From novice to expert: Student conceptual growth in understanding experimental error using a hands-on laboratory...

This study investigates how a targeted, sustainable laboratory activity can be used to develop students' understanding of measurement errors and experimental uncertainty. The activity prompted students to critically consider sources of error in an experimental context and the need for calibration of measuring devices, thereby reinforcing principles of Good Laboratory Practices and Quality Assurance. Unlike complex procedures that often involve multiple variables and chemicals, this activity was intentionally designed to isolate and highlight the issues related to measurements using simple, sustainable materials: an analytical balance, a weighing container, an adjustable volume micropipette, and water. The primary aim of this study is to investigate students' conceptual development regarding error, uncertainty, and calibrations. To accomplish this, a pre-test/post-test (prelab/postlab) design was used to compare student understanding before and after the laboratory activity. Students were given a prelab and postlab assessment that included a scenario: A student pipettes 1.00 mL of water into a weighing container and determines the mass using an analytical balance. The assessment included two open-ended questions (OEQs): 1) What are the sources of error associated with the process? and 2) What are some ways to minimize the errors associated with the process? Student responses from the two questions before (prelab) and after (postlab) the experiment were collected. Using qualitative analysis, responses were thematically analyzed, and codes were grouped according to the level of conceptual sophistication (e.g., novice ideas and expert ideas). Analysis of student responses over two semesters showed a shift in student understanding. Before the activity, the most common errors identified by students (OEQ1) were novice ideas (86% novice, 32% expert). After the experiment, a greater number of expert responses were encountered (33% novice, 67% expert). Before the experiment, the most common solutions identified by students (OEQ2) were novice ideas (60% novice, 40% expert). After the experiment, a greater number of expert responses were encountered (37% novice, 63% expert). These findings highlight the pedological value of incorporating targeted, conceptually focused, sustainable laboratory activities to support student learning in measurement, uncertainty, and calibrations. Supplementary materials, including the qualitative analysis codebooks and experimental protocol are provided to support adoption of the activity and further research.