P341: Making predictions about chemical reactivity: Assumptions and heuristics

Author: Vicente Talanquer, University of Arizona, USA

Co-Author: Jenine Maeyer, University of Arizona, USA

Date: 8/4/14

Time: 2:05 PM2:25 PM

Room: MAN 107

Related Symposium: S31

Diverse implicit cognitive elements seem to support but also constrain reasoning in different domains. Many of these cognitive constraints can be thought of as either implicit assumptions about the nature of things or reasoning heuristics for decision-making. In this study we applied this framework to investigate college students’ understanding of structure-property relationships in the context of chemical reactivity. The ability to understand and apply structure-property relationships to explain the behavior of physical, chemical, and biological systems is a core competence that many science and engineering majors are expected to develop. Core findings were derived from semi-structured interviews based on a ranking task. Study participants relied on intuitive, spurious, and valid assumptions about the nature of chemical entities in building their responses. In particular, many of students appeared to conceive chemical reactions as macroscopic reassembling processes thought to be more favored the easier it seemed to break reactants apart or put products together. Students also expressed spurious chemical assumptions based on the misinterpretation and overgeneralization of chemical ideas. Reasoning heuristics for decision-making also played a significant role in the construction of answers to ranking questions. Specifically, interviewees demonstrated strong over-reliance on variable reduction strategies and recognition memory in their reasoning. Our findings reveal the need for educational approaches that more effectively affect the conceptual sophistication and depth of reasoning about structure-property relationships of college students. Our research framework provides a productive approach for the analysis of student reasoning in scientific domains.

P311: Teaching assistants in leadership roles: Pairing TAs for success

Author: Jenine Maeyer, University of Pennsylvania, USA


Date: 8/4/14

Time: 3:05 PM3:25 PM

Room: MAK A1117

Related Symposium: S24

Like other colleges and universities, our general chemistry laboratory program relies heavily on teaching assistants. With enrollment increasing over the past few years, we have reevaluated the roles of the laboratory teaching assistants. After considering and piloting several different positions over the past few years, we have implemented two new leadership TA positions to better support our program as a whole. This presentation will discuss the two new roles: Head TA and Mentor TA. The head TA serves as an assistant to the course’s faculty instructor. This TA not only helps answer emails and prepares course documents (i.e. rubrics, TA presentations), but also serves as a valuable resource for many students in the course. The mentor TA works closely with less experienced TAs. Since very little instruction or training is offered between semesters, TAs that were unable to teach in the fall because of language difficulties begin teaching in the spring, several months after formal training occurs. This gap has led to struggles in the past for new TAs. To address this issue, a mentor TA is formally paired with first-time TAs to help with the transition. We have found this pairing eased new TA fears, led to higher quality student-TA interactions, and resulted in improved end-of-semester TA evaluations. This presentation will discuss the specific TA roles and the experiences we have had over the past two years implementing the leadership TA positions.