(a)[2]
She sets a beaker of water on a top-pan balance, as in Fig. 1.1. Fig. 1.2 shows the beaker on the balance 14 days later, after some water has evaporated. Calculate the average loss of mass per day by evaporation.
(b)[2]
A second student repeats the same experiment using a beaker with a larger diameter. The students compare the outcomes and conclude that the rate of evaporation rises with surface area. State two other quantities that must have been kept the same in the two experiments if they are to be confident in that conclusion.
(c)[1]
The experiment required 14 days. To complete it in a shorter time, suggest a piece of apparatus that would increase the rate of evaporation.