  Pencasts are videos of problem solving with narration by the problem solver.
Pedagogically, students can create pencasts to illustrate their own problem
solving to the instructor or to their peers. Pencasts have implications for
teaching at multiple levels from elementary grades through university courses.
In this article, we describe the use of pencasts in a university level
upperdivision Electromagnetic Fields course usually taken by junior and senior
physics majors. For each homework assignment, students created and submitted
pencasts of ordinary problems several days before the problem set was due. We
compare students' performance in the class (grades for pencast submission
excluded) with the pencast submission rate. Students who submitted more
pencasts tend to do better in the course. We conclude with some practical
suggestions for implementing pencasts in other courses.
