What happens to the temperature of air as it is compressed?

When air is compressed, the molecules become closer together, resulting in an increase in temperature. This phenomenon is based on the principles of thermodynamics, specifically the ideal gas law, which indicates that pressure and temperature are directly related when the volume is constant. As the air is compressed, work is done on the air, converting energy into thermal energy, which raises the temperature.

In the context of density, as air is compressed and its temperature rises, its density actually increases because the mass of the air remains constant while the volume decreases. This principle explains why the air becomes heavier as it is compressed. The molecular interactions and the energy associated with those when compressed lead to a scenario where the temperature rises and the density increases, making the air denser rather than lighter.

Thus, the correct understanding of the relationship between compression, temperature, and density illustrates why the selected answer accurately represents the behavior of air under compression.