1. Weathering and Erosion

2. Weathering
The breakdown of the materials of Earth’s crust into smaller pieces.

3. TYPES OF WEATHERING Physical Weathering Chemical Weathering
Biological Weathering

4. Physical Weathering
Process by which rocks are broken down into smaller pieces by external conditions.
Types of Physical weathering
Frost heaving and Frost wedging
Temperature changes
Wind Erosion

5. Frost Wedging

6. Change in size
Especially effective at breaking up rocks that contain clay.
Clays swell up when wet and shrink when dry.

8. Wind Erosion

10. Biological Weathering
**Plant roots
**Burrowing of animals
**breaking of rocks

11. Plants roots

12. Plant Roots

13. Burrowing of Animals

14. Burrowing by animals

15. Action of plants and animals:
Lichens and mosses grow on rocks
They wedge their tiny roots into spores and crevices.
When the roots grow, the rock splits.

16. Types of Mechanical Weathering

17. BY HUMANS

19. Chemical Weathering
The process that breaks down rock through chemical changes.
The agents of chemical weathering
Water
Oxygen
Carbon dioxide
Living organisms
Acid rain

20. Water
Water weathers rock by dissolving it

21. Oxygen
Iron combines with oxygen in the presence of water in a processes called oxidation
The product of oxidation is rust

22. Carbon Dioxide CO2 dissolves in rain water and creates carbonic acid
Carbonic acid easily weathers limestone and marble

23. Living Organisms
Lichens that grow on rocks produce weak acids that chemically weather rock

24. Acid Rain
Compounds from burning coal, oil and gas react chemically with water forming acids.
Acid rain causes very rapid chemical weathering

25. AFL Identify the Type of Weathering

26. FREEZING OF WATER IN THE ROCKS

27. BURROWS

28. Acid Rain

29. CAMPING

30. Holes in the rocks due to reaction between mineral and water

31. Spreading of
roots