Which of the following does not describe a convection process?

Question: Which of the following does not describe a convection process?

Of the following, the movement of air in a closed room due to a fan does not describe a convection process.

Convection is a heat transfer process that occurs due to the movement of a fluid (such as air or water) from one place to another. The fluid moves because it is heated, which makes it less dense and therefore more buoyant. The less dense fluid rises, while the denser fluid sinks. This creates a cycle of fluid movement that transfers heat from one place to another.

A fan creates air movement, but it does not heat the air. Therefore, the movement of air in a closed room due to a fan is not a convection process.

The other three options all describe convection processes:

• The rising of hot air from a campfire
• The movement of air in a thunderstorm
• The movement of water in a radiator

In each of these cases, the fluid is heated and therefore rises. The rising fluid transfers heat from one place to another.

Here are some examples of convection currents in the real world:

• Ocean currents: Ocean currents are driven by convection currents. The warmer water near the equator rises, while the cooler water near the poles sinks. This creates a cycle of water movement that transfers heat from the equator to the poles.
• Wind currents: Wind currents are also driven by convection currents. The warmer air near the equator rises, while the cooler air near the poles sinks. This creates a cycle of air movement that transfers heat from the equator to the poles.
• Air circulation in a building: When a heater is turned on in a building, the air near the heater is heated and rises. The rising air transfers heat to the rest of the building. This creates a cycle of air movement that circulates the heat throughout the building.

Convection is a very important heat transfer process. It plays a role in many different natural and man-made processes.