AQA GCSE Physics · EnergyTriple only
Thermal insulation required practical
Investigate the effectiveness of different materials, or different thicknesses of a material, as thermal insulators.
A beaker of hot water is wrapped in layers of newspaper and left to cool. The better the insulation, the smaller the temperature drop in 10 minutes, because less energy is transferred to the surroundings.
This one is only on the separate Physics GCSE, so it won’t come up in Combined Science.
Equipment
- Small beaker inside a larger beaker (or on its own)
- Kettle of hot water
- Thermometer and stopwatch
- Newspaper (or other insulating materials) and elastic bands
- Cardboard lid with a hole for the thermometer
Variables
- Independent you change
- Number of layers of newspaper
- Dependent you measure
- Temperature drop in 10 minutes
- Control you keep the same
- Same volume of water
- Same starting temperature
- Same beaker and lid
- Same time
Method
- 1
Wrap the beaker in one layer of newspaper, held with elastic bands.
- 2
Pour 150 cm³ of hot water from a kettle into the beaker and put a cardboard lid on it.
- 3
Put the thermometer through the lid and record the starting temperature (e.g. 80 °C).
- 4
Start the stopwatch and record the temperature after 10 minutes.
- 5
Repeat with 0, 2, 3 and 4 layers, starting from the same temperature each time.
- 6
Calculate the temperature drop for each and plot it against the number of layers.
Worked example
150 cm³ of water, starting at 80.0 °C, cooling for 10 minutes.
| Layers of newspaper | Temp after 10 min (°C) | Drop (°C) |
|---|---|---|
| 0 | 62.0 | 18.0 |
| 1 | 66.0 | 14.0 |
| 2 | 68.5 | 11.5 |
| 3 | 70.5 | 9.5 |
| 4 | 72.0 | 8.0 |
Working
Temperature drop = start temperature − temperature after 10 min
2 layers: 80.0 − 68.5 = 11.5 °C
Conclusion
More layers of newspaper give a smaller temperature drop, so they reduce the rate of energy transfer. Each extra layer helps less than the one before. Newspaper traps air, which is a poor conductor.
Risks
- Hot water can scaldPour carefully, stand the beaker on the bench, and don’t carry it while full.
- Glass can crack with hot waterUse heat-resistant beakers.
Common mistakes
- Starting at different temperatures. Hotter water cools faster, so the starting temperature must be the same.
- Leaving off the lid. A lot of energy is lost from the top by evaporation and convection.
- Saying insulation stops heat loss. It reduces the rate of energy transfer.
Better results
- Use a data logger with a temperature probe to record readings automatically.
- Repeat each thickness and take a mean temperature drop.
- Stir the water gently before reading so the temperature is even.
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.