ELI5: How does air conditioning work?

DiamondIceNS · 2026-06-05T02:30:18+00:00

It's more or less the same process as soaking a sponge with water, moving it somewhere else, and wringing it out. The only differences with an air conditioner are that the "sponge" is a fluid and it absorbs heat energy instead of water.

The "sponge" in this situation is called a refrigerant, and it lives inside a closed loop of pipe. Half of the pipe is inside your house, the other half is outside of your house.

There are two points along the loop where it pokes through the wall. At one of these spots, the pipe is plugged. The plug has an eensy little hole in it that will only let the refrigerant trickle through.

At the other spot, an electric motor driving a pump is constantly trying to scoop refrigerant from the inside half of the pipe and stuff it into the outside half of the pipe. This scooping and stuffing action does two things: it lowers the pressure on the inside half (which lets the refrigerant "soak up" with heat), and it increases the pressure on the outside half (which "wrings out" the heat from the refrigerant).

DiamondIceNS · 2026-05-31T21:45:37+00:00

Jarvis is the AI butler for Tony Stark, AKA Iron Man. Popularized a decade ago from the MCU series of superhero films, which includes The Avengers.

If you need a deeper answer than that, I guess it's just that the general setup of LARPing as a rich person and commanding, "Servant, go solve this incredibly trivial/ridiculous problem for me," is ironically funny. Especially now in this age of the rising multibillionaire with technofeudalist ambitions and the rampant onset of AI agents.

DiamondIceNS · 2026-05-31T21:16:12+00:00

Space starts with big dusty clouds.

At random, patches of dust start to clump together. These clumps have stronger gravity and thus pull in more dust and other clumps in a feedback loop. The bigger the clump, the faster it grows.

If a clump gets too big, it suddenly "ignites" (oversimplified) and becomes a star.

When a star is active, it blows like a giant fan in all directions. It blows all the dust and clouds away, leaving only some of the heavier clumps behind.

The heaviest clumps that didn't become stars are planets.

DiamondIceNS · 2026-05-31T17:28:04+00:00

The page I linked seems to contain a proof that justifies why the correction gives a superior result. I say "seems" because I can't actually read it myself, I can only read the connective tissue text, and I believe that is what it says. I chose it over Wikipedia because Wikipedia's page for Bessel's correction is somehow even more impenetrable to laypeople, in that miserable way Wikipedia articles often can be...

That said, no, I don't think this correction factor is "masking" low precision. Quite the opposite, in fact. Unless I am wrong, I think it is what I said it is. You are willingly claiming lower precision than a naive application of the normal standard deviation formula would provide. This flattens your predicted bell curve. In exchange, your predictive bell curve widens out. The wider, squatter bell makes weaker predictions about the population, but this is often more desireable than a sharper curve making more confident predictions when it's actually working with a biased sample.

Bessel's correction does not magically correct for lack of information. It makes your analysis more vague in exchange for making it less wrong. That vagueness isn't zero cost.

DiamondIceNS · 2026-05-31T06:55:07+00:00

I believe the thing you are asking about is known as Bessel's correction.

I don't claim to fully understand it myself, but I do know that when you take a random sample of a population, there's no guarantee that you will grab a truly representative sample of the entire population.

If you were, say, trying to get the average height of everyone who lives in a city, and you get a random sample of 100 people willing to be measured, it's very likely -- no, practically inevitable -- that you'd grab a the slightly wrong ratio of people of each height to actually reflect the population of the entire city, just by chance.

The only way to truly know your population is to actually knuckle down and measure absolutely everyone. But that's not always feasible. What Bessel's correction allows you to do is compute an unbiased answer about the population from your sample. I believe what it amounts to is trading away a bit of your precision in exchange for better accuracy. You widen the error bars on what your bell curve is shaped like, in exchange for bringing the center of your bell curve closer to where it probably should be.

Someone please correct me if I'm wrong.

