Podcasts · Bunsen Bites — small bites, big discoveries

Ice, Water, Steam: One Substance or Three? (Chemistry Level 8)

24 Oct 2026 · 9:48 · S1 E2

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