PRESENTATION OUTLINE
Animal Actions
Animals that dig into the ground such as moles and prairie dogs. They loosen up the soil and break away rocks.
Freezing and Thawing
When water freezes into to a crack it expands it. Frost wedging also can widen the cracks. One year you see a crack then over a while you see that it has gotten bigger that is mechanical weathering called freezing and thawing.
Plant Growth
Plant roots enter cracks as they grow they expand the cracks. Over time even a small plants can tear away cracked soil or rocks
Release of Pressure
As erosion removes material from a rock the pressure on a rock is reduced. The release of pressure causes the outside of the rock to crack and flake off in layers.
Abrasion
Have you ever seen a rock that looks like its about to fall off well I can explain that. Particles that are carried by wind, water, or ice wear away exposed rock and this happens more where there is an open area.
