Mantle convection is a process that occurs in the Earth's mantle, the layer between the crust and the core. It involves the movement of molten rock due to heat from the Earth's interior. As the material heats up, it becomes less dense and rises toward the surface. When it cools, it becomes denser and sinks back down, creating a continuous cycle. This convection process is essential for driving the movement of tectonic plates, which are large sections of the Earth's crust. The movement of these plates can lead to geological events such as earthquakes and volcanic eruptions, shaping the Earth's surface over time.