The Earth's structure

The Earth is made up of different layers:

The crust is the outer layer of the Earth. Under this is the mantle, then the outer core and the inner core in the middle.
  • The inner core is the hottest part of the Earth with temperatures up to 5,500°C. It is solid.
  • The outer core is a liquid layer.
  • The mantle is made up of semi-molten rock called magma. There are convection currents in the mantle which move, carrying the plates above them.
  • The crust is the outer layer of the Earth. It is a thin layer between 0-60 km thick. The crust is the solid rock layer upon which we live. It is either continental (found under land masses or continents) or oceanic (found underneath the oceans). The Earth's crust is broken into plates.

Demonstrating the movement of the Earth's crust and how tectonic plates interact at plate margins

The theory of plate tectonics

  1. The Earth's crust is broken into plates.
  2. Heat rising and falling inside the mantle creates convection currents.
  3. The convection currents move the plates floating on the mantle.
  4. Where convection currents diverge near the Earth's crust, plates move apart.
  5. Where convection currents converge, plates move towards each other.

The movement of the plates, and the activity inside the Earth, is called plate tectonics.

Circular convection currents in the mantle move the plates on top - either diverging (plates move away from each other) or converging (plates move towards each other).