0. WEATHERING

2. What breaks down rocks?
1. Erosion: process of wearing down and carrying away rocks
2. Weathering: breakdown of rock material by physical and chemical processes
Erosion works continuously to weather and carry away rocks at Earth’s surface.

3. Physical Weathering
Process by which rock is broken down into smaller pieces by physical changes.
Agents of Physical Weathering:
Temperature Change
Pressure Change
Plant and Animal Actions
Water
Wind
Gravity

4. Temperature Change Frost Wedging: 1. Water seeps into cracks
2. Water freezes into ice
3. The ice expands
4. Ice forces rocks apart
Warming and Cooling:
Warm/hotter rocks expand, cool rocks contract.
Repeating of this causes weak structure and crumbling.

5. Pressure Change
Release of Pressure: erosion removes material from mass of rocks and reduces pressure causing surface of rock to crack and flake
Exfoliation: process by which outer layers of rock slowly peel away due to pressure changes

6. Plant and Animal Actions
Animal actions: animals burrowing can loosen and break apart rocks in the soil, burrowing exposes more rock
Plant growth:
1. Plant roots enter cracks in rocks
Roots continue to grow, putting pressure on rock
3. Roots force cracks apart

7. Wind, Water, and Gravity
Abrasion: breaking down and wearing away of rock material by other rock
Wind: small particles carried and hit against other rock surfaces
Water: in moving water rocks become rounded and smooth
Gravity: rocks fall from higher slope and break rocks below