Some water vapor also enters our atmosphere from the leaves of plants by a process called transpiration . Water returns to the surface by condensation in the atmosphere and precipitation. Clouds of water droplets form when water vapor condenses in the atmosphere. These water droplets may then precipitate to the surface in the form of rain or snow. You are all well aware, however, that clouds to do necessarily lead to precipitation.
Evaporation removes heat energy from the source of the water.
When the water vapor condenses in the atmosphere, the heat energy in the vapor is released. The evaporation of water, the movement of moist air masses, and the subsequent release of heat energy through condensation and precipitation help to redistribute the uneven heat energy from the Sun. You have already learned in a previous lesson why the Sun does not heat the Earth in a uniform way. Movement of moist air masses also transports water from the oceans to the land areas across our entire planet. At any temperature, there is a limit to the amount of water vapor that the atmosphere can contain.