The objective of this project is the construction of a well-grounded and systematic description of how students in general chemistry reason about solutions using qualitative and quantitative descriptions. The work focuses on in-depth studies of students' conceptions of chemical phenomena in solution (identity, concentration, and reactivity), how these are described using qualitative (submicroscopic, macroscopic, and symbolic) representations, and how quantification helps or hinders these conceptions and descriptions. Intellectual Merit: Contemporary research on learning indicates that effective instruction needs to take into account the conceptions that students bring to learning tasks, especially when those conceptions diverge from, and potentially conflict with, conceptions accepted by the scientific community. When these conceptions are not taken into account, there are two typical results: fleeting, superficial learning or little learning at all. At the same time, there is clear evidence that college students have significant problems reasoning about chemical systems. Furthermore, they tend to treat calculations and numbers algorithmically rather than conceptually, thus turning mathematical procedures into blindly-applied algorithms. As a result, underlying concepts that ought to link multiple representations are frequently absent and students are less able to design and carry through on purposeful investigations using measurement. The project adapts the Facets cluster approach that Minstrell (1992, 2001) developed in the context of basic physics concepts (e.g., forces and motion, acceleration, etc.) to map the space of students' conceptions related to the three chemical phenomena of solutions and the four different forms of representation through in-depth work with a small but diverse group of students. The research is being done in consultation with faculty who teach general chemistry in four college environments in the Chicago area, including three community colleges (Kennedy-King College, Harold Washington College, and Harper College). These institutions serve student populations that are traditionally underrepresented in the STEM disciplines. The in-depth studies lay the groundwork for the design of a computer-based assessment system that could be used to further define the conceptual space of student understanding in this domain as well as provide diagnostic information to instructors. This project is producing a prototype of such a system. Broader Impacts: Facet clusters for chemical phenomena are expected to have significant impacts on the knowledge base required for implementing effective teaching, learning and assessment practices in undergraduate science with diverse student populations. The project is having its most significant initial impact in general chemistry, a key course for the success of students in many different STEM career tracks, including many outside the chemical sciences. Major initiatives in the reform of general chemistry course content have proceeded with relatively little specific data about student reasoning using numerical information. This project is providing additional insight into what students do when they encounter multiple representations including quantification. Beyond general chemistry the work also is expected to impact other teaching and learning environments where students must work with qualitative and quantitative descriptions, including other chemistry courses, health professions, life, earth, and environmental sciences. In addition, the problems being studied also are found in K-12 education, making this research relevant to pre-college science education.
