Adapting Meaningful Learning Strategies for an Introductory Laboratory Course: Using Thin-Layer Chromatography to Monitor Reaction Progress

摘要

Introductory-level laboratory courses provide students with hands-on experience using the discipline's tools and theories. These courses often rely on recipe-based experiments due to the constraints of large enrollments, short lab periods, and the desire to minimize complexity. In addition, covering a breadth of topics can lead to a fragmented curriculum with little carryover in learning from week to week. Herein, we describe an overhaul of an introductory organic chemistry laboratory curriculum, informed by the strategies of meaningful learning and a desire to make the course experience mimic a research lab. This new course, primarily taught to first-year undergraduate students at the University of Michigan, is framed with three interconnected modules. We present herein the first module, which focuses on thin-layer chromatography (TLC). In the first week, students learn how to perform TLC using a variety of compounds and solvent mixtures, gaining an understanding of how intermolecular interactions affect their retention. In the second week, they practice using TLC to distinguish reagents and reaction byproducts and in the third week apply TLC to monitor reaction progress and test their hypothesis. We assessed student learning through a writing assignment at the end of the three-week module. We also assessed how the overall course affects student comprehension of TLC concepts and confidence. Our findings suggest that this learn, practice, apply approach toward teaching introductory organic chemistry laboratory concepts leads to learning gains and increased confidence.