How things begin to wear away.

1. Weathering the breakdown of rock at or near the earth’s surface into smaller and smaller pieces…

2. Mechanical or Physical Weathering Happens when rock is broken or weakened by physical processes; the make up of the rock itself is not changed, it only becomes smaller Tree Roots Frost Wedging

4. Physical Weathering from plant roots on the Duckabush River in the Olympic Mountains in Olympic National Park in Washington

6. Mount Rushmore

7. Chemical Weathering A change occurs in the mineral make up of the rock, or the minerals are combined with new chemical elements Water and CO2 most important factors – combine to make carbonic acid, a weak solution that dissolves away rocks Wetter and warmer climates promote a faster process of chemical weathering

8. Acid Rain occurs when chemicals in the atmosphere combine with water vapor and fall back to earth’s surface as rain and... Destroys forests Eats away surfaces of stone buildings or monuments, and rock formations Pollutes water

9. Causes of Acid Rain... Industrial Pollution Volcanic Ash

10. Some Obvious Effects of the Weathering Process... Old Stone Structures Rock Formations Mountains worn from Jagged Peaks