Explain why the water is stirred before taking a temperature reading.
The student uses $200\,\text{cm}^3$ of hot water in the same beaker for every test. State one further experimental variable that the student keeps unchanged so the three sets of results can be compared fairly.
Complete Table 2.1 by finding the mean time for the water to cool by $5.0^{\circ}\text{C}$. Give your answer to the correct number of significant figures.
Suggest one explanation for why the time needed for the water to cool by $10.0^{\circ}\text{C}$ is not twice the time needed for it to cool by $5.0^{\circ}\text{C}$.
Describe how the cooling of the water differs in the two beakers. Use the results in Table 2.1 and Table 2.2 in your answer.
Suggest one explanation for the difference.