1. Section 12.1 WEATHERING

2. TWO TYPES: ·Physical Weathering: ·Chemical Weathering: rocks are broken down without a chemical reaction. chemical reaction occurs changing the composition of the rock

3.  Ice and water  frost wedging – water seeps into cracks in rock  expands when it freezes causing the crack to expand Mechanical Weathering

4. Which type of climate has the greatest amount of rock weathering caused by frost wedging? 1a dry climate in which temperatures remain below freezing 2a dry climate in which temperatures alternate from below freezing to above freezing 3a wet climate in which temperatures remain below freezing 4a wet climate in which temperatures alternate from below freezing to above freezing Checkpoint #1

5.  Abrasion  Striking rock with sand, pebbles, and large rocks Mechanical Weathering

6. Examples of Abrasion 1. Ice: Glacial

7. 2. Gravity: Mass Movement

8. 3. Water: River, Ocean, Lake action

9. 4. Wind

10. The picture (see image) shows a geological feature in the Kalahari Desert of southwestern Africa. Which process most likely produced the present appearance of this feature? 1Wind Erosion 2Volcanic Eruption 3Earthquake Vibrations 4Plate Tectonics Checkpoint #2

11.  Plants and animals  The breakdown of rock due to plant and animal activity Mechanical Weathering

12.  Upward expansion  Rock outcrops lift, exposing them to weathering Mechanical Weathering

13. The diagram shows the stump of a tree whose root grew into a small crack in bedrock and split the rock apart. The action of the root splitting the bedrock is an example of 1Chemical Weathering 2Deposition 3Erosion 4Mechanical Weathering Checkpoint #3

14.  http://www.classzone.com/books/earth_science/terc/ content/visualizations/es1201/es1201page01.cfm http://www.classzone.com/books/earth_science/terc/ content/visualizations/es1201/es1201page01.cfm Mechanical Weathering

15.  Hydrolysis  Reaction of water with other substances Chemical Weathering

16.  Oxidation  oxygen reacts with rock, breaking them down  produces rust Chemical Weathering

17. Th ink: After thousands of years Cleopatra's Needle looked like the picture on the left. After 100 years in NYC it looks like the picture on the right. Why do you believe this happened? Pair: Discuss this with someone near you Share: Be ready to be called on to share your answers Think-Pair-Share

18.  http://www.classzone.com/books/earth_science/terc/ content/visualizations/es1202/es1202page01.cfm http://www.classzone.com/books/earth_science/terc/ content/visualizations/es1202/es1202page01.cfm

19.  Surface Exposure  More surface area more weathering  Composition of rock  Some rocks weather better than others  Climate  Some climates are more conducive to weathering Rates of Weathering