RED BEANS AND RICE: A SIMPLE LAB EXPERIMENT TO INVESTIGATE SLOPE STABILITY AND LANDSCAPE EVOLUTION IN THE CAJUN LAB!

In the quest for a quality, hands-on lab experience on slope stability (in the face of numerous, sterile, engineering-based approaches), I stumbled upon an article that appeared in Science (Densmore et al, 1997). The authors constructed a simple acrylic box with a sliding door, filled the box with red beans, lowered the sliding door in increments, and measured the amount of beans that failed with each incremental drop. I adapted this experiment into my “Cajun Lab: Red Beans, Rice and Slope Stability.” In this exercise, students simulate the failure of fractured sedimentary rock (red beans) as a river undermines the toe of a slope (the dropping door). Some students use red beans, others use white rice, in an effort to investigate the behavior of different materials. Initially, I ask students to speculate on the behavior of the experiment, thereby generating a hypothesis. They then run the experiment to determine the behavior of the experimental ‘slope.' Finally, they are asked to submit a lab write-up where they describe their results and critically evaluate the experiment. This lab is followed by a group discussion assignment centered on the Science article and a field trip to a local ravine where many of the processes illuminated by the experiment can be seen in the real world. The lab is very hands-on, students collect data and generate time-series plots of slope behavior in Excel, and they immediately make the connection between slope-forming processes and long-term landscape evolution. I have also tailored the lab to serve as a demonstration in a large (100+ students) introductory geology lecture course and it is sufficiently simple that it could be modified easily for a younger audience. Sometimes, I even start the lab with a bit of Hank Williams' version of “Jambalaya.”