How does the earth change?

Water and Ice

weathering

Mechanical Weathering:

Water and Ice

Frost Wedging

Lima Beans – Mechanical Weathering

Physically Broken

Mechanical Weathering

Plant Roots

Mechanical Weathering

• Old Man of the Mountains

Chemical weathering

• Rocks break down through Chemical Changes:• Changing rocks• Can be done by:

– Water– Oxygen– Carbon Dioxide– Acid RainChemical Weathering CHANGES rocks permanently!

Water• Water weathers rock by dissolving it

Oxygen• Iron combines with

oxygen in the water (oxidation)

• The product of oxidation is rust

Carbon Dioxide

• CO2 dissolves in rain water and creates carbonic acid

• Carbonic acid easily weathers limestone and marble

Living Organisms

• Lichens that grow on rocks produce weak acids that chemically weather rock

Limestone near the surface

Caves

Chemical Erosion

• breaks down rocks one atom at a time

• dissolves or changes minerals • minerals carried away in water

Agent Erosion

Agent Erosion

Water Erosion

• Rivers, streams, and runoff

Ice Erosion

• Glaciers

Wind Erosion

Mass Movements

• Landslides, mudslides

Which Agent?