Search

Organic reaction mechanisms are often represented by the electron-pushing formalism and reaction coordinate diagrams. These representations pose a challenge to students because valuable information is encoded within each representation, and students must know how to reason about mechanisms using both. Hence, it is important to understand whether and how students consider these two representations when reasoning about reaction mechanisms. We have collected responses to a writing-to-learn assignment administered in a second-semester organic chemistry laboratory course to investigate students' reasoning. The assignment was designed to elicit students' reasoning about the most likely of two mechanisms for a catalyzed intramolecular aldol reaction when given the electron-pushing scheme and reaction coordinate diagram for both mechanisms. As part of the assignment, students submitted initial drafts, participated in content-focused peer review, and submitted revised drafts. We analyzed each component using a mixed methods approach to identify students' reasoning about the most likely reaction pathway and how their reasoning changed after peer review and revision. In this article, we present a quantitative overview of changes students made about their decisions for the most likely reaction pathway and how these changes are related to providing and receiving feedback. Additionally, we present our analysis of the features of representations students used to reason about the likelihood of alternative reaction mechanisms. This study demonstrates how existing research about students' reasoning with representations was operationalized for classroom practice using writing-to-learn. Furthermore, the analysis illustrates how writing-to-learn to can be used to develop students' reasoning and offers implications for teaching students to reason about reaction mechanisms using multiple representations.

Student affect is an important factor in the learning process and may be especially important in gateway courses such as organic chemistry. Students' recognition of the relevance of the content they are learning and interactions with their peers can support their motivation to learn. Herein, we describe a study focused on how Writing-to-Learn assignments situate organic chemistry content within relevant contexts and incorporate social elements to support positive student interactions with organic chemistry. These assignments incorporate rhetorical elements--an authentic context, role, genre, and audience--to support student interest and demonstrate the relevance of the content. In addition, students engage in the processes of peer review and revision to support their learning. We identified how the authentic contexts and peer interactions incorporated into two Writing-to-Learn assignments supported students' interactions with the assignments and course content by analyzing student interviews and supported by feedback survey responses. Our results indicate that assignments incorporating these elements can support student affect and result in students' perceived learning, but that there should be careful consideration of the relevance of the chosen contexts with respect to the interests of the students enrolled in the course and the complexity of the contexts.

Writing is a key disciplinary practice in STEM used to construct scientific knowledge and communicate research findings. With its role in the scientific process, writing is often incorporated into STEM classrooms to train students in scientific writing. The importance of incorporating writing in STEM classrooms is heightened by the role it can play in supporting student learning of disciplinary knowledge and thinking. However, the characteristics of a writing assignment can shape how and what students are learning. Although faculty recognize the value of writing in instruction, they often face barriers that constrain the amount and types of writing they incorporate into their classes. This article describes the design and propagation of Writing-to-Learn assignments in introductory STEM courses at the University of Michigan through the MWrite program. Our aim is to present a framework that could inform similar efforts from the classroom to institutional levels. The Writing-to-Learn assignment design described herein incorporates a context-driven prompt followed by content-focused peer review and revision. We also describe the structures incorporated into the MWrite program to support the large-scale implementation of writing in high-enrollment introductory STEM courses.

Organic chemistry is a required course sequence for many STEM students. However, research indicates that organic chemistry reaction mechanisms are especially challenging for students due to a mixture of underlying conceptual difficulties, the process-oriented thinking inherent to the discipline, and the representations commonly used to depict mechanisms. While student reasoning about many of the reaction types covered in the organic chemistry curriculum has been studied previously, there is minimal research focused specifically on how students think about the mechanisms of addition reactions. Understanding students' conceptions about addition reactions is valuable for both instructors and researchers, as these reactions are among the first for which students must consider different chemical properties to make a decision about alternate reaction pathways. This study provides insight into how students think about these reactions by probing first semester organic chemistry students' thinking using think-aloud interviews as they worked through two addition reactions. To elicit a range of thinking, students worked through the mechanisms using either paper and pencil or an app that dynamically represents the molecules. Generally, students were able to identify the steps of the two addition reactions but did not always successfully apply chemical thinking during the mechanistic steps. Most prominently, both groups of students struggled with the concepts related to carbocation stability, frequently misapplying stabilization via substitution and demonstrating difficulty in identifying the potential for resonance stabilization. Our results suggest that instructors should emphasize the conceptual grounding that directs mechanistic steps, in particular when determining carbocation stability. More generally, our findings suggest that instructors must emphasize the skill of considering and weighing different chemical properties when making decisions about alternative reaction pathways.

An understanding of acid-base reactions is necessary for success in chemistry courses and relevant to careers outside of chemistry, yet research has demonstrated that students often struggle with learning acid-base reaction mechanisms in organic chemistry. One response to this challenge is the development of educational applications to support instruction and learning. The development of these supports also creates an opportunity to probe students' thinking about organic chemistry reaction mechanisms using multiple modalities--i.e., using an app interface or the traditional paper-pencil. This study used think-aloud interviews conducted with undergraduate students in their first semester of organic chemistry to understand how they worked through two acid-base reactions using either paper-pencil or an app. Analysis of the interviews indicates that students from both groups recognize the steps of acid-base reactions, but do not always apply the underlying concepts, such as assessment of pK[subscript a] values or resonance, when determining how a reaction will proceed. The modality seemed to somewhat influence students' thinking, as the app prevented students from making chemically unreasonable mistakes. However, some students relied on the cues it provided, which could potentially be problematic when they are required to respond to assessments that do not provide these cues. Our results suggest that instructors should emphasize the conceptual grounding for the steps that govern acid-base reactions to promote chemical thinking about the relationships between the reaction components and how those influence reaction outcomes, as well as support students to think critically about the chemical information contained within the modalities they are using.