Get premium membership and access revision papers with marking schemes, video lessons and live classes.
In an investigation a student extracted three pairs of pawpaw cylinders using a cork borer. The cylinders were cut back to 50mm length and placed in a beaker containing a solution. The results after 40 minutes were as shown in the table below.

(a) Account for the results in the table above.
(b) What would be a suitable control set up for the investigation?