Influence of gravity upon gases Are gases influenced by gravity?
If yes: so how you can demonstrate that?
Is there are a difference in distribution of gases in the air? So CO2 will be close to surface more than O2?
Si no: why ?
(I know that the gravity even excite will not be important but .. I want to know !)
 A: All matter, including gasses, are influenced by gravity. It is proven by the fact that we have air to breathe. If the air were not held to the Earth by gravity, then it would dissipate into space. Another proof is that helium weighs less than air, so balloons may float. As we move higher above sea level, such as on top of a mountain, the air becomes thinner (less air pressure), because there is less air above us pressing down because of gravity. Even though some gasses in our atmosphere are heavier than others they stay pretty well mixed together because the sun heats the ground, making the air close to it warm. The warm air rises up and outwards, and helps keep the gasses in the air mixed.
A: 
“Are gases influenced by gravity? If yes: so how you can demonstrate
  that?”

The pressure of the atmosphere is greatest at the surface of the earth. This is due to weight of the air above the surface bearing down on the air near the surface. That weight is, of course, due to gravity. That shows the collective influence of gravity on gases.

“Is there are a difference in distribution of gases in the air? So CO2
  will be close to surface more than O2? Si no: why ?”

Our atmosphere is a mixture of gases mainly nitrogen and oxygen but also carbon dioxide and others. It’s my understanding that carbon dioxide is well mixed with the other constituents of air at the surface of the earth and is about 400 ppm. Even though carbon dioxide is heavier than oxygen gas which is heavier than nitrogen gas they don’t separate from each other at the ground according to their molecular weights. This is because gases are highly miscible with one another at ordinary temperatures and pressure due to convective currents resulting from heating by the sun.
Hope this helps 
