CONDUCTION 



Heat travels more readily through some substances than 

 through others. All metals conduct heat well; irons placed 

 on the fire become heated throughout and cannot be grasped 

 with the bare hand ; iron utensils are frequently made with 

 wooden handles, because wood is a poor conductor and does 

 not allow heat from the iron to pass through it to the hand. 

 For the same reason a burning match may be held without 

 discomfort until the flame almost reaches the hand. 



Stoves and radiators are made of metal, because metals 

 conduct heat readily, and as fast as heat is generated within the 

 stove by the burning of fuel, or introduced into the radiator 

 by the hot water, the heat is conducted through the metal 

 and escapes into the room. 



Hot-water pipes and steam pipes are usually wrapped with 

 a non-conducting substance, or insulator, such as asbestos, 

 in order that the heat 

 may not escape, but 

 may be retained within 

 the pipes until it reaches 

 the radiators in the 

 rooms. 



The old-fashioned 

 out-of-door brick ovens 

 (Fig. 17), used so much 

 by our grandparents, 

 depended for their value 

 on the fact that bricks 

 are poor conductors of 

 heat. These huge ovens 

 were built out in the 

 open, and just before the 

 family baking was to be 



done, large logs were FIG. 17. An old-fashioned out-of-door brick oven 



