Exploring Gold Nanoparticles, the IBI Prize-winning module, guides students' construction and evidence-based refi nement of their personal models of gold nanoparticles.T he President's Council of Advisors on Science and Technology stresses the importance of adoption of empirically validated instructional practices, such as inquirybased laboratory experiences, in higher education (1). The Exploring Gold Nanoparticles laboratory module employs an inquiry-based instructional tool called the Model-ObserveRefl ect-Explain (MORE) Thinking Frame (2) to support student construction of evidencebased models of nanoparticles in introductory chemistry courses. Using MORE has been shown to enhance students' understanding of the nature of science and of scientific models compared with traditional teaching methods (3,4).The MORE Thinking Frame scaffolds students' thinking as they work to construct and evaluate evidence-based, molecular and/or nano-level models of chemical systems. A MORE module begins with a written, prelaboratory assignment (5) that prompts each student to describe his or her ideas about the system under study from macroscopic and molecular-level perspectives. This serves as the student's initial model. In writing their models, students are encouraged to refl ect upon and articulate their own ideas, rather than to look up scientists' ideas. Next students conduct experiments in the laboratory (observe) and are explicitly prompted to refl ect upon the implications of their observations as they relate to their initial model ideas. Students then refi ne their models and explain how their revised molecular-level ideas are consistent with the experimental evidence they collected.After completing an iteration of MORE, students apply MORE to a subsequent set of laboratory activities, which provides additional opportunities for them to refi ne their models. Each student presents a refined model, explains why it has (or has not) changed from his or her previous model, and proposes a generalized model that could be used to understand new situations. At the end of a module, each student proposes a next experiment that would help further refi ne or test his or her molecular-level model.Although the MORE Thinking Frame is well-suited to guide students' thinking as they conduct original research, in our general chemistry laboratory course, we have more often applied it to investigations for which there is a fundamental, scientifi cally accepted model that has not yet been presented to students. Research has shown that instructional paradigms in which students fi rst work to develop general rules or models, and expert ideas are presented only after students complete their investigations, promote deep understandings that facilitate transfer of learning [e.g., (6)]. Research in the context of another MORE module (7) indicates that student engagement in three thinking processes is strongly correlated with subsequent successful reasoning in new contexts. These include (i) constructing molecularlevel models that are consistent wi...