What is the term for a current caused by the rising of heated fluid and sinking of cooled fluid?

The term for a current caused by the rising of heated fluid and sinking of cooled fluid is called "Convection Current".

Here are the steps that explain how it works:

1. Heating the Fluid: Everything starts when the fluid (it can be a gas or a liquid) gets heated. The particles in the fluid near the heat source get more energy and start to move faster.

2. Rising of the Heated Fluid: As the particles move faster, they start to spread out and the fluid becomes less dense. Because of this decreased density, the fluid rises.

3. Cooling of the Fluid: As the fluid rises, it moves away from the heat source and starts to cool down. As it cools, the particles start to lose energy.

4. Sinking of the Cooled Fluid: As the fluid cools, it becomes denser again. This increased density causes the fluid to sink back down.

5. Continuation of the Cycle: Once the fluid has sunk back down, it can be heated again and the cycle continues. This continuous cycle of heating, rising, cooling, and sinking results in a convection current.

This process is responsible for many natural phenomena, including wind, ocean currents, and the movement of tectonic plates.