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Conduction; Conductivity of Solids

المؤلف:  GEORGE A. HOADLEY

المصدر:  ESSENTIALS OF PHYSICS

الجزء والصفحة:  P-248

2025-11-22

510

If one end of a copper wire 10 cm. long is held in the hand and the other end is placed in the flame of a Bunsen burner, the end in the flame will become red-hot, and in a short time the end in the hand will become uncomfortably warm. This method, of transmission, by which the heat is transferred from molecule to molecule along the body, is called conduction. If the same experiment is made with a glass tube, the glass can be melted to within 4 or 5 cm. of the fingers without burning them, while a stick can be burned to the very fingers without harm. 

These three examples illustrate bodies that are good, medium, and poor conductors of heat. A good conductor feels either warmer or colder than a poor conductor if not at the same temperature as that of the hand. This is due to the fact that it conveys its heat to the hand, or takes heat from the hand, more readily than the poor conductor.