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Wind PowerPoint Presentation

Wind

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Wind

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Presentation Transcript

  1. Wind Earth’s Changing Surface

  2. Review • 5 Agents of Erosion • Gravity • Running Water • Glaciers • Wind Waves

  3. Erosion by Wind • Wind by itself is the weakest agent of erosion. • Powerful force where there are few plants to hold the soil in place.

  4. Wind Erosion • Deflation • The process by which wind removes surface material.

  5. Abrasion • Abrasion • Sand carried by wind can polish rocks

  6. Wind Deposition • Wind Erosion and Deposition form sand dunes and loess deposits. • Sand dunes – A deposit of wind-blown sand • Forms when the wind strikes an obstacle. The sand then begins to pile up. • Sand dunes move over time

  7. Sand Dune

  8. Sand Dune Worksheet

  9. Loess Deposits • Sediment that is finer than sand, such as particles of clay and silt, is sometimes deposited in layers far from its source.

  10. Waves Earth’s Changing Surface

  11. How are Waves formed? • The energy in waves comes from wind that blows across the water’s surface.

  12. Waves • Waves shape the coast through erosion by breaking down rock and transporting sand and other sediment.

  13. Erosion by Waves • Impact – large waves can hit rocks. The energy in waves can break apart rocks. • Abrasion – sediment picked up by waves wear away rock. • Waves changing direction – waves begin to drag on the bottom as they approach the shore.

  14. Deposits by Waves • Waves shape a coast when they deposit sediment, forming coastal features such as beaches, spits, and barrier beaches.

  15. Beaches • As waves reach the shore, they drop the sediment they carry, forming a beach • A Beach is an area of wave-washed sediment along a coast. • Usually sand • Some are made of small fragments of coral or sea shells, Florida

  16. Beach in Southern California

  17. Lake Superior Beach

  18. Florida Keys Beach