Interactive Lecture Demonstrations

Interactive Lecture Demonstrations (ILD) are a student centered teaching method, in which students are asked to predict the outcome of an experiment, observe the outcome, and discuss it with respect to their former expectations. The demonstrations are designed to contradict students’ known misconceptions, generate cognitive conflict and dissatisfaction with the existing conception, and promote a process of conceptual change. An ILD based course was used to explore the effect of cognitive conflict on the conceptual change process, and the role of student interactivity in this process. Three major levels of conceptual change were identified: high – students who remember the outcome of the demonstration, and explain it using the consensus model; medium – students who can recall the outcome, are dissatisfied with their alternative model, but do not switch to the consensus model; and low – no meaningful recollection of the outcome, and no change in the alternative model. A multiplechoice test based on the lecture demonstration was given to two groups, one of which only observed the demonstrations, without predicting and discussing. We found a significant difference between the groups, with an obvious drop in students’ ability to recall the outcome of the demonstrations in the noninteractive group. Background on Normalized learning gains and Interactive Engagement: Interactive-engagement vs traditional methods: A six-thousand student survey of mechanics test data for introductory physics courses* Richard R. Hake Department of Physics, Indiana University, Bloomington, Indiana 47405 A survey of pre/post test data using the Halloun-Hestenes Mechanics Diagnostic test or more recent Force Concept Inventory is reported for 62 introductory physics courses enrolling a total number of students N = 6542. A consistent analysis over diverse student populations in high schools, colleges, and universities is obtained if a rough measure of the average effectiveness of a course in promoting conceptual understanding is taken to be the average normalized gain . The latter is defined as the ratio of the actual average gain (% – % ) to the maximum possible average gain (100 – % ). Fourteen "traditional" (T) courses (N = 2084) which made little or no use of interactive-engagement (IE) methods achieved an average gain T-ave = 0.23 ± 0.04 (std dev). In sharp contrast, forty-eight courses (N = 4458) which made substantial use of IE methods achieved an average gain IE-ave = 0.48 ± 0.14 (std dev), almost two standard deviations of IE-ave above that of the traditional courses. Results for 30 (N = 3259) of the above 62 courses on the problem-solving Mechanics Baseline test of Hestenes-Wells imply that IE strategies enhance problem-solving ability. The conceptual and problem-solving test results strongly suggest that the classroom use of IE methods can increase mechanics-course effectiveness well beyond that obtained in traditional practice. Normalized gain: = (post – pre) / (100-pre)