A student investigates the rate of cooling of a hot liquid using a plastic beaker wrapped in bubble wrap to model the insulated walls of a container.
She puts a fixed volume of hot water into the beaker and measures the temperature of the water every three minutes.
Describe a method she can use to investigate how the rate of cooling changes with the thickness (number of layers) of the bubble wrap insulation.
The table below shows the results of one of her experiments using 3 layers of bubble wrap.
| Time (minutes) | Temperature of water (∘C^\circ\text{C}∘C) |
|---|---|
| 0 | 85 |
| 3 | 72 |
| 6 | 61 |
| 9 | 52 |
| 12 | 45 |
| 15 | 40 |
| 18 | 36 |
Describe how the temperature of the water changes with time. Use data from the table to support your description.
The student repeats the experiment, but this time she uses 6 layers of bubble wrap. Suggest how the temperature-time curve for 6 layers would compare to the curve for 3 layers on a graph.
Suggest two ways the student could improve the investigation to make her results more reliable or precise.
Explain why the rate of cooling would be different if she used a copper beaker instead of a plastic beaker, assuming the thickness of the walls of both beakers is identical.
47 exam-style questions on OCR GCSE Physics Practical skills. Each one has a worked solution and a mark scheme showing where the marks go.