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Cloud
Introduction References & Edit History Related Topics
Images & Videos
View a time-lapse video of cloud formations rolling across the sky followed by a thunderstorm
How do clouds float?
Learn about the four main types of clouds formed at different altitudes
What Is Cloud Seeding?
cloud: cumulonimbus lightning: cloud-to-ground Sun Altocumulus undulatus clouds form parallel, wavy bands across the sky, brightly illuminated in orange and gold by the setting or rising sun above a dark horizon. cloud vortices false-colour mosaic of the Great Red Spot
At a Glance
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cloud summary
Quizzes
Lightning over a farm field. Weather electricity thunderstorm light energy tree
Facts You Should Know: Weather Quiz
Umbrella colored like a rainbow sticking out above a sea of black umbrellas while it rains. (storm, weather)
Weather Words Vocabulary Quiz
Model of a molecule. Atom, Biology, Molecular Structure, Science, Science and Technology. Homepage 2010 arts and entertainment, history and society
Science Quiz
rain. Child in the rain, wearing a rain coat, under a yellow umbrella. April Showers weather climate rain storm water drops
April Showers to March’s Lions and Lambs
ten types of clouds and their elevation: cirrus, cirrocumulus, cirrostratus, altocumulus, altostratus, nimbostratus, stratocumulus, stratus, cumulus, cumulonimbus
Earth’s Atmosphere and Clouds
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Cloud

meteorology
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Britannica Editors
Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree....
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Cloud, any visible mass of water droplets, ice crystals, or a mixture of both that is suspended in the air, usually at a considerable height (see video). Fog is a shallow layer of cloud at or near ground level. Clouds are formed when relatively moist air rises. As a mass of air ascends, the lower pressures prevailing at higher levels allow it to expand. In expanding, the air cools adiabatically (i.e., without heat exchange with...

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