UC San Diego

he central focus of my dissertation concerns the issue of representation. The issue of representation is important for science education research for two reasons: (1) the use of external representation in science teaching and learning, particularly in chemistry education, is ubiquitous as microscopic entities are not directly visible, and (2) the study of student learning relies on linguistic representation of student conceptions as thoughts are not directly visible. Therefore, the issue of representation is an issue of making the invisible visible, more specifically, an issue of making differences, whether differences among submicroscopic entities or differences among students, visible. If we take seriously Gombirch’s (1980) notion that scientific images “do not, of course, aim to record what is visible, their purpose is to make visible” (p.185), we must account for the practices of “making visible” and the underlying philosophical assumptions. With a focus on representation, my dissertation sets out to explore the implications of engaging with philosophical assumptions that may unsettle the normative worldview in science education research by working towards three goals: (1) to critically examine the implicit philosophical assumptions, namely representationalism, metaphysical individualism, and humanism, thatxii underpin the current normative worldview in discipline-based science education, (2) to engage with the relational ontology of agential realism and develop agential variation theory as a framework for exploring the potential of conducting chemistry education research from post- humanist perspectives, and (3) to advance qualitative methodology for investigating representational practices in college chemistry education. The findings of my dissertation explore the analytical implications for the theoretical movement and methodological consideration. Starting with an analysis from the cognitive perspective of variation theory, my findings continuously weave in Marton’s notion of critical features, Vygotsky’s notion of semiotic mediation, and Barad’s notion of intra-action to reconfigure the meaning of qualitative interview data. This weaving of multiple theories reconfigured these constructs to semiotic features, signifying practices, and participation of materiality. Coordination multiple theoretical constructs and onto-epistemological standpoints produced a multilayered reading that showed the fluid and situated evolution of external representations’ meaning. Chemistry cultural practices such as structural-activity analysis is shown to both constitute and limit the possibility of external representations’ meaning. In addition, the materiality of external representations is shown to play an active role in the production of meaning. These findings complement the interpretive perspective of the representational competence model of student learning with representations.