William K. Purves
The Mona Group LLC
2817 N. Mountain Avenue, Claremont, CA 91711-1550, U.S.A.
Mary E. Williams
Department of Biology, Harvey Mudd College
301 E. 12th Street, Claremont, CA 91711-5990, U.S.A.
The important questions for instructors to address concern what skills the student is to learn and how the student is to be motivated to acquire those skills. Questions about simulations, graphics tools, and the like are unimportant until the first two questions have been answered adequately. We discuss the role of explanation by students and describe a mechanism for motivating students to learn.