1. AIM: What is Weathering? Do Now – Choose one of the following pictures and describe what is/has happened.

2. I.Weathering the breaking down of a rock into small pieces. As Surface area increases the amount of Weathering increases

3. II. Mechanical (Physical) Weathering - changing the size and shape of the rock. Abrasion: rocks hitting and smashing against each other.

4. III. Types of Mechanical Weathering a) Frost Wedging Do Not Copy the expansion of frozen water in cracks of rocks cause it to break. -This broken material is called talus What happens to water when it freezes?

5. b) Biological Activity - organisms, plants, burrowing animals, and humans break down rocks.

6. IV. Chemical Weathering changing the rocks chemical composition. -forms a new material. * Water is the most important agent.* Acid Rain Damage Soluble: a material that can be dissolved by water.

7. V. Types of chemical weathering a) Acid Rain - water combines with different elements to make acids. - this is known as Hydrolysis. - H 2 O + carbon dioxide = carbonic acid * - H 2 O + sulfur = sulfuric acid (acid rain) What material will all these acids react with? Do Not Copy

8. Acid rain reacts with calcite and dolomite in the rocks (Limestone). This dissolves the rock creating Karst Topography (caves), stalactites and stalagmites. Karst Topography

9. b) Oxidation - Water and oxygen react with metal to create rust.

10. VI. Rate of Weathering A) Rock Characteristics: - Mineral composition and solubility of the rock (the minerals that make the rock) determine the rate of weathering. Granite Limestone

11. - amount of surface area determines amount of weathering

12. - Some rocks are more resistant (harder) to weathering. Mineral composition is the greatest determining factor. Hoodoo In the diagram below, which letter rock is most resistant to weathering?

13. B) Climate: - Temperature and moisture are the most crucial factors. - Chemical weathering is most effective in areas with high temperatures (heat) and abundant moisture (water).

14. Explain the difference in weathering of the two headstones (roughly the same age). What caused the difference in weathering? Slate HeadstoneMarble Headstone Closure: In your Notes

15. Cleopatra’s Needle 1900 - Egypt Present Day - Central Park 2) Describe one factor that explains why Cleopatra’s needle changed after it was brought from Egypt to New York.