Geography- Plate tectonoics, Earth's structure (Year 8)

Plate Tectonics, Earth's structure:

The Earth has four main layers- the inner core, the outer core, the mantle and the crust. 

The inner core is 5,500 degrees Celcius and is extremely hot. It is made from iron and nickel. 

The outer core is 2,000 km thick and is a liquid. 

The mantle is semi-molten and about 3,000 km thick.

The crust is the rocky outer layer. It is thin compared to the other sections, around 5 to 70 km thick. The crust is made up of pieces called plates. There are two types of crust: oceanic and continental crust. The oceanic crust is found under the sea and is thinner and more dense than the continental crust. 

Plate movement:

Plate movement is driven by a mechanism called slab pull. Slab pull occurs where older, denser tectonic plates sink into the mantle. As these older sections of plates sink, newer and less dense sections of plate are pulled along behind. Sinking in one…