Development of a discovery-based organic chemistry lab module: Evaluation of student attitudes and ability to interpret spectroscopy

Abstract

Laboratories are a central component of the undergraduate organic chemistry curriculum. For years, educators have questioned the effectiveness of laboratories in science classes, their impact on students' learning, and what constitutes an effective laboratory experience. This research examines the addition of a discovery-based (guided inquiry) component to the traditional organic chemistry laboratories at Middle Tennessee State University and its effect on students' abilities to interpret NMR spectroscopy and their attitudes toward the laboratory.

Students in two groups of organic chemistry laboratories were compared. One group used the traditional stand-alone laboratories on the topics of distillation, chromatography and spectroscopy. In the traditional laboratories, students were given the same step-by-step instructions and the outcomes of the laboratory experiments were known. The other group used a three-week discovery-based unit on terpene isolation and characterization incorporating the same three topics. Although the students were provided with basic procedures, each group of students used similar, but not identical procedures. The outcomes of this unit were predictable, but often unspecified to the students.

At the end of the term, students' understanding of spectroscopy and their attitudes toward the laboratory were measured using a survey. The survey grouped the spectroscopy content into four categories: predicting number of signals, splitting patterns, fitting spectroscopic data to chemical structures, and assigning signals on a spectrum to the atoms in a given structure. The students' attitudes toward spectroscopy and the laboratory in general were measured using a Likert scale. Although there were no significant differences in the spectroscopy content knowledge of the two groups, students in the discovery-based laboratory generally scored higher on the content portion of the survey. Students from the discovery-based laboratory also had stronger opinions, whether positive or negative, about their ability to interpret 1H-NMR than the students in the traditional lab. Anecdotal evidence suggests that the nature of the discovery-based unit led students and instructors to think more critically about separation techniques and interpretation of spectral data.