Three types of heat transfer that can occur in a system are conduction, convection, and radiation.

Conduction involves the direct transfer of heat through a substance without much the substance. In order for conduction to happen, there must be direct contact. An example of this is a spoon gradually becoming hotter in a cup of coffee.

Convection involves the transfer of heat through a flowing current. An example of this is water gradually becoming hotter through in a pot over an open flame.

Radiation involves the transfer of heat by electromagnetic radiation. An example of this is using a microwave to reheat food.

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Key Points

• Heat can be transferred via physical touch (conduction), physical flowing current (convection), or electromagnetic waves (radiation).

• Heat can be lost from items via conduction, convection and radiation.

Key Terms

Conduction: movement of heat by direct contact

Convection: movement of heat in liquids and gases as a movement of particles

Radiation: where heat is transferred by electromagnetic radiation and does not require matter