone system actually gives a better approximation approximation to the major third and a *much* better approximation to the minor third, at the cost of a slightly worse approximation to the fifth. A 31-tone system also gives excellent approximations to the important intervals, though having so many notes is arguably a bit cumbersome from a notational standpoint. A 19-tone system, however, actually fits into the standard Western musical notation system; we just now distinguish sharps from flats of the key above.

I am not arguing that 19-tone equal temperament is a better system than 12-tone, but I do think that by ignoring the alternatives, composers have neglected a massive amount of artistic possibilities that are unavailable in a 12-tone system. Many modern composers have experimented with microtones, creating pieces that do not fit into any equal-temperament system, but to my knowledge, very few have composed works that still fit into an equal-temperament system, but not the standard one. I think that doing so would open up a new world of possibilities in music composition, and that our society has missed out on an infinitude of beautiful music as a result.

[Assistant]
Whatever tonal system you use, two factors limit its applicability: the ability to discern notes and produce pleasing scales. It was researched discerning quarter note intervals can be taught, but that doesn't mean the arabic scale can faithfully reproduce all western-scale songs. Furthermore, arabic and indian scales have a form of complexity to them that wouldnt reflect well in all types of feelings conceived through music. But id agree it be probably best if we taught music including quarter notes.

Although we might've missed out in the past, electronic music certainly progressed far beyond this limitation. Every detune you add in a synthesizer could be used to convey even more complex emotions or any reproducible sound for that matter. So we missed out, but the lack of discerning skills in listeners could've dimished the popularity of such music in the first place. Right now its either a deliberate choice or a lack of musical education.


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

[User] ELI5: If our cells are constantly regenerating, why do we have permanent scars?

[Assistant]
Humans are, as an animal, incredibly difficult to bring down. We can walk off injuries that would kill or cripple most mammals.

One of the things that helps us do this is our hyperactive healing process. Put simply, we heal fast. *Really* fast. The downside of that is scarring. We scar because instead of healing nice and neatly our bodies are programmed to do it quick and dirty. Scar tissue isn't pretty, but it's the fastest way to close a wound.


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

[User]
[Atttack on titan] wouldnt the rumbling cause only for the people within wall sina to survive?

The rumbling means that all the titans within the walls would begin to walk outward and begin flattening all the land outside of the walls. However if thats the case why do places like paradi islands port, and its railroad still seem to be intact despite being well outside the safety of the walls? Not to mention that logically speaking, because the walls are within each other the rumbling would kill the residents of walls Maria and rose. However they seem to be perfectly fine, what happened?

[Assistant] Eren had the Wall Titans march in a single neat line towards the coast, only dispersing once they reach mainland Marley. Paradis Island was unharmed except for the immediate vicinity of the crumbling Walls, and the land in the direct path of the Titans' march.


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

[User]
What exactly is "Information"?

In many other posts they say that information can not travel faster than the speed of light, but what exactly is information and what can be considered not information.

[Assistant]
At its most fundamental, information is any propagation of cause and effect within a system. The degree to which the the past state of one part of the system can be known through observation at another part of the system. Effect can only propagate at the speed of light (since nothing can go faster).

Information is carried in a "signal", which is the variation of any physical property, over time, against the backdrop of random variation (entropy).

Different fields discuss information in different contexts. E.g. in physics you'll probably be talking about the propagation of cause and effect. In information theory, you're probably talking about formal logic, statistics, signalling, bandwidth, [edit: also, should include language, coding, compression, cryptography, etc.] etc.


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

[User] ELI5: Why does the moon appear red in the "Total Lunar Eclipse" instead of being invisible as happening in "Partial Lunar Eclipse"?

[Assistant] When the earth is squarely in front of the sun, from the moon's perspective, you're still seeing sunlight through the edges of the earth's atmosphere. Like a 360-degree horizon. What does the sun look like when it's just at the horizon during sunrise or sunset? It's red. You're seeing every sunrise and sunset happening on Earth at that moment, all at once.


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

[User]
[Star Wars] Why could the dark side not be sensed in palpetine?

Also how the hell are they able to jump and fall so far?

[Assistant]
Palpatine is possibly the galaxy's greatest master of deception. He spent decades insinuating himself into galactic politics, and put much work into masking his presence. He allowed it to grow very slowly, manifesting as the "fog" over the Force that the Jedi Council detected but could not penetrate. The defining aspect of the Jedi Council, as well as the greater Republic in this time period is deep-seated complacency that left them ill-prepared to deal with any of the problems Palpatine created. He used their system of bureaucracy directly against them.

As for the latter, Jedi are able to move things with the Force. It's not a stretch to believe that they can self-levitate. They are able to enhance their natural abilities directly, too, as you can see when Luke Force-jumps out of the carbonite device, when Qui-Gon and Obi-Wan use Force Speed to get away from the droidekas, and when Yoda does anything with a lightsaber.

