Measuring heat energy
3 marks · NormalDescribe what happens to the movement and arrangement of particles when a solid turns into a liquid as it is heated.
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As a solid is heated, particles vibrate more and eventually break free from their fixed positions, becoming able to move around each other. The regular pattern is lost, and the substance becomes a liquid where particles are still close but move randomly.
Common mistakes: Forgetting to mention breaking of pattern or increased movement
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Marking points
B1 · 1 mark · States particles vibrate more as solid is heated.
B2 · 1 mark · States particles break out from fixed positions / lose regular pattern at melting.
B3 · 1 mark · Particles move more freely/randomly but are still close in the liquid.
Worked solution
When a solid is heated, its particles vibrate more energetically. At the melting point, they break free from their fixed positions, the regular arrangement is lost, and they begin to move around each other. The substance becomes a liquid, with particles close together, but moving randomly.