Presented are two studies examining effects of using expressive writing in the science classroom. The first study, "Writing to Think About High School Chemistry," was conducted by a high school English teacher who enrolled in a high school chemistry course. The course was typical with the exception that students were encouraged to keep a journal in which they were to write whatever they wished, or whenever they were confused or the teacher thought they had gone over difficult material. Analysis of three student journals (including the author's) indicates that writing provoked these students to reflect on their own thoughts, take responsibility for their own learning, and begin to raise and answer their own questions. The second study, "Using Expressive Writing to Teach Biology," examined use of writing assignments (reading logs, notes, practice essays, summaries) in two high school biology classes. It was predicted that writing encourages students to think about subject matter and to discover and clarify points of confusion. Although posttests showed generally similar levels of achievement for experimental (N=69) and control (N=67) groups, the experimental group appeared to do better on the delayed posttests. Statistical analyses were not reported. (JN)