Classical physics has a long history of using demonstrations and experiments to develop ideas in introductory courses. The purpose of this exploration is to examine the effectiveness of a desk-top activity for helping students develop abstract reasoning. In the pilot exploration, students in three laboratory sections of a single physics course were given different supplemental instructions on development of free body diagrams: standard instruction, system schemas, and a new approach building physical models of those schemas. Students using the physical models avoided common errors made by the other two groups. More importantly, their discussion with a student researcher about developing diagrams showed a deeper understanding of the concepts and less guessing than responses of the control groups. In a subsequent use of this activity with an entire class, similar positive results were found for free body diagrams although the activity did not have an impact on related topics in the course.