This article describes the structure and content of a one-semester course dealing with chemistry, science, and technology designed for nonscience majors. The course uses a hybrid of two active learning methodologies—problem-based team learning and the case study method—to present chemistry- and, more broadly, science-based case studies in a manner designed to engage, instruct, and challenge its audience.
As a result of the introduction of distribution requirements into college curricula, many nonscience majors (NSMs) take courses of the “physics for poets” genre. In general, such courses are designed to be compatible with the liberal arts or business backgrounds of these students and to appeal to their interests, with the goal of improving students’ scientific literacy. This type of course is often the only science class that these students take during their college careers. To say that to teach such a course effectively is a challenge is certainly no overstatement.
It is ironic that the United States has both the world’s finest science establishment and a general population that is anything but scientifically and technologically literate. The students taking NSM science courses today are often destined to be the people who, later in their careers, will be responsible for making decisions about our scientific and technological future as business leaders, politicians, influential citizens, and informed voters. It is incumbent upon us as members of the science teaching profession to provide them with course content and teaching methodologies that are consistent with this situation when planning what may be the only science course these students take during their college careers.
It is unlikely that the challenge of teaching science literacy to NSMs can be met effectively by exposing these students to simplified versions of introductory-level chemistry, physics, biology, or other science courses. The focus of such courses is normally too narrow to meet the needs of NSMs. If such courses are taught by the lecture method, it becomes even less likely that they will have the desired effect on their intended audience. The animosity that many NSMs have for the traditional lecture method as it is typically used in science courses was amply demonstrated in Shelia Tobias’s classic study (Tobias 1990). Tobias convincingly demonstrated that bright NSMs in introductory-level mainstream science lecture classes were turned off by the passive role that the method imposed on them as compared to the more participatory classes they were accustomed to in their liberal arts classes.
These thoughts guided me when I was asked to plan and teach a chemistry-based science course for NSMs. As a key part of the design of the course, I sought to have the students work actively and cooperatively with important ideas in chemistry, and, more broadly, science and technology. The four main goals that I established for the new course, which I decided to call “Chemistry by the Case,” were
to enable students to learn the course’s science content in a cooperative, interactive manner that involves extensive teamwork;
to show students how science works by exposing them to controversial science/technology-based problems of significant societal importance;
to have students research and analyze complex, realistic problems dealing with science and technology that would enhance their critical-thinking and problem-solving skills; and
to allow students to apply their newly acquired knowledge to these problems, as they will soon need to do in the real world.
Problem-Based Team Learning
One of the methods I wanted to incorporate into the new course is a teaching method I developed and have used to teach introductory organic chemistry since 1993. I call the method “problem-based team learning” or PBTL. A description of an early form of this method has been published (Dinan and Frydrychowski 1995).
PBTL is a highly modified form of the team-learning method, which was originally developed by Larry Michael-sen to teach organizational behavior at the University of Oklahoma (Michael-sen 1985). PBTL requires students to read and interpret the assigned material before coming to class. It encourages each student to develop a personal-learning strategy that is tailored to his or her own learning style and transforms the instructor’s role from that of exposing students to new knowledge to one of helping them develop their individual-learning strategies and assisting them with their efforts to understand the assigned material.
In PBTL, each learning cycle begins with a learning guide. This is a document that specifies the material to be covered in the next class. A learning guide is always distributed to students at least two days before the class in which the material to be read will be covered. The learning guide informs the students of exactly what they should read and do to prepare for that class.
Each PBTL class begins with a three-question, five-minute, multiple-choice reading quiz on the material assigned for that class. To promote careful reading and thorough preparation for class, the students are allowed to use the notes that they have taken on the reading assigned for that class while working on the quiz. In my experience, the small amount of class time allocated for the reading quiz pays off richly in terms of solid student preparation for class. This past semester, the average grade on the quizzes for the “Chemistry by the Case” class was 84.7 percent, and an end-of-the-semester course evaluation indicated that the students found the reading quizzes to be very effective in prompting thorough preparation for each class. On a five-point scale, strongly disagree (1 point) to strongly agree (5 points), the student responses to the statement “Reading quizzes are a strong incentive for me to prepare well for class” averaged 4.81.
The reading quiz response forms are very simple. A student assistant grades the responses while I review the reading quiz questions with the class. The grades are recorded and the graded quizzes are returned to the students before the end of each class.
