The water cycle

The Water Cycle

Water on the Earth moves in a cycle, from the surface, into the air as a gas, and when it cools, back down to the ground as a liquid.

How does it happen?
When the Sun shines it heats water on the surface of the seas, the oceans and rivers and the liquid changes into a gas called water vapour. This change is called evaporation. Water also evaporates from streams, lakes and ponds and from puddles after rain. The warm air rises.

When the warm air meets cooler air, the water vapour cools and changes into a liquid again, as tiny drops of water. They form the clouds. This change is called condensation.

As the drops in the clouds get cooler they join together and fall as rain.

Go here for an excellent animation that illustrates the water cycle.
http://www.epa.gov/OGWDW/kids/flash/flash_watercycle.html

At this site there is some information about the temperature of the air and why hot air rises. http://www.sciencekidsathome.com/science_topics/hot_air.html

When warm air rises, colder air moves in under it. This causes the winds.

Acknowledge this source in your bibliography like this:
Thomas & Sydenham, The Water Cycle. [Online] www.kidcyber.com.au 2008

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