Use the following words to fill in the blanks. potholes acid rain climate cracks Chemical moisture Frost wedging temperatures Rust Freezing minerals Mechanical Pressure Pieces

Weathering is the breaking of rocks into . There are two main types of weathering. weathering involves breaking rocks without changing their chemical composition. In , water trapped in rocks freezes and expands, forcing the rocks apart. can also cause mechanical weathering. Plant roots put pressure in rocks and cause small to widen and split the rock. weathering involves water, air and other substances’ to react with the minerals in rocks. When metal is exposed to water and oxygen, oxidation occurs and forms. Carbonic acid in plant roots and mosses also react with the in rocks. Water and carbon dioxide form which deteriorates many stones. How rapidly these changes occur depend on the of the area. Chemical weathering happens more slowly in the desert because there is little . Low in polar regions cause more physical weathering. Whenever and thawing alternate, mechanical weathering becomes very detrimental forming many on the roadways.