Question 1 (3 marks)
Calculation
A 0.50 kg block receives 4500 J and warms by 20 °C. Calculate specific heat capacity.
Show model answer / marking points
c = 4500 ÷ (0.50 × 20) (1) = 450 J/kg °C (2).
Required Practical 14: Specific Heat Capacity | AQA GCSE Science | The Science Department
About this practical and its aim
Aim
Determine specific heat capacity of a metal block by measuring electrical energy transferred and temperature change.
Introduction
The specific heat capacity of a material links the amount of energy needed to raise its temperature per kg. Rather than simply completing a calculation, you will measure the mass of the substance, measure the change in temperature and calculate the energy input. After calculating the specific heat capacity, your value will differ from the official number, look at ways that you could improve the experiment.
The science behind the practical
Specific heat capacity is energy needed to raise 1 kg of a substance by 1 °C. Electrical work heats the metal block.
Key things to remember
Measure mass, voltage, current, time and temperature change; insulate the block.
Equipment and apparatus
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Metal block
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immersion heater
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thermometer or probe
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d.c. power supply
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ammeter
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voltmeter
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stopwatch
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balance
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insulation
Method: How to carry out the experiment
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Collect all of the equipment and set it up on your bench.
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Check the circuit diagram, voltmeter is parallel and ammeter in series.
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Find the mass of your metal block and record the initial temperature.
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Start the clock at the same time that you turn on the power supply
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Every 60 seconds, record the potential difference from the voltmeter and the current from the ammeter.
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After 10 minutes, turn off the power and record the final temperature. Leave the equipment to cool down.
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Calculate the mean voltage and mean current recorded.
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Use the equations to calculate the energy input: Power = voltage x current also use Energy = power x time
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Now use the value of the energy input along with the mass of the block and the change in temperature to find the specific heat capacity of the block.
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Extension - find out the official value and explain why your value was different. You can then design another method that would give you an answer that is closer to this official value.
Variables and fair testing
| Type of variable | What is measured or controlled? |
|---|---|
| Independent variable | Energy supplied to the block |
| Dependent variable | Temperature change (°C) |
| Control variables | Metal/block type; insulation; surroundings; heater position |
Safety and managing risks
Follow your teacher's instructions and your school's risk assessment. This page is not a substitute for a formal risk assessment.
| Hazard | Risk | Precaution |
|---|---|---|
Electric heater and hot block |
Burns and electrical hazards |
Use low-voltage supply; do not touch heater or block while hot. |
Trailing leads |
Trips or apparatus pulled from bench |
Route leads safely; secure heated apparatus. |
Results, calculations and analysis
Recording, presenting and interpreting results
Record time, potential difference, current, initial temperature and final temperature.
Calculations
E = VIt and specific heat capacity c = E ÷ (mΔT).
Conclusions, accuracy and evaluation
Drawing a conclusion
Different materials require different amounts of energy for the same mass and temperature rise.
Evaluating the investigation
Reduce heat losses, keep heater inserted securely, and recognise measured energy includes energy lost to surroundings.
More to learn
Electrical energy input
Calculate heater work from E = VIt, then compare with thermal energy gain mcΔT.
Common exam mistake
Convert block mass from grams to kilograms before calculating c in J/kg°C.
GCSE examination practice
Answer each question in full before opening the model answer. Check your work against the marking points and look for scientific key words.
Question 2 (3 marks)
Method
Which electrical measurements determine heater energy input?
Show model answer / marking points
Potential difference V (1), current I (1) and heating time t (1), using E = VIt.
Question 3 (2 marks)
Evaluation
Why might measured specific heat capacity be too high?
Show model answer / marking points
Electrical energy also heats surroundings or equipment, so not all measured energy warms the block (2).
Question 4 (2 marks)
Evaluation
Suggest one improvement to make the investigation more reliable and explain why it helps.
Show model answer / marking points
Repeat measurements and calculate a mean (1), reducing the influence of random variation/anomalies (1). Alternative valid improvement specific to the experiment with explanation can gain both marks.
This page was updated on: 20th June 2026