Edit: If you ask me, there's no good reason Mace Windu should be assumed dead, thanks to the abilities already displayed elsewhere in the movies, much less the EU.


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

[User] ELI5: why are loud noises so scary to many animals and humans?

[Assistant]
We evolved hearing to both find food and identify threats.

The worst threats are those that don't care if something else hears them - that indicates confidence which is NOT good for the animal hearing it.

This is why lions roar - to show everyone around them they're the boss. "Come get it."


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

[User] ELI5: How are potholes in the road formed? Seems like theres nothing then one day 50 potholes overnight.

[Assistant] So the road expands and shrinks as it heats and cools.  This cycle, along with a metric boatload of traffic, creates weak points in the road that eventually result in cracks.  Once the cracks form, water can get inside them.  In the summer it's not a big deal, but in the winter the water freezes and expands, which then significantly weakens sections of the road.  Then the plows come over and are basically applying a literal truckload of force on the road, and if you hit a section that's weak and not well aligned with the rest of the road it just knocks the whole section out of the road.


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

[User] [D&D] I'm a Archmage and a scholar and I'm cataloging obscure planes of existence, what Do I need to catalogue?

[Assistant]
Everything. Or at least everything that you reasonably can.

Probably start with the 5 senses. What does it look like? Smell like? Feel like? Sound like? Ok, maybe not taste (unless you find some edible flora or fauna).

How did you get there? Are there certain spells or rituals you need to cast? Any special requirements for travelling to that particular plane?

Gravity, or the lack of gravity.

Does effect follow cause, or is it the other way around?

Do regular physics apply? Is movement a matter of physically moving your legs or just thinking about moving from one place to another?

Are there any inhabitants?


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

[User]
ELI5: How do waves transfer Energy

Im talking about Tsunami waves.

How much energy does it transfer? Where does it come from, where does it go?

How fast do they move?

[Assistant]
Tsunami waves like all ocean waves occur because two molecules can't be in the same place at the same time. This is a basic fact of fluid dynamics.

So when waves 'move' the water is mostly staying in the same place because it moves very little. But it bumps up against the water molecules around it giving up their energy and stopping as they've given it up. But whatever molecules they just bumped into now have the energy and so they move a short distance, bump into something, give it up and stop etc.

It's like those desktop toys with the metal balls clanking back and forth. The balls themselves don't move, or they move very little. They mostly act as a conductor of energy.

So a tsunami originating in Japan travels as an energy wave 'through' the water. The water itself doesn't move so Japanese water stays in Japan even if the tsunami is moving towards Hawaii.

This is also the reason why at sea a tsunami is not even really noticeable. The energy is spread out immensely from top to bottom, so you have a huge mass of water bouncing around but the wave is only centimeters high. It still has energy because of how much water is in play though.

As the wave approaches shallower depths, the energy stops being spread out among large masses of water, and starts being concentrated, by the decreasing depth, and the wave starts growing taller and taller. This focusing of the energy also causes the waves to slow down in speed, and increase in height. In the open ocean a tsunami energy wave travels incredibly fast, like jet speed fast. As it comes up onto shore though it's much slower, but much taller, and at that point water is moving not just acting as a conductor. The slow waves at the coast, with fast waves coming in behind it, causes a surge, pushing large amounts of water near the shore so not only do the waves get tall, but the local sea level also rises. This is why the water on land looks like it's risen and flooded instead of just immediately washing back out to sea.


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

[User]
ELI5: If all homo sapiens originated from the African continent, and homo sapiens is the only human species left, then why do we have different races, colors and features?

Why do we have skin colors and drastically different features if we all came from the same region? Was it a result of mixing with other human species?

[Assistant]
Evolution applies within a species, too.  Dogs are all the same species, and all descended from domesticated wolves, but they come in a massive variety of shapes, sizes, and colourations that are better-suited to different environments.  That's mostly *artificial* selection, but all that does is accelerate the process, so the same principle applies to humans.

Let's take the example of skin colours:

In areas where there's a lot of sunlight, and particularly where UV levels are high, melanin is an advantage, so people with more melanin (and therefore darker skin) will tend to live longer and have more children survive to adulthood, and before long you find the local population is quite dark-skinned.  Meanwhile, in places where there's much *less* UV, having more melanin is a slight disadvantage because it inhibits vitamin-D synthesis and has a slight associated energy cost, so there's a small advantage to being paler.  It doesn't have to be huge; over large numbers of generations even a small advantage adds up.

Combine all of this with some groups of humanity being geographically isolated from others, so that the cultures don't mix and therefore start to diverge, and cultural beauty standards will result in an effective selective-breeding programme, which further differentiates people.

All these differences exist, but humans are similar enough to each other and can still produce fertile offspring when they're from different ethnic groups, so we call them a single species.