Question

Air pressure describes:

A. the weight of air molecules pushing sideways on Earth.
B. the weight of air molecules pushing up on Earth.
C. the weight of air molecules pressing down on Earth.
D. the weight of air molecules pressing on Earth.

Answer 1

Air pressure is the weight of air molecules pressing down on Earth, with the average sea level pressure being about 101 kPa.

Step-by-step explanation:

Air pressure describes the pressure exerted by gas particles in Earth's atmosphere as those particles collide with objects. The correct answer to the question is C. the weight of air molecules pressing down on Earth. This pressure is due to the weight of the air above a given height, with the average pressure at sea level defined as standard atmospheric pressure, typically measured to be about 101 kPa (1.01 × 105 N/m²). As altitude increases, atmospheric pressure decreases, because the density of the air becomes progressively less.