The process in nature that breaks down rocks is called physical weathering. Physical forces such as abrasion, frost action, salt crystal growth, thawing, freezing and temperature fluctuation weaken rocks and cause them to crack and disintegrate over time. Fluctuations in temperature over time can cause rocks to break as a result of constant stress from contraction and expansion.
The surface of a rock can break down from constant friction caused by ice, water and wind. Constant frost exposure causes rocks to break down because the melting ice becomes trapped inside cracks in the rock and then expands when freezing, resulting in significant outward pressure. Rocks can also fall apart because of salt crystal growth, which is a process that takes place when a rock is exposed to groundwater that seeps into its empty spaces and pores.