Clouds are basically made of tiny drops of water of small ice crystals. Water vapors from the surface of water rises into the air, they get change into droplets of water by cooling and condensing process. When enough amount of water vapors condenses into large amount of crystals it is a stage when cloud is formed. Clouds are form in different conditions. Depending on cloud formation there are different types of clouds.

There are three main types of clouds are found in sky.

Cumulus
Cumulus clouds are white in color. And they are fluffy and seem like fluffy balls in the sky. In process of formation of clouds the warm and moist air from the surface of the earth rises, and cool off rapidly. Cumulus clouds form clusters and are mostly found on the surface of sea in irregular shape. These clouds take might 10 minutes to break up. When the cumulus cloud turn into dark gray colors, cumulonimbus cloud is formed. Cumulonimbus clouds are one of those clouds which cause heavy rain, hail or lightning.

Stratus
Stratus clouds are in shape of flat sheets. They do not move so much, mostly they stay at one place for sometime. Overcast weather or rain is caused by stratus. When air rises slowly over the large area Nimbostratus clouds are formed. Nimbostratus clouds result long steady rain.

Cirrus
Cirrus clouds are completely made up of ice crystals. They are found at height in the sky. They look like feathers in the sky. They are very light and wispy. When a large number of Cirrus clouds are formed in the sky. They run into each other and form cirrostratus clouds.

Fog is similar to the clouds because they are also made of water droplets. Clouds are formed higher in the sky while fog is formed near ground. Fog is formed on cool night because ground is cold. The water vapors get condensed and change into droplets near the ground to form fog. These droplets are very small. It takes 7 trillion of these droplets to make one tablespoon of water.