Photograph of cumulus clouds in the mountains of Colorado.
Click on image for full size
Courtesy of Lisa Gardiner
Clouds can come in all sizes and shapes, and can form near the ground or high
in the atmosphere. Clouds are groups of tiny
water droplets or ice crystals in the sky and are formed by different processes. They can make different
kinds of precipitation depending on the
Cloud types are classified by height and
appearance. The shape depends on the way the air moves around the cloud. If air moves
horizontally, clouds form spread-out layers. Clouds grow upward if air
is moving vertically near the cloud.
At any given time, clouds cover about 50% of the Earth. We would not have rain,
thunderstorms, 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
Did you know that Earth is not the only planet with clouds? Other planets, like Venus
, and Saturn
, have clouds too!
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