Lichens and other chemicals get into rocks to cause chemical weathering Water, sand and wind can cause physical weathering. When the water freezes, cracks are widened and rocks are broken apart. Ocean waves pound against the coast are constantly changing the shore line. Rivers carry pebbles, sand and constantly rub against the riverbed. The Grand Canyon in Arizona is a result of erosion caused by the Colorado River.
Glaciers can cause erosion and carry material from one location to another.