A science education process model was proposed for ultimate use in research on science teaching. In this model, classroom interaction was presented as the middle component of a three-phase system. The on-going process of classroom interaction was viewed in terms of a communications model: interaction exchanges provided communications paths through which symbolic meanings were exchanged. Micro-analytical units of behavior and events were introduced, defined, and their formulation described. The unit was used as basis for studying interaction. Three uni-dimensional instruments were used. Eight classrooms using inquiry-discovery approaches to science teaching were used as data sources. The dimensions of classroom interaction were analyzed to produce a reduced number of factors by means of a principal axis factor analysis with verimax rotation. A concept of dynamic structure in classroom interaction was defined and formulated mathematically. The components were considered to be the paths and pedagogical moves. The coefficient of dynamic structure was calculated for various transactional styles and showed characteristic differences consistent with hypothesized views. Plots of this coefficient across time intervals, interaction intervals or transactional styles can give a physical picture of changes in classroom interaction and be the basis for comparing classrooms, students and teachers. (Author/EB)