Physics 0625 · syllabus 2.2
Cambridge IGCSE Physics 0625 — Thermal properties and temperature topical past papers
Thermal expansion and its uses, internal energy and specific heat capacity, and melting, boiling and evaporation, including why evaporation cools a liquid.
- Questions
- 1,345
- Years
- 2009–2026
- With mark scheme
- 99%
- Questions 2022–2026
- 486
Anyone can browse these pages. Opening the questions and their mark schemes takes a free Momentum account.
What Thermal properties and temperature covers
Most materials expand when they are heated, gases most and solids least. Extended candidates explain the order with particles: the particles of a solid are held by strong forces and only vibrate a little further apart, while those of a gas are already far apart with almost no forces between them. Expansion is allowed for with gaps in railway lines and bridges and with slack in overhead cables, and it is put to use in liquid-in-glass thermometers and in the bimetallic strips of thermostats.
Heating an object raises its internal energy. Extended candidates go further: a rise in temperature is a rise in the average kinetic energy of the particles, and the specific heat capacity of a material is the energy needed to warm 1 kg of it by 1 °C, c = ΔE/(mΔθ). They describe measuring it for a metal block and for a liquid, with an electric heater of known power, a stopwatch, a thermometer and a balance. Water's specific heat capacity is unusually high, about 4200 J/(kg °C), which is why water warms slowly and is used to carry energy in heating systems.
While a substance melts or boils, energy goes in but its temperature stays constant until the change of state is complete; pure water melts at 0 °C and boils at 100 °C at standard atmospheric pressure. Evaporation happens only at the surface, and at any temperature: the more energetic particles escape, lowering the average kinetic energy of those left behind, so the liquid cools. Extended candidates contrast evaporation with boiling, explain why a higher temperature, a larger surface area and a draught over the surface all speed evaporation up, and explain why something in contact with an evaporating liquid cools, as sweat cools the skin.
In the syllabus
The headings this topic has in the Cambridge International 2026–2028 syllabus, as the board prints them.
- 2.2 Thermal properties and temperature
What you should be able to do
- Describe the thermal expansion of solids, liquids and gases, with everyday uses and the problems it causes
- Explain why gases expand more than liquids, and liquids more than solids, using particles (Extended)
- Use c = ΔE/(mΔθ), and describe an experiment to find the specific heat capacity of a metal block or a liquid (Extended)
- Explain why the temperature stays constant while a substance melts or boils, and read heating and cooling curves
- Describe condensation, solidification and evaporation in terms of particles, and explain why evaporation cools
- Compare boiling with evaporation, and explain what affects the rate of evaporation (Extended)
Key ideas
- For the same temperature rise, gases expand far more than liquids, and liquids more than solids
- Heating increases internal energy; a temperature rise means a higher average kinetic energy of the particles (Extended)
- Specific heat capacity c = ΔE/(mΔθ), in J/(kg °C) or J/(g °C) (Extended)
- Water melts at 0 °C and boils at 100 °C at standard atmospheric pressure
- Evaporation: at the surface, at any temperature, cooling the liquid; boiling: throughout the liquid, at the boiling point only
How Thermal properties and temperature has been examined
From 2022 to 2026, Thermal properties and temperature was on Paper 4 · Theory (Extended) in 14 of 14 exam series, worth about 16% of that paper’s marks.
| Paper | Questions | Share of marks | Series |
|---|---|---|---|
| Paper 1 · Multiple Choice (Core) | 187 | 15% | 14 of 14 |
| Paper 2 · Multiple Choice (Extended) | 180 | 14% | 14 of 14 |
| Paper 3 · Theory (Core) | 41 | 12% | 13 of 14 |
| Paper 4 · Theory (Extended) | 49 | 16% | 14 of 14 |
| Paper 6 · Alternative to Practical | 29 | 22% | 14 of 14 |
Momentum’s own count, over the questions in its bank for these years: a series is one exam session, every zone included, and a question filed under two chapters counts in both. Median marks per question: 1. The bank files this topic together with neighbouring ones, so these figures count every question in its chapters, including some on those topics.
Filed in Momentum under: Thermal Effects.
A worked example
A 2.0 kg aluminium block is heated by a 50 W heater for 4.0 minutes, and its temperature rises from 20.0 °C to 26.5 °C. Find the specific heat capacity of aluminium from these results, and say whether the true value is higher or lower.
- Energy supplied ΔE = power × time = 50 × 240 = 12 000 J
- Temperature rise Δθ = 26.5 − 20.0 = 6.5 °C
- c = ΔE/(mΔθ) = 12 000 / (2.0 × 6.5) = 923 J/(kg °C)
- Some of the 12 000 J escaped to the surroundings, so the block gained less than this, and the true value is lower than 923 J/(kg °C)
Answer: About 920 J/(kg °C), a little above the true value because of energy losses
Written by Momentum for this page, with its own numbers; it is not taken from a past paper.
Mistakes that cost marks
- Saying the temperature rises while ice melts — the energy supplied goes into separating the particles, and the temperature stays at 0 °C until all the ice has melted
- Using a temperature instead of the change in temperature — water heated from 20 °C to 35 °C has Δθ = 15 °C
- Mixing grams and kilograms — with c in J/(kg °C), 500 g must go in as 0.50 kg, or the answer is wrong by a factor of 1000
- Explaining evaporative cooling as the liquid 'losing heat' — the mark goes to the most energetic particles escaping, which lowers the average kinetic energy of the particles left behind
- Saying energy losses make a measured specific heat capacity too low — losses mean less energy reached the block than the heater supplied, so the calculated value comes out too high
Exam technique
- In a specific heat capacity method, name each instrument and what it measures, give the equation you will use, and say that insulation reduces energy losses
- On a heating curve, label each flat section with the change of state and each sloping section with the state being heated
- When comparing boiling and evaporation, give at least two differences: where each happens and at what temperature
- For expansion questions, describe the material getting bigger, then explain it with the particles moving more and further apart
Practising in Momentum
- Every question in a chapter as one list, from every paper and year in the bank, newest first or shuffled.
- Each question turns over to its own part of the mark scheme, where the board published one.
- Narrow by paper, year, session, zone and marks, and star the questions worth keeping.
- Pick chapters, a number of questions and a time, and the exam builder draws a mock to sit and mark.
Past-paper questions and mark schemes are the copyright of Cambridge International. Momentum shows them to signed-in learners for revision and does not publish them on these pages.