Conduction is the movement of heat or electricity through a material by direct contact. When you touch a metal spoon that's been sitting in hot soup, the handle gets warm because heat travels through the metal by conduction. The fast-moving molecules in the hot soup bump into the molecules in the spoon, which bump into their neighbors, passing the heat along like a chain of dominoes falling one after another.

Some materials conduct heat or electricity better than others. Metals are excellent conductors: copper wires conduct electricity to power your lights, and aluminum pans conduct heat to cook your food. Materials that don't conduct well are called insulators. Wood, plastic, and rubber are poor conductors, which is why pot handles are often made of these materials and why electrical wires are wrapped in rubber or plastic.

Understanding conduction helps explain everyday experiences. Why does a tile floor feel colder on bare feet than a carpet, even though they're the same temperature? The tile conducts heat away from your feet faster. Why do winter coats work? They trap air, which is a poor conductor, preventing your body heat from conducting away into the cold air outside.