Thermal insulation practical
Compare cooling data fairly and explain controls in an insulation investigation.
Practise the calculations · Print a classroom set
Apparatus and measurements
Compare identical vessels containing equal masses of warm water, with different insulation materials. Record temperature with probes positioned equally in each vessel. Use the same lid arrangement.
Larger apparatus diagram
Method and controls
- Choose the insulation material as the independent variable. Keep vessel size, exposed surface, water mass, insulation thickness and starting temperature the same.
- Start the timer at the same defined point and measure at fixed intervals. Run vessels together in the same room if possible, away from draughts.
- Repeat each condition, including an uninsulated comparison. Plot temperature against time. Compare temperature falls over the same interval when starting temperatures match.
Results to analyse
Original synthetic data for practice.
| Time / min | Material A / °C | Material B / °C | No insulation / °C |
|---|---|---|---|
| 0 | 60 | 60 | 60 |
| 2 | 56 | 54 | 50 |
| 4 | 53 | 49 | 43 |
| 6 | 50 | 45 | 38 |
Questions
- Which material gives the smaller temperature fall after six minutes? State the evidence.
- Why would starting one vessel at 80 °C and another at 60 °C spoil a simple comparison of temperature fall?
- What can these results establish about all possible insulation materials?
Show worked answers
- A falls by 10 °C; B falls by 15 °C. A is more effective at reducing cooling under these conditions.
- The rate of heat transfer depends on the temperature difference from the surroundings. Different starting temperatures change that difference.
- They compare these materials at the chosen thickness and conditions. They do not establish a universal ranking for every thickness, vessel or environment. Repeats are needed to assess variation.
Evaluation
A lid reduces evaporation, which otherwise contributes to cooling. If every vessel has the same lid, this helps isolate the effect of side insulation.
Use warm water at a temperature agreed by the teacher and handle vessels securely. A cooling curve normally becomes less steep as water approaches room temperature; do not assume constant cooling power.
Specification links
AQA 8463: Required practical 2 (Physics only). OCR Gateway J249: P7.1 energy transfer; investigative skills (no matching required-practical claim). Selected skills only; no practical-completion assessment.
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