Weathering is the breaking down of rocks and materials at the Earth's surface through mechanical and chemical processes. Mechanical weathering occurs via physical processes like temperature changes and ice wedging, while chemical weathering alters the composition of minerals through reactions with water, acids, and oxygen. The rate of weathering depends on factors like climate, topography, rock composition, and exposure time.

1. Weathering

3. Two Types of Weathering

13. Exfoliation or unloading - rock breaks off into leaves or sheets along joints which parallel the ground surface; caused by expansion of rock due to uplift and erosion; removal of pressure of deep burial

19. Lichens such as these growing on the rocks in the picture can produce weak acids that react with the rock.

21. 3000 year old Egyptian Obelisk 3000 year old Egyptian Obelisk after 100 years in NY

22. The Parthenon in Greece shows discoloration and chemical weathering effects from air pollution and acid rain.

25. In which shape will weathering occur faster?