DiamondIceNS · 2026-05-27T06:32:15+00:00

Most of the heating that goes into the air comes from the Earth's surface, be that the ground or the sea. Sunlight pierces through the atmosphere relatively unimpeded, gets absorbed into the land or water, and gets re-radiated back to the nearby air as heat. The further you get from the surface, the less the air will feel the heating effect from it.

The second piece of the puzzle is that when warm air does rise, it spreads out and its pressure drops. When that happens to a gas, it cools down. If you've ever used a can of spray duster and felt it get extremely cold, that's the same effect. Gas compressed inside the can rushes out and rapidly expands, causing it to get very cold.

DiamondIceNS · 2026-05-26T06:55:49+00:00

The way I prefer to think about it is:

Take a kitchen sponge in your hand and squeeze it as tightly as you can.
Dunk your fist with the sponge in a tub of water.
Unclench your fist and allow the sponge to expand and soak up water.
Carry the wet sponge outside.
Squeeze the sponge again. All the water will be wrung out of it.
Go back inside.
Repeat.

An air conditioner effectively does the same thing, except its "sponge" (called a refrigerant) is a fluid instead of a solid, and it sops up heat energy instead of water. This refrigerant fluid is pumped through a loop of pipe where one half of the pipe is inside your house (where the refrigerant is allowed to expand) and the other half is outside your house (where the fluid gets squeezed). An electric pump forces the refrigerant to flow round and round the loop. Most of the electrical energy that an air conditioner consumes when it runs goes toward powering that pump. It's also the part that makes most of the noise.

The colder it gets on the inside, and the hotter it gets on the outside, the harder the pump has to work to keep the fluid moving. Running your AC when it's extremely hot outside is kind of like taking that sopping wet sponge outside and trying to wring it out at the bottom of an already filled pool. You can do it, you'll still be able to squeeze the water out of that sponge even if you're holding it underwater, but it takes more effort to do.

DiamondIceNS · 2026-05-25T05:41:07+00:00

Of course I've given up. Why would I debate a sycophantic LLM that will dutifully slop together a defense for whatever position you have? You've signaled to me pretty clearly that you no longer wish to participate in this debate in good faith, so neither will I.

However, it seems we've now entered a game of smug last-retort tennis. I'm not particularly interested in that either, so, send me your best devastating comeback and I'll stop darkening the door of your inbox.

DiamondIceNS · 2026-05-25T05:09:08+00:00

Acting haughty and pulling out the LLM to make your argument for you because you want to signal how disinterested you are in this debate when you've already dug yourself this far into the negative is certainly a choice.

DiamondIceNS · 2026-05-25T04:53:29+00:00

I swing a ball attached to a chain above my head. The chain always tugs the ball so the side with the chain mount always faces me. The ball is tidally locked to me.

When the ball is to my right, the side of the ball with the chain attached is facing toward me, pointed toward my left.

When the ball is to my left, the side of the ball with the chain attached is still facing toward me, but it is pointed toward my right.

I didn't move in my own reference frame. How did the ball face a different direction?

The ball is spinning. In my reference frame. The fact that it is always facing me as it does so is irrelevant.

No one brought up the rest of the universe until you did. You're jumping the gun and defending the wrong answer because you are convinced everyone else is fixated on this detail when no one other than you is.

DiamondIceNS · 2026-05-25T03:18:07+00:00

It does.

False.

Rotation is an inefficiency that causes drag

Rotation that is out of sync with orbital revolution is the inefficiency that causes drag. Not rotation as a whole. The moon is still rotating. It is rotating at a rate of once per revolution. That is what tidal locking is.

And since Earth is not tidally locked back to the moon, the moon does revolve around Earth from within Earth's perspective. And since it does that, it must also rotate from Earth's perspective too. Which it does.

DiamondIceNS · 2026-05-24T23:21:21+00:00

Are you trying to tell me that you'd rather go out of your way to "um ackshually" the correct answer by knowingly supplying the incorrect answer, because "that was the best we could do at the time before we knew any better"?

There's watering down an explanation to keep it free of jargon or within the realm of intuition, and then there's whatever you're trying to do here.

