A few causes of physical weathering, also known as mechanical weathering, are swiftly moving water, ice and growing plants. Physical weathering refers to the process that breaks rock structures apart but does not change their chemical composition.
When water moves through rocks quickly, it can cause them to break apart and fall onto other areas. When these rocks fall, they may chip, crack and break as they collide with one another and other structures in the environment. When water in a crevice or hole freezes, it expands. The resulting pressure causes cracks in a structure and is another source of weathering. The growing roots of a plant exert pressure on rock structures, causing them to crack and fall apart.