This HTML5 simulation demonstrates how friction affects temperature and molecular motion. Rub two books together to generate friction and watch the temperature increase as the molecules' kinetic energy increases. As greater friction is applied, some of the molecules in the "Chemistry" book break free of their bonds. However, the molecules in the "Physics" book are much more tightly bound. (No amount of heat will remove them.) This simulation is appropriate for conceptual physics courses as a way to introduce friction in terms of both macroscale and molecular-scale interactions. Teaching ideas and activities are included.

This is part of a larger collection developed by the Physics Education Technology project (PhET).

Please note that this resource requires Flash.