Clouds are an essential part of the weather conditions which exist around us. Warm air rises upwards in the atmosphere carrying with it dust and moisture from evaporated surface water. At higher altitudes the air is cooler and the vapour in the warm air reaches its 'Dew point' where it changes either to small particles of ice or into water thus forming clouds. Since cloud formation takes place at different heights and temperature, clouds are of different types.
There are basically three main types of clouds. Upto about 1.5 km from the ground we generally see the first type called the 'Stratus' clouds, on occassions it is the grey status clouds which bear light rain. In the colder areas the water in these clouds freezes thus resulting in snow fall. Slowly rising warm air produces thes clouds. Above these and upto about 4.5 km lie the 'Cumulus' Clouds, these are the fluffy clouds which is a result of quickly rising warm air. Above the cumulus clouds, at an altitude of about 14 km float the 'Cirrus cloud'. This cloud are wispy cloud formed at such a high altitude that they contain only Ice crytals.
Lying between these three main types of clouds are other types of clouds are other tupes like the Stratocummulus, Altocummulus, which are medium sized and consist of rounded massess, Cirrocummulus which contains rippled clouds or rounded masses, Altostratus which is a greyish sheet cloud and Cumulonimbus clouds which cause thunderstorms and so on. Cumulonimbus carry in them both negative and positive charges, the positive charge tend to move to the upper levels of the cloud while the negative remains below, the separatin of the charges results in the discharge of lightning. As lightning strikes, it is followed by thunder which is caused by the heat created by lightning.