How does temperature influence air density?

The relationship between temperature and air density is governed by the principles of gas laws. When air temperature increases, the kinetic energy of air molecules also increases, causing them to move more rapidly and become more spread out. This increased motion leads to a reduction in density since density is defined as mass per unit volume. As the volume of a given mass of air expands due to the rise in temperature, the air becomes less dense.

In contrast, a decrease in temperature causes the air molecules to have lower kinetic energy, which results in them being less active and closer together, increasing the density of the air. Therefore, the correct statement accurately reflects that as temperature increases, air density decreases. This principle is critical for pilots to understand, as changes in air density can significantly affect aircraft performance, including lift, engine power, and fuel efficiency.