Simple Definition:

Convection is a process where heat is transferred from one place to another by the movement of fluids [liquids or gases]. This movement occurs because warmer fluids are less dense and therefore rise, while cooler fluids are denser and therefore sink. This process happens naturally in the Earth’s atmosphere, oceans, and even in our homes.

For example, when you boil water, the heat causes the water to become less dense, so it rises to the top and cooler water sinks to the bottom. The air in your home also moves through convection, as warm air rises to the ceiling and cooler air sinks to the floor.

Very Simple Definition:

Convection is when hot stuff rises and cold stuff sinks, making things move around. This happens naturally in the air and water around us. For example, when you see steam rising from a pot of boiling water, that’s convection in action!