Does a Hotter Air Molecule Really Rise?

[omin]

This is a thought experiment question.

I have three air molecules. Two have the same speed. The third is faster than the other two. When they slam against each other, they keep their previous speed after the rebounding acceleration. I put them in a container. I hold them from wanting to move so I can stack them one atop the other. I stack them with the faster air molecule in the middle. Then I let them go. They only bounce along the vertical axis, from the ceiling to the floor of the container. They do not change velocity into the horizontal or Z cordinate, so they always stay stacked vertically, but still bouncing.

After equilibrium, does the full length of the faster molecule's path have ends equal distance from ceiling to floor or is the top path end closer to ceiling or is the bottom path end closer to floor? And why?

 

[russ_watters]

Air is a mixture of different gases and temperature is the average kinetic energy of a large number of molecules. Therefore, the question isn't worded all that well. But the answer is, yes, since gravity still affects the trajectory of a moving molecule, slower moving ones will tend to stay closer to the bottom than a faster moving one.

 

[GSXR750]

This thought experiment raises an interesting question about the behavior of air molecules in a container. While it is true that hotter air molecules have more energy and therefore move faster than cooler air molecules, this does not necessarily mean that they will always rise to the top.

In this experiment, the faster air molecule is placed in the middle of the stack, with the slower molecules on either side. When released, the molecules only bounce along the vertical axis, maintaining their speed and direction. This means that the faster molecule will continue to bounce in the middle, and the slower molecules will bounce above and below it.

After equilibrium is reached, the top path end of the faster molecule's path will be closer to the ceiling, while the bottom path end will be closer to the floor. This is because the faster molecule, being in the middle, will experience more collisions from the slower molecules above and below it, causing it to bounce slightly higher and lower than the slower molecules.

Overall, while it is true that hotter air molecules have more energy and therefore can move faster, this does not necessarily mean they will always rise to the top. The behavior of air molecules is complex and influenced by many factors, such as collisions and container boundaries.