Weathering and soil formation

1
Weathering and soil formation
2
Weathering the breaking down rock and other
substance on earths surface.

• It is a process that takes a long time and acts
  slowly.
• Mechanical rock that is physically broken down.
• Chemical breaks down rocks through a chemical
  change.

3
Mechanical Weathering

• Release of pressure
• Freezing and thawing
• Plant growth
• Abrasion
• Animal action

4
Release of Pressure

• This release of pressure causes the outside of
  the rock to crack and flake off like the layers
  of an onion.

5
Freezing and Thawing

• When water freezes in a crack in a rock, it
  expands and makes the crack bigger. The process
  of ice wedging also widen cracks in sidewalks and
  causes potholes in street.
• Freezing

6
Plant growth

• Roots of tree and other plants enter cracks in
  rocks. As the roots grow, they force the cracks
  father apart. Over time, the roots of even small
  plants can pry apart cracked rocks.

7
Abrasion

• Sand and other rock particles that are carried by
  win, water, or ice can wear away exposed rock
  surfaces like sandpaper on wood. Wind driven can
  shape rock.

8
Animal Action

• Animal that burrow in the ground including moles,
  gophers, prairie dogs, and some insects, loosen
  and break apart rocks in the soil.
• lichen