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Science

Energy transfer by heating

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Keeping warm or cool

The bigger the difference in temperature between an object and its surroundings, the greater the rate at which heat energy is transferred. Other factors also affect the rate at which an object transfers energy by heating. These include the:

  • surface area and volume of the object
  • material used to make the object
  • nature of the surface that the object is touching.

Animal adaptations

Small animals like mice have a large surface area compared to their volume. They lose heat to their surroundings very quickly and must eat a lot of food to replace the energy lost. Large animals like elephants have a different problem. They have a small surface area compared to their volume. They lose heat to their surroundings more slowly and may even have difficulty avoiding overheating.

Elephants have large ears with a large surface area compared to their volume. These allow heat to be transferred from the elephant to its surroundings, helping to keep the animal cool.

In general, similar animals have different ear sizes depending on the climate in which they live. The arctic fox has much smaller ears than the fennec fox, which lives in the desert. The arctic fox must conserve its heat energy in the cold climate, while the fennec fox must avoid overheating in the hot climate.

Engineering design

Engineers design heat transfer devices so that they gain or lose heat energy efficiently. For example, car radiators are flat, with many small fins to provide a large surface area. Similarly, household radiators are thin and flat, and may have fins so that heat energy is transferred to the room quickly.

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Back to Heating and cooling index

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