A student investigated the role of skin insulation in mammalian thermoregulation using two metal cylinders filled with hot water to model heat loss. Cylinder C was left uninsulated to simulate an animal with shaved skin, while Cylinder D was wrapped in a layer of synthetic wool to simulate thick fur. Both cylinders were left to cool in a draft-free room.
Their results are shown in the table below.
| Time (minutes) | Cylinder C (uninsulated) temperature (°C) | Cylinder D (insulated) temperature (°C) |
|---|---|---|
| 0 | 88.5 | 88.5 |
| 3 | 77.0 | 83.5 |
| 6 | 66.2 | 79.0 |
| 9 | 56.4 | 75.0 |
| 12 | 47.6 | 71.5 |
| 15 | 39.8 | 68.2 |
| 18 | 33.0 | 65.0 |
Calculate the rate of temperature change in Cylinder C from 3 to 15 minutes. Show your working.
