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Integrating research methods into geochemistry using local resources

Jeanette Pope
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DePauw University
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Summary

This is a semester-long project that introduces students to research methods and practices. Students learn both field and lab techniques and how to develop testable hypotheses. Using local resources is an easy way to engage students in a comfortable environment.

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Context

Audience

This activity is for a 300-level undergraduate course in geochemistry. The pre-requisites for the course are Physical Geology and Inorganic Chemistry.

Skills and concepts that students must have mastered

Students need to know basic concepts about aqueous chemistry (concentration units, dissolution processes, etc). A basic understanding of the hydrogeologic cycle would also be advantageous.

How the activity is situated in the course

This activity is conducted during the laboratory section of the course, which is a three-hour block once a week. Each week we build upon previous experience and incorporate new skills.

Goals

Content/concepts goals for this activity

The overriding purpose of this activity is to teach students how to perform geochemical analyses (field sampling, acid/base titrations, alkalinity titrations, water composition analysis, etc.) using samples collected from local environments. This is a standard skill set associated with most chemistry/geochemistry courses. The interesting feature is that students perform the analyses on real samples and with a directed purpose (see below).

Higher order thinking skills goals for this activity

Through this activity, students are introduced to the process of research, including hypothesis formation, data collection, analysis, and interpretation.

Other skills goals for this activity

The project also involves a written final report and oral presentation. Through drafts and practice session, students have the opportunity to develop their writing and speaking skills through out the semester.

Description of the activity/assignment

This project is a semester-long investigation in which students learn the field and laboratory skills required to do geochemical analyses and also how to how to ask interesting questions about their environment. On the first week, students are presented with a geochemical situation and asked to generate a research question. For example, my most recent class wanted to know if there was a hydrogeologic connection between a local pond and stream. Other, more generic questions include "how does the water chemistry vary with discharge, time, and climate" or "how does lithology influence water chemistry?" The research question does not need to be novel to make the project compelling, although students generally do not respond well when they feel that they are jumping through hoops. Using a local resource is advantageous because students become more invested in the project. Once a question has been asked, class discussion focuses on what information is needed to generate a hypothesis and then test it. This is typically done with the whole class, although it may be wise to break larger classes into groups. The remainder of the semester is spent teaching students the methods they need to know to continue their investigation. For example, with the stream-pond interaction, students collected samples through out space and time, performed acid-base and alkalinity titrations, and measured anion concentrations with IC and cation concentrations with AAS. Each of these activities is conducted in sequential lab periods. In addition, each student's collects his/her own data so that the results can be pooled and that class is introduced to statistical methods. After collection the data is analyzed and interpreted. Clearly, this is the most difficult part of the exercise, but also the most worthwhile. I like to demonstrate different ways that the students can look at the data (graphs, tables, correlations, etc.) and then provide one or two examples of possible interpretations. Students are left on their own to generate more interpretation of the data and to consider potential directions of future research. Each student writes a final report that contains an introduction, methods, results, interpretation, and conclusions. The class also does a group presentation in which each person is responsible for one segment. Through this process, students learn the skills that would gain in a traditional geochemistry lab and also gain research experience.

Determining whether students have met the goals

Each week students are responsible for turning in a lab report of the new skill that they are learning. I also grade the final paper and talk for clarity of thought, organization, and level of analysis.

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Other Materials

Supporting references/URLs

I do not have any files available for this exercise, as most material is developed with the students in the classroom.

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