1. Chapter 4 in Old Textbook – pg. 115
Plate Tectonics:
How did it happen?

2. Chap 7, Sec 1A (Convection Currents and the Mantle)
Objectives:
How is heat transferred?
What causes convection currents?
Sea-Floor Spreading

4. Tech Terms:
heat transfer – when energy moves from a warmer object to a cooler object (water in ice cube tray transfers heat to inside of freezer).
*When you open the front door in the winter are you letting the cold air in, or the warm air out??

5. radiation – heat transfer that requires NO direct contact between a heat source and an object.
conduction – heat transfer by direct contact of molecules of matter.

7. convection – heat transfer by movement of fluid (liquid or gas).
Red/Blue Dye Demo

9. The heating and cooling of the mantle material
convection current – created when there are differences in temperatures and densities within fluids (liquid or gas).
The heating and cooling of the mantle material
(which changes its density) and the force of gravity are what powers the convection currents.

11. One More Time!

12. So What’s Next? How does this movement create continental drift?
How is Sea Floor Spreading Related?

13. Sea Floor-Spreading
6. mid-ocean ridge – longest chain of mountains extending into all of Earth’s oceans, that curves like the seam of a baseball along the sea floor.

15. sea floor spreading – the process that adds new material to the ocean floor at the mid-ocean ridge. Molten material erupts and spreads out through the valley that runs along the center of the mid-ocean ridge.
** It then pushes aside the rock that was already there.**

16. It’s all about …
CONVECTION CURRENTS!!!!!!