Two volunteer BEd student teachers in their fourth year of a BEd degree at a metropolitan university in the Western Cape of South Africa designed and taught lessons to two classes of the same age and ability in grade 7 (ages 12-13), using drama role-plays (intervention) and more conventional non-drama methods (control). Lessons were observed and video-audio recorded to identify episodes critical to successful learning. Learners (pupils) in both sets of classes were tested in associated content using tests designed by the student teachers. In both cases test outcomes were in favour of drama lessons (F=.56 and .55) but were not necessarily linked to the number of positive teaching episodes. Lack of interaction between student teachers and their learners, insufficient structure to the role-plays or a tendency to over-contextualise scenarios did not seem to have hindered conceptual understanding. Findings suggest a more nuanced and progressive programme of training in using drama for teaching science would be beneficial and that subject knowledge for planning activities must be particularly sound. © 2018 Royal Society of Biology