Colorado CDL Practice Test

How does air pressure change with temperature?

1. Decreases with temperature

2. Stays constant

3. Increases with temperature

4. Is unaffected by temperature

The correct answer is: Increases with temperature

Air pressure increases with temperature because warmer air expands, leading to an increase in the energy of air molecules. As temperature rises, the kinetic energy of the molecules also increases, causing them to move more rapidly and collide with surrounding surfaces more forcefully. This results in a higher pressure. In a closed container, as the temperature increases, the air molecules occupy more space and move more vigorously, leading to more frequent and forceful collisions against the walls of the container, thus increasing the air pressure. This relationship is described by the ideal gas law, which illustrates that pressure is directly proportional to temperature when volume is held constant. In contrast, air pressure does not remain constant nor is it unaffected by temperature; it changes significantly with fluctuations in thermal conditions.