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How Plates Move PowerPoint Presentation
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How Plates Move

How Plates Move

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How Plates Move

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  1. Earth’s lithospheric plates move at a rate of about 2 to 5 centimeters per year (1 to 2 inches); about the same speed that your fingernails grow. Why do they move?

  2. How Plates Move All the land on earth floats, but not on water. It floats on the Mantle of semi-liquid rock just beneath Earth's crust. The mantle is solid in its center, but soft on its upper boundary. Like a thick liquid, the upper mantle has convection currents--which make the plates move. When the mantle oozes out of a plate boundary, or out of a volcano, we call it lava.

  3. The continents float around on the surface of the earth in super-slow-motion. They float on "rafts" of rock called tectonic plates . There are about 8 major plates, and many small plates.

  4. How Do We Know that Plates Move?

  5. Theory of Continental Drift Alfred Wegener’s Theory of Continental Drifts suggests that continents were once a single land mass that drifted apart. Fossils of the same plants and animals are found on different continents Called this supercontinent Pangea, Greek for “all Earth” 245 Million years ago Split again – Laurasia & Gondwana 180 million years ago

  6. Evidence of Pangea