Combining Stream Table Experiments, High-tech Particle Analysis, and the Web to Help Geomorphology Students Evaluate Landform Evolution

Abstract

Three sequential geomorphology labs introduce students to concepts of landform evolution, hypothesis testing, and grain-size analysis. Students combine qualitative observations with quantitative measurements from cutting-edge analytic equipment to critically evaluate their understanding of delta formation.In the first lab, students predict graphically how a stream-table delta will develop through time, and hypothesize how and why sediment grain sizes change across and within the delta. Digital Web cameras provide remote viewing and a time-lapse MPEG video sequence of delta formation.In the second lab, students compare the final landform with their original predictions of landform development. They sample delta topset, foreset, and bottomset beds for analysis on a laser particle-size analyzer to test their original hypotheses about grain-size distributions in the delta. Students operate the analyzer and produce grain-size distribution graphs of each sample. The graphs are posted to the course Web page, allowing students to compare visually the measured results to their Lab-1 predictions and to re-assess the processes of delta formation.The third lab is a field trip to local stranded late-Pleistocene deltas. By comparing the sediments of natural deltas to the stream-table version, students report improved understanding of the similarities, as well as the differences, in formation of each. Student assessment of the labs indicates they feel improved understanding of and interest in landform development compared to more traditional lecture and field trip-based instruction on the topic.