Conduction

Conduction occurs when heat passes from a hot area of an object to a cooler area. Heat is passed molecule by molecule. That is, as one molecule absorbs heat and vibrates, it passes heat along to a nearby molecule, which vibrates in turn. Conduction of heat energy continues molecule by molecule, until eventually the entire object is hot. Because direct contact is needed for heat transfer by conduction, it is sometimes described as a form of direct heat transfer.