chemistry

Effect of peer-led team learning (PLTL) on student achievement, attitude, and self-concept in college general chemistry in randomized and quasi experimental designs

Julia Y. K. Chan and Christopher F. Bauer

This study investigated exam achievement and affective characteristics of students in general chemistry in a fully-randomized experimental design, contrasting Peer-Led Team Learning (PLTL) participation with a control group balanced for time-on-task and study activity. This study population included two independent first-semester courses with enrollments of about 600. Achievement was measured by scores on exams written by an instructor blind to student participation. Established instruments were used to assess changes in attitude to chemistry and self-concept as a chemistry learner. No differences were found in achievement, attitude, or self-concept for students who participated in PLTL vs. those who participated in documented alternative study activities. Overall, certain aspects of attitude and self-concept showed a slight but significant decline from beginning to end of semester, consistent with previous studies. Males have higher positive attitude and self-concept than females, and first-year students have higher positive attitude, self-concept, and achievement than non first-year students. In a quasi-experimental comparison of 10 other course sections over seven years, students who self-selected into PLTL showed stronger exam achievement than those who did not choose to participate. These findings suggest that past reports of improved student performance with PLTL may in part be a consequence of attracting students who are already motivated to take advantage of its value.

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Replicating Peer-Led Team Learning in cyberspace: Research, opportunities, and challenges

Joshua Smith, Sarah Beth Wilson, Julianna Banks, Lin Zhu2, Pratibha Varma-Nelson

This quasi-experimental, mixed methods study examined the transfer of a well-established pedagogical strategy, Peer-Led Team Learning (PLTL), to an online workshop environment (cPLTL) in a general chemistry course at a research university in the Midwest. The null hypothesis guiding the study was that no substantive differences would emerge between the two workshop settings. Students in the PLTL (n = 220) condition were more satisfied with their workshop and earned statistically significantly higher course grades, yet earned comparable standardized final exam scores. They also had lower incidence of students’ earning D or F course grades or withdrawing from the course (DFW rates) than students in the cPLTL setting (n = 175). Interviews with 10 peer leaders and 2 faculty members, as well as discourse analysis of workshop sessions, revealed more similarities than differences in the two conditions. The final exam scores and discourse analysis support the null hypothesis and use of both face-to-face and synchronous online peer-led workshops in early science courses.

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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.

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College chemistry students’ understanding of potential energy in the context of atomic–molecular interactions

Nicole M. Becker, Melanie M. Cooper

Understanding the energy changes that occur as atoms and molecules interact forms the foundation for understanding the macroscopic energy changes that accompany chemical processes. In order to identify ways to scaffold students’ understanding of the connections between atomic–molecular and macroscopic energy perspectives, we conducted a qualitative study of students’ conceptualization of potential energy at the atomic–molecular level. We used semi-structured interviews and open-ended surveys to explore how students understand potential energy and use the idea of potential energy to explain atomic–molecular interactions in simple systems. Findings suggest that undergraduate chemistry students may rely on intuitive interpretations of potential energy, incorrect interpretations of curricular definitions (including the idea that potential energy represents stored energy) and heuristics rather than foundational understandings of the relationships between atomic–molecular structure, electrostatic forces and energy. Thus, we suggest that more explicit attention to the nature and role of potential energy in the undergraduate chemistry curriculum may be needed.

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