Using Stable Carbon and Nitrogen Isotopes of Hair to Teach about Sustainable Agriculture through Active Learning

Article excerpt

ABSTRACT

The call for reform of science education is nearly three decades old (National Commission on Excellence in Education, 1983), but the implementation of such education improvements in the form of active learning techniques in large enrollment classes remains difficult. Here we present a class project designed to increase student involvement and quantitative analysis skills in a large enrollment lecture geared towards nonscience majors. We use the stable carbon and nitrogen isotopic analyses of hair to teach students about the impacts of industrial agriculture through quantitative assessment of diet in an environmental science course. Assessment of student learning, which was determined through exam questions and also through a feedback questionnaire, was overwhelmingly positive, demonstrating the usefulness of this technique in bringing active learning to the large enrollment classroom.

© 2013 National Association of Geoscience Teachers. [DOI: 10.5408/12-309.1]

Key words: active learning, large enrollment, stable isotopes, sustainable agriculture

INTRODUCTION

Improving science literacy among nonscience majors has been outlined as a major teaching goal by many national scientific organizations (American Geophysical Union, 1994; National Science Foundation, 1996; National Research Council, 1997), but most introductory sciences classes for nonscience majors are large enrollment lectures, which sometimes lack the opportunity for hands-on active learning. Many studies demonstrate that laboratory components of courses are important for the development of critical thinking skills by involving students in the process of inquiry and investigation (i.e., Hofstein and Lunetta, 1982, 2003). Traditionally, laboratory portions of classes have contributed to the active learning component of science teaching, but high enrollment classes for nonscience majors sometimes do not have accompanying laboratories (Springer et al., 1999). Thus, a major difficulty with increasing science literacy among nonscience majors is determining how to engage students in large enrollment classes.

Many studies have sought to increase material retention in large enrollment classes through active learning. Some examples of implementation of active learning in these types of classes include introduction of online course assignments (Riffell and Sibley, 2005), in-class clicker questions and small group active learning activities (Elbert-May et al., 1997; Deslauriers et al., 2011), and data analysis in workshop format (Kitchen et al., 2003). Few studies have tried to incorporate laboratory-based research projects as active learning components of the course. Here we discuss a technique to teach about sustainable agriculture to an introductory environmental geology class using stable isotopes of hair. Following a brief introductory lecture in class, students donated hair during their weekly discussion sessions as a sample population to include them in the research and teaching processes. Our goals were twofold: (1) to introduce students to the process of isotope analysis to increase participation by involving students in the research process and introduce students to some ongoing research topics at the University of Michigan, and (2) to quantitatively show the students their impact on the environment and introduce them to sustainable issues. With this class project we aimed to involve the students directly in the study through the donation of hair samples and an introduction to the laboratory instruments and capabilities during guided tours of research facilities. This type of experiment is typically done at the graduate level, and is rarely done in undergraduate classes because of large class size and access to analytical equipment.

The use of real data in the classroom for the geosciences is now common for all levels and class types, with the development of the NOAA Ocean Data Education project (NOAA, 2010, for K-12), as well as the development of modules to use real data to teach college-level online geology classes (SERC, 2012). …