1. EARTH’S MOVING SURFACE
CHAPTER 4 LESSON 1
EARTH’S MOVING SURFACE

2. 4.1 INFORMATION

3. WHY PLATES MOVE

4. DENSITY
The amount of matter per unit of volume

5. DENSITY Density = mass / volume
How heavy it is divided by how much space it takes up

6. DENSITY

7. DENSITY
When a fluid is heated, its molecules spread out and it becomes less dense.

8. DENSITY
When fluids heat unevenly, the warmer, less- dense fluid rises, and the cooler, denser fluid sinks.

9. CONVECTION
the circulation within fluids caused by differences in density and thermal energy.

10. CONVECTION

11. CONVECTION
Convection in the mantle can drag plates over Earth’s surface.

12. CONVECTION

13. SUBDUCTION
Plates can also move as a result of subduction.

14. SUBDUCTION
When two plates collide, one can subduct or sink into the hotter, less-dense mantle.

15. SUBDUCTION
The sinking part of a plate pulls the rest of the plate along.