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Weathering and Erosion

Weathering and Erosion. Essential Question: How does weathering and erosion shape our Earth?. What is Weathering?. Weathering is the process of breaking down rocks Two forms of weathering: Mechanical/Physical Chemical. What is Mechanical Weathering?.

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Weathering and Erosion

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  1. Weathering and Erosion Essential Question: How does weathering and erosion shape our Earth?

  2. What is Weathering? • Weathering is the process of breaking down rocks • Two forms of weathering: • Mechanical/Physical • Chemical

  3. What is Mechanical Weathering? • Mechanical weathering is breaking down by natural or physical processes

  4. The 3 Types of Mechanical Weathering

  5. 1. ICE WEDGING When water goes into fractures in rock and freezes, the force of expansion is great enough to break the rock into smaller pieces.

  6. Mount Rushmore – South Dakota Bryce Canyon – Utah

  7. 2 . Abrasion • Abrasion • Collision of rocks • Makes rocks more spherical Bighorn Mountains – Wyoming Antelope Canyon – Arizona Wyoming What causes abrasion? 1. Water 2. Wind Elephant Rocks Park – Missouri 3. Ice 4 . Gravity

  8. Not Just Limited to Rocks…..

  9. 3. Root Action Slow process When roots spread to break rock

  10. Close to Home

  11. What is Chemical Weathering? • Chemical weathering occurs when minerals are chemically changed causing them to dissolve or change to another mineral • Oxidation • Acid • Plants

  12. Oxidation • Oxidation - chemical reaction with oxygen and iron rich rocks. Causes rocks to “rust” • iron-rich rock have reddish stains from "rusting" due to iron and oxygen reacting

  13. Close to Home

  14. Plant Acids • Some roots and decaying plants give off acids that also dissolve minerals in rock. When these minerals dissolve, the rock is weakened. • Eventually, the rock will break into smaller pieces.

  15. Plants Plants – called lichens produce rock dissolving acids that can break down rock.

  16. Acid precipitation (Acid Rain) Sulfur & CO2 from cars and coal/oil mix with water to produce acidic precipitation. • Rain • Snow • Sleet • Hail

  17. How does the Environment affect Weathering? • Temperature • Different temps give different type of weathering • Moisture • High moisture, chemical Weathering • Low moisture, mechanical

  18. Effects of Climate • Chemical weathering is more rapid in warm, wet climates. • Lack of moisture in deserts and low temperatures in polar regions slow down chemical weathering. • In cold climates, where freezing and thawing are frequent, mechanical weathering rapidly breaks down rock through the process of ice wedging.

  19. IDENTIFY THE PROCESS!!!

  20. 1

  21. 1-AbrasionMechanical

  22. 2

  23. 2-Onion Skin Weathering Mechanical

  24. 3

  25. 3-ChemicalWater is wearing away the rock

  26. 4

  27. 4-Freezing and ThawingMechanical

  28. 5

  29. 5-Mechanical

  30. 6

  31. 6-Mechanical & Chemical….how?

  32. 7

  33. 7-MechanicalAnimal Actions

  34. 8

  35. 8-Mechanical with a little Chemical

  36. 9

  37. 9-Chemical

  38. 10

  39. 10- Mechanical but could possibly be chemical

  40. 11

  41. 11-Another rusted bike!

  42. 12

  43. 12-Release of Pressure Mechanical

  44. 13

  45. 13-Chemical – Lichen grow, they release chemicals when they grow

  46. 14

  47. 14-They call this Potato Chip RockCould mechanical or chemical….

  48. 15

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