2. Warm-Up 1.If a bone specimen contains 12.5% of its original amount of Carbon-14, how many half lives have passed? 2.How old if the bone? Time’s Up!

3. Evidence of Continental Drift

4. Making Inferences Observation: Information that can be collected using your senses. Inference: a conclusion made based on observations. Today we will be EVALUATING evidence of continental drift.

5. Take 2 minutes to observe the world map. – One observation I would make is that the coast lines are uneven rather than smooth and straight. – Make 2 more observations about the continents coast lines. – Make 1 inference based on your observation End

6. Continental Drift Puzzle (2 minutes) – Work with your partner to try and fit the continent puzzle pieces together. End

7. Continental Drift Do they fit together perfectly? What may have caused the coastlines to change over time? – Come up with 2 possible reasons (2 minutes) End

8. Continental Drift Look at the small pictures on your puzzle pieces. Those are fossils found in those areas of each continent. Rearrange your puzzle so that all of the fossil segments line up. (3 minutes) – Make 3 observations (the same fossils are on more than one continent) – Make 1 inference End

9. Earthquakes Volcanoes End

10. Plate Tectonics Plates = divisions of lithosphere Moving on asthenosphere

11. Continental Drift Continental Drift: The continents are moving.

12. History of Plate Tectonics Alfred Wegener hypothesized in 1912 that continents were slowly drifting around the Earth.

13. Wegener – Continental Drift Theory Early 1900s Once single landmass - Pangaea Broke up – Laurasia, Gondwana Drifted to present location

14. Evidence of Continental Drift 1.The continents fit together.

15. Evidence of Continental Drift 2.Fossils of the same animals are found along the coasts of different continents.

16. Evidence of Continental Drift 3.Seismic, volcanic, and geothermal activity along plate boundaries.

17. How would you explain this evidence?

18. 4. Sea-Floor Spreading Mid-ocean ridges – Tectonic plates moving separating – New magma rises – Form new oceanic crust – Older crust pushed away

19. 5. Magnetic Reversals Molten rock – Magnetic minerals – Align with magnetic field Magnetic field reverses – 177 times in 85 million years – Last 600,000 years ago Recorded in rock – Similar pattern to age of rocks

20. Cause of Continental Drift Convection – Asthenosphere – Heated rock Expands and rises – Cools More dense

21. Pangaea 300 million years ago scientists believe that all of Earth’s landmass was together in one single supercontinent. Over the past 300 million years the continents have spread apart from each other.