Chapter 1 Earth: The Water Planet Section 3 The Water Cycle

The Water Cycle The water cycle continually moves water through the living and non-living parts of the environment. The sun’s energy is what drives this cycle.

Water Evaporates As the sun warms the surface of a body of water, some of the water molecules change from a liquid to a gas and rises into the atmosphere in a process called evaporation.

Water Evaporates Water vapor can also be released into the atmosphere from plants that give off water through their leaves in a process called transpiration.

Clouds Form The higher in the atmosphere these gas molecules go, the colder it gets, causing them to turn back into liquid water in a process called condensation. Condensed water droplets in the sky tend to clump together around tiny dust particles, forming clouds.

Water Falls as Precipitation As more water condenses, the cloud’s water droplets get larger and larger until eventually they fall back down towards Earth in a process called precipitation.

Water Falls as Precipitation Once the water falls onto Earth, it can take a number of paths before it eventually goes through the cycle again.

A Global Process Precipitation and evaporation are balanced around the world. We may feel like we are getting a lot of rain, but somewhere in the Sahara Desert, they are barely getting any rain.