Question

When used as a theatrical effect to simulate fog carbon dioxide gas tends to stay near the floor of the stage. what might account for this effect?

Answer 1

Carbon dioxide is denser than air, which means it is heavier, which makes it stay near the floor of the stage.

Answer 2

Answer: because the carbon dioxide gas is denser than the air.

Explanation:

This happens because the carbon dioxide gas is way denser than the air, as you may know, density is equal to mass/volume, so the fact that the carbon dioxide is denser means that a fixed volume of the gas is heavier than the air, and this is why the carbon dioxide "falls down"

Another similar example of this is the helium-filled balloons, as the helium is less dense than the air, the balloon tends to go upwards.