Symposium
From the chemistry of responsible environmentalism to environmentallly responsible chemistry
Context in Chemistry: Integrating Environmental Chemistry with the Chemistry Curriculum Judith A. Swan and Thomas G .Spiro Frick Chemistry Laboratory, Princeton University, Princeton, NJ 08544 Environmental chemistry is generating considerable interest. Ozone depletion, greenhouse effect, oxygenates in gasoline-hardly a week goes by without some chemical aspect of the environment making it into the news. Within the academic community a s well, environmental chemistry is a hot topic. In upper level courses, environmental examples illustrate interesting and instructive chemistry (see companion articles). I n introductory textbooks such a s Chemistry: An Enuironmental Perspectiue ( I ) , environmental issues are being applied to developing the principles of first-year chemistry. With the publication of the ACS text Chemistry in Context (21,even more enthusiasm surrounds using environmental topics to teach science to nonscience students. There are good reasons for all this excitement: Environmental topics are familiar, tangible, and intriguing; they show up in many contexts and walks of life. Moreover, concern for the environment is taught early to children; in the elementary school, the three Ks oofreading, kiting, and 'rithmetic" have been joined by "reduce, reuse, and recycle." The circumstances are right for channeling some of this interest into learning chemistry. But environmental issues and the standard chemistry curriculum do not map onto one another exactly. Many environmental subjects require understanding chemical principles t h a t a r e not taught until fairly advanced courses. Teaching both environmental issues and basic chemistry to nonscience students requires making choices in emphasis: to teach mainly environmental topics with chemical "facts" introduced when necessary, to teach mainly basic chemistry with environmental "points" interjected when possible, or to integrate the two subjects so that both are taught simultaneously. In a chemistry course for nonscience majors a t Princeton University, we opted for the integration of these two subjects, only to find integration far more difficult t h a n we had imagined. I t was straightforward to identify common themes and topics; it was relatively easy to identify links between environmental issues and basic chemical principles; but it turned out to be surprisingly difficult to structure the course so that the linkages were visible to students and allowed both topics to emerge coherently. To do so we needed to consider more than the course's chemical content; we needed to consider a s well its communication. I t mattered not only what chemistry was presented, but when and how. Although this course was designed for nonscience students, the pedagogical issues we encountered apply to the teaching of chemistry a t all levels. Environmental chemistry has been taught a t Princeton University in two courses. One course, "Environmental Issues in Chemical Perspective" was a n upper level elective first developed by one of us in the early 1970's; it led to publication of a textbook with the same name (3).Geared
primarily toward students majoring i n chemistry and chemical engineering, the course assumed a solid background in organic and inorganic chemistry. The second course, "From Ozone to Oil Spills," is a more recent addition and the focus of this article. Although derived from the upper level course, it was developed a s a chemistry course for nonscience majors, one that assumes no training in chemistry, but rather uses environmental issues to present introductory chemistry. Parallel courses for nonscience students were developed hy colleagues V. Jack Shiner of Indiana University a t Bloomington and Zafra Lerman of Columbia College, Chicago. Because these three institutions differ significantly (Princeton is a small, suburban, private university; Indiana University is a large Midwestern public university; and Columbia College is an urban, oDen admissions colleae - e m ~ h a s i z i-n acommunications). developing a single course for use a t all three intrigued the National Science Foundation, which funded curriculum develonment and made ~ o s s i b l eextensive collaboration among the institutions. Table 1. Outllne of Lectures and T o ~ i c in s One Semester Environmental Chemistry course for Nonscience Majors, "from Ozone to Oil Spills. Environmental Issues Energy and Society: The Entropy crisis, recycling Hydrogen and fuel cells future energy systems? Gas and oil: How long will they last? From coal to plastics Renewable sources Solar Energy Materials, recycling Nuclear energy, radioactive waste, radon Acid rain, ground water Water quality and purification Greenhouse effect Ozone shield Photochemical smog
Topics of lndroductory Chemistry Materials and energy conversions; efficiency; moles Electrons and atoms. Atomic orbltals elements; perlodlc table chem~calbondmg Shapes of molecules; hydrocarbon chemistry; from wax to water Organic molecules and reactions Light and matter Solar cells and semiconductors Intermolecular forces; hydrogen bonding Nuclear fission and fusion. isotopes, radioactivity Water chemistry, pH, acidsbases, neutralization, buffering Metals, nutrients, water cycle. disinfection Light and heat Ozygen chemistry,catalytic chain reactions Oxygen; free radical reactions
