1. Plate tectonics And Continental drift
Pangea
Plate tectonics
And
Continental drift

3. Layers of the earth crust
The crust is made of light elements
eg. Silicon which is sand
It floats on top
It is solid
It is made of several different plates or pieces
These are called tectonic plates.

4. Mantle The mantle is made of heavier minerals.
It is liquefied because of pressure and heat.
The heat from the core causes a convection current.

5. Convection currents and the link to density
Density= Mass/Volume
Increase the volume you decrease the density.
Heating fluids makes them expand.
This means the volume gets bigger and it becomes less dense.
fluids that are less dense float.
fluids that are more dense sink.

6. Convection currents make the tectonic plates move
The core heats the liquid mantle.
The lower mantel gets less dense and rises
This pushes the crust
The top of the mantle cools and becomes more dense and sink
This pulls the crust

7. Pre lab Wood chips Crust Water Mantle
and coffee with convection current
Hot plate Core

8. Evidences of continental drift
The edges of the continents fit together like a jig saw puzzle.

9. Evidence of continental drifts
Mountain ranges and special rocks are formed in one place when the continents were together
Now we see the same rocks or mountain ranges on the opposite sides of the ocean.

10. Evidences of continental drift
Fossils of the same animal are found in South America and Africa
They used to live in the same area then the continents moved apart

11. Evidences of continental drift
Glaciers are made in arctic cold regions
Glacial scratches on the rocks in Africa
Therefore Africa used to be in a cold place
Coal is made in tropical swamps
Arctic regions have coal
Therefore the Arctic used to be in a warm place

12. How plates move When plates spread apart this is called divergence
When they push together its called convergence
When they slip past each other its called transformation

13. DIVERGENCE The Atlantic ocean is spreading 2 cm per year
Causes rift valley’s and underwater volcanoes.

14. Convergence
When plates collide there is mountain building

15. Subduction When two crusts collide and one goes under the other
It causes trenches and volcanoes

16. Slip faults or transformations
This shifting of crusts is happening in California on the San Andreas fault .
It causes earthquakes

17. Read text book Pages 317-325 Answer the Memory check questions P325