The physical, biological or chemical factors that erode rock, from sand to ice, rain to plants, and even footsteps.
- "Weathering" refers to the breakdown of rocks into smaller pieces.
- Physical weathering occurs as wind, water and smaller rock particles scour exposed rock surfaces.
- Chemical weathering occurs as a result of weak acid in the atmosphere and rainfall reacting with rock forms.
- Biological weathering is caused by living creatures, e.g. plant roots, barnacles and sea urchins all bore into rocky surfaces.