(a)[1]
Suggest why the student waits for $30\,\text{s}$ before reading the initial temperature of the hot water.
(b(i))[1]
Calculate the average cooling rate $R_1$ of the hot water during the first $60\,\text{s}$. Use the equation $R_1 = \frac{(\theta_0 - \theta_{60})}{60}$.
(b(ii))[1]
Calculate the average rate of cooling $R_2$ of the hot water between $t = 240\,\text{s}$ and $t = 300\,\text{s}$.
(c)[1]
Use the values you calculated in part (b) to describe how the rate of cooling changes as the hot water cools.
(d)[1]
At the end of the investigation, the student leaves the water in the beaker. Predict the water’s final temperature $2$ hours later.
(e)[1]
Suggest how the student can make the temperature readings as accurate as possible.