25 July 2008

Teaching Tools for a 3D World

Posted by Jessica Ball

Though you wouldn’t expect it from my slight obsession with volcanoes, my undergraduate training was focused strongly on structural geology. My undergrad adviser is a structural geologist, and his class was probably the toughest I’ve ever taken. It was also the most in-depth, challenging, make-you-think-really-hard class I’ve had, but there was something immensely satisfying in being able to grasp those concepts. The class had one major project, a mapping exercise conducted entirely from the confines of the department. Each week, we’d be given a new set of “field” samples to identify and take measurements from (they were firmly fastened to the tables in particular orientations), and then we’d place them on our maps (which showed a fantasy land created by my adviser). As the weeks went by, we “collected” enough samples to produce proper geologic maps and cross-sections.

What I always had trouble with was visualizing the subsurface well enough to create the cross-sections. The area we were mapping (“Pandora”, for my class) wasn’t just underlain by a nice neat series of tilted sedimentary layers, nor did the cross-sections cut perpendicularly across them. There was much calculating of angles and hand-waving, accompanied by experiments with Play-Doh. I always had difficulty with the math, and I used to spend a lot of time trying to draw the subsurface in 3D, or create Play-Doh reconstructions, so I could visualize the connection between the structure measurements, surface patterns and what was supposed to be happening below the surface. Pandora was a major undertaking, and it is with great satisfaction that I displayed the final map on my wall.

Which is why, when I saw Andrew Alden’s post about a new tool for teaching structural geology, I was quite excited. Dr. Yvette Kuiper, an assistant professor at the Department of Geology and Geophysics at Boston College, has created a cube out of dry-erase board in order to help her own students visualize the complexities of structural measurements and geologic mapping. While many people use 2D whiteboards to try and depict 3D concepts, Dr. Kuiper has taken the next step, and added a dimension.

Here’s her description of the new cubes:

“A cube made of white opaque high-density plastic, which serves as dry- (or wet-) erase material, makes teaching and learning three-dimensional geology much easier and fun. Maps, cross sections and block diagrams can be drawn (and erased!) and seen in three dimensions, and compared with their two-dimensional projections on paper. For example, the cubes are very useful for teaching the concept of apparent dips, which is essential in the construction of cross sections and block diagrams, and is confusing to many students. Plotting apparent dips on block diagrams is especially difficult, because of the distortion caused by the projection. The dry-erase cube provides an intermediate step. Students can first draw the actual apparent dip on the cube and subsequently construct the same angle on the projection of the block on paper. This can be made especially easy if the edges of the cube have the same length as the edges of an isometric block diagram on paper, so that they can simply be lined up.

“Several dry-erase cubes can be placed adjacent and on top of each other, so that multiple levels of maps, and parallel and perpendicular cross sections can be constructed. The relationship between maps and cross sections is then clearly visible. The cubes are also an aid in the understanding of stereographic projections, because structural data can be made visible as three-dimensional planes and lines before they are plotted. The dry-erase cubes are not only useful for geoscience teachers, but or anyone teaching or dealing with geometries and block diagrams, e.g. engineers and mathematicians, geologists in the petroleum or mining industries, hydrologists and K-12 teachers.”

I’m quite excited to see something like this, not only because it will make my life easier, but because I’m going to shortly be TAing for intro geo labs. Geologic mapping is a difficult skill to acquire for even the geologically-inclined, and for a generation of people who have grown up with Mapquest and talking GPS units, it’s also a very important skill. If you can handle a geologic map, then you can handle a regular old road map, which is an ability that’s becoming rarer and rarer nowadays. Hopefully, having one of these cubes will make it easier for me to explain the connection between surface patterns and the underlying geology of a region.*

The dry-erase cube are currently being published in the newest issue of JGE:
Kuiper, Y.D., 2008. The dry-erase cube: making three-dimensional visualization easy. Journal of Geoscience Education v. 56, n. 3, May, 2008, 261–268.

Dr. Kuiper estimates that the price should be no more than $15 per cube (plus shipping from Boston College); inquiries and requests should be emailed to her at kuipery – at – bc.edu

*Only if I can brush up on those drawing skills, though!