Question 35
Eight similar leaves from the same kind of plant are labelled A–H. Apply petroleum jelly as follows: A/B none; C/D upper surface only; E/F lower surface only; G/H both surfaces. Hang the leaves in their original order and compare their measured mass losses after at least one day. Imagine that you are asked to do this experiment again. Suggest two improvements you would make (other than using more leaves for each treatment). For each of your suggestions, explain why this would improve the strength of the evidence you collect.
