1. Internal and external forces
Forces of the earth
Internal and external forces

2. Core – center of the earth – iron and nickel Outer core – molten rock
Internal Layers
Core – center of the earth – iron and nickel
Outer core – molten rock
Mantle – several layers
Crust – thin layer of rock at the earth’s surface

3. - pieces of the lithosphere called tectonic plates
Internal forces
Earth’s crust is made up of several plates that sit on top of a layer of magma.
- pieces of the lithosphere called tectonic plates
These plates are constantly moving around.

4. INTERNAL FORCE- Plate tectonics
How do tectonic plates move?
Divergent- plates separate
Creates basins and rift valleys

5. INTERNAL FORCE- Plate tectonics
How do tectonic plates move?
Convergent- plates collide
Creates mountain ranges

6. INTERNAL FORCE- Plate tectonics
How do tectonic plates move?
Subduction
Heavier layer slides on top of lighter layer
Ocean to ocean – creates deep trenches
Land to land - creates volcanic mountains

7. INTERNAL FORCE- Plate tectonics
How do tectonic plates move?
Transformation- plates slide along each other
Creates giant fault lines and trigger earthquakes

8. Earth’s surface has changed
Over the past 200 million year the plates of the Earth have shifted to form the modern day world

9. internal force- Earthquake
Focus – center of earthquake – epicenter is the point directly above the focus of the earth’s surface

10. Underwater earthquake causes water to rise up and cause coastal damage
Internal force- Water
Underwater earthquake causes water to rise up and cause coastal damage
Creates tsunamis and hurricanes

11. Internal force- volcanoes
Magma, gasses, and water below the surface of the earth
Convection layer
Ring of Fire – Rim of the Pacific Ocean

12. Lithosphere – Crust, uppermost mantle
External Layers
Atmosphere – Oxygen
Lithosphere – Crust, uppermost mantle
Hydrosphere – water elements on earth
Biosphere – lithosphere and hydrosphere together

13. External forces
Weathering
Breakdown of rock and other materials into smaller pieces
Mechanical weathering – physical breakdown of rocks and minerals
Chemical weathering – breakdown of rocks and minerals through chemical processes (e.g. oxidization)

14. External forces
Erosion
Movement or removal of pieces of rock or soil through wind, glaciers, or water
Wears away at the earth’s surface

15. aCtivity
On the back of your continent/ocean map, copy the map of the world’s plates (pg 16 in atlas)