USING DISCUSSION BOARDS TO ENGAGE STUDENTS IN CONSTRUCTING MEANING FROM PLATE BOUNDARY DIAGRAMS

Geoscience concepts are visually complex and therefore diagrams can be important for learning. Discussion boards are one tool that can be used to engage students in active learning in online courses. This study evaluates discussion board posts made by undergraduate students in an online introduction to geology course. The students were asked to describe and reason about differences between two diagrams associated with plate tectonics and melting. Diagram A was commonly used in textbooks while Diagram B was created based on conceptual errors documented in previous studies. The purpose of this investigation was (1) to test how effective discussion boards with diagrams were for an online class and (2) to see where students had reoccurring conceptual errors on melting at plate boundaries. Using descriptive and magnitude coding, we identified the best and worst understood diagram features. Descriptive coding categories included: melting, hot spots, and water, and were counted. The most common features mentioned were magma and volcanic mountains/islands while the least mentioned were faulting and asthenosphere/lithosphere. Other less frequently mentioned but important features were water, arrows and melting. Magnitude coding was then used to rate the scientific correctness of a student’s response (e.g., none, incorrect, partial, full). Out of the 68 unique posts about reasons for differences between diagrams A and B, 28 reasons were coded as none and 23 were coded as incorrect. Students with partial (n = 22) and full (n = 9) correct responses focused on flux melting. The common incorrect responses related to misunderstanding of the videos included in the module. The outcomes of this study suggest: students’ confusion about melting persisted after the activity and discussion prompt instructions needed more structure to yield better posts. While the use of discussion boards with diagrams revealed students’ thinking about the processes at plate boundaries, and engaged students in working together to apply video content, future online activities should help students distinguish between mantle plumes in hot spots and lithospheric melting associated with plate tectonics, and specify the desired content and structure the students’ posts to yield more productive answers.