USING STUDENT-MANIPULATED MODELS TO DEMONSTRATE KEY CONCEPTS IN PLATE TECTONICS

Students in 160-person earth science classes for non-majors were provided simple physical models that they used to demonstrate concepts associated with plate tectonics. In each case, the student demonstrations were used to scaffold learning from simpler to more complex concepts. One paper model was introduced as a hands-on manipulative that students could use in small groups to explore kinematics of plate motion. The model base was constructed of laminated, heavy gauge letter-size cardstock with slots cut at plate boundaries. Plain legal-size paper strips were labeled by type of lithosphere to represent movable tectonic plates. Guided inquiry was used to assist students in modeling sea-floor spreading and subduction. Erasable markers afforded students the opportunity to predict patterns in the age of the seafloor, trench locations, earthquake patterns and volcano locations directly on the laminated cardstock. Another version of the model directed student activities toward exploring the distribution of subduction zone earthquakes. That model was manipulated by students to demonstrate relationships between subduction angle, foci and epicenter patterns. Student learning was assessed using pre-, during- and post-modeling conceptual questions, formatively through instructor feedback regarding annotations on models and summatively on exams. External observers used a standard observation protocol to document student actions during the activities and some participants were interviewed after the activities. Initial analyses revealed that two-thirds of students correctly answered plate tectonics conceptual questions after instruction compared to one-third prior to demonstrating the motions with the model (n = 248 responses, p < 0.0001). The observational data and interviews indicated that student engagement with the models was mixed, primarily dependant on the complexity of the activity and group dynamics. There were no significant gender differences in conceptual question answer distributions prior to or after instruction. Authentic summative assessments from six conceptual questions indicated that the majority of these students retained their understanding two weeks after demonstrating plate motions.