Student understanding of light as an electromagnetic wave: Relating the formalism to physical phenomena

During an investigation of student understanding of physical optics, we fou nd that some serious difficulties that students have with this topic may be due, at least in part, to a lack of understanding of the nature of light a s an electromagnetic wave. We therefore decided to look carefully at how st udents interpret the diagrammatic and mathematical formalism commonly used to represent a plane EM wave. The results of this research have guided the development and modification of tutorials that address some of the difficul ties that we identified. These instructional materials are an example of ho w, within a relatively short time allotment, a curriculum developed on the basis of research can help students relate the concepts and formal represen tations associated with EM waves to physical phenomena. (C) 1999 American A ssociation of Physics Teachers.