knowledge structures

Teachers’ knowledge structures for nature of science and scientific inquiry: Conceptions and classroom practice

Stephen A. Bartos, Norman G. Lederman

Research on nature of science (NOS) and scientific inquiry (SI) has indicated that a teacher’s knowledge of each, however well developed, is not sufficient to ensure that these conceptions necessarily manifest themselves in classroom practice (Lederman & Druger, 1985; Lederman, 2007). In light of considerable research that has examined teachers’ subject matter knowledge structures and their classroom practices (e.g., Gess-Newsome & Lederman, 1993, 1995), what was conspicuously absent was an assessment of teachers’ knowledge structures for NOS and SI. The current investigation inferred the classroom practice knowledge structures for NOS and SI for four physics teachers. These results were then compared to responses communicated through the Knowledge Structures for NOS and SI (KS4NS) questionnaire and subsequent interview. The degree of congruence between the two knowledge structures was gauged at the level of included concepts, connections between concepts, and for other organizational or thematic elements. The results indicated limited congruence between teachers’ knowledge structures for NOS and SI and those espoused in their classroom practice. Most notable was the dearth of connections evidenced between constituent aspects in the latter. The necessity of having teacher candidates explicitly reflect on the structure of the subject matter they are learning for teaching is reiterated through the findings of the current study. The utility of the KS4NS as tool to foster such reflections specifically regarding conceptualization of NOS and SI independent of, or in conjunction with, traditional subject matter also warrants further investigation, particularly in light of the recently released Next Generation Science Standards and their highly integrative conception of science.


Ethnically diverse students’ knowledge structures in first-semester organic chemistry

Enrique J. Lopez, Richard J. Shavelson, Kiruthiga Nandagopal, Evan Szu, John Penn

Chemistry courses remain a challenge for many undergraduate students. In particular, first-semester organic chemistry has been labeled as a gatekeeper with high attrition rates, especially among students of color. Our study examines a key factor related to conceptual understanding in science and predictive of course outcomes—knowledge structures. Previous research on knowledge structures has focused on differences between experts and novices. Given the increasing ethnic diversity of college classrooms and research indicating unique differences in certain higher order cognitive processes associated cultural practices and ethnicity, it is important to investigate whether similar patterns exist with respect to knowledge structures. Our study utilized concept maps to measure knowledge structures. Two separate analyses where performed to determine whether or not ethnically diverse students’ organize their knowledge of organic chemistry content in structurally different ways. The first analysis utilized concept map proposition scoring to examine the influence of prior science achievement and ethnicity on knowledge structures. The second analysis examined holistic map structures to determine whether or not ethnically diverse students show qualitatively distinct structures overall. Results show significant mean differences on concept map proposition scores related to both prior science achievement and ethnic group membership. However, examination of holistic structures revealed that students’ qualitative holistic structures did not vary by ethnic group membership. Taken together, our findings suggest that variation in students’ knowledge structures are related to prior science achievement across ethnic groups, not qualitative differences in the ways ethnically diverse students’ structure knowledge. Implications for teaching and learning in organic chemistry are discussed.