Extended data:
Gas is composed of a large number of irregularly moving molecules, and these molecules are bound to collide with objects immersed in the air constantly. Every collision, air molecules will give an impact force to the surface of the object, and the result of continuous collision of a large number of air molecules is reflected in the atmospheric pressure on the surface of the object, thus forming atmospheric pressure.
The more molecules per unit volume, the more times air molecules collide with the surface per unit area in the same time, and the greater the pressure.