The problem of teacher isolation and lack of collegial relationships has been extensively documented and considered one of the obstacles to improvement of instruction. The study reported here analyzed some empirical evidence about how that situation can change in junior high school science. The study investigated: (1) what happens when science teachers interact with each other on a frequent basis about instructional matters? and (2) what are some of the aspects of the school environment that make such conversation possible and fruitful? The data came from inventories, structured interviews, fieldnotes, transcripts of audiotapes, support teacher logs, meeting agendas and notes, exemplars of student work, and other such sources. It was found that extended interaction of science teachers about instructional matters feeds into the improvement of their practice, motivates experimentation, and allows the transformations in practice to feed back into the conversation. The study findings indicate that teachers' isolation is not impossible to break. There is a need, however, for teacher-based departmental effort and administrative support. (Most of the paper is comprised of a literature review on teacher isolation.) (Author/AMH)