After the reading quiz, the class splits up into its permanent, four-person student teams to work on the corresponding “ChemDo” problem set. Teams are created at the beginning of the course by the instructor using available data to maximize each team’s diversity in terms of academic ability, gender, and racial diversity. The “ChemDo” problem sets deal with the material specified in that day’s learning guide. The assigned problems are sequenced to build on each other in the “scaffolding” manner originally described by the Russian educational psychologist, Lev Vygotsky (1997).
During the class, the student assistant(s) and I circulate among the teams, providing them with assistance upon request. I call a halt to the teams’ work about 10 minutes before the end of each class and use the remaining time to respond to any questions the teams have and to review key concepts. At the end of each class, I provide a new learning guide, and another PBTL learning cycle begins. In the “Chemistry by the Case” course, a case study, depending on its nature and complexity, may require anywhere from two to five PBTL-learning cycles before the students begin to consider it.
Normally, about four case studies are included in a semester of PBTL-based organic chemistry. These cases allow the students to consider interesting, challenging ideas that would otherwise be difficult to fit into such a highly structured, content-driven course.
I have also used PBTL to teach general chemistry, polymer chemistry, and intermediate organic chemistry. In all of these courses, as well as in the introductory organic chemistry course, the method has been characterized by good student performance, a complete lack of problems with content coverage, favorable course evaluations, very low withdrawal and failure rates, and attendance that borders on perfect. Such favorable outcomes in hard-core science courses led me to wonder how the PBTL method would work in a NSM course, where the content is not as rigidly structured and defined as it is in courses designed for science majors.
Because the emphasis on the use of PBTL in the chemistry courses mentioned above is very heavy on content coverage, case studies are used mainly in a supporting role. A NSM chemistry/science course, in contrast, seemed to offer an ideal opportunity to place a much greater emphasis on the use of case studies as a primary-teaching tool rather than as a supplement.
The title of the new course, “Chemistry by the Case,” is a bit misleading because, while the course’s content deals extensively with chemistry, it also deals more broadly with science and technology. Its structure integrates aspects of both PBTL and case teaching. PBTL is used to provide the instruction needed for students to understand the science/chemistry-based concepts they must grasp to appreciate the issues raised in cases they consider. As previously mentioned, the number of PBTL-learning cycles used in preparation for a case varies depending on the complexity of the science/technology background required for its comprehension. The students, however, quickly realize that the technical material that they learn using PBTL is by no means abstract because they immediately apply it to a case study dealing with important real-life issues, the analysis of which requires the students to apply their newly acquired technical and scientific knowledge.
“Chemistry by the Case” uses this basic methodology to present seven science/chemistry-based case studies over the course of a semester. The content and goals of each of these cases are described briefly below. One PBTL unit, “The Evolving Atom,” and the case study used in conjunction with it, “Just Tell Me the Truth,” are discussed in a bit more detail to provide deeper insight into the way the method works.
The Case Studies
One of the important concepts that I sought to have the students appreciate is the provisional nature of scientific truth. Often, the general public has difficulty with changes that occur in science because of the commonly held belief in life that something is either true or it is not true, and if it is true, it should always be true. An oft-heard critical comment made about some scientific concept is that “it’s only a theory.” People who make such comments do so because they are inadequately acquainted with the workings of the scientific method and the manner in which it leads to provisional scientific truth.
The “Evolving Atom” unit demonstrates how the scientific community’s ideas on an issue of fundamental importance—the nature and structure of the atom—have changed over many centuries and continue to change today. The case study introduced at the conclusion of this unit uses several science-based issues that are of current societal concern to illustrate that the search for scientific truth goes on continually even today.
The learning guides for “The Evolving Atom” unit direct the students’ readings in either the course text (Stine 1994) or in supplemental writings that I have prepared dealing with the technical background needed to appreciate the case study that accompanies this unit. The readings generally emphasize the incremental steps by which science’s view of the atom has evolved and changed over many centuries. They describe the first ideas on the existence of atoms that were proposed by Democritus and the ancient Greeks (~400 b.c.) and the subsequent work done over centuries by Lavoisier, Faraday, Crookes, Thomson, Rutherford, Bohr, deBroglie, and Schrodinger that led to ever-changing and increasingly sophisticated views of the atom’s structure. Special attention is given to the atomic structure proposed by Bohr, since this is the atomic model used in this course. In addition, the natures of ionic and covalent bonding as well as the structure of the periodic table are concepts used throughout this course, so they are also considered in more detail.
After each learning guide and the corresponding reading quiz is completed, the student teams work with PBTL problem sets that emphasize the relevant introductory-level chemistry concept: atomic structure, isotopes, valance, the periodic table, and the electronic nature of ionic and covalent chemical bonds.
