The Earth's structure and plate movement

The earth has four key layers: inner core, outer core, mantle and crust.

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

  • The inner core is 5,500°C - extremely hot. It is a very dense solid 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, approximately 5 to 70 km thick. If the Earth was scaled down to the size of an apple, the crust would be about the thickness of the apple skin. 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

Heat from the core causes convection currents in the mantle. These currents slowly move the crust around. In some places the crust is destroyed. In other places new crust is formed.

The Earth's core creates convection currents which moves tectonic plates and can cause volcanoes

Earthquakes and volcanoes are primarily found at plate boundaries. The plates are like giant rafts that slowly move around. Their movement is driven by convection currents in the mantle. The mantle is much hotter than the crust and its rock is molten. At the boundaries between plates, molten magma is able to force its way to the surface and escape as lava.