The aims of this study were considered under three headings. The first was to elicit misconception that science and physics student teachers (pre-service teachers) had about the terms, "inertial mass", "gravitational mass", "gravity", "gravitational force" and "weight". The second was to understand how prior learning affected their misconceptions, and whether teachers' misconceptions affected their students' learning. The third was to determine the differences between science and physics student teachers' understanding levels related to mass and gravity, and between their logical thinking ability levels and their attitudes toward physics lessons. A total of 267 science and physics student teachers participated in the study. Data collection instruments included the physics concept test, the logical thinking ability test and physics attitude scale. All instruments were administered to the participants at the end of the 3rd semester of their university years. The physics test consisting of paper and pencil test involving 16 questions was designed, but only four questions were related to mass and gravity; the second test consisted of 10 questions with two stages. The third test however, consisted of 15 likert type items. As a result of the analysis undertaken, it was found that student teachers had serious misconceptions about inertia, gravity, gravitational acceleration, gravitational force and weight concepts. The results also revealed that student teachers generally had positive attitudes toward physics lessons, and their logical thinking level was fairly good.