States and changes of state · 3 parts · syllabus 1.1

Why does ice melt but stay water?

Predict what the thermometer will do, then heat one block of ice until it melts and boils away. Read the thermometer every 30 s, plot your own heating curve, and watch the same molecules change their arrangement.

Start learning Explore the experiment

Ice melting in a glass of water beside a T-shirt drying in the sun.

Follow the idea

Same water, three states
Properties and particles of solids, liquids and gases
Not started
Where does the heat go?
Melting, boiling, evaporating and the heating curve
Not started
Cooling it back down
Condensing, freezing and the cooling curve
Not started

An ice cube floats in water in a beaker on a hotplate; the dish where it started stands beside it.

The experiment · One block of ice · heat it to the end

Run it yourself, or project it for the class

Use the apparatus step by step and look closely at what happens. The whole experiment fits one screen, so it works on a projector too.

Open the experiment

Final check

Explain it on your own across all three parts. Hints and keys stay closed until you submit.

Take the final check

Return and recall

Come back after one to two weeks and answer with the lesson closed.

Recall questions

For teachers

Printable worksheets with their answer keys, the final check and the return questions for this module.

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Your saved work

Answers and earlier attempts stay in this browser. Export a copy to keep, to move to another device or to hand to your teacher. Importing a copy keeps your current answers and adds earlier attempts.

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Scope and sources

Cambridge IGCSE Chemistry 0620 · 2026–2028 v2 · Original learning materials.

Distinguishing properties and particle structure of solids, liquids and gases; melting, boiling, evaporating, freezing and condensing; heating and cooling curves explained with kinetic particle theory (1.1.1–1.1.3, Supplement 1.1.5). The experiment heats one ideal 50 g ice sample; freezing and condensing are taught with figures and practice. Gas volume with temperature and pressure (1.1.4, 1.1.6) comes in a later module.

Apparatus, amounts and times in the experiment are illustrative. Real practical work follows a teacher-approved safety method.

Official Cambridge syllabus

Why does ice melt but stay water?

Follow the idea

Same water, three states

Where does the heat go?

Cooling it back down

Run it yourself, or project it for the class