Heat Transfer

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Conduction

Heat energy can move through a substance by conduction. Metals are good conductors of heat but gases and non-metals are usually poor conductors. Poor conductors are called insulators. Heat energy is conducted from the hot end of an object to the cool end. As the object gets heated, the particles vibrate and collide with other particles as the object gets hotter.

Convection

Liquids and gases are fluids. Convection occurs when particles with a

lot of heat energy in a liquid or gas take the place of particles with less heat energy. Heat energy is transferred from hotter places to cooler places by convection (or convection currents). The liquid or gas in hot areas is less dense than the liquid or gas in cool areas, so it rises into the cool areas. The denser cold liquid or gas falls into the warm areas and a current is set up.