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Hands-On Experiences with Stable Isotopes in the Geosciences Curriculum https://sites.google.com/a/kent.edu/d-edgeo/ Anne J. Jefferson 1 , Elizabeth Griffith 2 , Joseph Ortiz 1 , and David Dees 3 1 Department of Geology, Kent State University, 2 Department of Earth and Environmental Sciences, University of Texas at Arlington, 3 Faculty Professional Development Center and School of Foundations, Leadership and Administration, Kent State University This material is based upon work supported by the National Science Foundation under Grant No. DUE-1140980. Project Goals: • Understand the effectiveness of hands-on experiences and and data analysis on student content knowledge and motivation. • Develop and disseminate educational materials using stable isotopes Stable isotopes are used throughout earth and environmental science, and students may be exposed to isotope concepts in multiple undergraduate courses. However, students may struggle to correctly interpret isotope ratios and few students understand how isotope measurements are made. Measure content knowledge & motivation Teach with hands-on activity + data + lecture Teach with only data analysis + lecture Teach with lecture only Measure content knowledge & motivation Develop modules Peer-review modules Refine and publish modules New laser-based technologies lower the barrier to entry for giving students hands on experience with isotope measurements and data analysis. We hypothesize that such integrating such activities into the curriculum will increase student content knowledge and motivation to learn. Our approach: Isotopic Hydrograph Separation (Watershed Hydrology) Example Pre/Post-Test Question Illustrated below is the hydrograph response of a forested watershed to the given input of precipitation. Draw a line on the diagram indicating the relative proportions of pre-event versus event water at each timepoint. Isotopic Concepts: fractionation; conservative behavior; variability in precipitation Hydrologic Concepts: Movement and storage within catchments; streamflow generation mechanisms Application: An approach to dividing streamflow into contributions from the current precipitation event versus water already stored within the watershed before precipitation started (new vs. old water). This technique revolutionized understanding of catchment processes. Timeline: • Spring 2013: Lecture only approach Spring 2014: Data collection during a rain event and analysis on Kent State’s Picarro L2130i • Spring 2015: Data from 2014 will be provided for students to separate the hydrograph, but no new events will be sampled • Summer 2015: Publication of module and data on project website Hands-on Activity: • Lecture content on isotopic concepts and watershed processes will precede this activity • Students will collect baseflow, deploy autosamplers, and pressure transducers before a rain event in April 2014 • Composite and incremental precipitation samples will be collected during the event • Students will receive training and analyze samples on a Picarro L- 2130i • Students will use data to complete a hydrograph separation and interpret results Hydrograph separation will take place for the West Branch of the Mahoning River, which flows through a research reserve on Kent State University property and is used by numerous classes Rayleigh Distillation (Environmental Geochemistry / Sedimentology and Stratigraphy ) Isotopic Concepts: fractionation; Rayleigh distillation; isotopologues Environmental Geochemistry Concepts: tracers of hydrologic cycle, stable isotope geochemistry, isotopic equilibrium and fractionation Sedimentology and Stratigraphy Concepts: Climate proxies, isotope effects in the oceans, glacial-interglacial cycles Hands-on Activity: Students used distillation apparatuses to produce varying fractions of initial reservoir and condensate waters. Isotope data were analyzed to calculate fractionation factors, which were compared to the literature. Timeline: • Spring 2013: Hands-on activity with Picarro (Kent State University) • Fall 2013: Hands-on activity without Picarro (University of Texas – Arlington) • 2013-2014: Lecture only and data analysis approaches tested; materials peer-reviewed • Summer 2014: module and data published to project website Students at Kent State (top) and UT- Arlington (bottom) conduct the distillations. Students preparing samples for analysis in the isotope lab at Kent State. Measuring Student Outcomes • We obtained IRB approval for the study and students consent to participate. Instructors are blinded to participation/non-participation. • Before and after the isotope module, we use surveys designed to identify the influence that the environment has on students’ approaches to learning • Learning and Studying Questionnaire (LSQ) (pre) • Experiences of Teaching and Learning Questionnaire (ETLQ) (post) • Surveys are not administered by instructors • Content knowledge is evaluated using pre- and post- tests written and administered by instructors • After the semester, focus groups provide further insight as follow-up from surveys Follow the project and access modules and data here: https://sites.google.com/a/kent.edu/d-edgeo/
