GCSE Physics · AQA 8463 · Topic 4.3.2
Internal energy and energy transfers
Key points
- Internal energy is the total kinetic energy and potential energy of the particles that make up a system.
- Heating increases internal energy. This either raises the temperature or causes a change of state.
- Temperature rise: . A high specific heat capacity (like water's) means a lot of energy is needed for each degree.
- During a change of state the temperature stays constant: the energy breaks or weakens bonds between particles, increasing potential energy rather than kinetic energy.
- Specific latent heat: . Fusion is for solid ↔ liquid; vaporisation is for liquid ↔ gas.
- On a heating graph, the flat sections show changes of state.
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When you heat something, the energy goes into its particles. Sometimes the temperature rises; sometimes, as when ice melts, it stays put while the substance changes state. This sub-topic explains both, using the ideas of internal energy…
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