1. Weathering and Erosion

5. Wearing Down the Land from Above In addition to the tectonic processes operating within the Earth, there are forces operating outside the lithosphere that impact the Earth’s surface. In addition to the tectonic processes operating within the Earth, there are forces operating outside the lithosphere that impact the Earth’s surface. These process of gradation originate in the atmosphere and the hydrosphere. These process of gradation originate in the atmosphere and the hydrosphere.

6. Processes of Gradation Gradation includes three different and complimentary processes: Gradation includes three different and complimentary processes: Weathering Weathering Transportation Transportation Deposition Deposition

7. Weathering Weathering is the wearing away and breaking down of the surface of the lithosphere. Weathering is the wearing away and breaking down of the surface of the lithosphere. http://www.brainpop.com/science/weathe r/weathering/ http://www.brainpop.com/science/weathe r/weathering/ http://www.brainpop.com/science/weathe r/weathering/ http://www.brainpop.com/science/weathe r/weathering/

8. Types of Weathering: Mechanical Weathering: Mechanical Weathering: –Physical break down of rocks into smaller and smaller pieces. –Caused by fast moving water or particles carried by wind.

9. Biological Weathering: Biological Weathering: –Break down of rocks caused by living things.

10. Chemical Weathering Chemical Weathering –Break down of rocks into smaller particles caused by chemicals. –Caused by chemicals in rain, or in limestone.

11. Transport Transport refers to the movement of weathered material from one place to another. Transport refers to the movement of weathered material from one place to another.

12. Erosion Erosion occurs when both weathering and transport take place in an area Erosion occurs when both weathering and transport take place in an area Brain Pop Brain Pop http://www.brainpop.com/science/earthsy stem/erosion/preview.weml http://www.brainpop.com/science/earthsy stem/erosion/preview.weml http://www.brainpop.com/science/earthsy stem/erosion/preview.weml http://www.brainpop.com/science/earthsy stem/erosion/preview.weml

13. Process of Erosion Run off from riverbanks carries sediment, (gravel, sand, silt and mud) into the river. Run off from riverbanks carries sediment, (gravel, sand, silt and mud) into the river. Heavy sediment in a river or stream can change the habitat of the plants and animals living there. Heavy sediment in a river or stream can change the habitat of the plants and animals living there.

14. Types of Erosion Erosion by Water: Erosion by Water: –Waves hitting the shore and strong currents can wear away sediment along the shoreline.

15. Erosion by Wind: Erosion by Wind: –Dry light soil can be picked up by wind and blown away, leaving behind layers of soil unable to grow crops.

16. Erosion by Ice: Erosion by Ice: –Glaciers move slowly, due to their size. As they move down a mountainside they slowly scrape the rock layer below causing it to break up.

17. Erosion by Living Things: Erosion by Living Things: –Living things such as moss and lichens can grow on and into rocks causing cracks in the rocks to expand.

18. Deposition Deposition: The process where sediment settles on the bottom of a river. Can cause the filling in of rivers and lakes. Deposition: The process where sediment settles on the bottom of a river. Can cause the filling in of rivers and lakes.

19. Base Level Base level is the point where a river does not deepen a valley anymore it diverts its energy into widening it. Base level is the point where a river does not deepen a valley anymore it diverts its energy into widening it. Gravitational processes try to reach base level by filling depressions and smoothing down high points. Gravitational processes try to reach base level by filling depressions and smoothing down high points.

20. A Deadly Avalanche Read the Deadly Avalanche Case study on page 110 and answer the questions. Read the Deadly Avalanche Case study on page 110 and answer the questions.