From the perspective of science classrooms Klette (Norway) discusses how time scale(s) and analytical categories serve as different lenses for analyzing classroom learning. By means of in depth analyses of video data from lower secondary science classrooms, she argues how different scales and conceptual frameworks of analysis provide support for different and diversified interpretations and conclusions. By moving between different scales with different levels of functioning, for example time scale of analyses, or analytical focus, she shows how conclusions arrived at on the basis of one scale and analytical framework might be scrutinized, and even challenged, if another level of scale and coding framework is used as the basis for interpretations. The performed analyses investigate aspects of classroom talk in science classrooms (n=45) from the perspective of instructional format; classroom discourse; and features of language used in the observed classrooms. Depending on different theoretical perspectives and unit of analyses, stable and emerging patterns of teacher-student interaction can be exposed.