- Insulate the block
- A drop of water for contact
- Zero the joulemeter
Launch practical
About 40 minutes
- Set up the bench with the 10 items of apparatus.
- Take the readings yourself, into the results table you draw first.
- Process your results and plot the graph.
- Answer exam questions on your own results, which you mark against the mark scheme.
Runs in your browser: a 3D bench with 2D close-ups of each instrument for exact readings. Nothing to install and no account.
What you measure, and how
One run takes 21 readings. You take every one yourself, the way you would in class.
- On the 3D bench (Fig. 1) you set out the apparatus and read each instrument where it stands.
- In the 2D close-up (Fig. 2) the same instrument is drawn large, from the same run, for an exact reading. It is also how the practical runs on a device that cannot show 3D.
- In your table you write what you read, to the instrument’s resolution, and the notebook checks it against the instrument.
How to read it. Eye level with the top of the red liquid. Each small division is 1 °C: read it to the nearest 0.5 °C.
What it shows
ΔE = m c Δθ
The specific heat capacity of a material is the energy needed to raise the temperature of 1 kg of it by 1 °C. Heat a block electrically, measure the energy with a joulemeter and the temperature rise with a thermometer, and c = ΔE ÷ (m Δθ).
The graph to expect. A short curve while the heater warms up and energy conducts to the thermometer, then a straight line. Energy lost to the surroundings makes it bend slightly towards the energy axis at the end, more so without insulation.
On the AQA 2027 Physics Equations Sheet. Pick it from the sheet, then rearrange for c. Energy in J and mass in kg.
Apparatus
| Item | What it is for | Resolution |
|---|---|---|
| 1 kg metal block with two holes | The material being tested. | — |
| Top-pan balance | Measures the mass of the block. | 0.1 g |
| Immersion heater (12 V) | Transfers energy into the block. | — |
| Thermometer (−10 to 110 °C) | Measures the temperature of the block. Its scale is marked every 1 °C; read it to the nearest 0.5 °C, halfway between two marks. | 1 °C |
| Joulemeter | Measures the energy transferred by the heater. | 1 J |
| Low-voltage power supply | Powers the heater. | — |
| Pipette and water | A few drops in the thermometer hole for good thermal contact. | — |
| Insulation jacket | Reduces energy transfer to the surroundings. | — |
| Stopwatch | Times the readings. | — |
| Heatproof mat | Protects the bench from the hot block and heater. | — |
Method
In our own words, as the Lab runs it. Your school's method sheet may differ in detail.
Which version are you doing?
Boards set this practical differently. Your course setting picks one; you can change it before you start.
Why: AQA heats a metal block; Edexcel heats a beaker of water. The method, the graph and the exam questions follow your board.
Choose your block
Take one 1 kg block from the tray. Each group tests one metal and the class compares.
Do: Aluminium.
Why: Different metals have different specific heat capacities, so the same energy warms them by different amounts.
Measure the mass of the block
Check the balance reads 0.0 g with nothing on it (press tare if it does not). Then put the block on the balance and write down its mass.
Why: You need the mass to calculate c, and the block is not exactly 1 kg.
Insert the immersion heater
Put the heater into the larger hole in the block.
Why: The heater transfers energy into the block from the inside. Only switch it on when it is fully inside the block.
Add water to the thermometer hole
The thermometer is a loose fit in the smaller hole. Decide whether to fill the gap before it goes in.
Do: Put a few drops of water in the hole with the pipette.
Why: Air is a poor thermal conductor. Water fills the gap, giving good thermal contact, so the thermometer reads the temperature of the block.
Insert the thermometer
Check the thermometer reads room temperature and the liquid thread is not split. Then put it into the smaller hole so the bulb is surrounded by the block.
Why: The thermometer measures the temperature of the block.
Wrap the block in insulation
Decide whether to wrap the insulation jacket around the sides of the block before you heat it.
Do: Wrap the insulation jacket round the block.
Why: Insulation reduces energy transfer to the surroundings, so more of the energy supplied raises the temperature of the block.
