The purpose of this study was to examine the relationship between science teacher knowledge and changes in student content knowledge after students experienced microcomputer-based laboratory (MBL) instruction about heat energy and temperature. Investigation of teacher knowledge included evaluation of content knowledge and pedagogical content knowledge. The teachers' MBL instruction was described in terms of the type and number of MBL activities conducted. The study sample consisted of experienced eighth grade teachers (n=6) and their students (n=22). Interview transcripts serve as the sole data source for the teachers and students in this study. Participants' knowledge was identified using prepositional analysis. The strongest evidence of a relationship between teacher pedagogical content knowledge and student content knowledge was between changes in student knowledge and the amount of a particular type of instruction. The relationship existed only with those activities that emphasized the distinction between heat energy and temperature. Nine tables present the data. (LZ)