Conduction — Science definition

Heat transfer through direct contact, particle to particle.

Where it is taught

In use

The first is conduction, which moves heat through direct contact, particle bumping into neighboring particle.

Thermal Energy & Heat Transfer

Questions using conduction

Problem 1

An object receives energy across a vacuum gap from a warmer source. Which of conduction, convection or radiation can explain the gap transfer? What would a full net-exchange account include?
Answer and explanation

Radiation can cross the vacuum. Convection needs moving material and conduction needs an interacting material pathway. A full net account includes both objects’ emission/absorption and their temperatures.

Use the presence or absence of matter to distinguish mechanisms.

Do not mistake a selected one-way arrow for every transfer in the full exchange.

Radiation can cross the vacuum. Convection needs moving material and conduction needs an interacting material pathway. A full net account includes both objects’ emission/absorption and their temperatures.

Response criteria

  • Use the named labels, directions or supplied quantities accurately.
  • Connect the visual evidence to the scientific mechanism or calculation.
  • State the relevant model conditions or limitation.

Problem 2

Illustrative equal warm-water samples cool from 40 °C to 31 °C in an uncovered cup and to 36 °C in an otherwise matched insulated lidded cup over 10 min. Compare changes and propose follow-up tests separating insulation from a lid. Explain conduction, convection and evaporation in plain words.
Answer and explanation

The drops are 9 and 4 °C. The treatment changes both walls and lid, so separate wall-only and lid-only comparisons can distinguish effects. Contact interactions transfer energy through walls; moving fluid transfers energy between regions; escaping water removes matter and energy. A lid and insulation reduce some rates but do not guarantee zero exchange.

The drops are 9 and 4 °C. The treatment changes both walls and lid, so separate wall-only and lid-only comparisons can distinguish effects. Contact interactions transfer energy through walls; moving fluid transfers energy between regions; escaping water removes matter and energy. A lid and insulation reduce some rates but do not guarantee zero exchange.

Response criteria

  • Use the supplied conditions and relevant evidence.
  • Explain the scientific mechanism or calculation.
  • State a meaningful limitation or testable next step.

Problem 3

Independent chapter check: An object receives energy across a vacuum gap from a warmer source. Which of conduction, convection or radiation can explain the gap transfer? What would a full net-exchange account include?
Answer and explanation

Radiation can cross the vacuum. Convection needs moving material and conduction needs an interacting material pathway. A full net account includes both objects’ emission/absorption and their temperatures.

Use the presence or absence of matter to distinguish mechanisms.

Do not mistake a selected one-way arrow for every transfer in the full exchange.

Radiation can cross the vacuum. Convection needs moving material and conduction needs an interacting material pathway. A full net account includes both objects’ emission/absorption and their temperatures.

Response criteria

  • Use the named labels, directions or supplied quantities accurately.
  • Connect the visual evidence to the scientific mechanism or calculation.
  • State the relevant model conditions or limitation.

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