Connect the circuit
Check the leads are not damaged. Connect the heater to the power supply through the joulemeter, reset the joulemeter to 0 J and leave the power supply switched off.
Why: The joulemeter measures the energy transferred by the heater. (Without one, measure the current and potential difference: energy = potential difference × current × time.)
Take the readings
Zero the joulemeter, then switch the heater on and start the stopwatch together. Read the joulemeter and the thermometer at 0 s and every 60 s up to 600 s, and switch off as soon as the last reading is taken.
Repeats: AQA’s method takes one set of readings, every minute for 10 minutes. Repeating the whole run and taking a mean of c reduces the effect of random errors, but it does not remove the energy transferred to the surroundings (a systematic error).
Make safe and clear upSafety
Switch off the power supply as soon as the last reading is taken. Leave the heater and block to cool on the heatproof mat; do not touch them while hot. Take the thermometer out carefully and put it back in its rack. Disconnect the leads from the power supply and the joulemeter. Wipe up the water, then return the apparatus to where you collected it once it is cool.
Hazards and control measures
| Hazard | What could happen | Control measure |
|---|---|---|
| Hot heater and block | Burns | Do not touch the heater or block while hot; let them cool before packing away. |
| Heater switched on outside the block | Burns, or a fire if it touches the bench | Only switch on when the heater is fully inside the block; stand it on a heatproof mat. |
| Water near electrical connections | Electric shock or a short circuit | Use only a few drops of water, keep the leads and power supply dry and mop up any spills straight away. |
Variables
- Independent: you change
- Energy transferred to the block in J
- Dependent: you measure
- Temperature of the block in °C
- Control: you keep the same
- Mass of the block. Use the same block throughout.
- Material of the block. One block per run.
- Power of the heater. Keep the power supply setting (potential difference) the same.
- Insulation. Keep the same insulation around the block for the whole run.
Results from a specimen run
| Time in s | Energy transferred in J | Temperature in °C |
|---|---|---|
| 0 | 0 | 22.0 |
| 60 | 1643 | 22.5 |
| 120 | 3286 | 24.0 |
| 180 | 4929 | 25.5 |
| 240 | 6572 | 27.5 |
| 300 | 8216 | 29.0 |
| 360 | 9859 | 29.0 (anomalous, left out of the mean) |
| 420 | 11502 | 32.5 |
| 480 | 13145 | 34.0 |
| 540 | 14788 | 35.5 |
| 600 | 16432 | 37.5 |
Anomaly spotted: Temperature at 360 s, left out of the mean.
- Used for the line
- Warming up, or left out
Processing the data
- Mass of the block
- 1.0015 kg
- Shape of the graph
- A short curve at the start, then a straight line.
- Gradient (temperature rise per joule)
- 0.00102 °C/J
- Specific heat capacity
- 980 J/kg °C
- Compare with the data book
- Higher than the data-book value
| Quantity | Specimen run | Accepted |
|---|---|---|
| Specific heat capacity of aluminium (data book) | 980 J/kg °C | 900 J/kg °C |
Across 120 simulated careful groups, specific heat capacity (c) came out between 921 and 1100 J/kg °C (median 986). That is the simulation's model, not a promise of what a real class gets.
Common mistakes and the fix
Mistakes to check in this practical, and what to do instead. In a write-up or an exam answer, the mark goes to naming the step and saying what it does to the readings.
Method: Leave the hole dry
The thermometer lags behind the block, so early readings are low and the graph takes longer to straighten.
The fix: Add water to the thermometer hole. Air is a poor thermal conductor. Water fills the gap, giving good thermal contact, so the thermometer reads the temperature of the block.
Method: Leave the block unwrapped
More energy is lost to the room, so the temperature rises less and your value of c is too high.
The fix: Wrap the block in insulation. Insulation reduces energy transfer to the surroundings, so more of the energy supplied raises the temperature of the block.
Temperature at the start (0 s): Typed 23 °C
The fix: One degree out: find the numbered line just below the top of the liquid and count the 1 °C marks up from it.
