A Tactile Lab: Contours, Ocean Bathymetry, and Scaling

JESSICA KLEISS (jkleiss@lclark.edu) is an assistant professor in the Environmental Studies Department, Lewis & Clark College, Portland, Oregon.

Many oceanography laboratory manuals include activities to improve students' spatial abilities with contoured maps, ocean bathymetry, and coastal navigation (Chauffe and Jefferies 2012, Pipkin et al, 2000, Thurman & Savin 1995). Inspired by a lab developed by Dr. Sally Warner and Dr. Anitra Ingalls, I would like to share with you a lab that encourages students to work with contour maps and depth soundings in a kinesthetic, 3-dimensional setting.

The first lab component involves the scaled construction of an ocean floor feature. Teams of students are given a bathymetric map with a notable sea floor feature on it, such as a seamount, tablemount, mid-ocean ridge, ocean trench, or coastal shelf. They are also provided with multiple sheets of cardboard and a rigid plastic box with a lid. Students use the tracing paper to extract polygons at discrete contours from the bathymetric map. They affix these polygons in the plastic boxes to reproduce a 3D model of the ocean floor feature. The thickness of the cardboard and the height difference between contours can create a vertical scale for their model, which they mark on the outside of the box, as well as the horizontal scale of the map.

The second lab component simulates ocean depth observations from an ocean vessel, and reconstruction of the unknown sea floor below. Teams of students are given a mystery box that was prepared by a different lab group. Multiple holes are drilled into the lid. Using bamboo skewers, they take a "sounding" at each of the drilled holes. After recording the depth soundings on a sheet of paper, they attempt to draw contours and identify which ocean feature is contained in the box.

Students commented that this lab activity helped them conceptualize the scale and appearance of ocean floor features beyond viewing a bathymetric map alone. They also enjoyed the "puzzle" nature of mapping the ocean floor from a research vessel; they tasted the excitement of exploration as well as the difficulties of remote sensing and interpolation. I was surprised by the difficulty the students had with generating a precise scale for their models and interpreting the model scale when taking depth soundings. I was reminded of the importance of reinforcing basic quantitative skills in my courses regardless of the level of students' incoming mathematical sophistication. Overall, this is a nice lab activity for a land-locked campus that requires low-cost materials and gives students hands-on activities to appeal to kinesthetic learners.

Further details about this activity available at http://nagt.org/nagt/teaching_resources/teachingmaterials/124130.html.

REFERENCES

Chauffe, K. M., and Jefferies, M. G., 2012, Laboratory Manual to Accompany Invitation to Oceanography (6th edition): Burlington, Massachusetts, Jones & Bartlett Learning, 220 p.

Pipkin, B. W., Gorsline, D. S., Casey, R. E., Dunn, D. A., and Schellenberg, S. A., 2000, Laboratory Exercises in Oceanography (3rd edition): New York, W. H. Freeman, 272 p.

Thurman, H. V., and Savin, S. M., 1995, Laboratory Exercises in Oceanography (4th edition): Upper Saddle River, New Jersey, Pearson, 150 p.