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Table 2. Effective Outline of Lectures in "From Ozone to 011 Spills" When Transporting environmental chemist r y from i t s upperlevel elective to a Environmental Examples Are Presented Only after the chemistry Pertaining to Them Has Been Introduced and Discussed. course for students whose background includes a t most high school chemistry Energy and society: The entropy depended upon linking environmental Materials and energy conversion; efficiency; moles crisis, recycling i s s u e s w i t h i n t r o d u c t o r y topics i n chemistry. Such a linkage is possible, Electrons and atoms. Atomic oi%italelements; peri- Hydrogen and fuel cells future energy systems? a s diagrammed in the course outline doc table chemical bonding From coal to plastics (Table 1).I n the column on the left of Organic molecules and reactions the outline are listed important topics Light and matter, solar cells and semiconductors Renewable sources, solar energy in environmental chemistry: fuels and Intermolecular forces; hydrogen bonding Materials, recycling energy consumption, properties of maNuclear energy, radioactive waste, terials, issues in the hydrosphere and Nuclear fission and fusion, isotopes, radioactivity radon atmosphere. I n the column on the right Acid rain, ground water, water quality are listed many of the major topics of Water chemistry, pH acidwbases, neutralization, first-year chemistry: conservation of buffering,metals, nutrients, water cycle, disinfection and purification Greenhouse effect matter and energy, entropy, bonding, Light and heat structure, catalysis, pH, and others. Oxygen chemistry,catalytic chain reactions Ozone shield With t h e exception of atomic orbital Oxvaen: free radical reactions Photochemical smog structure, we have been able to introduce every chemistry topic by introThe process of communicating science is more complex ducine. a n environmental topic on the opposite list. I t is .. and less direct than it appears. Most of us imaeine it a s even possible to tie the intricacies of chemical bonding to some sort of encoding/deciding process: Here is ;he scienthe structures and properties offossil fuels. tific fact here are the words that corres~ondto that fact: if Most intriguingly, these two lists suggested a way of given the words, the listener or reade; will decode the& oresentine the topics of first-vear chemistw a s a "need receivine the fact. We assume that material intended for heuristic rather t"han by the more standard to know" inclusion by the communicator will be received by the auuroach. I n the traditional chemistrv curriculum. stuaudience automaticallv. provided the recipients will apply dents begin with fundamental b u t abstract concepts themselves to extracting "the meaning." But a s &n$ within the field and only gradually work their way out authors have armed (7).the meaning of a passage is not to more familiar territory. The connections between the fixed and unchanging: it is assembled% themom& when principles of chemistry and topical issues are presented the text is encountered by rmdcrs, who do not decode but late in the process, if a t all. This approach has been critirather interpret. The writer's intended message is only one cized for discouraging students by its formalism, its lack particular interpretation among many possible; whether of connection to student experience and enthusiasms (4, the audience receives t h e intended message depends 5). In contrast, a "need-to-know" approach starts with mainly on whether the majority of the audience interprets the familiar. concrete. and taneible and uses i t to dethe laneuaee as the author intended. In other words. it demodels what students velop the chemical principles. pends upon the audience's active process of interpretation. alreadv do. reinforcine their experience and tendencies The surprising news from several sources is that the r a t h e r t h a h contradictkg them: process of interpretation is heavily dependent on the strucYet despite these considerations, our first attempts a t ture of language, on where information is situated relative teaching by "need to know" were frustrating. Not only did Readers and audiences have to other information (6,8-10). the first offering of the course not "work," in and of itself, relativelv fixed expectations about where in the structure but it produced the same complaints engendered by tradiof disco;rse they will encounter pieces of its substance. tional science courses (4). Students felt the lectures diThey look in particular places for particular kinds of inforrected not a t themselves but a t some invisible cognoscenti mation that they need in order toeonstruct "meaning." in the class; they remained confused and disoriented; they One kind of information that readers regularly need is failed to see the connections between the problems, the context, preexisting knowledge brought to the moment of laboratories, and the lectures; and most distressing, they making meaning. Context is critical. It allows us to make could not see the connections between the chemistry and sense out of information bv selecting amone comwetin~inthc. cnvironmentsl topics. Despite the inclusion of environterpretations, 1 by valorizing what comes next, or by allowmental issues. thls new course still felt like the traditional ing us to take a new piece of information and integrate it into a preexisting framework. Without context, new inforlirst-year chemistry c ~ ~ u r sWhat