Earth’s crust is broken up into many plates
Credit: USGS
The crust covers Earth in a jigsaw of giant slabs of rock called tectonic plates. They sit on top of the mantle, a layer of hot rock that’s thousands of kilometres thick. The mantle is made of solid rock. But since it’s really hot and under extreme pressure, it can flow or creep very slowly. The mantle is being heated by the extreme temperatures of the core at the centre of Earth.
Tectonic plates move about 2 to 10 centimetres a year. This mostly makes for very very slow change. But when two plates collide, it can make for some impressive mountains, including Mount Everest!
Hot moves
Back to Earth’s core and the incredible amount of heat it releases. Scientists have thought it’s the energy from this heat that moves the tectonic plates. But how?
The heat from the core transfers into the mantle’s flowing rocks. Hotter material is less dense than the cooler material above so it moves upwards, losing heat as it goes. Then as it cools, it drops back towards the core.
This process is called convection. It can be seen in pots of water on the stove, in ocean currents and in big weather patterns. But is convection strong enough to move the tectonic plates? Some scientists question this theory.
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