Science is viewed as a neglected subject in many U.S. elementary schools. Many elementary school teachers feel unqualified and uncomfortable when asked to teach it. A study looked at a teacher who is enthusiastic about teaching science at the elementary school level. The constraints the teacher faced and ways in she dealt with them in her teaching were addressed. In order to examine the transition from university student to student teacher of this beginning teacher, she was observed during the 45-minute science period that took place 4 mornings a week. The data sources for this project were field notes taken during observations; transcripts of interviews with the student teacher, her cooperating teachers, students, and the principal; and documents including lesson plans, class handouts, and tests. Data analysis consisted mainly of inductive analysis in repeated examination of these data sources that led to the development of categories for organizing data. Assertions were generated and their validity tested by triangulating the various data sources. From the data, a picture of the student teacher's vision of teaching elementary school science, including her views on inquiry, textbooks, and group work was compiled. The constraints the student teacher perceived and the coping patterns used by the student teacher are discussed. The findings suggest that in order to implement reforms the position of the preservice teacher negotiating idealistic beliefs about science teaching within the existing school structure must be taken into account. This study established a theoretical base from which we can begin to understand science enthusiasts among prospective teachers and their transition from novice to experienced teachers. (34 references) (KR)