What is conduction? How does the heat transfer occur by conduction? What are the heat transfer methods and information?
If you hold a cold spoon for a minute, heat moves from your fingers into the spoon. The spoon gets warmer, and your fingers feel cooler. But if you pick up a hot spoon, heat moves from the spoon into your fingers. This time the spoon gets cooler, and your fingers feel warmer. Heat always moves from warmer places to cooler places, or from places of higher temperature to places of lower temperature. When heat moves from one place to another, it travels, or is transferred, in different ways. One way is called conduction.
Now you can understand why conduction is a good name for this method of heat transfer. It comes from a Latin word that means to lead. In conduction, heat seems to be led along from place to place. According to the molecular theory, this is what happens. The molecules in any material are always moving. When one part of a material is heated, the molecules in this part move faster and bump into the molecules next to them. These molecules also move faster and bump into other molecules and so on. In this way, heat is conducted from molecule to molecule all through the material.
Any material through which heat is easily conducted is called a conductor. Some materials, such as metals, are better conductors of heat than others. This is one reason why metals are used in cooking utensils, stoves, and radiators. Other materials, such as cloth and wood, are nonconductors of heat. They conduct heat slowly or hardly at all. A folded napkin or a table pad is a non-conductor put under hot dishes to keep them from ruining the varnish on a table. When a non-conductor is used to prevent the conduction of heat, it is usually called an insulator. The handles on cooking utensils and stoves are often covered with wood or plastic, which are insulators. Almost any material with air spaces in it is a good insulator, because air, like other gases, is a poor conductor of heat.