Convection is the movement of heat through a liquid or gas as the warmer parts rise and the cooler parts sink, creating a circular flow. You can see convection in action when you watch a pot of water heating on the stove: the hot water at the bottom becomes lighter and rises to the top, while cooler water sinks down to replace it, creating a rolling, churning motion.

This same process happens all around us, often invisibly. Convection currents in the air create winds and weather patterns. When the sun heats the ground, the warm air above it rises, and cooler air rushes in to take its place. That's what creates a breeze on a hot day. Convection also happens inside the Earth, where extremely hot rock slowly churns and flows, helping to move continents over millions of years.

Many ovens have a convection setting that uses a fan to circulate hot air, cooking food more evenly and quickly than regular ovens. This differs from conduction (heat moving through a solid by direct contact) or radiation (heat traveling through empty space, like sunlight warming your face).