USING HANDS-ON PHYSICAL MODELS TO PROMOTE LEARNING IN LARGE INTRODUCTORY EARTH SCIENCE CLASSES

Active learning exercises employing physical modeling activities were developed, tested and evaluated over two semesters in large-class (160-student) introductory earth science courses for non-majors. The intent of this research was to determine the extent to which student manipulation of physical models engaged students and promoted learning when compared to more traditional lecture. For example, the nature of radioactive decay was explored by students using a coin-flip type model adapted for group work; the processes involved with using oxygen isotopes as proxy-climate indicators were investigated using students to simulate isotope flow through the water cycle. Students manipulated plastic 3-D block models to discover principles of relative time. The geometry of subduction zone earthquakes was modeled using a writable overlay on a 2-D map that could be folded to mimic subduction while other concepts associated with plate tectonics were reinforced using writable 3-D globes. Researchers designed these and other activities spanning the content of the course to use readily available materials and for logistical simplicity. A standard protocol was used to evaluate modeling activities. Conceptual questions related to the major concept were posed prior to the modeling activity. Students in four-person groups completed an activity during class with trained external observers documenting students' actions. Conceptual questions were posed after the activity. Student learning was evaluated individually and collectively using responses to conceptual questions related to the modeling activities. Analyses of notes made by external class observers appeared to indicate that very simple models engaged students more effectively than more advanced modeling activities with multiple steps. Analyses of students' responses to conceptual questions were mixed. In cases where modeling activities required few steps and were directly related to a single aspect of a complex process, learning was reinforced. Complex models with multiple steps were less effective, particularly if they required significant instructor intervention.