1. How do scientist explain Earth’s Features
Chapter 8 Lesson 3

2. Theory of Plate tectonics
Earth’s lithosphere is broken into 20 plates
The continents and the ocean floor make up the surfaces of the moving plates
The plates can move in one of 3 ways
Toward one and another
Away from one and another
Sliding past each other
The plates move about 2 cm each year

3. 50 million years from now
The plates will have begun to move back together
Another Pangaea like continent is expected

4. Plate boundaries A plate boundary is the area where two plates form.
A spreading boundary- where two plates move apart
Huge valleys can form
Responsible for sea floor spreading
Caused the Mid- Atlantic Ridge

5. Fracture Boundaries
At a fracture boundary- the plate slides past each other
A fault- a break in the Earth’s crust is made
Responsible for strong earthquakes

6. Colliding boundaries
Colliding boundaries occur when two plates push against each other.
1. One plate could slide beneath another- subduction zone and volcanoes occur
2. The two plates collide making mountains
It is also possible to have earthquakes and ocean trenches at this boundary