Mechanical (or physical) weathering is the process by which physical forces break down rock, minerals and soil into finer particles. This article treats mechanical weathering as being separate from chemical weathering, even though both types of alteration occur concurrently in nature.

Mechanical weathering, also called physical weathering and disaggregation, causes rocks to crumble. Water, in either liquid or solid form, is often a key agent of mechanical weathering. Changes in temperature cause rock to expand (with heat) and contract (with cold).

Mechanical weathering is the breaking down of rocks into smaller pieces without changing the composition of the minerals in the rock. This can be divided into four basic types – abrasion, pressure release, thermal expansion and contraction, and crystal growth.

One type, biological weathering , is caused by animals and plants. For example, rabbits and other burrowing animals can burrow into a crack in a rock, making it bigger and splitting the rock. You may have seen weeds growing through cracks in the pavement. People can even cause biological weathering just by walking.

Physical weathering is caused by the effects of changing temperature on rocks, causing the rock to break apart. There are two main types of physical weathering: Freeze-thaw occurs when water continually seeps into cracks, freezes and expands, eventually breaking the rock apart.

The whole process of weathering of rocks involving living organisms is called biological weathering. Examples: Lichens, mosses, burrowing animals, and even humans due to o all their activities.

Some of the effects of biological weathering are breaking of particles, movement of minerals, mixing of materials and production of carbon dioxide.

Disadvantages Of Weathering And Erosion Chemical weathering also results to a process called oxidation which is responsible for rusting. Weathering and erosion may cause natural disasters through mass wasting like rockslides and mudslides that kill hundreds of people annually.