Compare chemical weathering to mechanical weathering

Chemical weathering is the process by which the internal structure of a mineral is altered by the addition or removal of elements, while mechanical weathering is the breaking down of big rocks to small rocks.

It affects the rocks in place and no transport is involved. This distinguishes weathering from erosion. Mechanical / physical weathering - physical disintegration of a rock into smaller fragments, each with the same properties as the original. Occurs mainly by temperature and pressure changes