Launch practical
About 60 minutes
- Set up the bench with the 8 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 10 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. The thermometer in beaker A (no insulation). Record the display exactly as it shows.
What it shows
ΔE = m c Δθ
Hot water transfers energy to its cooler surroundings, faster the hotter it is. An insulator, with a low thermal conductivity and trapped air, lowers the rate of energy transfer, so the water cools more slowly. The drop in temperature in the same time compares how well each material insulates.
The graph to expect. A cooling curve: the temperature falls fastest at the start, when the temperature difference between the water and the room is biggest, then more and more slowly. The insulated water’s curve is less steep.
On the AQA 2027 Physics Equations Sheet. The practical compares temperature drops over the same time; the equation turns a drop into energy.
Apparatus
| Item | What it is for | Resolution |
|---|---|---|
| Kettle | Boils the water. | — |
| Beakers: 100 ml, 250 ml and 800 ml | Hold the hot water; the 800 ml beaker holds the insulation around the 100 ml one. | — |
| Measuring cylinders (100 ml and 250 ml) | Measure the same volume of water for every beaker: 80 ml in the 100 ml cylinder, 200 ml in the 250 ml one. | 1 ml (100 ml), 2 ml (250 ml) |
| Two thermometers (digital or liquid-in-glass) | Measure the temperature of the water in each beaker. | 0.1 °C or 1 °C |
| Two stopwatches | Time the 5-minute readings for each beaker. | 0.01 s |
| Cardboard lids with a hole | Cover the beakers; the thermometer goes through the hole. | — |
| Insulating materials and rubber bands | Bubble wrap, polystyrene granules, sawdust, corrugated card and newspaper. | — |
| Heatproof mats and a tray | Protect the bench; catch spilt granules. | — |
Method
In our own words, as the Lab runs it. Your school's method sheet may differ in detail.
Check the thermometers
Compare each thermometer with the room thermometer. If one does not agree to within about 1 °C, swap it for another.
Why: A thermometer that reads high or low adds the same error to every reading it takes (a zero error).
Choose your investigation
The class splits the work. Which investigation will your group do?
Do: Different materials (Part 1).
Why: Each group tests one thing against a beaker with no insulation. The class pools its results so everyone can compare every material. Here the other groups are simulated for you.
Choose your material
Which insulating material will your group test? The rest of the class tests the others.
Do: Bubble wrap.
Why: Only the material changes between groups. Everything else should be the same, so the results can be compared fairly.
Choose your thermometers
You need one thermometer in each beaker.
Do: Digital thermometers (0.1 °C).
Why: The temperature drops you compare are only a few degrees apart, so the resolution of the thermometer matters.
Stand the beakers on heatproof matsSafety
Stand each beaker on a heatproof mat on the bench. Pour into it there: never hold a beaker while you pour.
Why: Near-boiling water scalds. A beaker held in the hand can tip or slip while you pour.
Measure the water
Measure the hot water in a measuring cylinder before you pour it into each beaker: 80 ml (Part 1) or 200 ml (Part 2). Stand the cylinder on the bench and read the bottom of the meniscus with your eye level with it.
Why: More water stores more energy, so it cools more slowly. Both beakers (and every group) must use the same volume for a fair test.
Pack the insulation
Pack the material firmly and evenly into the space around beaker B, the insulated beaker, right up to the top. Beaker A is the control.
Why: Gaps full of air let convection currents carry energy away. Every group must pack its material the same way.
Put on the lids
After pouring, cover each beaker with a cardboard lid with a hole for the thermometer. The bulb must be in the water, not touching the glass.
Why: Hot water loses a lot of energy from its surface by evaporation. A lid on every beaker keeps that the same for each one.
Take the readings
Pour the same volume of hot water into each beaker, put a thermometer in each and start timing. Read both thermometers every 5 minutes for 20 minutes: at 0, 5, 10, 15 and 20 minutes.
Repeats: A cooling reading cannot be repeated: by the time you try again, the water has cooled. To repeat, do the whole run again with fresh hot water, or compare your results with other groups who used the same material (the class pools its results). Repeating reduces the effect of random errors, such as different starting temperatures, but not systematic ones, such as a missing lid.
Make safe and clear upSafety
Switch off and unplug the kettle, then leave the beakers on their mats until they are cool enough to hold. Take out the thermometers and put them back in their case. Pour the water away at the sink. Tip the insulation back into its bag over the tray and sweep up any granules.
While you take readings
When will you start the stopwatch?
Each beaker gets its own stopwatch.
Do: When its thermometer reads 80 °C.
Why: A hotter beaker cools faster. If the two beakers (and every group) start at different temperatures, the comparison is not fair.
