The amount of force that air is placing on the Earth is called air pressure.

Here's why:

* Force: Air has weight, and its weight exerts a force on the Earth's surface.

* Pressure: Pressure is defined as force distributed over an area. The weight of the air column above a particular point on the Earth's surface creates a pressure at that point.

So, air pressure is essentially the weight of the air pressing down on the Earth's surface.