Rayleigh isotope distillation module – development and transferability in geoscience education

The Watershed Hydrology lab will be out in force for the Geological Society of America annual meeting in Vancouver in October. Over the next few days, we’ll be sharing the abstracts of the work we are presenting there.

RAYLEIGH ISOTOPE DISTILLATION MODULE – DEVELOPMENT AND TRANSFERABILITY IN GEOSCIENCE EDUCATION

GRIFFITH, Elizabeth M., Earth and Environmental Sciences, University of Texas at Arlington, 500 Yates St, Arlington, TX TX 76019, lgriff@uta.edu, ORTIZ, Joseph D., Department of Geology, Kent State University, 221 McGilvrey Hall, Kent, OH 44242, JEFFERSON, Anne J., Department of Geology, Kent State University, 221 McGilvrey Hall, Kent, OH 44240, DEES, David, Faculty Professional Development Center and School of Foundations, Leadership and Administration, Kent State University, 231 Moulton Hall, Kent, OH 44242, and MERCHANT, William, Department of Evaluation and Measurement, Kent State University, 111L Nixon Hall, Kent, OH 44242
Rayleigh distillation is an important concept in geochemistry – applied to isotopic and elemental systems ranging from crystallization in magma chambers to oxygen isotope stratigraphy across glacial-interglacial periods. A teaching module that allows students to discover first-hand consequences of isotopic fractionation and Rayleigh distillation was developed, peer-reviewed, modified and used in thre upper-division geoscience courses: Sedimentology/Stratrigraphy, Environmental Geochemistry and Paleoceanography. In the module “Rayleigh isotope effect in the oceans: building glaciers” students perform (or are given data from) a simple batch distillation experiment that they model using open system Rayleigh isotopic fractionation. Insight on isotopic fractionation during phase transitions and a fundamental understanding of oxygen isotope stratigraphy is learned first-hand by the students preforming simple experiments and analyzing the data on sophisticated equipment. The teaching module is adaptable for the geoscience curriculum, including upper division courses and introductory courses. The module has only been tested in three upper division courses, but future work adapting and implementing the activity in an Introduction to Oceanography lab is planned.
Funding by the NSF Division of Undergraduate Education allowed us to study the impact on student learning and motivation from teaching the material within the module using different pedagogical approaches including a paper-based data analysis activity and hands-on data collection with and without access to the water isotope analyzer. Assessment techniques were developed and implemented through the close collaboration with a faculty expert within the educational field. The 3-year project is in its second year and initial quantitative results and reflections from the faculty and students will be presented. Both faculty noted a difference in the classroom dynamic with the students performing the experiments vs those completing the paper-based data analysis. Additional strategies will be highlighted for the transferability of the hands-on experiment to institutions and departments without access to the water isotope analyzer.