A student tests bubble wrap, cotton wool and felt as insulators. State the independent variable, the dependent variable, and one control variable.
[3 marks]
Total for this question: 3
Physics required practicals
Thermal insulation
AQA 4.1 · RP2 (physics only)
GCSE Physics (8463) · Required practical 2 — method, variables, the marks examiners report students losing.
(physics only) means this content belongs to AQA GCSE Physics (8463), the separate-science qualification, but not AQA Combined Science: Trilogy (8464). It is not an exam tier: (HT only) separately marks Higher-tier content.
Board and spec code confirmed against AQA 8463 · registry checked 2026-07-17How this checking works
Investigate how effective different materials are as thermal insulators, and how a factor such as thickness or the number of layers affects the insulation.
Apparatus
- Beaker (with a lid) to hold the hot water
- Insulating materials to test (e.g. bubble wrap, cotton wool, felt, newspaper)
- Thermometer or temperature sensor
- Stopwatch and measuring cylinder
- Kettle or hot water, and an elastic band to hold the material on
Method
- 1Measure a fixed volume of hot water into the beaker with a measuring cylinder.
- 2Wrap the beaker in the material being tested and hold it with an elastic band; put on the lid and thermometer.
- 3Record the starting temperature, then the temperature every minute for about 10 minutes.
- 4Repeat with each material, using the same volume of water at the same starting temperature.
- 5Compare the temperature drop over the fixed time; the smallest drop is the best insulator.
Variables
Independent
The insulating material (or its thickness / number of layers)
Dependent
The temperature drop of the water over a fixed time
Control
- Volume of water
- Starting temperature of the water
- Time the water is left, and beaker size
Results & processing
- Record temperature against time for each material and plot cooling curves on the same axes.
- The material giving the smallest temperature drop (or highest final temperature) is the best insulator.
Where students lose marks
Starting with different volumes or temperatures of water.
Fix: Keep the volume and starting temperature of the water the same for every material — they are control variables.
Leaving the beaker without a lid.
Fix: Use a lid, or a lot of energy escapes from the open top by evaporation and convection and the material is not being tested fairly.
Comparing thickness and material at the same time.
Fix: Change only one variable — test different materials at the same thickness, or one material at different thicknesses.
Improve the method
- Use the same volume and starting temperature of water each time.
- Fit a lid and use a data logger to record temperature automatically.
- Repeat each material and take a mean; run the test for longer to get a bigger, clearer temperature drop.
Try it — exam-style
Easy
ORIGINAL
Medium
ORIGINAL
With no insulation, water cools from 80°C to 62°C in 5 minutes. Wrapped in wool it cools from 80°C to 74°C in the same time. State which is the better insulator and how much less the water cooled.
[2 marks]
Total for this question: 2
Questions are written in the style of past AQA papers — never copied from them.
Drill it properly
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