My favorite part of the unit was learning about Wegener's proofs of continental drift.

Earth's Layers

Crust

Lower Mantle (Asthenosphere)

Outer Core

Inner Core

Upper Mantle (Lithosphere)

Convection currents are rotating currents based on uneven heating.

Convection currents cause movements of the lithospheric plates above.

Alfred Wegener proposed the Continental Drift theory, and he gave several different plausible pieces of evidence.

His theory was not accepted because he could not prove it at the time.

The Mesosaurus was a freshwater lizard that was found in South America and Africa

The Continents seem to fit together like a jigsaw puzzle

Similar rock deposits were found on opposite sides of the Atlantic Ocean

The Glossopteris's seeds are too big to move long distances, yet they were found on opposite sides of the Atlantic Ocean

Harry Hess proposed the theory of Sea Floor Spreading

Reason 1: The crust closer to the mid-ocean ridge were newer than the crust farther from the ridge

Reason 2: Drilling Samples showed that there was magma underneath an area near the ridge

Reason 3: There were magnetic stripes in the oceanic crust

This is important because it proved Alfred Wegener's previous theory about Continental Drift and Pangaea.

The Plate Tectonic Theory was a combination of the Continental drift theory and Sea Floor Spreading.

The theory states that the crust is split into a dozen plates that move and push against each other.

The Oceanic plates are pushed away from the mid-oceanic ridges and recycled from subduction.

The Three types of Stress are:

1) Compression - two objects being pushed together

2) Tension - two objects being pulled apart

3) Shearing - two objects sliding past each other

Compression Formations:

Ocean to Ocean: Trenches

Ocean to Continent: Trenches and Volcanoes

Continent to Continent: Mountains