e. had happened? mation burdens us; we are forced to hang on to it while we From the ~ w s ~ e c t i of v echemistrv. it is temptine to focus search for something it can do. Given enough pieces of new on the content: If both this en&onmental cKemistry information. even the most motivated of audiences will course and first-year chemistry courses confuse students, eventually cdlapse, dropping the information and abanthen the common content might be the cause; perhaps the donine the task of inter~retation. students are discouraged by the chemistry. Indeed, since ~ e c i u s econtext is both so central to interpretation and most students complain about how difficult they find the so critical early on, readers and audiences look to the bechemistry to understand, the solution seems to be to ideng i n ~ n ~ o f s t m c t u rfor e s contextual infbnnation. They look tify the difficult material and simplify or even remove it. at the beginnings of pamqaphs for a statement of the 1sHowever, another possibility opens when the course is sue, the matter at hand; they look at the beginnings ol'senviewed from the perspective of communications. From this tences for linkage to the previous sentence; they Imk at angle, the argument becomes not that the students are introductions to scientific articles for b a c k ~ ~ o u ninformtid confused because the science is hard, but rather that the science seems hard because the students are confused by '"Red means stop" without context makes no sense, not because its communication. Their attempts to understand and it has no interpretation but because it has too many. Its "meaning" make sense of the chemistry are thwarted by the failure of shins dramatically depending upon whether we are discussing traffic information thev need to a m v e when thev. expect . i t or can lights with children or titrations in the laboratory. use it (6).
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tion that makes the article significant. I n lectures, they listen to what comes first a s context, using i t as a scaffold upon which to assemble the unfolding exposition. Most lecturers recomize these expectations about context (often unconsciou~ly)and use tliem to assemble their lectures. Consider, for example, the usual treatment of polymers. The discussion often begins with the chemistry of polymers: The chemist describes the structures of the general class of molecules called polymers, develops the major methods of synthesizing polymers, and closes with examples of polymers in common use or with interesting ~ronerties.This nrocedure follows the standard oathwav: ~ i v ;the principfe; discuss and illustrate the prkciple in detail: then a o ~"l vit to examnles that the students should find interesting. Because interests vary even among chemists, the examples vary according to the particular class: In a course for chemical engineers, the polymer examples mieht derive from those nolvmers most ahundantlv manu" factured; in courses for students interested in the environment, the examples might center on the polymers in paper and polystyrene to see which are more environmentally friendly To chemists, such a narrative is perfectly reasonable, even graceful. In moving from a general principle to specific details, i t recapitulates t h e lecturer's understanding of the material, explaining its chemical topic i n ways that make sense to real chemists. The chemistry provides the context. Unfortunately, for most students (but especially for nonscience students), chemical principles are not context; they a r e new information (8). These students do not know enough chemistry to use the logic and perspective of chemistry to guide their interpretations. The information they could use for context is not the chemistry but the environmental connection. But in the first offering of this course, the environmental examples arrived too late, about 45 minutes into the discussion, long after most students had given up trying to understand. Even though the course explicitly included environmental topics, using the standard structure to lecture had the effect of t r a n s ~ o s i n athe two on the left lists i n Table 1,placing the chemical and the environmental issues on the right (Table 2). I t is almost impossible to read 'hble 2 as anything but an outline of a course whose main narrative i s chemistrv " sup-. ported by topics from environmental chemistry. I t was not enough merely to include environmental information for context when its use a s context was precluded by its placement. What students learned depended not onlv on what was presented-the substance-but a t least a s much on where and how i t was oresented-the structure. In order to make "need to know" a successful heuristic, we had to chanee the relationship between the substance and structure of the lectures. I t was not suff~cientsimply to identify information that students "needed-to-know"; we had to decide why they needed to know it-to what use would they put the informatiou-and then structure the presentation accordingly. In particular, we needed to move the more intriguing informaiion we wanted to function a s context, the environmental examples, to the place where students would treat them a s context, up front. We now start the class by displaying two cups, one of coated paper and one of polystyrene, and by asking students to vote on which is better for the environment. (We use polls frequrntly. Our polling no1 unly engages the 5tudenis and fibcuses thrir :ittmtim, but it helps s ~ u d e n t sto realize th:~r they are not tabulae msae, unir;formed until the professor grants them knowledge; they come to the class with opinions, information, and prejudices already formed. The experience is empowering for them and informing for us: We often discover that though they have very strong opinions, they have precious little awareness a s to why they hold
