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

When air is compressed, its temperature increases due to the principles of thermodynamics, specifically the ideal gas law. When the volume of a gas decreases under compression, the particles are forced closer together, which increases the frequency and intensity of collisions between them. This increase in molecular activity raises the kinetic energy of the air, resulting in an increase in temperature.

Additionally, in a practical sense, when air is compressed in a piston or a compression chamber, mechanical work is done on the air, which also contributes to an increase in its internal energy and consequently its temperature. This phenomenon is why compressors often experience heat buildup and may require cooling systems to prevent overheating.

In contrast, options suggesting a temperature decrease or that the temperature and volume both decrease or increase are not aligned with the principles of gas behavior under compression.