What happens to air temperature as it is compressed?

When air is compressed, the molecules are forced closer together, which results in an increase in the kinetic energy of the molecules. This increase in kinetic energy translates directly into an increase in temperature. The gas laws, specifically Gay-Lussac’s Law, state that for a given amount of gas at constant volume, the pressure of the gas is directly proportional to its temperature. Therefore, as air undergoes compression, both its pressure and temperature rise.

Additionally, the statement about air becoming heavier relates to how density changes with compression. When air volume decreases due to compression, its density increases, which can be interpreted as the air becoming "heavier" in a sense. Thus, the increase in temperature and density correlates appropriately during compression, making this the correct choice. Understanding this principle is critical in aviation, particularly regarding performance and safety during operations involving changes in air pressure, such as takeoff and altitude changes.