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Schematic graphic illustrating narrational linkages needed to interweave environmental chemistry storyline with development of chemical principles. them.) We then compare the cups explicitly, leading the class to recognize that the disposal issues that dominate the newspapers concern only one part of the cups'life-cycles. If we want to assess rigorously the environmental impact of choosing paper or plastic, we need to consider not merely disposal but also synthesis, manufacturing, transport, and a host of other chemical issues. This forces u s to consider the materials t h a t make up paper and plastic, both of which are polymers; the rest of the lecture falls in place. We end up covering the same chemistry, but with all the details imbedded in a context that interests and engages the students. Theend result surprises them-plastic turns out to have fewer environmental costs.2 The discussiun is typically full; students remain alert throughout the exposition of the chemistry because they have received first a context to which that discussion relates. Placing the environmental context u p front where students can use i t effectively enlarges the issue of the lecture so t h a t i t includes both t h e motivating environmental t o ~ i cand the chemical concept. Notice t h a t the lecture's success hinges on a rhetorical move: By linking t h e environmental issue immediatelv to the chemical principle, we effectively enlist the class (11) in our goal of teachine chemistrv" bv" ~. e r s u a d i .n. gthem t h a t their goal of un&rstanding this envirunnlrntal is,ue is more d~rectlvn t t a i w d by followinr! our path. N h r n what thev "need to know" includes t h e chemistry, they maintain their focus and concentration through lengthy complex a n d quantitative analyses because they perceive our goals a s corresponding to their needs. This experience h a s become a model for the entire course. We use the links between the environmental storv and the chemistry not to switch channels between a cbemfcal narrative and an environmental narrative but to interweave the two. We take care that no new information arrives that cannot already be put to work in a context we have previously established. We analyze a n environmental ~ r o b l e nuntil l we need more chemistrv, then introduce the chemistry Yet the chemistry is not separate and a d hoc; i t informs the order of presenting the environmental issues. a 45-m n lec14re n lnree sentences: Tne po ymer 2 ~ s.mmarue o mat makes LP past c C-PS. PO yslyrene, repe s water wnereas tne polymer in paper, cellulose,absorbs water and falls apart. A s a result, to make a paper cup requires more material per cup as well as the addition of a water repellent wax coating. More material requires using more energy at every step of the process; surprisingly, the detrimental effects of increased energy consumption for paper cups more often outweigh the benefits of paper's biodegradability.
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The environmental story begins with energy concerns, moving from hydrogen, the "ideal fuel," ("ideal" in that the sole product of its combustion is water) through methane to petroleum and then to coal. Although logical from a n environmental issues perspective, the order parallels the chemistry a s well, moving from the properties of the simplest element through atomic structure and into the funhamenta~.;of organic c h e n ~ k t r yneeded to understand coal's structure and properties. The two narratives become tiehtlv interwoven. k i t h each stom buildine on itself and ~----~ ~" on the other narrative. The effect is almost triangular (see the figure) supporting three distinct but interconnected storylines. Why is narrational linkage so important? Because the need for context is so great that it drives students to look for linkage, even to the point of creating linkage where it ,does not exist. If a lecture goes off on a tangent, the task of com~rehensionis com~lexenough when the tangent is announced. But if the tangent is not announced, &dents will attempt to construct links between unlinked elements in ways that can amaze. At the very least, the failure to satisfy students' needs for contextual linkage causes confusion a s students waste time and energy trying to figure out what in the lecture does and does not go together. At the worst, students may assemble a n understanding that satisfies their needs, only to discover later that the "sense" they made of the material was in fact "nonsense." The need for connection pertains not only to the lectures, but to the laboratories and problem sets a s well. Students arrive a t their understanding of a subject by actively constructing i t using the material a t hand. When that material is not integrated, when the linkages between the different parts of the course are not explicit, students are forced to spend much of their energy simply figuring out how the different parts of the course fit together. The results