Conduction
Heat passing through a solid as vibrating particles bump into their neighbours. Metals are the best conductors.
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Analogy
A row of people passing a bucket along the line.
In practice
A metal spoon in hot soup gets hot at the handle. A wooden spoon does not.
Practice
Flashcards
- Why are metals good conductors?Free electrons carry energy through the metal.
Interview questions
- Describe how heat travels from a radiator to warm the whole room.
- Air touching the radiator is warmed by conduction
- Warm air expands, is less dense and rises
- Cool air sinks to replace it, forming a convection current
- Some heat also travels as infrared radiation
Questions people ask
Why are metals good conductors of heat?
Metals contain free electrons that can move through the whole solid and carry energy quickly. As well as particles vibrating and passing energy along, these free electrons spread it much faster. Materials such as wood, plastic and air have no free electrons, so they conduct heat poorly.
What is an insulator?
An insulator is a material that conducts heat poorly. Examples are wool, plastic, foam and trapped air. They slow down heat transfer, which is why a wool jumper keeps you warm and a plastic handle on a pan stays cool enough to hold.