4mo ago

Anon questions physics

55 comments

The water thought you were so stupid, it left.
- Only scientifically correct answer :D

Each individual molecule did reach an excited state and entered the air, as the air molecules themselves are already highly excited. Also, if the air already has enough moisture then the moisture molecules in the air can accumulate on surfaces that are cold enough that they lose their excited state energy, and a puddle could remain even in warm temperatures because as water leaves the puddle more can also accumulate there.
- Also diffusion and vapor pressure and latent heat - reality is messy
  
  Someone needs to clean up this fucking sim, the rules make no sense

Hence why there's "boiling" and there's "evaporating" - two things that aren't the same hence two different words.

go into grocery store
find both sexy and repulsive people
What the hell, since when have people been ahomogenous?
- Hey, who are you calling gay‽
  
  Some genius
- ahomogenous
  You mean heterogeneous, lol.
  
  Apologies, I meant to write “contrahomogenous”

My chemistry teacher once explained it to me like below. Does anyone know how much truth there is to this explanation?
Temperature as measured by a thermometer or your finger is an average. Not every single molecule has the same temperature. The molecules constantly bounce around, smashing into each other, transferring heat to each other. By chance, some molecules will get hit in just the right way by other molecules to reach a very high temperature and then it evaporates. So there is constantly a gradient of temperatures among the molecules and the ones with the highest temperature are the ones evaporating, until there is no liquid left at all.
As the average temperature increases, the chance of some molecules reaching a high enough temperature also increases, so warm water evaporates faster than cold water.
This also explains why evaporation cools down (like when you sweat): the molecules with the highest temperature are the ones evaporating, so the average temperature decreases as those high-temperature molecules leave the system. Only the relatively colder molecules are left behind - thus it cools as a whole.
- I think it's much easier and truthful to stop talking about temperature and introduce speed in that context.
  The average speed is what we percieve as temperature, but single molecules can be fast, so fast as to break the boundaries of the liquid pool and shoot up toward space.
  Single unbounded molecules are what gas is.
  
  But temperature is not just the speed of a molecule right? Isn't it also like the "energy" stored in the molecule, or its "wiggling" or something? Like a molecule moving very fast through space can still be at a very low temperature, right?
  
  Next explain what mass is in 10,000 words or less. I know two whole ass physics classes aren't enough, so. I'm trying to be generous.
- There's a bit more to it, but it's because of this effect.
  There is actually a balance between liquid and gas state, just overwhelmingly in favor of liquid when at normal temperatures. There is a ratio of molecules that will hit each other and transition to gas, and an equal amount gas hitting liquid and condensing. At least when there is a balance between the two sides, aka 100% moisture in the air. Which is not how it is most places.
  Normally there is always evaporated water in the air, and anything that evaporated will be moved away in any mildy ventilated area, as you say, it leaves the system. So it never reaches a balance, which is why things dry up at lower temps as water will always evaporate and leave the system.
- @SorteKanin
  This also explains why evaporation cools down (like when you sweat): the molecules with the highest temperature are the ones evaporating, so the average temperature decreases as those high-temperature molecules leave the system. Only the relatively colder molecules are left behind - thus it cools as a whole.
  The main principle at work here is the enthalpy of vaporization. When matter changes state, there is an associated amount of energy that is absorbed or released - in the case of vaporization, energy must be absorbed. So when sweat forms on your skin and evaporates, it absorbs heat energy from your body in order to undergo that state change.
  For water, the energy involved here is remarkably high, much higher than the energy stored by a few degrees difference in temperature. For example, if you wanted to boil off 1kg of water, it would take about 300 kJ to bring the temperature up to boiling from room temperature and over 2000 kJ to boil it all into steam.

Anon doesn't realise that his mum cleared it up. Bet they think there's fridge fairies as well!
- I used to have this magic basket. I would put dirty clothes in, and later those clothes would turn up clean
  
  And folded, right on the bed.
  
  Reminds me of this skit

What exactly is this idiot suggesting some sort of conspiracy to hide all the water?
Obviously the water fairies take it.
- Big Science doesn't want you to know this one simple trick.
- Bigfoot gotta drink something.

Some asshole needs to remind him of something called evaporation and vapor pressure...
- Triple point.
  If 3people point at some spilled water, it will evaporate in a few hours

This is your friendly reminder that the majority of people on the Internet are children.
- I don't believe that, I just think the children are more vocal.

Homie should have paid attention in physical chemistry.
- That is one bold assumption right there.

The reason being that at any temperature where a liquid can be a gas (over zero degrees Celsius at standard pressure) some of that liquid will become gas.
Over time all of the liquid will become gas
- And the reason for that is because the concept of temperature doesn't really work when you're talking about individual molecules. The average temperature might be 10° C but an individual molecule may very well get up to evaporation temperature, of course at that scale it doesn't really do anything other than disassociate itself from its neighbors.

In case anyone here hasn't heard the news: https://news.mit.edu/2023/surprising-finding-light-makes-water-evaporate-without-heat-1031
- That's not surprising. That's just how electromagnetism works
  
  Fucking magnets.
  
  Oh yeah, I'm sure you know all along and just didn't want to help with desalinization efforts.

Vapor pressure: "Am I a joke to you?"
Jokes aside, the boiling point exists because as the temperature of the water increases, so does its vapor pressure. At the boiling point, the vapor pressure becomes equal to the atmospheric pressure (1 standard atmosphere, or 760 torr). This is the reason why water boils at lower temperatures at higher altitudes!

He rather questions modus ponens? Things can have many causes, that is why the presence of the effect in absence of the cause does not mean there isn't a causal effect. Rain makes grass wet, even if the grass is wet without it having rained first, because there are presumably many reasons the grass can be wet (eg sprinklers), even if they are unknown to us. That having been said, this specimen is a hilarious face palm, all the same.

OP took the bait.

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