literacy. I t is an exciting and brave attempt to portray chemistry's utilitarian role. In the future an ecological approach may prove to be the most nromisine. The dictionarv defines ecoloev u -" as the "study of relations between organisms and their environment!' and if we think of the oreanisms as human and the envirbnment as the whole earth; then we have a sense of what the ecological approach might entail. I shall discuss this approach later, but first let us consider what to present in the chemistrv for nonscientists course. What? It is hard for me to see how the goals of chemistry for nonscientists can be achieved without the following content 1) Scientific methods and knowledee-a review and summarv of course; parts of the ar~enee-humanities 2) Chemical principle. t u illwtrate scientifir mrthoda nnd
knwledae in chemistry and 11, provide barkground for srience-society issues; 3) Descriptive chemistry-to put flesh on the theoretical skeleton and to demonstrate the relevance of our science to everyday life; 4) Social problems and decision mnking-to support an understanding of our science's utilitarian role. If this course is to be manageable, I think we must narrow the scooe of each area. We cannot hone..nor sbould we trv. to incorporate the philosophy, history, and sociology of science that should go into the science-humanities and social science of science course. The principles and descriptive chemistry should be accessible and understandable. That means fewer principles presented in greater depth and a t a higher level than is currentlv fashionable. That means descriptive chemistry that relates to the real world experienced'by our students, not the more exotic and esoteric world of the professional chemist. As Davenport bas observed, we should avoid presenting "inscrutable theory to explain unknown facts" ( 8 ) .Finally, I think we sbould pass on the more minor social problems like food additives and concentrate on the major ones like enerev -" and nuclear war and world hnneer. How? How to present chemistry for nonscientists is in part a matter of structure and in part a matter of style. A structure that is available to us and that represents a synthesis of some of the more successful features of other courses is the following ecological approach
.
-
First Semester
Second Semester
Cultural chemistry Nuclear chemistry Geochemistry Biochemistry
Agriculture and mining Industrial chemistry Consumer chemistry Clinical chemistry Science-society issues
'
,
After an introductory section on scientific methods and knowledge, the formation of the earth and its elements would be presented t o set the stage for study of man's and abuse of his natural environment. In the first semester geochemistry (9) would provide a logical context for the descriptive chemistry of the natural environment and the principles required to understand it. In the second semester applied chemistry topics would show how man extracts a living from the natural environment and what this costs. History would be employed throughout t o illustrate the knowledge, methods, and utility of chemistry and provide perspective. The course would conclude with a consideration of a few major social problems that threaten our future. Some features of this approach are apparent in a few texts (5, 10-12) and especially in Weil's article on his excellent course, "Chemistry in a Watershed" (13). The style of the chemistry for nonscientists course is of great practical importance. The course sbould have variety
Activities for Chemistrv for Nonscientists( 1 4 )
Assignments
Lecture
Biographies Case studies Anicles TV programs Library research (1.5) Calculations
Demon~bations Learning cycles (167 AV aids Guest speaken Puzzles Real world examples (17) Debates Oral Reports
Interviews ( 19) Surveys
Lab
Inquiry labs (14
Research projects Field trips Field work Scientific conferences Guided design exercises
and interest. humor and enthusiasm. I t should be fun. I t should also have rigor and a sense of purpose and commitment. Activities to s u ~ n o rthis t kind of course stvle are listed in the table. For moreideas and specific examiles, see refs. (14-19). Concluslons I have argued that the purpose of "Science for Citizens" sbould be an understanding of science and its social aspects, that "A Science Curriculum for Citizens'' is a plan that can accomolish this . ournose. . . and that traditional cbemistrv courses are an important part of this plan. But atpresent i t is a plan and not a reality. Turning the plan into a reality will be a difficult and demanding task. I t will also be rewarding and worthwhile. I t offers an excitina- o~nortunitv for chal.. lenging, creative, and extremely important work-in science education. Literature Cited I11 Bmanowaki, J.."Selanaand Human Values," Haper and Raw,New Vork, 1%5. I21 Snow, C. P., "The Two Cdtures and a Second Lwk: Cambridge Unlvereity P-, Npvl Ynrk 1969 ~
~
(31 Hostcttier, J. D.. and Brwk8, K.,J. Cm~Eouc., 51.430 (1980). 141
Zinbem. D.. Science. 179.1187 119781. eai Soeiety, 1984.
