Weathering's the decomposition of Earth rocks, soils and their minerals through direct contact with the planet's atmosphere. Weathering occurs in situ, or "with no movement", and thus shouldn't be confused with erosion, which involves the movement of rocks and minerals by agents such as water, ice, wind and gravity. Two important classifications of weathering processes exist — physical and chemical weathering. Mechanical or physical weathering involves the breakdown of rocks and soils thro… (More on Weathering)