Hazards and control measures
| Hazard | What could happen | Control measure |
|---|---|---|
| Near-boiling water poured from the kettle | Scalds to the hands and arms | Stand the beaker on a heatproof mat and pour slowly; never hold the beaker while pouring. |
| Hot beakers after pouring | Burns from picking them up | Leave the beakers on their mats until they have cooled before moving them. |
| Kettle and its mains lead near water | Electric shock | Check the lead before use, keep the kettle away from the water work and handle the plug with dry hands. |
| Glass thermometer knocked off the bench | Cuts from broken glass | Keep the thermometer in the lid hole or its case, never loose on the bench. |
| Polystyrene granules or sawdust spilt | Slips, or dust in the eyes | Pour the material over a tray and sweep up spills straight away. |
Variables
- Independent: you change
- Type of insulating material (Part 1), or number of layers (Part 2)
- Dependent: you measure
- Temperature of the water in °C
- Control: you keep the same
- Volume of water in ml. Measure 80 ml (or 200 ml) with a measuring cylinder.
- Starting temperature in °C. Start the stopwatch when the thermometer reads 80 °C.
- Lid. A cardboard lid on every beaker.
- Size and type of beaker. The same beakers for every group.
- Thickness of material (Part 1) or type of material (Part 2). Pack to the same depth; use the same newspaper.
- Room temperature in °C. Everyone works in the same room at the same time.
Results from a specimen run
| Time in min | Temperature with no insulation in °C | Temperature with bubble wrap in °C |
|---|---|---|
| 0 | 80.0 | 80.0 |
| 5 | 73.5 | 76.4 |
| 10 | 67.9 | 67.7 (anomalous, left out of the mean) |
| 15 | 63.1 | 69.9 |
| 20 | 58.6 | 66.8 |
| Drop | 21.4 | 13.2 |
Anomaly spotted: Bubble wrap, 10 min, left out of the mean.
- Beaker B
- Beaker A
Processing the data
- Drop in temperature: beaker A
- 21.4 °C
- Drop in temperature: beaker B
- 13.2 °C
- Shape of the graph
- The temperature falls quickly at first, then more and more slowly.
- Energy transferred from beaker B
- 4440 J
- Where the energy goes
- 3 of 3 right first time
- The class’s results
- Bubble wrap: mean drop 13.7 °C (4 groups)
| Quantity | Specimen run | Accepted |
|---|---|---|
| Drop with no insulation (class mean) | 21.4 °C | 23.5 °C |
| Drop with bubble wrap (class mean of the other groups) | 13.2 °C | 13.8 °C |
Across 120 simulated careful groups, temperature drop in 20 minutes (Δθ) came out between 12.4 and 17.8 °C (median 15.2). 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: Use them as they are
If one thermometer reads 2–3 °C high, every reading from that beaker is 2–3 °C too high (a systematic error). Its temperature drop is hardly changed, but its curve sits higher than it should.
The fix: Check the thermometers. A thermometer that reads high or low adds the same error to every reading it takes (a zero error).
Method: Number of layers (Part 2)
200 ml of hot water in a 250 ml beaker. You wrap one beaker in layers of newspaper and leave the other bare.
The fix: Choose your investigation. Each group tests one thing against a beaker with no insulation. The class pools its results so everyone can compare every material. Here the other groups are simulated for you.
Method: Polystyrene granules
You pack polystyrene granules around one beaker. The class results show the other materials.
The fix: Choose your material. Only the material changes between groups. Everything else should be the same, so the results can be compared fairly.
No insulation, 0 min: Typed 22.7 °C
The fix: That is the room thermometer, which stands beside the two thermometers. This reading is the thermometer in the beaker of water.
No insulation, 0 min: Typed 8 °C
The fix: Check the order of the digits: the display shows the tens first, then the units, then the tenth.
Exam answer: Leaving out: Independent variable: (type of) insulation / material (do not accept thickness of material)
The fix: The independent variable is the one the student changed: the type of insulating material.
Exam answer: Leaving out: Dependent variable: time (taken to cool from 80 °C to 60 °C)
The fix: The dependent variable is the one the student measured: the time taken to cool from 80 °C to 60 °C.
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 1Variables · Knowledge[2 marks]
Another student compared four insulating materials. The student wrapped each material around a beaker of hot water and timed how long the water took to cool from 80 °C to 60 °C.
Give the independent variable and the dependent variable in this investigation.
Worked answer and how the marks are given
A full-mark answer
Independent variable: the type of insulating material.
Dependent variable: the time taken for the water to cool from 80 °C to 60 °C.Mark scheme
- Independent variable: (type of) insulation / material (do not accept thickness of material) Do not accept “thickness / thick / layers / amount of material”.
- Dependent variable: time (taken to cool from 80 °C to 60 °C)
Where marks are usually lost
- Missing: Independent variable: (type of) insulation / material (do not accept thickness of material). The independent variable is the one the student changed: the type of insulating material.
- Missing: Dependent variable: time (taken to cool from 80 °C to 60 °C). The dependent variable is the one the student measured: the time taken to cool from 80 °C to 60 °C.
