Many studies in the chemical education literature report students' alternative conceptions in chemistry and the difficulty they present for future learning. In this paper, we review existing diagnostic tools used to uncover students' alternative conceptions in chemistry and suggest that there are two fundamental issues with such instruments, namely, the breadth of topics and concepts assessed and the reliance on forced choice responses. We argue that while existing instruments provide a way to assess students' overall understanding of chemical concepts, they cannot assess depth of understanding of any single concept, such as the particulate nature of matter -one of the central, organizing ideas in chemistry. Instead, we propose using qualitative approaches that utilize drawing tasks as an alternative diagnostic tool to uncover students' underlying struggles with fundamental chemistry concepts. Using this approach, we investigated college students' ability to balance chemical equations and draw appropriate particulate representations of those reactions. Emerging categories from students' particulate drawings were coded into several subcategories and revealed a number of underlying issues, such as lack of understanding of appropriate relationships between reacting species in solution, oxidation numbers, states and valences of species, the characteristics and nature of ions in solids and differences between ionic and covalent bonds. We describe these findings and consider the implications of qualitative-based diagnostics for instruction and science learning as a formative assessment tool.

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Much research has focused on student views about physics concepts, with an emphasis on the identification of alternative conceptions, and how curricula and professional development may ameliorate the situation. However, there has been little work on determining the extent of, and in separating, the student and teacher/classroom level variables that may impact student physics achievement. This study examined the effect of different student and teacher/classroom level variables on student understanding of physics concepts using hierarchical linear modeling (HLM), a regression based technique. The data were collected from 68 different teachers and 3,119 students who were using a reform curriculum, Active Physics. Teachers and students completed surveys asking about their beliefs, their classes and their personal characteristics. Students also completed a physics achievement test. The data show that students of teachers who used Active Physics for a greater portion of the year scored higher on the achievement test than did students of teachers who did not use the curriculum as much. Furthermore, the data show that the achievement gap was narrowed between boys and girls and between students with different attitudes toward physics. Additionally teachers who received inservice instruction on how to implement Active Physics narrowed the gap between students with different views of their classroom involvement. ß