1. Review Earth’s Structure Today we will be reviewing the Earth’s structure…… You will first watch a review video, then you will rotate around the room to answer your worksheet Your homework will be completing the assessment on the back! This will be due next class!

2. Video “A Journey Inside the Earth” (6.27 minutes) Journey inside the Earth

3. crust mantle Outer core Inner core

4. Increased density as we go to the center of earth The 4 layers have different densities which causes them to separate Least dense = crust Most dense = inner core

5. The Earth’s Inner Core: Solid iron and nickel layer Densest layer (causing it to sink to the middle) The inner core + the Earth’s rotation, creates the Earth’s magnetic field

6. The Earth’s Outer Core: Liquid layer made of nickel and iron Spins around the inner core Earth’s only liquid layer

7. The Earth’s Mantle: below the crust Made of silicon, magnesium, iron, oxygen Has CONVECTION CURRENTS

8. The Earth’s Crust: Thin, solid outer layer Least dense layer 2 types of crust: continental crust oceanic crusts

9. Oceanic Crusts: under the oceans More dense (because the ocean compresses it) Thinner Made out of basalt

10. Continental Crust: under the continents Less dense Thicker Made out of granite

11. The Earth’s crust is divided into 12 major tectonic plates These plates sit on the dense, hot, layer of the earth known as the lithosphere Lithosphere = the crust and uppermost portion of the mantle

12. The Earth’s plates move about 2 inches per year (5 centimeters) Convective currents within the mantle cause the plates to move As they move, the plates: Press against one another (convergent boundary) Pull apart from one another (divergent boundary) Scrape against one another (transform boundary)

13. Plate boundaries……

14. Convection Currents within the Earth Explained 1. The heat source for these currents is heat from Earth’s core and from the mantle itself. 2. Hot mantle material slowly rises 3. Causes the tectonic plates to move within the lithosphere (crust and upper mantle) 4. As it moves, it cools off and then sinks back into the mantle 5. Convection currents have been moving inside Earth for more than 4 billion years (caused Pangaea to separate into 7 continents today we know today).

15. Volunteers….