First Advisor

Melissa Weinrich

First Committee Member

Murielle Watzky-Brewer

Second Committee Member

Molly Jameson

Third Committee Member

Joanna Lewis

Degree Name

Doctor of Philosophy

Document Type

Dissertation

Date Created

12-2024

Department

College of Natural and Health Sciences, Chemistry and Biochemistry, Chemistry and Biochemistry Student Work

Abstract

For students pursuing careers in medicine and science, general chemistry is often viewed as a gatekeeper course. Students struggle with general chemistry for a variety of reasons, one of the most common being mathematical difficulties. Compared to other lower division STEM courses, mathematical computation in general chemistry represents a unique challenge for the student due to the special emphasis placed on reporting answers to the proper degree of precision using significant figure (SF) rules. Although these rules feature in nearly every undergraduate chemistry course, their impact on the student experience of learning chemistry has never before been studied.

The purpose of this study was two-fold: first, to quantify the cognitive load difference associated with applying significant figure rules to chemistry problems, and to explore a possible interactive effect between significant figure rules and student math anxiety. Our second goal was to gain insight into student experiences and perceptions of the value of SF rules and the degree to which this value judgement affects student engagement with these rules. We investigated four research questions:

  • Q1 How do students describe their experiences with significant figures in general chemistry?
  • Q2 What were students’ perceived value for significant figure rules?
  • Q3 To what degree does the inclusion of significant figure (SF) rules represent a change in subjective mental workload when solving general chemistry problems?
  • Q4 To what extent do significant figure rules moderate the relationship between subjective mental workload and math anxiety?

To address these questions, we recruited 40 general chemistry students to participate in this mixed methods study. Participants first completed a written assessment in which they solved chemistry problems both with and without significant figure rules, subjectively rating the mental workload of each question using the NASA Task Load Index instrument (NASA-TLX). We analyzed the data with paired t-tests to determine if there were statistically significant differences in ratings. We then fit linear models to the data to see if significant figure rules moderated the relationship between average NASA-TLX rating and math anxiety. Afterward, each student participated in a 10 to 15-minute interview in which they were asked to explain their approach for working through significant figure problems, and share their personal experiences with these rules. These interviews were transcribed and thematically coded. Analysis of these interviews was framed by situated expectancy value theory.

We found a statistically significant increase in student self-reported cognitive load associated with the application of SF rules. We also found the SF rules moderated the relationship between math anxiety and mental workload, suggesting that students who enter general chemistry already at increased risk of not passing will experience more difficulty with SF rules than their non-math anxious peers. Qualitative interviews revealed that participants often did not engage meaningfully with the SF rules, frequently abandoning the rules or resorting to shortcuts that, while less effortful, led to incorrect answers. Students also associated the SF rules with negative experiences, such as their answers being rejected when using online homework platforms.

These results suggest that the standard textbook approach to teaching precision and significant figures in chemistry is both burdensome and ineffective, substantiating concerns raised by educators in the literature. In light of these findings, we would urge instructors and homework platform providers to be judicious in their enforcement of SF rules, as these rules add significant mental burden to the problem-solving process, particularly for math-anxious students. To promote conceptual understanding over rote memorization, we suggest reducing emphasis on precision and rounding in lecture courses and instead shifting it to lab courses, where students will be more likely to find meaning in these concepts.

Abstract Format

html

Language

English

Extent

131 pages

Local Identifiers

Britt_unco_0161D_11278

Rights Statement

Copyright is held by the author.

Digital Origin

Born digital

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