This research focused on the concept of "force" ("CHI-KA-RA" in Japanese) in Newtonian mechanics. The primary objective was to develop a tool, based on metaphor, to interpret student thinking in learning scientific topics. The study provides an example of using the tool to trace the process of mutual changes in thinking during a dialog among students who have different perspectives on the same topic. "Social metaphorical mapping" was used to interpret a dialog between two groups of junior high school students with different epistemological paradigms with regard to the concept of force (CHI-KA-RA) in the learning environment of a computer simulation. Both source domains were recontextualized through social metaphorical mapping and the process of mutual changes in concepts was traced. Participants noticed that the Buridanian concept of "force" differs from the Newtonian concept of "force," differentiated between the concepts of "force" that use the same Japanese term "CHI-KA-RA," and noticed that the Buridanian concept of "force" resembles the Newtonian concept of "momentum." (Contains 14 figures.)