Weathering is the process of breaking down or dissolving rocks and minerals on the surface of the Earth. It is a natural process that occurs due to various agents such as water, ice, acids, salts, plants, animals, and changes in temperature. Weathering can be classified into three types: physical, chemical, and biological.

• Physical weathering: This occurs when physical processes affect the rock, such as changes in temperature or when the rock is exposed to the effects of wind, rain, and waves. Water can get into cracks in a rock and, if it freezes, the ice will expand and push the cracks apart. When the ice melts, more water can get into the larger crack; if it freezes again, it expands and can make the crack even bigger. Wind can cause weathering by blowing grains of sand against a rock, while rain and waves cause weathering by slowly wearing rock away over long periods of time.

• Chemical weathering: This describes the process of chemicals in rainwater making changes to the minerals in a rock. Carbon dioxide from the air is dissolved in rainwater, making it slightly acidic. A reaction can occur when the rainwater comes into contact with minerals in the rock, causing weathering.

• Biological weathering: This is caused by the movements of plants and animals. For example, a rabbit can burrow into a crack in a rock making it bigger and eventually splitting the rock, or a plant may grow in a crack in a rock and, as its roots grow, cause the crack to widen. Even humans can be a source of weathering! Boots and shoes walking over the same patch of rock may eventually wear down the rock.

Weathering is an important process in geography as it contributes to the formation of various landforms such as mountains, valleys, and canyons.