Changes of State

This lesson covers changes of state as required by the AQA GCSE Physics specification (4.3.2). When a substance is heated or cooled, it can change from one state of matter to another. Understanding the names and nature of these changes, as well as how they relate to the particle model, is essential knowledge for your exam.

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The Three States of Matter

All matter exists in one of three states: solid, liquid, or gas. The state of a substance depends on the temperature and the arrangement and energy of its particles.