A third process is heat from the sun. Air heated by the sun rises, cools, and forms clouds. Heat from the sun can provide enough lifting to produce a thunderstorm. As water droplets form, they remain suspended in the atmosphere by hanging onto tiny particles also suspended in the air such as dust, pollution, ash from volcanoes or even salt particles from the sea. Because these particles are tiny and light-weight, they remain suspended in the air.
Clouds come in many different shapes.
There are four major types. Cumulus are white, puffy, fair weather clouds common on a warm summer afternoon. Cumulus clouds form when air, heated by the sun, rises and cools like bubbles rising in an aquarium. If conditions are right, a cumumlus cloud can grow into the cumulonimbus , a towering storm. The third type is stratus , a grey sheetlike cloud layer that blanket the sky.