2.1.1

States of matter

Cambridge IGCSE Physics (0625)  · Unit 2: Thermal physics  · 4 flashcards

States of matter is topic 2.1.1 in the Cambridge IGCSE Physics (0625) syllabus , positioned in Unit 2 — Thermal physics , alongside Particle model, Gases and the absolute scale of temperature and Thermal expansion of solids, liquids and gases.  In one line: Freezing.

Freezing is the process where a liquid transforms into a solid due to a decrease in temperature.

This topic is examined in Paper 1 (multiple-choice) and Papers 3/4 (theory), plus Paper 5 or Paper 6 (practical / alternative to practical).

The deck below contains 4 flashcards — 1 definition — covering the precise wording mark schemes reward.  Use the definition card to lock down command-word answers (define, state), then move on to the concept and application cards to handle explain, describe and compare questions.

Key definition

State the name of the change of state when liquid water at 4.1 °C turns into solid ice at 4.1 °C

Freezing.

Freezing is the process where a liquid transforms into a solid due to a decrease in temperature.

What the Cambridge 0625 syllabus says

Official 2026-2028 spec

These are the exact learning objectives Cambridge sets for this topic. Match the command word (Describe, Explain, State, etc.) in your answer to score full marks.

  1. Know Know the distinguishing properties of solids, liquids and gases
  2. Know Know the terms for the changes in state between solids, liquids and gases (gas to solid and solid to gas transfers are not required)
Key Concept Flip

State *four* distinguishing properties of a solid, compared to liquids and gases, focusing on arrangement and movement of particles.

Answer Flip

- Fixed shape
- Fixed volume
- Particles tightly packed/regular arrangement
- Particles vibrate about fixed positions

Key Concept Flip

Describe the arrangement and motion of particles in a gas and explain how this differs from the arrangement and motion in a solid.

Answer Flip

- Gas particles are far apart and randomly arranged; particles move randomly at high speeds.
- Solid particles are closely packed in a regular arrangement; particles vibrate about fixed positions.
- Thus, gases are compressible/fluid, solids are not easily compressible/rigid.

Definition Flip

State the name of the change of state when liquid water at 4.1 °C turns into solid ice at 4.1 °C.

Answer Flip

Freezing.

Freezing is the process where a liquid transforms into a solid due to a decrease in temperature.

Key Concept Flip

A block of solid wax is heated. State the name of the change of state that occurs when the wax becomes a liquid.

Answer Flip

Melting.

Melting is the process where a solid changes to a liquid due to an increase in temperature.

Review the material

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1.8 Pressure 2.1.2 Particle model

Key Questions: States of matter

State the name of the change of state when liquid water at 4.1 °C turns into solid ice at 4.1 °C.

Freezing.

Freezing is the process where a liquid transforms into a solid due to a decrease in temperature.

More topics in Unit 2 — Thermal physics

States of matter sits alongside these Physics decks in the same syllabus unit. Each uses the same spaced-repetition system, so progress in one informs the next.

2.1.2 Particle model

16 flashcards
2.1.3 Gases and the absolute scale of temperature

6 flashcards
2.2.1 Thermal expansion of solids, liquids and gases

6 flashcards
2.2.2 Specific heat capacity

8 flashcards
2.2.3 Melting, boiling and evaporation

16 flashcards
2.3.1 Conduction

8 flashcards
2.3.2 Convection

4 flashcards
2.3.3 Radiation

18 flashcards
2.3.4 Consequences of thermal energy transfer

4 flashcards

Key terms covered in this States of matter deck

Every term below is defined in the flashcards above. Use the list as a quick recall test before your exam — if you can't define one of these in your own words, flip back to that card.

Name of the change of state when liquid water at 4.1 °C turns into solid ice at 4.1 °C

Related Physics guides

Long-read articles that go beyond the deck — cover the whole subject's common mistakes, high-yield content and revision pacing.

IGCSE Physics MCQ mistakes

Single-letter mistakes most often costing marks in Paper 1/2

IGCSE Physics high-yield questions

Equations and reasoning chains that come up every series

IGCSE Physics 2-week revision plan

Daily breakdown for the fortnight before exams

How to study this States of matter deck

Start in Study Mode, attempt each card before flipping, then rate Hard, Okay or Easy. Cards you rate Hard come back within a day; cards you rate Easy push out to weeks. Your progress is saved in your browser, so come back daily for 5–10 minute reviews until every card reads Mastered.