According to the kinetic theory

a) there is no attraction between particles of a gas
b) only particles of matter in the gaseous state are in constant motion
c) gas particles are relatively close together
d) gas particles lose energy when they collide

A. when something is a gas it likes to break away, take water for an example, when solid ice the molecules still move around but almost nothing happens, when it becomes water they break away from each other and freely move. When it becomes steam it just flies away from one another like a wild animal set free from a cage, they are the most active and loose in this state.

The diaphragm is what i think ur talking about