Convection currents work by heat -driven cycles that moves the energy

Convection currents work in a similar comparison to lava lamps or boiling water.

For this particular question, I believe using a lava lamp would be best for this occasion. A lava lamp begins cool, once you've plugged it in, after a while the temperature slowly begins to rise. These rising temperatures cause glowing, heated materials to rise while leaving the cooler materials to sink.

This is much like Earth's mantle, when heated materials begin to rise and cooler materials, or denser materials, rather sink. This unique cycle creates a circulated pattern, better known as convection currents.

convection currents movies the hot material around, the least dense of the material rise to the crust and the heavier material sinks