TEACHING PENETRATIVE THINKING VIA PROGRESSIVE ALIGNMENT AND DIRECTED SKETCHING

The ability to visualize and reason about the interior of a structure from surface information is critical for success in the Geosciences. This skill is essential for understanding many geoscience concepts (e.g. rock deformation, mineral structure and ground water flow) yet penetrative thinking (Kali & Orion, 1996) is challenging for students. We outline a cognitive science approach for teaching penetrative thinking that draws on spatial alignment and sketching, two learning strategies thought to facilitate abstract spatial reasoning. Participants in a controlled experiment viewed a powerpoint presentation containing two sets of images: photographs of progressive cuts into a Play-doh model and block diagrams of a plunging fold. In the experimental condition participants viewed three progressive slices into a series of block diagrams. For each slice they sketched the cross-section that would result from a pictured cut. They then viewed the actual cross-section and the uncut block, spatially aligned (vertically) on the screen. This procedure repeated for each slice. In the control condition participants viewed the same images in a random order, estimated the amount of paint it would take to cover the surface of each block, and sketched what they could see on the screen. The experimental condition focused participants’ attention on the internal structure while the control condition focused their attention on the surface information. Analysis of pre- and post-test performance on the Geologic Block Cross-sectioning Test (Ormand et al., 2011) revealed significant improvement in the experimental condition and not in the control condition. Participants in the experimental condition were also more successful at identifying the structure of a Play-doh dome model than those in the control condition. Together these results suggest that viewing pictures of progressive slices into a 3D model, coupled with the intention to think about the internal structure of the diagram, facilitated penetrative thinking. Results are discussed in the context of teaching penetrative thinking.