The Oxford English Dictionary notes that the term model can be used as a noun or adjective that means: “A simplified or idealized description or conception of a particular system, situation, or process, often in mathematical terms ...” The kinetic molecular theory would be an example of such a model. The OED also notes, however, that the term model can be used as a verb in the following sense: “To devise a (usually mathematical) model or simplified description of (a phenomenon, system, etc.).” For our purposes, we will use the term modeling to describe attempts to construct a model of a system. Both students and their instructors use models throughout the undergraduate curriculum in chemistry, often without realizing that this is what they are doing. This paper will talk about what happens when an explicit attempt is made to get students to think about the models they use and get them actively involved in the process of modeling.