What causes convection currents in fluids?

Convection currents in fluids are primarily caused by density differences within the fluid, which are often due to variations in temperature. When a fluid is heated, it becomes less dense and rises, while cooler, denser fluid sinks. This creates a cyclical movement: the warmer fluid rises, loses heat to the surrounding environment, cools down, and then sinks, leading to a continuous flow known as convection.

While changes in temperature do contribute to the formation of density differences, it is the density differences themselves that are the driving force behind convection currents. This process plays a crucial role in various natural phenomena, such as weather patterns and ocean currents, as well as in engineered systems like heating and cooling in buildings or thermal management in electronics.