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Ice, Water, Steam: One Substance or Three? (Chemistry Level 8)
Description
We're going to find out what actually makes something the same stuff, even when it looks, feels and behaves completely differently. First we'll work out how scientists identify a substance. Then we'll see why the same substance can act like three different things, and how we know the invisible particles are really there.
The listener can now say that a substance is one type of particle. They can name melting point, boiling point and density as its identifying properties, and give density as mass ÷ volume in g/cm³. They can explain that one substance has different densities as a solid, a liquid and a gas because the gaps between its particles differ. The opening question, 'three substances or one?', finally has an answer they can defend.
Source: Chemistry Level 8, Chapter 1: The particle model and state change (2/2)
Sections: 1.1, 1.2, 1.3
Style: Exam prep
Length: 1453 words, 8 min target
Generated: 2026-10-24