We discuss an investigation of the difficulties that students in a university introductory physics
course have with the electric field and superposition principle and how that research was used as a
guide in the development and evaluation of a research-validated tutorial on these topics to help
students learn these concepts better. The tutorial uses a guided enquiry-based approach to learning
and involved an iterative process of development and evaluation. During its development, we obtained
feedback both from physics instructors who regularly teach introductory physics in which these
concepts are taught and from students for whom the tutorial is intended. The iterative process
continued and the feedback was incorporated in the later versions of the tutorial until the
researchers were satisfied with the performance of a diverse group of introductory physics students
on the post-test after they worked on the tutorial in an individual one-on-one interview situation.
Then the final…