| This research studies students' functional understanding of magnetic induction, the process by which changing magnetic flux induces electrical current in a circuit. This phenomenon is important since it has many practical applications. Induction involves the relationships among multiple inter-related in time. A preliminary study shows this topic is difficult for students. In order to improve instruction, we study student learning in detail.; We begin with an analysis of students' understanding of underlying concepts, such as field and flux, as well as students' awareness of the phenomenon of induction and the ideas they apply prior to any formal instruction.; We describe instructional materials that were developed. First, we discuss two versions of a set of laboratory activities designed to introduce students to induction: an inquiry version that guides students to develop Faraday's Law as an explanation for simple experimental observations, and a competing-hypothesis version that requires students to experimentally evaluate three possible explanations for observed phenomena. Second is a more advanced set of laboratory activities that involves a number of qualitative graphical predictions and a quantitative estimation problem. Third is a set of tutorial activities designed to emphasize critical issues that are common sources of difficulty.; Next, we describe the prevalence of students' ideas, and the degree to which they use a mix of ideas, before and after their initial induction-related instruction. We also describe common difficulties students exhibit throughout their instruction on induction, including a number of ways in which they misapply the correct idea.; We identify broader cognitive difficulties that are observed in this context. For example, students struggle to differentiate between a quantity and its rate of change, or between instantaneous rate of change and change over a finite time interval. We also describe the use of intuitive ideas students apply in the context of induction that, when applied appropriately, can serve as cognitive resources or, when applied inappropriately, seem to support incorrect ideas. Finally, we emphasize issues related to the representations of induction-related concepts and how they affect students' learning in both positive and negative ways. |
