When rocks, land formations and minerals begin to break down and dissolve, it's called weathering. After crumbling, the process of erosion transports these broken bits away by wind or rain. Agents responsible for weathering include ice, salts, water, wind and plants and animals.

Once the rock is exposed at the surface as an outcrop, weathering begins. The agents of physical weathering can be broadly classified into two groups: those that cause the outer layers of a rock to expand, and those that act like wedges to force the rock apart.

The principal sources of physical weathering are thermal expansion and contraction of rock, pressure release upon rock by erosion of overlaying materials, the alternate freezing and thawing of water between cracks and fissures within rock, crystal growth within rock, and the growth of plants and ...

Water, ice, acids, salts, plants, animals, and changes in temperature are all agents of weathering. Earth Science, Geology, Geography, Physical Geography Weathering is the breaking down or dissolving of rocks and minerals on Earth's surface.