Examining student ability to interpret and use potential energy diagrams   for classical systems
  The Physics Education Group at the University of Washington is examining the extent to which students are able to use graphs of potential energy vs. position to infer kinematic and dynamic quantities for a system. The findings indicate that many students have difficulty in relating the graphs to real-world systems. Some problems seem to be graphical in nature (e.g., interpreting graphs of potential energy vs. position as graphs of position vs. time). Others involve relating the graphs to total, kinetic, and potential energies, especially when the potential energy is negative. The results have implications beyond the introductory level since graphs of potential energy are used in advanced courses on classical and quantum mechanics. 
Brian M. Stephanik and Peter S. Shaffer
physics.ed-ph