Chapter 5, Problem 1LC

To determine

To explain: The reason for the decrease in the atmospheric pressure with an altitude.

Answer to Problem 1LC

The atmospheric pressure usually decreases as the altitude increases because of the compressible nature of Earth’s atmosphere, and the weaker influence of Earth’s gravity at the higher altitudes.

Explanation of Solution

The atmospheric pressure can be defined as the force exerted by the mass of gas molecules on a unit area of Earth's surface as well as on any other body on Earth.

The atmosphere is composed of gases that contain mass. As atmosphere has a weight, this mass is being pulled towards Earth by gravitational force.

The atmospheric pressure is omnidirectional, means it exerts the force equally in all directions (above, below, sides, and diagonally).

The atmospheric pressure is about 14.7 pounds per square inch at the sea level. Atmospheric pressure decreases with an increasing altitude because the actual number of gas molecules is also reduced. As we move farther away from Earth and its gravitational pull, the number of gas molecules present in the atmosphere will be lesser.