5 agents of Mechanical Weathering

Animal Actions

• Animals that burrow in the ground
• Including moles, gophers, prairie dogs, and some insects
• The ground loosens and breaks apart rocks in the soil

Freezing and Thawing

• When water freezes in a crack in a rock
• It expands and makes the crack bigger
• The process of frost wedging also widens cracks
• Examples are sidewalks and causes pot holes in streets

Plant Growth

• Plant roots enter cracks in rocks
• As roots grow, they force the cracks apart
• over time, the roots of even small plants can pry apart cracked rocks

Release of Pressure

• As erosion removes material from the surface of a mass of rock
• pressure on the rock is reduced
• This release of pressure causes the outside of the rock to crack and flake 
• off like the layers of an onion

Abrasion

• Sand and other rock particles that are carried by wind, water, or ice
• wear away exposed rock surfaces like sandpaper on wood

The End