Temperature at the start (0 s): Typed 32 °C
The fix: Ten degrees out: check which numbered line (10, 20, 30 …) is just below the liquid.
Exam answer: Leaving out: To reduce energy transferred (lost) to the surroundings
The fix: Say what insulation does: it reduces energy transfer to the surroundings.
Exam answer: Leaving out: So more of the energy from the heater increases the temperature of the block / the value of c is more accurate (ignore "more precise")
The fix: Then link it to the result: more of the energy supplied heats the block, so the value of c is more accurate.
Worked exam-style questions
Written for Study Hack in the style of exam questions, on the specimen run above. They are not taken from any exam board's papers. Try each one before you open the worked answer.
- Question 1Reducing energy losses · Knowledge[2 marks]
You wrapped the block in insulation before switching on the heater.
Explain why.
Worked answer and how the marks are given
A full-mark answer
Insulation reduces the energy transferred from the block to the surroundings, so more of the energy from the heater increases the temperature of the block. This makes the value of the specific heat capacity more accurate.
Mark scheme
- To reduce energy transferred (lost) to the surroundings
- So more of the energy from the heater increases the temperature of the block / the value of c is more accurate (ignore "more precise")
Where marks are usually lost
- Missing: To reduce energy transferred (lost) to the surroundings. Say what insulation does: it reduces energy transfer to the surroundings.
- Missing: So more of the energy from the heater increases the temperature of the block / the value of c is more accurate (ignore "more precise"). Then link it to the result: more of the energy supplied heats the block, so the value of c is more accurate.
- Question 2Calculating specific heat capacity · Applying knowledge[4 marks]
The mass of the block was 1.002 kg.
Table 1 Time in s Energy transferred in J Temperature in °C 0 0 22.0 60 1643 22.5 120 3286 24.0 180 4929 25.5 240 6572 27.5 300 8216 29.0 360 9859 29.0 420 11 502 32.5 480 13 145 34.0 540 14 788 35.5 600 16 432 37.5 change in thermal energy = mass × specific heat capacity × temperature change ΔE = m c Δθ
Use your readings at 120 s and 600 s in Table 1 to calculate the specific heat capacity of aluminium.
Use the Physics Equations Sheet.
Specific heat capacity = J/kg °C
Worked answer and how the marks are given
A full-mark answer
ΔE = 16 432 − 3286 = 13 146 J
Δθ = 37.5 − 24.0 = 13.5 °C
13 146 = 1.002 × c × 13.5
c = 13 146 ÷ (1.002 × 13.5)
c = 972 J/kg °CMark scheme
- ΔE = 16 432 − 3286 = 13 146 J (method)
- Δθ = 37.5 − 24.0 = 13.5 °C (method)
- Substitution and rearrangement: c = 13 146 ÷ (1.002 × 13.5) (method) Allow error carried forward.
- c = 972 J/kg °C (allow error carried forward)
- Allow answers from 962.1 to 981.6 J/kg °C (the marker's tolerance; correct rounding of the student's own working is also accepted).
- Allow the unit written as j/kgc, j/kg/c, jkg-1c-1, j/kgk, j/kg/k, jkg-1k-1 and 2 other spellings.
- Error carried forward: method and answer marks follow correctly from the student's own earlier value.
- A correct answer with no working scores full marks.
Where marks are usually lost
- Answer 1060 J/kg °C (gains 2 marks). Your method is right, but you used the reading at 0 s. Use the readings at 120 s and 600 s, as the question asks.
- Answer 0.00103 J/kg °C (gains 2 marks). You found the changes correctly but rearranged the equation upside down. Specific heat capacity = change in thermal energy ÷ (mass × temperature change).
- Missing: ΔE = 16 432 − 3286 = 13 146 J. Start with the energy transferred between the two readings: 16 432 − 3286.
- Question 3Describing the method · Knowledge[6 marks]
Describe a method a student could use to determine the specific heat capacity of a metal block.
