Clouds

Clouds are part of weather conditions and can be signs of weather to come. Clouds form when air rises and cools in the troposphere. Air contains water vapor. The amount of water vapor in the air is measured as humidity. Humid air feels moist and sticky. Warm air can hold more water vapor than cold air can. As air cools, its molecules move closer together. The water vapor molecules in the air also move closer until they join and turn into water droplets. If water vapor joins at freezing temperatures, it forms ice crystals. The droplets or crystals are so light that they stay in the air as clouds. The three main types of clouds are stratus, cumulus, and cirrus. Stratus clouds are gray, layered clouds. Cumulus clouds are puffy and white with flat bottoms. Cirrus clouds are thin, feathery clouds. They form from ice crystals.

This is a chart about clouds. Charts are used to organize all kinds of information to make a topic easier to study.View Larger Image

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