Mechanical Weathering

Freezing and Thawing

• When water gets in the rock from a crack, it freezes.
• When water freezes it expands and makes the crack bigger.
• Frost wedging makes cracks bigger in sidewalks and streets.

Animal Actions

• Animals burrow into the ground and loosen rocks.
• Rock breaking away there can cause holes in mountains

Plant Growth

• Plant roots get in cracks in rocks.
• The roots grow and force cracks to get bigger.
• Small plant roots can do damage too.

Release of Pressure

• The pressure n the rock reduces when erosion takes away material.
• The outside of the rock cracks from the release of pressure.

Abrasion

• Small particles carried away by wind erode rock.
• It's like using sandpaper on wood.