The measure of force with which air molecules are pushing on the Earth's surface is called atmospheric pressure.

Here's a breakdown:

* Air molecules are constantly in motion. They collide with each other and with surfaces they encounter.

* These collisions create a force. The more collisions, the greater the force.

* Atmospheric pressure is the weight of the air above a certain point. It's like the pressure you feel when you dive deep in water – the deeper you go, the more water is pressing down on you.

* Standard atmospheric pressure at sea level is about 14.7 pounds per square inch (psi). This is also equivalent to 1013.25 millibars or 1 atmosphere (atm).

Note: Atmospheric pressure varies depending on altitude, weather conditions, and other factors.