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

Article excerpt

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.

INTRODUCTION

Students in undergraduate geomorphology classes often have difficulty relating landforms to their generative processes, and in developing methods to test hypotheses regarding those landforms and processes. They are also unaccustomed to using technical analytic equipment and quantitative data in such assessments. In this paper, we describe a set of lab activities that address these obstacles in the first two weeks of our Geomorphology course at Western Washington University (WWU). The labs combine active participation in creating and sampling a model landform with Web-based high-tech analyses and a traditional geologic field trip. The labs are an outgrowth of a larger initiative at WWU to enhance student access to and involvement with cutting-edge scientific analytic equipment via an Integrated Laboratory Network (ILN).

Geomorphology at WWU is a sophomore/junior-level course that is required for geology majors, but which also fulfills lab-science requirements for non-geology majors (e.g., computer science, anthropology, geography). The only prerequisite for the class is Physical Geology. As a result, geology majors typically are a minority in the class (typically consisting of 25-30 students), and most students have little experience with reading or using topographic maps, thinking in spatial or temporal contexts, or dealing with inherently complex natural systems. Rather than teaching the class as a broad survey of geomorphology, our goal has been to give students a hands-on experience in geomorphic investigation through the observation and analysis of surface processes and landform development. The labs represent our effort to get the students to begin the course (from day one) with an inquiry-driven investigation, thereby setting the tone for the rest of the class.

THE LABS

The project comprises the first three lab periods of our Geomorphology course, and reinforce (or introduce) some of the basic aspects of geologic (and geomorphic) studies. This is important because we require all students in the class to complete a research project involving an investigation of a geomorphic problem. The skills involved in this lab help prepare the students to conduct their own research.

The landform that we use as the centerpiece of these labs is a Gilbert-type delta built in a stream table. …