Evaluation of an instructional unit utilizing the worst case method in improving students' understanding of uncertainty analysis and propagation of error

Abstract

The objective of most physics laboratory exercises is to investigate the validity of a physical law or theory. Students compare predictions, based on theoretical grounds, with experimental results and are often confronted with a discrepancy between these two. Instead of submitting an analysis or a conclusion that incorporates uncertainty analysis, students will often resort to a list of excuses to explain the difference, such as equipment malfunctions or human error. They fail to recognize that their results may support the theory, even without perfect correlation.Physics teachers are challenged to provide instruction on uncertainty analysis rigorous enough to analyze laboratory data while, at the same time, understandable to entry-level students. This study focused on evaluating the effects of an algebra-based instruction unit on student understanding of uncertainty analysis and propagation of error. A comparison of scores on a pretest and posttest showed a statistically significant improvement in scores. In Phase Two of the study, student laboratory assignments were evaluated for changes in the level of understanding. Students demonstrated improved ability to incorporate uncertainty analysis and propagation of error in their laboratory reports, but most did not obtain an in-depth level of understanding. In a similar manner, conceptual change was evident at the lower level of assimilation, but few students achieved a complete conceptual change regarding uncertainty analysis.