Monday, August 03, 2009

Do Students Use and Understand Free-Body Diagrams?

A rather interesting paper on the analysis of whether students use the free-body diagrams in intro physics, and if they actually understood how and why it is used.

{I think you get get free access to all papers in PRST-PER}

Abstract: Physics education literature recommends using multiple representations to help students understand concepts and solve problems. However, there is little research concerning why students use the representations and whether those who use them are more successful. This study addresses these questions using free-body diagrams (diagrammatic representations used in problems involving forces) as a type of representation. We conducted a two-year quantitative and qualitative study of students’ use of free-body diagrams while solving physics problems. We found that when students are in a course that consistently emphasizes the use of free-body diagrams, the majority of them do use diagrams on their own to help solve exam problems even when they receive no credit for drawing the diagrams. We also found that students who draw diagrams correctly are significantly more successful in obtaining the right answer for the problem. Lastly, we interviewed students to uncover their reasons for using free-body diagrams. We found that high achieving students used the diagrams to help solve the problems and as a tool to evaluate their work while low achieving students only used representations as aids in the problem-solving process.

As a freshman, I think I wasn't consciously taught how to use the FBD, even though I end up using something similar to that, but not consistently. On, I definitely drew some diagram to help visualize and solve the problem, but again, this wasn't done consistently especially if I can visualize it in my head. I think I drew sketches in the problems that I solved more in illustrating to the grader or the instructor how I was approaching the problem, rather than in helping me to solve the problem.

It was later on, when I was a grad student and had to TA for intro physics classes that the "formal" use of using FBD, and its usefulness, were finally drilled into me. Now I can certainly see its usefulness, and will try to convey that to every student about to learn physics.


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