AP BIOLOGY

Detailed explanation-1: -It is a complex system that includes many different processes. Liquid water evaporates into water vapor, condenses to form clouds, and precipitates back to earth in the form of rain and snow. Water in different phases moves through the atmosphere (transportation).

Detailed explanation-2: -Water vapour in the air gets cold and changes back into liquid, forming clouds. This is called condensation. Precipitation occurs when so much water has condensed that the air cannot hold it anymore. The clouds get heavy and water falls back to the earth in the form of rain, hail, sleet or snow.

Detailed explanation-3: -Water Vapor Evaporates Into the Air When air cools, some of the water vapor condenses. As air pressure drops, some water vapor condenses too. The vapor becomes small water droplets and a cloud is formed.

Detailed explanation-4: -Clouds form when the invisible water vapor in the air condenses into visible water droplets or ice crystals. For this to happen, the parcel of air must be saturated, i.e. unable to hold all the water it contains in vapor form, so it starts to condense into a liquid or solid form.

Detailed explanation-5: -In the water cycle, evaporation occurs when sunlight warms the surface of the water. The heat from the sun makes the water molecules move faster and faster, until they move so fast they escape as a gas. Once evaporated, a molecule of water vapor spends about ten days in the air.