10 Science Seafloor Spreading theory.pptx

this is a grade 10 presentation in science about seafloor spreading theory

1. Most Essential Learning Competency Trace how the seafloor spreading theory was develop by the scientist. Identify the different evidences that support the seafloor spreading Explain how the evidences support the seafloor spreading Appreciate the significance of this evidences in the theory of plate tectonics Enumerate the lines of evidence that support plate movement

2. Alfred Wegener Despite the evidences presented in his theory, his idea that the continents were once joined together was not accepted by the scientific society until 1960s.

3. CONTINENTAL DRIFT THEORY Complete the concept map. Puzzlelike fit of continents Fossils Rock formation Coal and Glacial Deposits Climatic Change Paleomagnetism

4. SOUNDS LIKE

5. COIN TIN ANTS CONTINENTS

6. SEE FLOUR SEAFLOOR

7. SHH BREAD SPREAD

8. TEA YOU RAY THEORY

9. EVE AID DANCE EVIDENCE

10. MOLE TIN RACKS MOLTEN ROCKS

11. Ma’am Jeraldel Encepto EVIDENCES SUPPORTING SEAFLOOR SPREADING THEORY

12. Purpose of the Seafloor studies during WWII To understand the topography of the sea floor To find hiding places for both allied and enemy submarines

13. In 1950s and 1960s, new techniques and modern gadgets enabled scientists to make better observations and gather new information about the ocean floor.

14. SONARS SUBMERSIBLES

15. MID-OCEAN RIDGES A system of ridges or mountains in the seafloor like those found in the continents Located: Atlantic Ocean Cleft size: 32km-48km long Depth: 1.6 km Harry Hammond Hess Robert S. Dietz

16. Harry Hammond Hess Robert S. Dietz Seafloor Spreading Theory

17. Seafloor Spreading Theory

18. Seafloor Spreading Theory The process of seafloor spreading allowed the creation of new bodies of water.

19. The EAST PACIFIC RISE is one of the most active sites of seafloor spreading, with more than 14 centimeters every year

20. What happens to the ocean floor at deep ocean trenches? Continental Plate Oceanic Plate Subduction Zone

21. As the new seafloor is formed at the mid-ocean ridge, the old seafloor farthest from the ridge is destroyed at the subduction zone.

22. The rate of formation of a new seafloor is not always as fast as the destruction of the old seafloor at the subduction zone. Getting smaller Getting wider

23. If SUDBUCTION is FASTER THAN SEAFLOOR SPREADING, the ocean _ _ _ _ _ _ _ _ When the SEAFLOOR SPREADING is GREATER THANK the SUBDUCTION, then the ocean gets _ _ _ _ _

24. Evidences that explain/ support Seafloor Spreading Theory

25. AGE OF ROCKS Mid-ocean ridges Subduction Zone Rocks polarity

26. 1. Rocks are younger at the mid-ocean ridge. Findings that relate the age of rocks to the seafloor spreading theory 2. Rocks far from the mid-ocean ridge are older. 3. Sediments are thinner at the ridge. 4. Rocks at the ocean floor are younger than those at the continents.

27. It states that continents moved through unmoving oceans and that larger and sturdier continents broke through the ocean crust. Continental Drift Theory It shows that the ocean is the actual site of tectonic activity. Seafloor Spreading Theory

28. Evidences that explain/ support Seafloor Spreading Theory

29. -Magnetic evidence in rocks. MAGNETIC REVERSAL

30. Seafloor spreading was strngthened with discovery that the magnetic rocks near the ridge follow a pattern aside from the fact that rocks near the ridge are remarkably younger than those farther from the ridge.

31. The Earth’s magnetic field is a DIPOLE, North and S o uth Pole. MAGNETIC REVERSAL Magnetic Compass Direction of the earth Show earth magnetic field

32. MAGNETIC REVERSAL Simple Experiment Using a magnet rub the needle to the magnet 20 times. Slowly place the plastic bottle cap at the middle and place the needle on top of it. Observe what happen. How does the needle work?

33. The needle became magnetized after rubbing the magnet against it, and once magnetized, it will have a north and south pole, exactly like other magnets. N eedle The plastic bottle cap on the water’s surface was able to move freely after it was submerged. Plastic bottle cap The magnetized needle then force the plastic cap to spin around until the needle’s North and South poles aligned with the Earth’s N and S poles

34. Also called magnetic ‘fip” of the Earth It happens when the geographic North Pole is transformed into a South Magnetic Pole or vice versa. M a gnetic Reversal

35. The occur r ence of magnetic reversals can be explained through the magnetic patterns in magnetic rocks, esp.those found in the ocean floor.. M a gnetic Reversal When lave solidifies, iron bearing mineral crystallize. The minerals behave like tiny compasses and align with the Earth’s magnetic field.

36. M a gnetic Reversal

37. Over the last 10 million years, there has been an average of 4-5 reversals per milion years MAGNETIC REVERSAL

38. The Plate Tectonics Theory, which underpins our entire knowldege of how the Earth moves, was born out of the evidences of the sea floor spreading and the continetal drift.