A student investigates the rate of cooling of hot liquid to model how insulation reduces heat loss in homes.
She puts a beaker of hot water wrapped in felt insulation on a heatproof mat and measures the temperature of the water every three minutes. She wants to investigate how the rate of cooling changes with the number of layers of felt wrapping the beaker.
Describe a method she can use to carry out this investigation.
The table below shows the results from one of her trials using 1 layer of felt:
| Time (minutes) | Temperature of water (∘C^\circ\text{C}∘C) |
|---|---|
| 0 | 85 |
| 3 | 71 |
| 6 | 60 |
| 9 | 51 |
| 12 | 44 |
| 15 | 39 |
Describe how the temperature of the water changes with time. Use data from the table to support your description.
If the experiment is repeated with the beaker wrapped in three layers of felt, with everything else remaining the same, describe how this new temperature-time curve would compare to the one-layer curve.
Suggest one way to improve the investigation to get more reliable or accurate measurements.
Explain why using a beaker made of copper instead of glass (with the same wall thickness and no insulation wrapping) would affect the rate of cooling.