Thursday, September 27, 2001
Physics colloquium, Calvin College (Grand Rapids, MI)
Classroom demonstrations in science courses are intended to serve two important purposes: to increase students interest in the material being covered and to improve students understanding of the underlying scientific concepts. Student end-of-semester evaluations typically praise demonstrations as one of the most interesting parts of a course, suggesting that demonstrations accomplish the first objective. What about the second? Do demonstrations effectively help students learn the underlying concepts? We examined whether the manner of presentation of demonstrations affects their effectiveness as teaching tools. Seven demonstrations were presented to different sections of an introductory physics course in different ways: (1) students were shown the demonstration and the outcome was explained (traditional style); (2) students were asked to predict the outcome before the demonstration; (3) students completed a brief worksheet predicting the outcome, discussing it with partners, and then comparing their prediction to the actual outcome; (4) no demonstration was shown. After the course, students completed a free-response test asking them to predict and explain the outcome of physical situations identical to the demonstrations. The results indicate that students who have to predict the outcome of a demonstration before seeing it, and especially those who then compare their prediction to the actual outcome, remember and understand the outcome at a much higher rate than those who saw the demonstration in traditional style.