convection

Everyday

Convection is the way heat moves through a liquid or a gas: the warm part rises and the cooler part sinks, making a current that goes round. tree →

In the lessons

In science lessons convection is one of the three ways heat travels (conduction, convection, radiation). It explains why warm air rises, how radiators heat a room and how wind and sea currents form. Phrases: «convection current», «convection oven».

Examples

• Convection carries warm air up to the ceiling. tree →
• Hot water rises by convection in a pan. tree →
• A radiator heats a room by convection. tree →
• Draw arrows to show the convection current. tree →
• A convection oven has a fan to blow hot air around. tree →
• Sea breezes are caused by convection. tree →

Note

Uncountable. Compare: conduction (heat through solids by touching), radiation (heat travelling as rays, like from the Sun). Myth: «heat rises» — really, hot fluid rises because it is less dense.