The force exerted on the Earth’s surface by the weight of the air above it is called:

Correct answer: Atmospheric pressure. Atmospheric pressure is the force that the weight of the air exerts on the Earth’s surface.

Background: Air has weight, so the air column above any surface presses down on it. At sea level this pressure is about 101,325 pascals (1 atmosphere).

• Wind: Wind is the horizontal movement of air.
• Low pressure: Low pressure is a condition of weaker pressure, not the force itself.
• None of these: “None of these” is incorrect because atmospheric pressure is correct.

Did you know? Evangelista Torricelli invented the mercury barometer in 1643 to measure it.

Memory trick: Weight of air → pressure; the barometer measures it.