AQA GCSE Physics · Energy
Specific heat capacity required practical
Determine the specific heat capacity of a material by heating a block and measuring its temperature rise.
An electric heater transfers a known amount of energy to a 1 kg block. From the energy and the temperature rise you can calculate how much energy it takes to heat 1 kg of the material by 1 °C.
Equipment
- Aluminium block (1 kg) with holes for a heater and thermometer
- Immersion heater (12 V) and power supply
- Joulemeter, or an ammeter and voltmeter
- Thermometer and a drop of water or oil in its hole
- Insulation to wrap the block
- Balance and stopwatch
Variables
- Independent you change
- Energy transferred to the block (time heating)
- Dependent you measure
- Temperature of the block
- Control you keep the same
- Mass of the block
- Same power supply setting
- Same insulation
Method
- 1
Measure the mass of the block on a balance.
- 2
Wrap the block in insulation. Put the heater and thermometer in their holes, with a drop of water in the thermometer hole for good contact.
- 3
Connect the heater to the power supply with a joulemeter (or an ammeter in series and a voltmeter in parallel).
- 4
Record the starting temperature, switch on and start the stopwatch.
- 5
Record the temperature and the energy transferred every minute for 10 minutes.
- 6
Plot temperature against energy and use the straight part to calculate the specific heat capacity.
Worked example
1.00 kg aluminium block. Heater power: 12.0 V × 4.0 A = 48 W.
| Time (s) | Energy (J) | Temperature (°C) |
|---|---|---|
| 0 | 0 | 20.0 |
| 120 | 5 760 | 24.8 |
| 240 | 11 520 | 30.6 |
| 360 | 17 280 | 36.4 |
| 480 | 23 040 | 42.2 |
| 600 | 28 800 | 48.0 |
Working
Energy = power × time: 48 W × 120 s = 5 760 J
From 120 s to 600 s: ΔE = 28 800 − 5 760 = 23 040 J and Δθ = 48.0 − 24.8 = 23.2 °C
c = ΔE ÷ (m × Δθ) = 23 040 ÷ (1.00 × 23.2) = 993 J/kg °C
Conclusion
The measured specific heat capacity is about 990 J/kg °C, higher than the accepted 900 J/kg °C for aluminium. Some energy is lost to the surroundings rather than heating the block, so the temperature rises less than it should and c comes out too big.
Risks
- Heater and block get hotDon’t touch them while on, and let them cool before packing away.
- Electrical equipmentKeep water away from the power supply.
Common mistakes
- Using the first minute. The block takes time to warm up evenly, so use the straight part of the graph.
- Forgetting to insulate. Energy lost to the surroundings makes the calculated value too high.
- Mixing up mass units. Mass must be in kg for J/kg °C.
Better results
- Wrap the block in more insulation to reduce energy losses.
- Put water or oil in the thermometer hole so the thermometer is in good thermal contact.
- Use a joulemeter to measure energy directly, or a data logger for the temperature.
Launching November 2026
7 exam questions on this practical.
Practise the method, the variables, the maths and what the results mean, then revise the Energy flashcards. It opens to students soon: join the waitlist and we’ll email you once, when it does.