Scientists use four hypotheses to explain the movement of tectonic plates:
- Convection currents: convection in the Earth’s mantle drag and move the lithospheric plates.
- Magma injection: the injection of magma pushes plates apart.
- Continental drift: the plates above a spreading centre cool, become denser, and move away under the force of gravity.
- Descending plates: cold, dense plates descend into the mantle and pull the rest of the plate with it.
Many scientists think that the heat in the rising convection currents in the Earth’s mantle provides the energy to move the plates. The hot material becomes denser as it reaches the surface and cools. It flows downhill by gravity and eventually sinks again.
