Clouds are condensed or frozen atmospheric moisture. Fog is a specific type of cloud, but clouds are not a type of fog. The different types of clouds are:
Other types of clouds include:
At the very basic level, clouds form when air that is relatively warm and moist cools down for some
reason. In order for the
water vapor to
condense,
condensation nuclei are required. The condensing process releases
heat, which is part of how a
thunderstorm is fueled.
Dust and
water droplets can serve as condensation nuclei. In order for the water droplets to
freeze, an actual
solid particulate matter of some sort is required. If it is not present, the droplets will become
supercooled water - at a
temperature below
freezing, but still in a
liquid state.
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