Thermal energy — Science definition
Internal energy associated with random particle motion and particle interactions; temperature alone does not give its total amount.
Where it is taught
- States of Matter & Phase Changes — Phases of Matter, Physical Science: Matter, Forces & Energy, Grade 8
- Thermal Energy & Heat Transfer — Energy & Heat Transfer, Physical Science: Matter, Forces & Energy, Grade 8
In use
Thermal energy includes particle motion and interactions; it is not simply another name for temperature.
States of Matter & Phase Changes
Thermal energy also depends on the amount and kind of matter and on particle interactions.
Thermal Energy & Heat Transfer
Questions using thermal energy
Problem 1
Thermal energy always flows from
- cold to hot
- hot to cold
- large to small
- solid to liquid
Answer and explanation
hot to cold
Net transfer is from higher to lower temperature until they are equal.
Problem 2
Explain the difference between temperature and thermal energy using a cup and a bath of water at the same temperature.
Answer and explanation
Temperature measures the average kinetic energy of the particles, which is the same in both. Thermal energy is the total energy of all the particles, and the bath has vastly more because it contains far more particles. This is why the bath can warm a cold room noticeably while the cup cannot, despite the identical thermometer reading.
Response criteria
- State a scientifically accurate conclusion.
- Show the data, mechanism, or calculation that supports it.
- Include units, conditions, or limits where relevant.
Taught alongside
- solid
- liquid
- gas
- melting point
- boiling point
- condensation
- model
- evidence
- system boundary
- assumption
- heat
- conduction
- convection
- radiation