1. Earth’s Moving Continents Ch. 5, Lesson 2 Part 1

2. Wegener’s Evidence Land features- looked like pieces fit together, similar coal fields Fossils- fernlike plants and fresh water reptiles Climate- evidence that climate was colder in South Africa and had to be closer to South Pole

3. Plate Movement Over Time Pangaea- 260 million years ago 225 million years ago, Pangaea began to split

4. How Plates Move Theory of Plate Tectonics- upper mantle is in slow, constant motion driven by convection currents in the mantle

5. Mid-Ocean Ridges An undersea mountain chain where new ocean floor is produced; a divergent plate boundary Sonar- device that bounces sound waves off objects to determine their distance

6. Sea-Floor Spreading Harry Hess- studied mid- ocean ridges and proposed sea-floor spreading Magma causes sea-floor to spread apart along a mid- ocean ridge. This molten material forms new ocean crust Ocean floors move like conveyor belts taking the continents with them

7. Evidence for Sea-Floor Spreading 1. Molten Material- scientists found strange shaped rocks only formed when magma cools quickly after erupting under water

8. Evidence for Sea-Floor Spreading 2. Magnetic Stripes- molten rock cooled and the iron bits lined up in the direction of the magnetic poles

9. Evidence for Sea-Floor Spreading 3. Drilling Samples- samples of rock from the ocean floor showed rocks farthest away from the ridge were the oldest and the closest rocks were the newest