Layers of the Earth
Crust ~ solid rock 5-50km deep, split up into plates.
Mantle ~ molten rock with slow-moving currents, 2900km thick.
Outer Core ~ liquid metals, 2200km thick.
Inner Core ~ solid metals, 2500km wide.
Why do the plates move?
The earth's hot core heats up the magma
As it is heated it gets lighter and rises
Near the surface it cools and gets heavier (it sinks!)
The convection curants move the magma which causes the plates to move about
The contrasts between Continental and Oceanic plat
- Newer - most less than 200million years old
- Can sink
- Can be renewed or destoyed
- Older - most over 1500million year old
- Less dense
- Cannot sink
- Cannot be renewed or destroyed
Tectonic Plate Boundaries
Where two tectonic plates meet is called a Plate Boundary. This is where volcanoes and fold mountains are formed, and is also where earthquakes and tsnamis often happen.