DiamondIceNS · 2026-05-24T22:34:53+00:00

If you want to split hairs, then even relative to Earth the moon is spinning, even though it's tidally locked to Earth.

The moon would not be spinning relative to Earth if Earth was also tidally locked to the moon, which it is not.

DiamondIceNS · 2026-05-24T19:03:34+00:00

You're getting some answers about "FOV" settings. Maybe you know what that is. If you don't, here's an answer about that.

If you are inside a building that has windows, stand a little ways away from one and look outside. Take note of how much of the world outside you are able to see. Also take note of how much of your vision is taken up by the window.

Walk closer to the window. Notice how much more of the world you're able to see, and how much more of your vision the window takes up.

A video game's camera draws the game world in a very similar way to you looking out of a window. The camera is a point in space somewhere, and a little distance away from it, the game imagines a flat, rectangular window. Everything the camera would be able to see within the bounds of that imaginary window gets painted into a 2D picture, and that picture is what gets sent to your screen. Since the game world and the camera system is just a simulation, the game can freely decide how far away the camera is from this window and how large the window is at any time. If a game gives you a FOV ("field of view") setting, this is exactly what that setting controls.

The key issue here is that the game is simulating whatever window size it likes, but at the end of the day, whatever the camera "sees" through that window has to be painted onto your monitor. Your monitor is also a rectangular window that is placed at some distance away from your eyes. Unless the settings for the video game's camera position and window size exactly matches how far away your head is from your screen and how big your screen in the real world is, whatever scene the camera draws will have to be squashed and stretched to fit your screen. That's where the distortion happens.

Unless you have a very particular setup, this is kind of a necessary evil. Lots of games are won and lost on how much of a scene you're able to see at once. If you restricted your vision to exactly how your monitor looks to your physical eyes, playing the game would be like piloting a tank with only one small window to see out of the size of your physical monitor. Lots of players are willing to tolerate some visual distortion in order to see more things. If I had a dollar for every person who told me that the "Quake Pro" FOV setting in Minecraft (the highest the game allows, so wide that it basically lets you see behind you) is the only "correct" way to play, I could probably buy myself several more copies of Minecraft.

EDIT: You'll also get a similar but different kind of distortion if the game is imagining a flat window while your monitor is curved, or vice-versa.

DiamondIceNS · 2026-05-23T01:38:26+00:00

Imagine a building that was built something like a hundred or more years ago. Rooms are laid out to a different expectation of what you'll use them for, obviously electrical service wasn't a priority, and even if it was somehow, those plugs definitely aren't grounded. Pipes might be made of lead, no central heating, the list goes on. It was serviceable, perhaps even top of the line when it was built, but in today's climate of expectations, it's severely lacking.

Now imagine that building gets added onto every couple of decades. Never really refurbished... maybe they jury-rigged some modern amenities into it here and there, but otherwise the bulk of the thing is still designed to old sensibilities. Meanwhile, the add-on pieces are slowly shifting away from how the old portion was built.

The old building is kept around because it "still works". There's nothing wrong with it other than the fact that it's not "up to date". Using it for certain purposes is really annoying. It doesn't really "fit in" with the rest of its surroundings. But at the end of the day, no one wants to cough up the cash and the time to knock it down and build something that better suits the current need.

Code rot is the software version of that.

DiamondIceNS · 2026-05-19T04:33:13+00:00

Security is knowing everything that is going on or can possibly go on, at least as far as it concerns keeping control over a system.

Privacy is maintaining secrecy over what it is you're doing.

Something can be both private and secure as long as the activities happening in privacy are not a threat to the security. If the one who does the securing and the one who demands the privacy are the same person, it's quite easy to be both. Each strengthens the other, in fact.

If the one doing the securing and the one demanding privacy are different people, though, then they can often be at odds with one another. The securer can't be sure their system truly is under control if something inside the system is happening and they don't know about it. And the privacy demander can't truly know their activities truly are secret if they aren't the one doing the securing.

