Heat Transfer

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  • Created by: Olivia
  • Created on: 29-09-09 16:14

Heat Transfer

· Conduction

- Conduction happens mainly in solids

- All atoms vibrate, but vibrate more when heated

- Heat spreads by conduction when atoms increase their vibrations, and pass this energy on to those nearby.

- In metals free electrons carry the heat energy faster than the atomic vibrations and transfer it by colliding with other electrons and atoms.

· Convection

- Don’t say ‘heat rises’ say ‘hot air rises’ or ‘hot water rises’.

- Gases and liquids tend to change density with changes in temperature.

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E.G. If heated air decreases in density. The surrounding air is cooler and denser. This makes it heavier, so it falls beneath the hot air forcing it upwards.

- Radiators give off convection currents.

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