Okay physics nerds, solve this.
I have a box. The box is divided in two. One side contains fast moving hot particles. The other side contains slow moving cold particles. Both sides contain 50 particles each. I remove the divider and the particles interact. The box has reached its highest entropy state.
How long will it take for all the particles to return to their side of the box, effectively reversing entropy?
Why do you need the chin to make your homework ?
They won't. That's what entropy is.
Not enough information to give a full answer.
>Size of the box
>Diffusion rate
>Type of medium
However, the answer is basically never. The probability of all particles to return to their side is just to small.
Exactly 69 minutes and 420 seconds bro
Faster than the time it would take for you to lose your virginity.
>Size of the box
1 cubic meter
>Type of medium
Air
>However, the answer is basically never. The probability of all particles to return to their side is just to small.
There is still a non-zero probability chance for it to occur though. It would take an extremely long amount of time, but it will still happen. The number of states the particles can be arranged is 3.43*10^157.
Incorrect, and based on a limited understanding of particles because of ignoring the quantum fluctuations.
Correct
>the answer is basically never. The probability of all particles to return to their side is just to small.
Except in a situation where the situation has infinite time.
In any system small quantum fluctuations that would result in small, imperceptible reversals in entropy of a system can have 'runs', though these are incredibly unlikely. Unlikely does not mean impossible. Given enough time a 'run' of quantum fluctuations which effectively reverse ALL entropy in a system will eventually occur. Infinite time is by definition enough time to repeat every possible configuration infinite times. Therefore while I cannot answer your question with any certitude because the time required for complete reversal of entropy in your box is longer than the lifespan of this iteration of the universe, I can state conclusively that is must be possible, and those telling you it is not are people with sufficient understanding to have confidence to answer absolutely, but not sufficient understanding to draw accurate conclusions.
The entropy is a statistical effet, way more ways to be in mixed position so the question is not how much time, but in x time what is the chance of assuming the starting position. Regardles of time almost non existentiary
1: They never will.
2: The particles will continue to lose energy to the surrounding environment, unless you're going to claim the box is perfectly energy-reflective.
3: Quantum shit doesn't exist.
Never. That's like trying to seperate scolding hot water and ice cold water. How long will it take for the mixed water to seperate from hot and cold again?
It's a breath of fresh air to find someone scientifically literate on this shithole of a board. There's something I find reassuring about the idea of time repeating over and over again. It's hard to explain, but it makes me view life as more than just you're born and then you die and that's it. I guess the real question would be; is the version of you where you have red-haired still you? Is the version of you that's black still you? Is the version of you that's female still you? Will you experience those iterations of you or only this one. It's scary and beautiful and that's why I love physics.
>Except in a situation where the situation has infinite time.
if you're talking infinite time it doesn't matter
it'll happen an infinite amount of times in that timespan.
if you heat up the atoms of a car sufficiently to vaporize them, and cool it back down, you could have those atoms recombine into molecules, and bond such that you exactly recreate the original car. it's not likely, but given enough time it would happen. you would also get scale models of the car, and pyramids made of scale models of the car, and exact replicas of the car only with the tires sitting in the trunk instead of on the rims.
entropy is just a way of describing "the number of possible states versus the number of states that you consider valuable". a more concrete example, if you shake a box of sand and let it settle, in a truly random way, you'll get the mona lisa, and great works of shakespeare spelled with the grains, and the entire bible, and the bible in italian, and the bible in russian, and the bible in some language never invented, and so on.
this is quite literally, "particle in a box".
it's an adiabatic system. it's not even worth discussing the loss of heat.
Lol this.
Rule 4
Yes it is. The amount of time it will probably take for the atoms to spontaneously arrange themselves in the previous configuration will not occur before energy dissipation unless magic is involved or Maxwell's Demon.
>probably
that's the point of the illustration. i'm not arguing anything to the contrary. the reality is that even in a perfectly sealed box with some sort of immortal observer, it would be many eons past the heat death of the universe before the initial conditions would be randomly replicated.
however, the nature of probability means it could very well occur the first time you look.
you could buy lottery tickets and win every single one and bankrupt the world. you'd more likely lose, but there is a set number of possible outcomes, and one of them is "selected". the situation described in the OP is obviously not a realistic situation, as there is no "hot particle" and "cold particle". they would obviously exchange energy between each other and reach a ground state of energy, but if you were to describe a hot particle as one moving quickly, and a cold particle as one moving slowly, and the energy of the system is constant, then the slow particles could collide in such a way that their energy is transferred "up the gradient". this doesn't happen in any meaningful amount, nor on any meaningful timescales, but understanding that as a "possible state" is important to understanding why it is unlikely, and why other states are more likely.
So not impossible, just impossible in any way that matters.
absolutely.
it's a question of semantics more than anything. it's possible like how winning a thousand scratch cards in a row is possible, but it isn't impossible in the way that jumping to the moon from earth is impossible.
it's exceptionally unlikely, and for all practical purposes, "never going to happen".
>never
Is not a word we can apply.
>The particles will continue to lose energy to the surrounding environment, unless you're going to claim the box is perfectly energy-reflective.
No but the probability of a run of fluctuations reversing entropy in the box is nonzero. You objectively cannot prove otherwise.
>Quantum shit doesn't exist.
Demonstrably false.
Here’s the thing about this.
A. If the particles interact then there’s no way they will ever be the EXACT same temperature because they won’t go back to being hotter after cooling down for no reason, also if they get hotter than the cold side would heat up thus making them not the same.
However if you put that aside and just want a realistically improbably likely answer,
You’d need a big calculator because,
There’s 100 particles particles, meaning you’d have to account for each ones heat/cold.
That’s already 100*(temp, accounting for random temperature fluctuations), and then you get into dimensions because there’s even if it’s a 1 cubic meter box that’s 1e27 nanometers if we’re gonna pick that as the size.
Meaning you have 100*(temp) + 100*(1e27), at minimum if it all HAPPENED just so perfectly.
There’s too much variable change and not enough input.
We need the speed they travel at minimum
>How long does it take for an egg to unfry?
>effectively reversing entropy
You mean when does random chance overcome the law of entropy? Pretty much never.
>There is still a non-zero probability chance for it to occur though. It would take an extremely long amount of time, but it will still happen.
In order to calculate that you'd have to be able to precisely predict how every individual particle will behave, which, if it's even possible, could take longer than the universe has existed.
This thread is about looking for someone who will count it all.