The case study that I prepared to accompany this unit is unpublished. It is called “Just Tell Me the Truth” and deals with a health-conscious young woman who is frustrated by what she sees as the inability of science “to get anything right.” Her frustration arises from contradictory views that the media report on the health effects of the consumption of vitamin C, whether the use of butter or margarine is the healthier choice, the safety of tanning lotions, and where and how nuclear waste should be stored. She expresses her frustrations to a friend who is also puzzled by the apparently conflicting science and technology information that she is exposed to in the media.
The student teams are asked to analyze the dialogue that takes place between the two friends and to explain the origin of their frustrations. This analysis leads them to consider the societal problems, such as NIMBY (not in my backyard), and the role and limitations of the media in reporting science-based stories that are inseparable parts of these complex issues.
A case study dealing with memory loss in mice that have been subjected to an experimental procedure is used to introduce the students to the workings of the scientific method. For the PBTL portion of this unit, the students are provided with a learning guide for a specific set of readings on the scientific method (Latura 2000). Upon completion of these readings and the accompanying reading quiz, the students deal with a series of questions/problems designed to utilize and expand their knowledge of the scientific method.
Next, the teams consider the case entitled “A Case Study of Memory Loss in Mice” (Hudecki 2001), in which they are given a very brief newspaper account of a study and its outcome. They are then asked to apply their knowledge of the scientific method to assess the design of the experiment and the validity of the conclusions drawn from it. This has proven to be a very involving exercise that requires a great deal of critical thinking. It always evokes a strong student response and intense discussion. The case leads students to become aware of the important elements that must be present in the design of any well structured scientific experiment and links this design to the scientific method.
Another PBTL/case study unit is used to introduce the (often) dreaded element of quantitative calculations into the course. The students are given learning guides that direct their readings in the course text to the mole concept, scientific notation, unit conversions, and Avogadro’s number. After completing these readings and taking reading quizzes based on their content, the students work in their teams on problem sets that are designed to support and expand their knowledge of these concepts. These “ChemDo” exercises require the students to calculate the number of moles and the number of atoms present in varying amounts of elements and compounds, for example, and to express their answers in both conventional numbers and in scientific notation.
Upon completion of these “ChemDo” exercises, the students are presented with a case study entitled “Avogadro Goes to Court” (Bieron and Dinan 1999). This case is based on a Wall Street Journal report dealing with a professor at a New York City–area university who required his class to calculate the cost of a single aluminum atom in a roll of aluminum foil that he had purchased. The class, after many frustrating confrontations with the professor and the school’s administration, successfully sued for restoration of their tuition and for damages. Of course, the idea that a group of students could successfully sue their professor over the content of an assignment is fascinating to other students and immediately catches their interest.
The students are charged with carrying out the same task, but with a critical difference. They are given the total area of the aluminum foil roll and its cost, and each team is given an approximately 100 cm2 sample of foil taken from the roll. The teams are asked to design and carry out any laboratory experiments that they believe are required to provide them with what they judge to be needed data that is not available to them, and they are given the laboratory equipment that they request to do so. The NSMs respond with great vigor and interest to the challenge of trying to do what another group of students failed so dramatically to accomplish. They have always carried out this calculation successfully and managed to have a good deal of fun while doing so.
One of the more widely used tools for making technical/scientific policy decisions in our highly technological society is the risk/benefit analysis method (Glickman and Gough 1990). Whereas this method is well established and has been used extensively for some time, it is now being challenged by another policy decision-making method called the precautionary principle (VanderZag 1999).
The two methods are quite different. Briefly stated, risk/benefit analysis argues that the risks and benefits that result from a given technical course of action should be balanced against each other. If the benefits resulting from making a technical choice exceed the risks associated with it, the choice should be made. If the benefits do not exceed the risks, the choice should not be made. The more controversial precautionary principle, simply put, claims that if there are significant technical risks associated with a course of action, then, even if the risks cannot be proven with scientific certainty, that course should not be taken.
Unlike risk/benefit analysis, the precautionary principle focuses almost exclusively on the risks associated with a technical choice to the exclusion of its benefits. The precautionary principle has European origins and is more widely used in Europe than in the United States, although it is gaining acceptance in international law. Knowledge of the workings, strengths, and weaknesses of these widely divergent decision-making methods is becoming essential to both those charged with making sound scientific/technological decisions and to the citizens who must live with the outcome of these decisions.
