Why Are Metals Good Thermal Conductors And Why Are Non Metals Good Insulators?
All solids (metals and non-metals) are made up of tiny particles called atoms, or groups of atoms called molecules. However there is one important difference between metals and non-metals. Metals contain many free electrons which are able to move randomly between the molecules. For non-metals there are very few electrons. Lets take an example two rods. One made of Copper and another made of glass. When heat is supplied to one end of the rod, the molecules at the hotter end vibrate vigorously and jostle their neighbouring molecules, making them vibrate as well. Thus some of the energy of the vibrating molecules at the hotter end gets tranferred to their neighbours. This process of passing heat from the hot end to the cold end is common to both copper (metal) and glass (non-metal). It is relatively slow mechanism of heat transfer compared to another mechanism of heat transfer that is taking place in metals: Free electron diffusion. When the rods are heated the free electrons in the coppe
