Does cooling create more or less density in air?

Cooling air leads to an increase in its density. This happens because the molecules in the air move slower as the temperature decreases, which causes them to be closer together. When air cools, it contracts, and because density is defined as mass per unit volume, the result is that the same mass of air occupies less volume, leading to greater density.

In contrast, warmer air has more kinetic energy, causing the molecules to move more rapidly and spread apart, resulting in lower density. This principle is fundamental in meteorology and helps explain various weather phenomena, such as the behavior of warm and cold air masses and their interactions.