The process by which water vapor turns into liquid is called condensation. This occurs when water vapor cools to the point that molecules no longer have enough energy to remain in a gaseous state, leading them to cluster together and form liquid droplets. Condensation is a crucial part of the water cycle, contributing to cloud formation, fog, and precipitation. This process can be observed in everyday life, such as when water droplets form on a cold glass on a warm day, as the moisture in the air condenses on the surface of the glass.