- Question 2Rate of cooling · Applying knowledge[2 marks]
Table 2 shows your readings for the beaker with no insulation.
Table 2 Time in min Temperature in °C 0 80.0 5 73.5 10 67.9 15 63.1 20 58.6 Calculate the mean rate of cooling of the water in the first 10 minutes.
Mean rate of cooling = °C/min
Worked answer and how the marks are given
A full-mark answer
Fall in temperature = 80.0 − 67.9 = 12.1 °C
Rate = 12.1 ÷ 10 = 1.21 °C/minMark scheme
- Fall in temperature = 80.0 − 67.9 = 12.1 °C (method)
- Rate = 1.21 °C/min
- Allow answers from 1.198 to 1.222 °C/min (the marker's tolerance; correct rounding of the student's own working is also accepted).
- Allow the unit written as c/min, degrees per minute, degrees c per minute, °c per min, c per min.
- A correct answer with no working scores full marks.
Where marks are usually lost
- Answer 0.0202 °C/min (gains 1 mark). You divided by 600 s, which gives °C/s. The question works in minutes: 12.1 ÷ 10 = 1.21 °C/min.
- Answer 6.79 °C/min (no marks). Use the fall in temperature, not the temperature at 10 minutes: (80.0 − 67.9) ÷ 10 = 1.21 °C/min.
- Answer 1.3 °C/min (no marks). That is the rate in the first 5 minutes. For the first 10 minutes: (80.0 − 67.9) ÷ 10 = 1.21 °C/min.
- Question 3Planning the investigation · Knowledge[6 marks]
A student wants to investigate how the number of layers of newspaper wrapped around a metal can affects how quickly hot water in the can cools.
The student has: a metal can, sheets of newspaper, rubber bands, a kettle, a measuring cylinder, a digital thermometer and a stopwatch.
Plan an investigation the student could do.
Worked answer and how the marks are given
A full-mark answer
1. Wrap one layer of newspaper around the metal can and hold it with rubber bands.
2. Measure 200 ml of hot water from the kettle with a measuring cylinder and pour it into the can.
3. Put the digital thermometer in the water. When it reads 80 °C, start the stopwatch.
4. Record the temperature after 10 minutes.
5. Calculate the drop in temperature.
6. Repeat with 2, 3, 4 and 5 layers of newspaper.
7. Keep the volume of water, the starting temperature and the time the same each time, and put a lid on the can.
8. The more layers, the smaller the drop: compare the drops for each number of layers.Mark scheme
Indicative content:
- Wrap a number of layers of newspaper around the metal can (held with rubber bands)
- Pour a measured volume of hot water into the can
- Measure the initial temperature with the digital thermometer (and start the stopwatch)
- Measure the temperature after a set time (e.g. 10 minutes), or every few minutes
- Repeat with different numbers of layers
- Keep a control variable the same: volume of water, starting temperature, time, lid, room temperature, same type of newspaper
- Calculate the drop in temperature and compare it for each number of layers
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. 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 |
|---|---|---|---|
| The beakers started at different temperatures | Random | A beaker that starts hotter cools faster and falls further, so two materials can swap places in the ranking. | Start each stopwatch when its thermometer reads the same temperature, such as 80 °C. |
| Different volumes of water in the beakers | Random | Less water stores less energy, so it cools faster: the drop depends on the volume as well as the insulation. | Measure the same volume of water into every beaker with a measuring cylinder. |
| No lid: energy lost from the surface by evaporation | Systematic | Every drop is much bigger, and the insulation seems to make less difference. | Cover every beaker with a lid with a hole for the thermometer. |
| Insulation packed loosely, with air gaps | Systematic | Convection in the gaps carries energy away, so the insulated water cools faster than it should. | Pack the material firmly to the same depth every time (or wrap layers tightly with bands). |
| A thermometer with a zero error | Systematic | Every reading from that thermometer is too high (or too low) by the same amount; the drop is hardly changed. | Check every thermometer against the room thermometer before you start, and swap any that disagree. |
| Reading a glass thermometer from above (parallax) | Systematic | Every reading is a little too low. | Read with your eye level with the top of the liquid, or use a digital thermometer. |
| Thermometer resolution: 1 °C divisions on a glass thermometer | Random | Each reading can be up to half a division out, which matters when materials differ by only a few degrees. | Use a digital thermometer or a temperature probe and data logger (0.1 °C). |
| The thermometer lifted out of the water to read it | Random | A one-off reading several degrees too low, which does not fit the curve. | Leave the bulb in the water and bend down to read it, or use a data logger. |
Repeatable. When you repeat the whole run with the same material, method and equipment, you get a similar temperature drop.
Reproducible. Another group, or a different method such as a data logger, gets a similar temperature drop for the same material.
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 2 | This page | — |
| Edexcel | — | Not on its list | — |
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.