discour;~genot only students; most of us would prefer that our students mend the maioritv of their intellectual energy understandkg the contknt bf the chemistry, not sorting out the structure of the course. But with their needs and expectations for context and linkage satisfied, students can direct their attention to grappling with substantive issues in the science. This experience suggests t h a t environmental chemistry can be a significant part of teaching chemistry a t all levels. An environmental perspective clearly benefits nonscience students, who find in i t a context for learning chemistry. But even though nonscience students demonstrate the need for context most visibly, context is more t h a n a crutch for the weak. Rather, nonscience students might be considered a s canaries i n a mine: Although they may be t h e first to fall, the malady to which they succumb affects everyone. All students benefit from well-developed and explicit context; in fact, i t is the students with backgrounds i n science who tend to react to this method of teaching chemistrv most enthusiasticallv. Thev find the course complemknts traditional chemistry courses by providina the connections so often left out. Most students in conversation reported themselves a s reviewing a n d reconceptualizing their previous chemistry courses to arrive a t a deeper understanding. At the same time, our experience indicates that environmental chemistry per se is not a panacea; its effectiveness ~~
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in contextualizing chemistry depended greatly upon what we did with it. I n rethinking chemistry teaching, consideration is due not only to the content of the curriculum, but to when and where that content arrives. In this course, the answer to criticisms common to most introductory science courses was not less science but better placement of the science: more recognition of how students develop and use contextual information. the better to inteerate the detailed scientific material into a coherent whole. Our experience also illustrates that the division of the: intrllectuiil community into two distinct cultures as described by C . P. Snow r12 IS ~roblematicin both directions. scientists readily become exercised about the low level of scientific literacy; they are quick to point out ways in which ignorance of essential scientific principles limits the lives, professions, and overall effectiveness of the general population. But one can argue the point from the opposite side: that the lives, professions, and general effectiveness of scientists are limited by the scientific community's lack of familiarity with essential principles of communication, both oral and written, or what is traditionally known a s oratory and rhetoric. Rhetoric is almost a perjorative term in modern societv. where it has come to connote the sacrifice of content tosuperficial gloss; it is particularly suspect in the scientific commnnitv. ". which prides itself on concern for issues of substance, not surface. But these distinctions between substance and structure, between science and its presentation, miss the point; science and language are so tightly linked together that to use either effectively, one must understand both. Scientific literacy is not simply facts and data any more than linguistic literacy is simply vocabulary and grammar; what matters is how these tools are used to conned with and interpret the world around us. Scientific literacy alone cannot be the goal; we need both scientifically literate non-scientists and environmentallv and rhetoricallv aware chemists. who toeether can harness language and science toward solving the environmental and technological problems that affect us all.
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Acknowledgment Development of this course was supported by NSF grant USE 9150524 from the Division of Undereraduate Education a t the NSF to T.G.S; J.A.S. was suppoked in part by the Council on Science and Technology a t Princeton University Literature Cited 1. Buell, P: Girard, J. Chemilry:An Enuirbnmenlol Perspective; Prentice-Hall: Englewood Cliffs, NJ, 1994. 2. Schwartz,A.T.;Bunce,D.M.;Silberman.R.C.:Stsnitski,C.L.:Stratton. W J..:Zipp, A. P. Chemistry in Context: Applying Chamistry to Socialy: Brown: Oubuque, M, 1P9d .....
3. Spim. T C.;Stigliani, W M. Envimnmanlol Issws in Chemieol Perspellus: Kendall Hunt: Oubuque, M, 1980. 4. %bias, S.. T h e y h not Dumb, T h d m DiferenL: Stalking the Second Tiai; Research corporation: Tuseon, 1990. 5. Connolly, P: Yllardi, T., Eds. W ~ i l i n gla h r n Mathematics end Sciencp; 'hachers College Press: New York, 1989. 6. G0pen.G. D.:Swan,J.A.Am. Set. 1990,78,5SCL559, 7. Fish. S. Is There a k t in This Clam? T b Authorilv of lnleromliue Communities: EIiruard: Cambridge, 1980. 8. Williams, J. M. Style: Tpn L a s o n s in Clorjh. and Gmcc: Scott: Chicago, 1985. 9. Colomb. G. G.;Williams, J. M. In Writing i n NonAeodemic Sdtinga; Odell. L.; Goswami, D . , Eds; Guilford Press, 1986; pp. 87-128. 10. Gopen. G. D. The Common Sense of Wriria8: 7hching Writing from ihr R e d a r k Perselius.; unpublished manuscript. available from Duke University Writing
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11. Latour B. S e b n n inAetion:How lo Follow Seimiials o n d E n g i n w s Thmyeh Smirty; Hanard: Cambridge, M A , 1987. 12. Snow, C. P. The ' h a Culluros and fhr Seienfifle Revolution: Cambridge: New York, 1959.
