Using photographs to probe students' understanding of physical concepts: The case of Newton's 3rd law

The starting point of the present research is the following question: since we live in an age that makes increasing use of visual representations of all sorts, is not the visual representation a learner constructs a window into his/her understanding of what is or is not being learned? Following this direction of inquiry, the present preliminary study introduces and evaluates a novel technique for pinpointing learners' misconceptions, namely, one that has learners create and interpret their own photographs (CIP). 27 high-school students and 26 pre-service teacher trainees were asked to assume the role of textbook designers and create a display-photograph plus attached verbal explanation-which, in their opinion, best depicted Newton's 3rd law. Subsequent analysis of the participants' photographs yielded the following six misconception categories: 3rd law not depicted; 3rd law depicts a sequence of events; tendency to introduce irrelevant entities in explanations; the word 'reaction' used colloquially; tendency to restrict the application of the third law to dynamic situations; and informal explanations in which the word "force" is absent. The findings indicate that, indeed, the CIP method can be effectively employed to elicit, detect, and investigate learners' misconceptions. The CIP method joins the growing efforts to utilize the yet relatively untapped potential of visual tools for science education purposes.