Learning guides lead the students to appropriate readings dealing with these decision-making techniques, and after the accompanying reading quizzes and “ChemDo” problem sets are completed, they begin their consideration of the case study. The case used to provide a real-world context for these decision-making tools is one that deals with the use of DDT for the control of malaria in areas of the world in which that disease is endemic (Dinan and Bieron 2001). The case is entitled “To Spray or Not to Spray” and it involves two groups, one favoring DDT’s use to control malaria, arguing from a risk/benefit perspective, and another opposed to the use of DDT for this purpose, arguing from a precautionary principle point of view. In the case the United Nations (U.N.) is considering the implementation of a worldwide ban on the use of DDT. The two groups present their arguments to a U.N. official who will recommend what course the U.N. should take on this controversial question.
The closely interrelated topics of amino acids, proteins, DNA, RNA, and recombinant DNA are considered next in the course using the same general approach that has been described above. A series of learning guides are provided to the students to direct their reading of relevant material from the course text and from supplemental materials that I prepared for this unit. After the learning guides, reading quizzes, and PBTL problem sets have been completed, the class moves on to the accompanying case study. This case study is, however, not a conventionally formulated one. It consists of video segments taken from a Public Broadcasting System (PBS)/Frontline program, Harvest of Fear (Frontline 2001). The program deals with questions surrounding the safety of genetically modified foods. The selected clips consider the risks associated with the consumption of genetically modified (GM) foods, xeno-transplanted genes, the controversy surrounding the labeling of genetically modified foods, and the nature of the tactics commonly used to influence public opinion by those favoring and those opposing the use of GM foods. These issues, of course, raise a series of science-based public policy questions that require extensive critical thinking and are well suited for discussion in a NSM course.
A unit dealing with immunochemistry and vaccines is included in the course not only to allow the students to deal with this important and timely topic, but also to emphasize the complexity of the ethical issues that are frequently encountered in science. This unit was also designed to illustrate the potentially problematic nature of information that can be garnered from the Internet. The students are provided with learning guides that direct their reading in immunochemistry and chemotherapy in the course text, readings on the risk/benefit questions associated with vaccines (Christensen 2001), and web-based readings that discuss the origin and history of vaccines (www.who.int/vaccines-diseases/history/history.shtml. Each of these readings is followed by a reading quiz and a PBTL problem set.
The unpublished case study that I have written for this unit, “A Mother’s Choice,” deals with the plight of a mother who must decide whether to allow her child to be vaccinated with the DPT (diphtheria, pertussis, typhoid) vaccine. The case focuses on the mother’s concerns about the safety of the vaccine and the adverse reactions that children given this (or any) vaccine can undergo. A web search leads the mother to information that advises in favor of (www.commhlth.medic.ukm.my/penerbitan/buletin/khas00/combvaccine.pdf) and against (www.monitor.net/monitor/free2/dpt.html) the use of the vaccine. Ultimately, she must make her decision in the face of her still unresolved doubts, not an uncommon situation.
Among the issues raised in “A Mother’s Choice” is the reluctance of some companies to manufacture vaccines. This reluctance stems from the fact that a company producing a vaccine faces great financial risks. These arise from the fact that while vaccine costs, and, therefore, profits must be kept low if the vaccine is to be widely and easily affordable to a mass market, there are inevitably small but unavoidable risks associated with the use of any vaccine. No matter how carefully a vaccine is tested and manufactured, a few particularly vulnerable recipients will inevitably have adverse reactions. Juries, not always fully understanding the realities of the situation, have often brought substantial judgments against a vaccine’s manufacturer.
A conflict arises between the needs and interests of a family adversely affected by the vaccine, and those of the manufacturer who has acted in good faith to provide the public with a needed product at a low cost. The case, which again emphasizes decision making in the face of uncertainty, asks the students to consider how such conflicts can be resolved and what choice the mother should make, and how companies can be encouraged to manufacture vaccines in the face of financial risk.
The final case considered in the course, “The Benign Hamburger” (Peaslee, Lantz, and Walczak 1998), deals with the controversy surrounding the use of nuclear irradiation to prevent the spoilage of foods. The learning guides prepared for this case direct the students’ readings to sections of the course text dealing with nuclear radiation and to a set of supplementary notes that I prepared for this topic. After the customary reading quizzes and PBTL problem sets are completed, the teams begin their consideration of the case.
“The Benign Hamburger” focuses on the problems encountered by a restaurant chain that is considering the use of irradiated meat to prevent the possibility of life-threatening E. coli contamination of their products. It introduces the students to technical aspects, safety considerations, and public policy issues dealing with the irradiation of food. The tactics used to influence public opinion by groups who are opposed to the use of irradiation are also considered, and the recurrent use pattern of these tactics is stressed. Special emphasis is placed on conveying the idea that exposing foods to nuclear irradiation does not make them radioactive.
