(ii) Suggest why it is important to compare the change in length rather than the final lengths of the potato stick in this type of investigation.
.. (1)
(iii) Identify one source of error with the method and suggest an
improvement
errer
improvement
[2]
(b) Another investigation was carried out into the effect of different
concentrations of sucrose solution on potato sticks.
In this investigation students decided to measure the change in mass
rather than the change in length.
The students followed a similar method to the one in 3(a) but they left
the potato sticks to soak for three hours instead of 30 minutes.
(i) The students dried the potato sticks on paper towels before
measuring the mass of each potato stick.
Suggest why this step was not important in the investigation
described in 3(a), where length was measured.