1. Weathering
Chapter 5.1

2. Weathering Definition
A constant process of breaking down objects on the Earth’s surface

3. Mechanical Weathering
Breaking rock into smaller and smaller pieces.
It DOES NOT change the rock…it just changes the size!!

4. 4 Types of Mechanincal Weathering

5. Abrasion
Physical grinding of rock fragments
Think of sandpaper

6. Frost Wedging
Water fills in cracks in rock, freezes and expands, causing the rocks to break apart

8. Organic Activity
Plants grow in the cracks of rocks and their roots cause them to break

9. Thermal Expansion
Warming causes the rock to expand. When it cools, it contracts and breaks.

10. Changing the rocks chemical composition or chemical make up.
Chemical Weathering
Changing the rocks chemical composition or chemical make up.

11. 4 Types of Chemical Weathering

12. Oxidation
Iron + Oxygen = Rust

13. Carbonation Carbon Dioxide + Water = Carbonic Acid
Gets into the soil and dissolves the rocks underneath

14. Sulfur oxides + Rain = Acid Rain
Sulfuric Acid
Sulfur oxides + Rain = Acid Rain
AFTER
BEFORE

16. Hydrolysis Water can dissolve minerals or form new minerals
Water + Feldspar = Clay

17. Factors that Affect the Rate of Weathering

18. Composition of the Rock
The harder the rock, the slower it will weather
Ex. Sandstone
is easily
weathered
Moh’s Scale – 3.5

20. The more moisture, the faster the rocks weather
Climate
The more moisture, the faster the rocks weather

21. Surface Area
The amount of the rock exposed to the environment