Instantiation of multimodal semiotic systems in science classroom discourse

► Introduce a theoretical framework to describe how science content is instantiated. ► Broaden SFL instantiation hierarchy to include multimodality in science discourse. ► Demonstrate an approach to analyze students' multimodal meaning-making in science. ► Illustrate how three ideational meanings are instantiated from students' explanations. ► Show subtle variations among students' explanations and conceptual understanding.