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Photograph of cumulus clouds in the mountains of Colorado.
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Courtesy of Lisa Gardiner

Clouds

Clouds are the pretty white fluffs you see in the sky. They are made up of tiny water drops. Sometimes, if the wind is fast enough, you can even watch the clouds move.

Clouds can come in all sizes and shapes and are formed by different processes. They can be near the ground or way up high. Ever wonder what different types of clouds are called?

Different types of clouds cause different kinds of weather. Sometimes clouds get dark and scary looking when a thunderstorm or tornado has formed.

At any given time, about half of Earth is covered by clouds. We would not have rain, rainbows, or snow without clouds. Clouds make up some of the atmospheric optics we can see in the sky. The atmosphere would be boring if the sky was always blue!


Last modified May 21, 2009 by Becca Hatheway.

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Windows to the Universe, a project of the National Earth Science Teachers Association, is sponsored in part by the National Science Foundation and NASA, our Founding Partners (the American Geophysical Union and American Geosciences Institute) as well as through Institutional, Contributing, and Affiliate Partners, individual memberships and generous donors. Thank you for your support! NASA AGU AGI NSF