  An appropriate diagram is a required element of a solution building process
in physics problem solving and it can transform a given problem into a
representation that is easier to exploit for solving the problem. A major focus
while helping introductory physics students learn problem solving is to help
them appreciate that drawing diagrams facilitates problem solving. We conducted
an investigation in which two different interventions were implemented during
recitation quizzes throughout the semester in a large enrollment, algebra-based
introductory physics course. Students were either (1) asked to solve problems
in which the diagrams were drawn for them or (2) explicitly told to draw a
diagram. A comparison group was not given any instruction regarding diagrams.
We developed a rubric to score the problem solving performance of students in
different intervention groups. We investigated two problems involving electric
field and electric force and found that students who drew productive diagrams
were more successful problem solvers and that a higher level of relevant detail
in a student's diagram corresponded to a better score. We also conducted
think-aloud interviews with nine students who were at the time taking an
equivalent introductory algebra-based physics course in order to gain insight
into how drawing diagrams affects the problem solving process. These interviews
supported some of the interpretations of the quantitative results. We end by
discussing instructional implications of the findings.
