CONVECTION: AN EXCELLENT THEME FOR AN EARTH SCIENCE COURSE FOR PROSPECTIVE ELEMENTARY SCHOOL TEACHERS

At CSU Chico, students pursuing a career in elementary-school teaching must take a 3-unit course entitled Concepts in Earth and Space Sciences. In 1995, I redesigned this course to be laboratory-intensive and discovery-based. Since then, over 1700 students have taken the course. It is built around five recurrent themes: models, flow of energy and matter, apparent motion, changes of state, and--most important--convection. Convection plays this central role because students who fully understand convection (and the underlying concepts of thermal expansion, density and buoyancy) can readily come to understand many important natural processes such as subduction, wind generation, cloud formation, ocean circulation, the rising of magma, the differentiation of magma, the slab-pull driving mechanism for plate motion, and the buildup of pollutants during atmospheric temperature inversions.

Early on, we spend a full week focusing on convection because students come into the course with many misconceptions and little understanding of basic concepts such as volume, mass and density. Students begin the lab on convection by observing convection currents in miso soup. Students then proceed through a series of engaging hands-on discovery-based activities that build the concepts of density, buoyancy and thermal expansion. The lab culminates with a comparison of fluid flow (using food coloring as a tracer) within two different beakers: one heated from above and one heated from below. Through readings, homework and lecture, the concepts that students discover in this lab are reinforced and applied to mantle convection and plate motion.

Throughout the semester, students repeatedly apply the knowledge gained from that first lab as they build their understanding of other natural processes. Thus students learn, by experience, the inherent simplicity that underlies the amazing complexity of the universe. And they begin to perceive that the essence of scientific knowledge can be grasped and that science needn’t be an overwhelming barrage of confusing unrelated details.

The course materials on convection (and over 500 pages of additional course materials) for the Concepts in Earth Sciences course are available at www.csuchico.edu/~abykerkk. The development of these course materials was supported by NSF Grant #9455371.