"The students had memorized everything," said the late physicist Richard Feynman, "but they didn't know what anything meant." Many science educators have come to see this as the central challenge of their discipline: promoting "inquiry-based" instruction that encourages students to think critically and develop concepts on their own, rather than requiring students to learn only how to solve problems quantitatively.

Traditional methods of teaching physics often fail to help students understand fundamental concepts. The problem with the old approaches, says Lillian McDermott of the University of Washington, is that they are guided by the instructor's understanding of the subject rather than the students'. McDermott urges teachers to get inside their students' heads in order to help them make connections among concepts (like velocity), formal representations (like graphs), and the real world. Trying to teach fundamental skills without knowing how students naturally approach problems, she has found, just doesn't work.

Researchers are now experimenting with computer simulations to teach physics in a way that allows students to relate new information to what they already know. Chuck Whitney of Harvard's Center for Astrophysics has created a simulation program called "Billiards" to help high school physics students explore kinematics—the motions of objects—in an immediately accessible and familiar context. I have been helping Whitney test the program in the classroom.