Gases are kept in the air by their large kinetic energy

In summary, gases are kept in the air by their large kinetic energy, which keeps them propped up. If we observed one particle in the atmosphere, however, it would fall in a parabolic arc (in between collisions, which keep it propped up).
  • #1
daveed
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gases are kept in the air by their large kinetic energy, no? if we observed one particle in the atmosphere, however, would we not observe it to fall in a parabolic arc(in between collisions, which keep it propped up) much as a macroscopic particle would?

this just gets me thinking because-with singular particles in a box, wouldn't the particle go towards the bottom of the box? or... if at that level the collision is elastic, it would go back to its original height , but there have the lowest kinetic energy

is that why its cold in high places?
 
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  • #2
You neglected the fact that there are so many air particles(All kinds of mloecules) so that the "air particles" you mentioned would be in a medium of similar density. It's like pouring water into water; water does not sink through water like matter with high densities.
It's just that air has a very low density, so it doesn't seem that obvious.
 
  • #3
i said "in between collisions, which keep it propped up". aside from the collisions.
 
  • #4
daveed said:
is that why its cold in high places?

It's cold in high places for a couple of reasons. One is radiational cooling and another is that gases do work to expand as they climb thereby cooling.
 
  • #5
Essentially yes, that is correct. But you cannot neglect the temperature. Since the average velocity of the molecules in a gas is determined by the temperature, if the temperature is high enough, the molecule may well have a velocity greater the escape velocity. So the parabolic path could take the molecule into space and free of the Earth's gravitational field. This is one reason why we do not have free Hydrogen or Helium in our atmosphere. The fact that H loves to react, will be another reason we do not find it. However even if it were not reactive any free H would be lost to space.

It is possible of fill an open container with a heavy gas, such as Ar or CO2.
 
  • #6
I think kuenmao said it right:
Just think of air (gasses in general) as a low density liquid.

I had this feeling often when flying on a plane and watching the wonderous weird cloud formations, if you think of the air atmosphere as a liquid sea covering the whole earth, it doesn't look so weird anymore (yet beautiful anyway :-).
 

FAQ: Gases are kept in the air by their large kinetic energy

How does the large kinetic energy of gases keep them in the air?

The large kinetic energy of gases refers to the motion of gas particles. This motion causes them to constantly collide with each other and with the container they are in. As a result, gases are able to spread out and fill the space they are in, making them appear to be "kept" in the air.

Why do gases have more kinetic energy than liquids and solids?

Gases have more kinetic energy because their molecules are further apart and have higher speeds compared to liquids and solids. In liquids and solids, the molecules are closer together and have less room to move, resulting in lower kinetic energy.

Can gases ever lose their kinetic energy and fall to the ground?

While gases can lose kinetic energy through collisions with other particles or objects, they do not fall to the ground like solids and liquids. This is because the gas molecules are constantly in motion and are not affected by gravity in the same way as solids and liquids.

How does temperature affect the kinetic energy of gases?

Temperature is directly related to the kinetic energy of gases. As temperature increases, the molecules in a gas move faster and have higher kinetic energy. Conversely, as temperature decreases, the molecules move slower and have lower kinetic energy.

Is it possible for gases to have too much kinetic energy?

Yes, it is possible for gases to have too much kinetic energy. This can happen in extreme temperatures, such as in a gas flame, where the molecules are moving at very high speeds and can cause explosions or other dangerous reactions. In these cases, the gas must be carefully controlled and contained to prevent accidents.

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