Physical weathering : It is also called Mechanical weathering. It includes the breaking up of rocks without changing their composition. It means disintegration of rocks by mechanical means. This type of weathering results from the action of temperature changes, frost, wind and rainfall. It is important in dry areas. The change in temperature causes the bare rocks to expand when warmed by the sun, and contract when night falls and their heat is lost by radiation. The mineral grains of a bed rock expand or contract at different rates as a result of heating or cooling. This causes the breaking of rock into fragment of grains.
