Conduction is heat transfer between two bodies in contact and at different temperatures. It usually occurs between solids. Heat transfer by conduction is a slow process.
Conductors and insulators
Substances through which heat can pass easily are called good conductors of heat. Examples: metals, mercury, etc. Substances through which heat cannot pass easily are called insulators of heat. Examples: glass, wool, etc.
Uses of bad conductors of heat
Following are some uses of bad conductors of heat
In cold countries, windows are made with double glass walls with air in between them. Since air is a poor conductor, the temperature inside the room on one side of the window remains warm and heat is not lost to the cold surroundings outside.
Pipes carrying fluids whose temperature has to be preserved are provided with insulating material which are bad conductors. This ensures heat is not lost to the surrounding by conduction. In cold countries, if pipes carrying water are not insulated, the water has a risk of freezing causing pipes to burst.
Wool is a bad conductor of heat. We wear woolen clothes in winter to insulate our body from the cold temperature outside.
The space in between the two walls of a refrigerator is lined with an insulating material such as cork or glass wool or expanded polystyrene so that heat from outside of the refrigerator is not conducted through the walls into the refrigerator and keeps the material cool in the refrigerator.
Hair and the fur of animals are bad conductors of heat. They protect them from cold.
Cooking utensils are provided with handles of bad conductors of heat such as ebonite or wood to hold them as the handles of these materials do not allow heat to pass from utensil to our hand.