On several levels it can be said that the act of modelling in science is inherently an argumentative act. That is, in virtually all aspects of modelling, from developing a question to judging between competing models that might answer that question, an individual is engaged in persuasive acts. Those acts may be private or public. They may be mental, written or oral, but they are about judging ideas and making sense of them; convincing oneself or others that the ideas and ways of looking at and explaining a phenomenon are useful. These acts are what scientists find exciting. They are what make science intellectually interesting and challenging. Inviting students into this practice is one way to help them learn both the content and process of science. This paper introduces a framework that is attentive to the research on how people learn while simultaneously pushing for curriculum and instruction that engages students in elements of the practice of science. We explore how this framework can be used to foster argumentation by describing the theoretical underpinnings of the framework and using classroom examples to illustrate the utility of the framework for promoting argumentation. (Contains 1 figure.)