Who this is for: Cambridge IGCSE Coordinated Science (0654) students who want measurement of temperature — thermometers, Celsius and Kelvin scales, fixed points and sensitivity — to become a reliable source of marks in describe and explain questions.
What query it owns: how to understand and revise measurement of temperature in Cambridge IGCSE Coordinated Science.
Why this is safe: this page owns the measurement of temperature revision-guide angle, while Tutopiya’s Measurement Of Temperature subtopic page owns the learning resource and the free Measurement Of Temperature quiz owns the practice.

Temperature measures the average kinetic energy of particles in a substance. Cambridge IGCSE Coordinated Science (0654) expects you to describe how thermometers work, calibrate scales using fixed points, convert between Celsius and Kelvin, and explain sensitivity and range. A liquid-in-glass thermometer relies on thermal expansion — the liquid rises as it heats. This guide links thermometer design to the describe and explain questions examiners set.

Key takeaways

• Temperature is a measure of average kinetic energy of particles (not total heat energy).
• Liquid-in-glass thermometer: liquid expands when heated, rises in a narrow tube.
• Fixed points: ice point (0 °C) and steam point (100 °C) calibrate the Celsius scale.
• Kelvin (K): T(K) = T(°C) + 273; 0 K = absolute zero.
• Sensitivity: how much the reading changes per degree; range: lowest to highest measurable temperature.

What is measurement of temperature in Cambridge IGCSE Coordinated Science?

Measuring temperature requires a property that changes predictably with heating — typically thermal expansion of a liquid or metal. Thermometers are calibrated using fixed points: the temperature of melting ice (0 °C) and boiling water at standard pressure (100 °C). The scale between these points is divided equally. Kelvin is the SI unit; it starts at absolute zero (−273 °C), where particle motion theoretically stops. Examiners test thermometer design, scale conversion, and the meaning of sensitivity and range.

Study the diagrams and notes on Tutopiya’s Measurement Of Temperature subtopic page before attempting past-paper questions.

Temperature scales and conversion

Scale	Unit	Fixed points	Notes
Celsius (°C)	Degree Celsius	0 °C (ice), 100 °C (steam)	Everyday use
Kelvin (K)	Kelvin	273 K (ice), 373 K (steam)	SI unit; no negative values
Conversion	—	T(K) = T(°C) + 273	0 K = −273 °C (absolute zero)

Example: 25 °C = 25 + 273 = 298 K.

Thermometer properties

Property	Meaning	How to improve
Sensitivity	Smallest temperature change detected	Narrower bore, larger bulb
Range	Lowest to highest reading	Choose appropriate liquid (mercury vs alcohol)
Responsiveness	How quickly reading changes	Thinner bulb wall, smaller bulb
Linearity	Equal divisions between fixed points	Uniform capillary bore

Measurement of temperature in past-paper wording: command words that matter

Command word / phrase	What the question wants	Typical temperature stem
Describe	How a thermometer works	”Describe how a liquid-in-glass thermometer measures temperature.”
Explain	Reason using physics	”Explain why the liquid rises in a thermometer when heated.”
Convert	Change scale	”Convert 50 °C to kelvin.”
State	Name fixed points	”State the fixed points used to calibrate a Celsius thermometer.”

Worked exam-style stems (how to answer the wording)

1. “Describe how a liquid-in-glass thermometer is used to measure temperature.” The bulb contains liquid that expands when heated; the liquid rises in a narrow capillary tube, and the level is read against a calibrated scale marked with fixed points (0 °C and 100 °C). Reward: expansion + rises in tube + calibrated scale.
2. “Convert 100 °C to kelvin.” T(K) = 100 + 273 = 373 K. Reward: correct addition, unit K.
3. “Explain what is meant by the sensitivity of a thermometer.” Sensitivity is the change in reading (e.g. length of liquid column) per unit change in temperature — a more sensitive thermometer shows a larger change for a small temperature difference. Reward: change in reading per degree.

Test yourself with the Measurement Of Temperature quiz once you can describe thermometers and convert between scales.

How temperature measurement connects to the rest of Coordinated Science

Temperature measurement links to the Simple Kinetic Molecular Model Of Matter (temperature = average KE) and Pressure Changes (heating gas increases pressure). The Cambridge IGCSE Coordinated Science resource hub links every Thermal Physics subtopic.

Common mistakes students make

• Confusing temperature with heat energy (temperature is average KE, not total energy).
• Converting to Kelvin by multiplying instead of adding 273.
• Saying 0 K is the ice point (0 K is absolute zero; ice point is 273 K).
• Forgetting that thermometer readings depend on thermal expansion, not particle count.
• Mixing up sensitivity (small change detected) with range (max/min measurable).

When you need more support

If temperature measurement questions keep costing marks, work through the Measurement Of Temperature quiz, then get focused help from a Cambridge IGCSE Coordinated Science tutor.

Frequently asked questions

What is temperature a measure of? The average kinetic energy of particles in a substance.

How do you convert Celsius to Kelvin? Add 273: T(K) = T(°C) + 273.

What are the fixed points on a Celsius thermometer? 0 °C (melting ice) and 100 °C (boiling water at standard atmospheric pressure).

How do I revise temperature measurement effectively? Learn thermometer design, practise scale conversion, then take the quiz.

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