1. Weathering and Erosion

2. Weathering The process that breaks down rocks and other materials of Earth’s crust into smaller pieces.

3. Erosion The removal of rock particles by wind, water, ice, or gravity.

4. Weathering and erosion work together to wear down and carry away rocks on Earth’s surface

5. Avalon Wildwood

6. Weathering

7. Weathering can happen two different ways - Physical and Chemical

8. Physical Weathering Rock is physically broken down into smaller pieces

9. There are five types of physical weathering

10. 1. Freezing and thawing

11. Frost Wedging

12. Frost Heaving

13. 2. Plant Growth

16. 3. Animal Actions

17. Burrowing of Animals

18. 4. Friction and impact River rocks are rounded and smoothed due to the repeated tumbling along the river bed as they roll downstream

19. Evidence of past liquid water on Mars!

20. 5. Temperature Changes Rocks expand (get bigger) when they are hot, and contract (get smaller) when they are cold.

21. This brick wall has expanded and there is a visible crack

23. Chemical Weathering The process that breaks down rock through chemical changes.

24. There are five types of chemical weathering

25. 1. Water Water weathers rock by dissolving it

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

27. 3. Carbon Dioxide CO 2 dissolves in rain water and creates carbonic acid Carbonic acid easily weathers limestone and marble

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

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

31. All this weathering can create interesting landforms

32. Formation of Devil’s Tower, Wyoming http://www.youtube.com/watch?v=Hsh3_ZMKq-A

33. Karst Topography A type of landscape in rainy regions where there is limestone near the surface Created by chemical weathering of limestone

34. Features of Karst: Sinkholes

35. Features of Karst: Caves

36. Features of Karst: Disappearing Streams

37. Erosion

38. Erosion moves rock particles using four different methods

39. 1. Water Erosion Rivers, streams, and runoff http://www.youtube.com/watch? v=ReCt2AcydCg&feature=relate d

40. 2. Ice Erosion Glaciers http://www.youtube.com/watch?v=X OGbOOaPHsw&feature=related

41. 3. Wind Erosion http://www.youtube.c om/watch?v=mecKn kc9qMk

42. 4. Gravity Landslides, mudslides, slump and creep http://www.youtube.com/watch? v=ZVjr4mii3cE&feature=player_ embedded#http://www.youtube.com/watch? v=ZVjr4mii3cE&feature=player_ embedded#!

43. Summary Weathering breaks down rocks –It can be physical (ice, plants, animals, friction, temperature change) or chemical (water, oxidation, acid rain, carbon dioxide, living organisms) Erosion moves the rocks Together they produce soil http://www.youtube.com/watch?v=HjVSiuj7Lxk

44. Soil Soil is made from rocks, minerals (mostly sand and clay), and organic materials Soil forms layers of different characteristics called horizons

45. What is soil? Soil is a material that forms the crust of the earth. It comes from the weathering of rocks and decomposition of organisms. It is formed very slowly.

46. What’s in soil? Minerals Organic matter Air and water Living organisms

47. Soil is found in layers called horizons

48. Soil- notice the layers in the soil

49. O horizon (green) O = Organic The top, organic layer made up mostly of leaf litter and humus. Humus is decomposed organic matter.

50. A horizon (dark brown) A = Topsoil. Dark colored Where seeds germinate and roots grow. This is generally the most productive layer of soil.

51. B horizon (light brown) B = Subsoil Lighter colored Contains clay and mineral deposits (iron, aluminum, etc)

52. C horizon (tan) C = Parent Material Layer of large unbroken rocks

53. R horizon (black) R = Bedrock. The solid rock that is under the soil

55. Areas with a lot of humus and topsoil are great for growing plants.

56. Weak humus- mineral mixture Mosaic of closely packed pebbles, boulders Dry, brown to reddish-brown, with variable accumulations of clay, calcium carbonate, and soluble salts Desert Soil (hot, dry climate) Grassland Soil (semiarid climate) Alkaline, dark, and rich in humus Clay, calcium compounds

57. Acidic light- colored humus Iron and aluminum compounds mixed with clay Forest litter leaf mold Humus-mineral mixture Light, grayish- brown, silt loam Dark brown firm clay Acid litter and humus Humus and iron and aluminum compounds Light-colored and acidic Tropical Rain Forest Soil (humid, tropical climate) Deciduous Forest Soil (humid, mild climate) Coniferous Forest Soil (humid, cold climate)

58. Soil lab online Tomorrow you will meet in the computer lab (123) and compare rainfall amounts to topsoil depths. You will learn how rainfall affects topsoil depth.

59. Remainder of the period Answer the review questions as a group. Use this diagram to label the layers pictured in #4. You will still need to name and describe them (except layer E) Sharpen and return pencils and cup