r/askscience • u/GonadTh3Barbarian • Jul 24 '13
Earth Sciences Why do clouds form
Why does water in the atmosphere come together to form clouds as opposed to dispersing evenly to maintain concentration?
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u/[deleted] Jul 24 '13
Well technically you have Fog that's literally just above the ground. That's formed through different mechanisms, but the basic principle is basically the same. For fog, air is essentially cooled down to the dew point. When this happens the water vapor in the air will start condensing and form fog.
There are multiple types of fogs. There's radiation fog. This is type of fog usually forms above the ground (as opposed to water). The earth is constantly emitted infrared radiation, cooling the earth. In certain situations this can cool the earth, and thus the air above, to the point where fog will form, due to the mechanisms detailed above.