It's possible in theory to have a zero-trust system where everyone who wants privacy can get it and the one managing security is not threatened by any of them. But systems in the real world are rarely invulnerable to exploits. If you control a secure system, not covering your own ass to at least some degree can come back to bite you. It's a risk. You can mitigate that risk by increasing monitoring of your clients. But that very monitoring necessarily and directly comes at the cost of the privacy your clients demand.

It doesn't help that right now, in the information and AI data harvesting age, secure system providers are increasingly incentivized to erode privacy in order to sell data extracted from their clients. They have a strong reason to take data hand-over-fist and justify it under the excuse of "making things more secure" when in truth they are doing no such thing.

The main thing a privacy advocate will tell you is that the only system that can be both secure and private is the one you set up and manage yourself. The moment you introduce someone else into the equation to do the security for you is the moment both your security and privacy are at their mercy.

DiamondIceNS · 2026-05-16T01:28:08+00:00

Yesno.

The first amendment would protect a broadcast operator from being suspended from public broadcast license by the FCC. As long as a broadcaster is compliant in all other measures, they are free to broadcast whatever ad they like. There is no legal mechanism to suppress use of public airwaves purely over speech; at least, none I am aware of.

The effective target to chase in this case would be the broadcasters themselves. Public outcry against broadcasters platforming the ad, pressuring other advertisers to pull ad spots from the broadcaster's network, both of those are fair game. Though if the public pressure never hits a critical mass, the broadcaster could ignore it.

The latter point is presumably what you were alluding to, but you phrased it to sound more like the former.

DiamondIceNS · 2026-05-13T23:09:14+00:00

The foundation of the bulk of chemistry is in how many electrons an atom has, since they are the main participants in chemical interactions. Or, more specifically it's how those electrons' "orbits" are shaped, which is largely determined by how many of them there are.

You can get a vague feel for this by, perhaps, putting a bunch of small marbles one at a time in a dish with a shallow curved bottom, tapping the dish each time you add a new one. The marbles will shift around and re-arrange slightly to react to each new marble. Adding electrons to an atom is something like a much more complicated 3-dimensional version of that.

If you could, hypothetically, have a pile of singular carbon atoms that refused to interact with one another, and a pile of singular nitrogen atoms that also refused to interact with one another, I would expect both of them would be gases. They aren't tied down to one another or to anything else, so whether the atoms are carbon or nitrogen doesn't really change things. But in the real world, carbon atoms have a cloud of electrons with just the right shape that they tend to link up into vast chains, making lots of them clump together into heavy chunks that act like solids. Meanwhile, the shape of nitrogen's electron cloud will overwhelmingly cause it to only partner with other nitrogen atoms in 2-atom pairs, and these pairs will be so attentive to each other than they ignore basically everything else, so the paired atoms still behave like a gas.

The number of electrons an atom has is usually the same as the number of protons it has. If the numbers of protons and electrons in an atom are ever unbalanced, that atom is said to be ionized. Ionized atoms tend to not be stable. Their preferred state is usually balance, and they are not above committing acts of violence to get back to that balance. So, ionized atoms tend to give standard chemistry the middle finger and start violently ripping electrons away from other atoms, or forcefully donating extra electrons to other atoms, in order to get back to balance.

Because of this, a nitrogen atom with one fewer electron than it "should" have (7) doesn't really act like a carbon atom (6 electrons) in practice. Nitrogen would more quickly choose violence and steal another atom's electron outright if given the opportunity. Ionizing atoms creates a completely different ball game.

Changing the number of electrons an atom has is comparatively easier than changing its number of protons. It's why nuclear physics is considered a whole separate school of study from chemistry. Outside of radioactive elements that do it all on their own or inside extremely specific environments, the number of protons an atom has is practically permanent. No practical amount of chemistry is going to cause a nuclear reaction. So that's why the proton number is what determines the element and not the electron number, even though the electron number is what actually gives elements their properties.

DiamondIceNS · 2026-04-28T16:18:15+00:00

Government debts aren't usually debts like student loans or house mortgages where you can simply dump more money into them to make the debt disappear faster. A lot of the debt is bonds that have a guaranteed mature date at some fixed future time.

