A category system was developed to describe verbal and non-verbal classroom behavior of junior high school science students. The category system contained two major sections: communicative (symbolic) behavior and non-communicative (non-symbolic) behavior. The instrument was used in conjunction with a teacher behavior category system (developed in a companion study) to analyze videotapes made simultaneously of student and teacher behavior in eight ninth grade earth science classrooms. The percentage distributions of observed student behaviors in eight lecture discussion sessions and three laboratory sessions were reported. Conclusions from the analyses of the data included the following: (1) Student behaviors and teacher behaviors were related, (2) Student behaviors were both positively and negatively related to teacher behaviors, (3) Student classroom behavior was predominately communicative (symbolic) in nature. (EB)