Conduction

Conduction is the flow of heat from one part of a substance to another part of the same substance, or from one substance to another substance in direct contact with it. A piece of iron with one end placed in a fire will soon become warm from end to end. This is an example of the transfer of heat by conduction. The heat travels through the iron using the iron as the conducting medium.

Substances differ in their ability to con­duct heat. In general, substances which are good conductors of electricity are also good conductors of heat. Substances which are poor conductors of heat are called heat insulators. Such substances are used to insulate refriger­ators, homes, and any structure whose temperature is to be controlled regardless of it's surrounding (ambient) temperature.