Question

Which statements best describe conduction? Check all that apply.

Conduction only occurs within a substance.
Conduction can occur within a substance or between two substances.
Slow-moving molecules collide with fast-moving molecules.
Fast-moving molecules collide with slow-moving molecules.
Thermal energy is transferred from a warmer substance to a cooler substance.
Thermal energy is transferred from a cooler substance to a warmer substance.

Answer 1

Correct choices: 2, 3, 4, 5.

- 2 (True): Conduction can occur within a single material and also between two materials in direct contact.
- 3 (True) and 4 (True): Conduction involves collisions between particles of different speeds — fast-moving (hotter) particles collide with slow-moving (cooler) ones and exchange energy. (Both phrasings describe the same collision process.)
- 5 (True): Net thermal energy transfer by conduction is from the warmer object to the cooler one.

- 1 (False): Conduction is not limited to within a single substance; it also occurs at interfaces.
- 6 (False): Heat does not spontaneously transfer from cooler to warmer by conduction (that would violate the second law of thermodynamics).