Examined instructional materials, teacher planning, instruction, and student conceptions related to an activity unit on plants and photosynthesis. Reasons are offered about why the teacher was unsuccessful in helping students replace their misconceptions with scientific conceptions, although the teacher knew this misconception existed. (JN)

This study is part of a larger study of teachers' use of curriculum materials in planning and teaching fifth-grade science. The study focused on one of nine teachers observed teaching "Communities," an activity-based unit from the SCIIS science program (a revision of the original Science Curriculum Improvement Study).…