VISUALIZING EARTH’S INACCESSIBLE INTERIOR – WHAT WORKS FOR STUDENTS?
Students often enter an introductory geology course with misconceptions of how Earth works and unfortunately, all too often, they leave with these same ideas firmly in place. Many of the common analogies propagate alternative conceptions such as the mantle is molten. We tell students that the rigid plates float like rafts on the asthenosphere and that the mantle convects like a pot of boiling liquid. We often use the color of red like hot molten lava in cross sections showing seismic velocity variations in the mantle. The students know that the magma forming volcanoes comes from melting of the mantle but they do not know how little of the mantle is actually melted. While expert instructors qualify these analogies telling students that these processes occur over millions of years, and that the melt percent in the mantle is extremely small, the novice geoscience student often does not build these constraints into their mental models of Earths interior.
In seismology, we have the challenge of teaching the basics of seismic waves, something very abstract. Rocks breaking generate seismic waves, but why and how do they travel in solid rock? One of the most common visualization tools used to demonstrate wave propagation in the Earth is a computer simulation by Alan Jones called Seismic Waves. In my presentation, I will discuss the challenges of using simulations like this to help students dispel alternative conceptions about Earth and how waves propagate.