In an effort to improve science and social studies instruction, preservice teachers developed original science, technology, and society units to teach in elementary and middle school classrooms during their clinical field experience. Data revealed that the preservice teachers fell into categories of being skeptics, open-minded instructors, or positively engaged leaders as they negotiated science, technology, and society curriculum requirements. In follow-up interviews after a full semester of student teaching, the categories held, thereby suggesting that preservice teachers' dispositions have a strong influence on their approach to curriculum and instruction. (Contains 1 note, 3 tables, and 1 figure.)