In this theoretical paper we draw on two constructs that we argue are related to the appropriate interpretation of many representations in science education: frames and structures of awareness. By representations is meant, for example, images, diagrams and models. The idea of frames is taken from social semiotics and the idea of structures of awareness is taken from the variation theory of learning. Using both an everyday example and examples from science education we make the argument that students need to become explicitly aware of tacitly held structures of awareness that frame their interpretation of representations. A task for science educators would be to investigate the possibility to produce representations that could aid students in this work.