1. Weathering and Soil Formation
SWBAT identify processes that break rock apart; describe processes that chemically change rock; explain how soil evolves.

2. Weathering Weathering Quick Review:
a mechanical or chemical surface process that breaks rocks into smaller pieces.
Quick Review:
What is the difference between a physical or mechanical change and a chemical change?

3. Mechanical Weathering
does NOT change them chemically.
What are two causes of mechanical weathering?
Ice wedging
Water seeps into cracks then freezes creating larger cracks.
Plants and animals
Animals burrow into ground
Plant roots break up the ground

4. Chemical Weathering Chemical weathering
when the chemical composition of rock changes.
What type of climate is causes chemical weathering to happen the quickest?
Tropical regions where it is moist and warm

5. Chemical Weathering
What are 3 things that can cause chemical weathering?
Natural acids
Formed when water mixes with natural elements such as carbon dioxide
Plant acids
Plants produce tannin which can form into an acid that can dissolve minerals
Oxygen
Can cause chemical changes through oxidation

6. Soil Soil What 5 factors affect soil formation?
a mixture of weathered rock, organic matter, water, and air that supports plant life.
What 5 factors affect soil formation?
Parent rock
Slope of land
Climate
Time
Organisms

7. Soil Topography For Tomorrow: surface features
bring in a sample of soil from around your house, for an in class activity.

8. Homework:
On a separate sheet of paper answer self check questions 1-5 on page 321.
Be sure to use complete sentences.
You may work with a partner.