During the last two weeks of the course, each team is asked to prepare a unit of its own, consisting of a learning guide, appropriate readings, a reading quiz, a well structured set of PBTL problems, and an appropriately written and referenced case study. The central theme for each of these units must be the effect of a specific chemical contaminant in the environment on public health. The teams are charged with producing a case that is informative, interesting, factual, balanced, and well referenced. Because this is a very challenging task for the student teams, either I or a student assistant serves as a consultant to each team to help them in the preparation of the unit they have chosen. This unit, in its final written form, serves as the final examination for the course. All members of the reporting team share the grade that is awarded to this unit. (Readers interested in obtaining a sample copy of a learning guide and the corresponding reading quiz and ChemDo problem set should contact the author by e-mail at firstname.lastname@example.org.)
Measuring how effective any course is in reaching its goals is always a difficult task. However, the use of a pretest/posttest combination together with customized student evaluation forms has afforded valuable insight into the effectiveness of the “Chemistry by the Case” course. When results obtained on a pretest that was administered on the second day of the course were compared to those obtained when the same test was administered on the second to last day of the course, significantly improved understanding of both chemical and scientific topics was observed. The improvement in the students’ understanding of the nature of the scientific process and the characteristics of technology was especially impressive.
The test used the standard five-point scale (1= strongly disagree, 3= no opinion, 5= strongly agree) and required that the students make judgments that are both objective (e.g., “The structure shown below is that of an amino acid”) and subjective (e.g., “Environmental decisions that are backed by solid scientific evidence must be right”). A far greater percentage of students were, for example, able to identify an amino acid with certainty, and a greatly decreased percentage of students subscribed to the notion that having scientific evidence to back it automatically makes an environmental decision right.
A customized student evaluation form also provided valuable feedback on the effectiveness of the course and its content. The same five-point scale described above was used on this evaluation form. The student assessments of the course were uniformly positive. They frequently remarked on how engaging they found the PBTL/case study method to be and how quickly time passed during class sessions. In addition, attendance was uniformly high and the course had a zero failure and withdrawal rate despite content that its NSM audience found challenging. (Readers can obtain copies of these evaluations and the results by contacting the author by e-mail at email@example.com.)
In summary, the combined PBTL/case study method proved to be well suited for use in a science course designed for NSMs. I strongly recommend its use as an effective teaching methodology in courses of this sort.
Frank J. Dinan is a professor, department of chemistry and biochemistry, Canisius College, Buffalo, NY 14208; e-mail: firstname.lastname@example.org.
The author gratefully acknowledges the support of the William G. McGowan Foundation. The course described in this paper was originally designed to meet the needs of student members of the McGowan Learning Community at Canisius College.
Bieron J., and F. Dinan 1999. Avogadro goes to court. Journal of College Science Teaching 29(2): 81-84.
Christensen, D. 2001. Vaccine varities. Science News 160 (August 18): 110-111.
Dinan, F., and V. Frydrychowski. 1995. A team learning method for organic chemistry. Journal of Chemical Education 78:429-431.
Dinan, F., and J. Bieron. 2001. To spray or not to spray: A debate over DDT. Journal of College Science Teaching 31(1): 32-36.
Frontline/Nova Special. 2001. Harvest of Fear. Video tape. New York: PBS Video Department of the Public Broadcasting Service.
Glickman, T.S., and M. Gough. 1990. Readings in Risk. Washington, D.C.: Resources for the Future.
Hudecki, M. 2001. Alzheimer’s disease under scrutiny. Journal of College Science Teaching 31(1): 57-60.
Latura, B. 2000. The Scientific Method. home.xnet.com/~blatura/skep_1.html.
Michaelsen, L., W. Watson, and C. Shrader. 1985. Informative testing: A practical approach for tutoring with groups. The Organizational Behavior Teaching Review 9(4): 19-33.
Peaslee, G., J.M. Lantz, and M.M. Walczak. 1998. The benign hamburger. Journal of College Science Teaching 28(1): 21-22.
Stine, W.R. 1994. Applied Chemistry. Lexington, Mass.: D.C. Heath and Co.
Tobias, S. 1990. They’re Not Dumb, They’re Different. Tucson, Ariz.: Research Corporation.
VanderZag, D. 1999. The precautionary principle in environmental law and policy: Elusive rhetoric and first embraces. Journal of Environmental Law and Practice 8:355-358.
Vygotsky, L. 1997. Educational Psychology. Boca Raton, Fla.: St. Lucie Press.