Convection currents are movements of fluid caused by differences in temperature and density. When a fluid, like water or air, is heated, it becomes less dense and rises. As it rises, cooler, denser fluid moves in to take its place, creating a continuous cycle. This process is essential in various natural phenomena, including weather patterns and ocean currents. In the Earth's mantle, convection currents play a crucial role in plate tectonics. Hot magma rises towards the surface, cools, and then sinks back down, driving the movement of tectonic plates. This movement can lead to earthquakes, volcanic activity, and the formation of mountains.