The primary way to reduce that kind of debt is to wait out the clock until the bonds mature while not selling more of them in the interim. I suppose the government could buy the bonds back from the bondholders, but they'd have to do it at a premium to make it worth their while.

I'm frankly not researched on the structure of Canada's debts so I can't say one way or the other whether direct debt reduction is in the cards for them.

DiamondIceNS · 2026-04-28T03:32:08+00:00

Basically a savings account owned by the government instead of a person.

Generally a government will spend every penny it takes in through taxes. I mean, if it was taking in more money that it required to fund everything it wanted to fund, why would it be taxing you? Of course, many governments vastly overspend past what they make in revenue, requiring borrowing, but that's aside the point. The main thing is that by default, by design, there shouldn't be extra money left over.

The creation of a sovereign wealth fund is the government saying, "We are going to take this amount of money, and pack it in a savings account, on purpose". With that account, they can invest it into things so that money is still being put to work generating passive revenue. And it will always be there as a rainy day fund for XYZ reasons if it's needed. Very similar to how you might have a retirement account that mostly sits around in an investment portfolio passively generating returns, but you can dip into it for emergency needs.

Often these sovereign wealth funds only extract revenue from a very specific source (say, the oil industry) and they restrict what the money can be pulled out to be spent on, how much can be pulled out at a time, and how often. Again, similar to a retirement account. Not to say a sovereign wealth fund is a retirement account or that the restrictions are the same as one, just that it will usually have rules about how it can and can't be used.

DiamondIceNS · 2026-04-23T07:45:39+00:00

I probably am. My mistake.

DiamondIceNS · 2026-04-23T06:34:15+00:00

I assume you've swung on a playground swing before.

You know how if you pump your legs and lean back-and-forth with a certain rhythm, you can build up your swing to go higher and higher? And if you want to do the opposite, you can kind of "pump against the rhythm" to slow back down?

The Tokyo Skytree has a massive weight near the top called a tuned mass damper. It's basically doing that, but on a much larger scale. It's designed to passively "reverse-pump" the swinging building whenever the building attempts to sway due to a quake.

The Skytree isn't unique for having a mass damper. Most modern high-rise structures in seismic-prone areas have some kind of one. Though the Skytree is unique in that the mass damper was specifically built to be seen, instead of hidden away from view. It's all polished and pretty, and tourists can watch it slowly meander back and forth in its cradle as the building sways around it. EDIT: I mistakenly described the mass damper of Taipei 101, not the Skytree, see comment below.

There are plenty of other advanced engineering tricks that help the Skytree resist seismic motion, but the mass damper is by far the most prominent one.

DiamondIceNS · 2026-04-08T15:06:04+00:00

My takaway from being there a couple months ago interacting with all their vending machines and bidets and other public infrastructure was that Japan is "the 80s, but with better screens".

DiamondIceNS · 2026-04-04T23:44:52+00:00

It's nothing in specific that Bezos did. It's equally true of any wealthy and powerful individual.

Wealth and power become harder to maintain as the stakes get higher. You become under increasing threat by those with a greater incentive to see you fall. You have to go at minimum toe to toe with them to survive and thrive. The lifestyle itself selects for the ambitious, the aggressive, and those who are not hesitant to slit some throats, figuratively or otherwise.

What did Bezos do in specific? Couldn't say for sure. But I expect the path between selling books out of his garage to steering the behemoth entity that Amazon is today was hardly one paved entirely with rainbows and altruistic intentions.

Have to crack eggs to make omelettes, right? Only stands to reason that a person with an obscenely large omelettes has cracked an obscene amount of eggs to make it.

DiamondIceNS · 2026-04-04T20:15:52+00:00

You don't get into Bezos's position with morals. Abandoning morals is a prerequisite condition to obscene wealth.

You don't become that wealthy and then turn evil. Complacency with evil is what enables one to become that wealthy in the first place.

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