Hands-On Experiences with Stable Isotopes in the Geosciences Curriculum https://sites.google.com/a/kent.edu/d-edgeo/

Anne J. Jefferson1, Elizabeth Griffith2, Joseph Ortiz1, and David Dees3 1Department of Geology, Kent State University, 2Department of Earth and Environmental Sciences, University of Texas at Arlington, 3Faculty 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/