  Studies have shown that standard lectures and instructional laboratory
experiments are not effective at teaching interference and diffraction. In
response, the author created an interactive computer program that simulates
interference and diffraction effects using the Finite Difference Time Domain
method. The software allows students to easily control, visualize, and
quantitatively measure the effects. Students collected data from simulations as
part of their laboratory exercise, and they performed well on a subsequent
quiz---showing promise for this approach.
