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PCBs in the Last Frontier

A Case Study on the Scientific Method


Author(s)

Michael Tessmer
Chemistry Department
Southwestern College
mtessmer@sckans.edu

Abstract

This interrupted case study is based on current research involving the global transport of polychlorinated biphenyls (PCBs). Students are asked to propose several hypotheses and experiments in an attempt to determine how PCBs are transferred globally. As the case unfolds, it becomes clear that the transport mechanism is more complicated than scientists first thought. The case requires minimal background knowledge and is suitable for major and non-major courses in biology, chemistry, and environmental science.


Objectives

  • Help students review the scientific method.
  • Teach students how to better state hypotheses.
  • Encourage students to design experiments that test a hypothesis.
  • Introduce students to the scientific literature with a relatively easy-to-read article.

Keywords

Experimental design; PCB; polychlorinated biphenyl; bioaccumulation; persistent pollutants; sockeye salmon; Alaska

Topical Areas

Scientific method

Educational Level

High school, Undergraduate lower division

Format

PDF

Type / Methods

Interrupted; Journal Article

Language

English

Subject Headings

Biology (General)  |   Chemistry (General)  |   Analytical Chemistry  |   Environmental Science  |   Atmospheric Science  |   Earth Science  |  


Date Posted

06/16/05

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Comments


Margit Brazda Poirier
mpoirier@monroecc.edu
Department of Biology
Monroe Community College
Rochester, NY
09/22/2005
I found this case to be a very effective way to teach the Scientific Method to a group of non-major biology students. This is the first case I have taught since attending a Chautauqua Short Course this past summer with Kipp Herreid, and it worked extremely well. I asked the 23 students to self-select themselves into groups of 3 or 4 and then worked through the case with class discussion following each of Parts I–III. We did not have enough time to complete part IV in the 50 minute time frame.

I found that the case questions yielded some interesting and creative solutions. In many cases it offered up a springboard for discussion of local migration and PCB contamination issues. Students also asked about PCB contamination in Great Lakes Fish and other pertinent topics. This is one of the many topics that will be addressed throughout the semester.

Rather than use the last few minutes of class on Part IV (though it seems a valuable thing to do), we discussed the advantages and shortfalls of the Scientific Method. Learning the Scientific Method through case participation will likely help the students complete future labs, for which they will need to construct hypotheses, design experiments, etc.

I found the referenced Nature (2003) article to be helpful and did not use any additional resources in class given the time constraint.

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Zia Nisani
znisani@avc.edu
Biological & Environmental Sciences
Antelope Valley College
Lancaster, CA
02/08/2017
I found this case to be a very effective way to teach the Scientific Method to a group of major, non-major biology and Environmental science students. After a brief presentation on "What is Science?" and scientific method, I divided them into groups of 3 and 4 students. All the feedback was positive and the students really enjoyed this case study. The only modification (more like addition) I did was that I required them to type a one-page reflection paper on how what we did in class is an example of science in action. Just like the previous commentator, we also discussed the advantages and shortfalls of the Scientific Method.

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