There are two types of weathering: by chemical or mechanical means. Chemical weathering occurs when water is present, in which case the rock rots. The other type occurs when ice is present. This is frost shattering.

Notice that weathering occurs in the ground. If the weathered rock is not moved away, a soil forms. If the material is moved away, this is erosion.

In general frost shatter produces only sand or larger fragments, whereas chemical rotting produces fine material or soil.

The type of weathering, and the speed at which it occurs, depends on climate and the rocks being weathered. In the humid tropics chemicals work rapidly to reduce all rocks to clays. By contrast, in cold rainy climates, temperatures are too low for rocks to weather very quickly and frost shatter is more important. In mid latitudes a combination of chemical and frost shatter produces soils that have both coarse particles (stones) and fine particles. In the wet tropics, chemical weathering works fast and frost shatter never occurs. In this case the weathered material produced is all clay.

Two blocks of chalk are placed in a beaker.

Vinegar is added. The chalk fizzes and begins to dissolve. This is a fast version of chemical weathering. The chalk goes into solution and can be carried away by even slow-flowing rivers.