Heat Transfer

Conduction, Convection and Radiation

Convection

Heat can be transferred from one place to another via convection. In convection hotter particles rise and cooler particles fall circulating heat.

Conduction


When an object is heated, the particles in the object begin to vibrate. These vibrations are passed on through the object, transferring the heat from one end to the other.

Radiation

Radiation is the transfer of heat from one place to another using invisible waves. All objects give out heat via radiation but hot objects radiate more heat than cool objects. Dark objects radiate more heat than light objects.


Examples

CONDUCTION:

  • Touching a stove and being burned
  • Ice cooling down your hand

CONVECTION:

  • Hot air rising, cooling, and falling
  • An old-fashioned radiator creates a convection cell in a room by emitting warm air at the top and drawing in cool air at the bottom.

RADIATION:

  • Heat from the sun warming your face
  • Heat from a light bulb
  • Heat from a fire

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In Summary

Conduction is energy transferred from direct contact, convection is energy transferred by molecules, and radiation is energy transferred by electric waves.