Notes

The process of weathering breacks rocks into smaller pieces. Some of these tiny pieces combine with once-living material to form topsoil. Other small pieces of rock collect as sediments. This breackdown of rocks happens as they interact with air, water and living things. There are two basic types of weathering one of them is physical weathering. Physical weathering breacks big rocks into smaller ones without changing the minerals they contain widely swinging temperatures cause physical weathering. For example, rocks in a desert bake the day beneath the sun's scorching hear. As rocks hot, they expand. At night, tempetures in the desert fall. As rocks cool down they contractor shrink slightly. Expand contract-this endless cycle gradually causes rocks outher layer to crumble or flake off. Water also causes physical weathering. Water seeps into tiny cracks in rocks. If temperatures drop below frezzing