An ethnographic study of three public elementary school classrooms explored how teachers organized time and space and through this organization attempted to construct classroom power relationships. The study involved intensive observation of classroom interactions in two fifth-grade classes and one first-grade classroom and close analysis of videotapes of two of the classrooms. The videotapes were used for stimulated-recall interviews with two of the teachers; an in-depth interview was conducted with the third teacher. All the teachers were white women, two with 20 years experience and one with 5 years experience. The first fifth-grade classroom was arranged so that students had little opportunity to move about. In the other two classrooms, much more physical freedom was afforded the students. The classrooms also differed in the amount of time that the teachers devoted to highly structured, as opposed to more loosely structured, activities. Yet it was clear that in every case the arrangements the teacher had made were consonant with her beliefs about how children can best learn, and therefore were enactments of her agenda to control student actions in order to facilitate student learning. The study showed clearly that teachers have an institutional role that allows them to make contributions to power relationships through their organization of time and space. The amount of structure built into the learning activities available in the classroom also shapes power relationships effectively. Nevertheless, students find ways to resist teacher control, to create "seams" in environments and activities, and to use those "seams" to make their own contributions to power relationships. (Contains 20 references.) (JB)