You should include how the student would use the results to find the specific heat capacity.
Worked answer and how the marks are given
A full-mark answer
1. Measure the mass of the aluminium block using a top-pan balance.
2. Put the immersion heater into the large hole and the thermometer into the small hole. Add a few drops of water to the thermometer hole to give good thermal contact.
3. Wrap the block in insulation to reduce energy transfer to the surroundings.
4. Connect the heater to the power supply through a joulemeter.
5. Record the starting temperature of the block.
6. Switch on the power supply and start the stopwatch.
7. Record the temperature (reading the thermometer at eye level) and the joulemeter reading every minute for 10 minutes.
8. Plot a graph of temperature (y-axis) against energy transferred (x-axis) and draw a line of best fit through the straight part.
9. Find the gradient of the line. Specific heat capacity = 1 ÷ (mass × gradient).
10. The heater gets very hot, so do not touch it until it has cooled down.Mark scheme
Indicative content:
- Measure the mass of the block with a top-pan balance
- Put the immersion heater in the hole in the block
- Put the thermometer in the other hole
- Add a few drops of water to the thermometer hole for good thermal contact
- Wrap the block in insulation
- Connect the heater to a power supply and joulemeter
- Measure the temperature of the block with a thermometer
- Measure the starting temperature of the block
- Switch on the heater and start the stopwatch
- Record the temperature at regular intervals, e.g. every minute
- Record the energy transferred (joulemeter reading) each time
- Take readings for about 10 minutes
- Plot a graph of temperature against energy transferred
- Find the gradient of the straight part of the line of best fit
- Specific heat capacity = 1 ÷ (mass × gradient), or use ΔE = m c Δθ
- Safety: the heater gets hot, so do not touch it until it has cooled
- Repeat the experiment and calculate a mean
Levels of response Level Marks What the answer does 3 5–6 A coherent method that would give valid results: all the important steps are there, in a sensible order, including how the specific heat capacity is found. 2 3–4 A method that might not give valid results: most of the important steps are there, but some are missing or out of order. 1 1–2 A method that would not give valid results: some relevant steps are given, but they are not linked into a workable method. In Study Hack a six-mark answer is not given an automatic level: you tick the points your answer makes, then choose the level that fits it.
- No relevant content: 0 marks.
Evaluate
| Source of error | Type | Effect | Improvement |
|---|---|---|---|
| Energy transferred to the surroundings | Systematic | Temperature rise too small, so c too high (much more without insulation). | More insulation, including the top of the block; a lid; start below room temperature. |
| Energy heating the heater and thermometer | Systematic | c a few per cent too high, and a curved start to the graph. | Use only the straight part of the graph for the gradient. |
| Poor thermal contact around the thermometer | Systematic | Readings lag behind the block by about the same amount; the gradient hardly changes. | A few drops of water (or oil) in the thermometer hole. |
| Reading the thermometer | Random | Scatter of about ±0.5 °C about the line. | Read at eye level, or use a temperature probe and data logger with a higher resolution. |
Repeatable. If you get similar values of c when you repeat the run with the same apparatus and method.
Reproducible. If another group, or a different method (an ammeter and voltmeter instead of a joulemeter), gives a similar value of c.
Other exam boards
How this practical lines up with other GCSE boards' required or core practicals. Codes only; check your own specification for the exact activity.
| Board | Practical | Match | What is different |
|---|---|---|---|
| AQA | Required practical 1 | This page | — |
| Edexcel | 14.11 | Similar, with differences | Uses water as the sample and adds a melting-ice curve with a plateau at 0 °C; this lab heats a metal block. |
Print it
- Blank write-up: the nine-step lab book with the correct table headings, ready to print for a real lesson.
- Specimen lab book: this page's run written up in full, with its exam answers ticked against the mark scheme.
- Printable method card: the practical on one index card. Practise with the cards in Study Hack.
- Practical workbook: a full simulated data set to process on paper, with exam questions and answers.
- Teacher and technician pack: apparatus lists, technician notes and marking points.