VISUALIZING MOTION IN POTENTIAL WELLS

The concept of potential-energy diagrams is of fundamental importance in the study of quantum physics. Yet, students are rarely exposed to t his powerful alternative description in introductory classes and thus have difficulty comprehending its significance when they encounter it in beginning-level quantum courses. We describe a learning unit that i ncorporates a sequence of computer-interfaced experiments using dynami cs or air-track systems. This unit is designed to make the learning of potential-energy diagrams less abstract. Students begin by constructi ng the harmonic or square-well potential diagrams using either the vel ocity data and assuming conservation of energy or the force-displaceme nt graph for the elastic interaction of an object constrained by sprin gs or bouncing off springy blocks. Then, they investigate the motion o f a rider magnet interacting with a configuration of field magnets and plot directly the potential-energy diagrams using a magnetic field se nsor. The ease of measurement allows exploring the motion in a large v ariety of potential shapes in a short duration class. (C) 1998 America n Association of Physics Teachers.