Objectives:You will be able to contrast mechanical weathering and chemical weathering.Explain the effects of climate and weathering.

The process that breaks down rocks into smaller and smaller fragments. There is two types of weathering:

Mechanical Chemical

Breaks rock apart without changing their chemical composition.

Common causes are:plants roots or animals ice wedging

Ice wedging is the cycle of freezing and thawing of water in the cracks of rocks.

Water, air, and other substances react with minerals in rock. These change their chemical composition.

The chemical combination for water is H2O which stands for two hydrogen atoms and one oxygen atom.

When the hydrogen and oxygen atoms react with chemicals in some rocks, it causes then rock to wear away.

Water and carbon dioxide in the air produces carbonic acids. These acids “eat” away at rock.

This sometimes creates caves.

Some plants give off acid.

Oxygen reacts with iron to cause oxidation. (Rust)

Rocks containing iron turn a reddish color.

The climate plays a role on the rate and type of weathering.

•In cold areas, mechanical weathering is more rapid.

•In warm areas, chemical weathering is more rapid.