181 Davenport,D.. J. CHEM. EDUC., 52,782 (1975). I91 Ho8tcttler.J. 0.. "Geochemistry for Chamiau: J. CmM. Eouc.,in press. I101 Gymer, ,on
R. G..
"Chemistry: An Ecolagical Appmach:
Harper and Row, New York.
I111 Barrow, G. M.."Gwerai ChemiaUy," Wadsworth, Beimont, CA, 1972. 112) Moore. J. W. and Mwre. E. A,, '"Environmental Chemistry: Academic P m ,New York. 1976. (13) Weil, D. R., J. CHEM. EDUC.,MI, 1032 (19831. 114) Hoatettier, J.D., J.CHEM.EDUC. 56.33, (19791. 115) Hmtettler, J.D., end Wolfe, M. B., J. CHEM. EDUC., 61,622 119W 116) Karplus. R.,J. Res. Sci. Teh., 14.169 (19771. 1171 "Using 'Real WorlC Examplea in the Teaching of Chemistry-A Symposium: J. CHEM EDUC., 60.1031 119831. 118) Psveiieh, M. Land Abraham, M. R.,J.CHEMEDUC., 56,lW (19791. 119) Hoggard, P. E..J CHEM.E~~~..57,29@119801.
Chemistry for Citizens: Content and Strategies John W. Hill Universily of Wisconsin River Falls, WI 54022 What should we include in a chemistry-for-citizens course? There are certain basic laws of chemistry whose understanding is vital not only to us as chemists, hut to all citizens. In order to makc thew laws meaningful to nonscientists, they must be applied to everyday affairs. T o begin, let us look a t the idea of level. Sometimes, i t seems. we eauate a o ~ r o ~ r i a level t e with a hieh decree of abstrktion and WitL'ma'thematical rigor. We ;each itomic orbitals and stoichiometrv to music maiors and then wonder why they hate chemistry. As teachers,-we may feel that we are up there among the angels with our orbitals and integrals, but students have a different view of "level." They often feel that they are in i t up to their chin, hoping no one Volume 62 Number 9
September 1985
765
makes a wave (equation). My conclusion: to be successful, a chemistry-for-citizens course has to be mainly qualitative. Now for content. What are some of the really important ideas of chemistry? Certain to be on any such list are the atom, atomic structure (it does not have to be very detailed), the conservation laws, chemical change, entropy (scattering), oxidized and reduced forms of matter, acids and bases, structure/property relationships, and (most importantly) the reproducibility of evidence. I have already described aoolications of the law of conservation of matter and of acidbase principles to an understanding of drugs (1,2)and those will not be repeated here, but I would like to elaborate on how the other ideas can he presented in terms interesting to the nonscience student.
duce the concept of entropy as scattering. Scattering is spontaneous. Just dump some PCB's anywhere and they will scatter over the eround and wash into the rivers. Then let us see how you ge't i t out. Gathering requires energy. Let a pollutant get scattered widely enough, and all the scientists and engineers in the world can't get i t hack together again. There are more elegant, more mathematical, ways to treat entropy but these cannot be used a t the introductory level. A qualitative approach, as outlined here, can be enormously useful to our students. And the simple but powerful concepts of entropy and of conservation of matter, if properly applied, lead to a better understanding of recycling, pollution, concentration of ores and minerals, and many other contemporary problems.
Chemical Change Matter is conserved: i t cannot be destroved. but i t can be changed from one form to another.That's a h a t chemistry is about-transformations of matter. One of the hardest concepts to get across t o students is that of chemical change. Sodium ion (Naf) is dramaticallv different from sodium metal (Na), and chloride ion ( ~ 1jis - dramatically different from chlorine gas (Clz). We can change highly reactive sodium metal and very toxic chlorine gas to relatively harmless sodium chloride. Indeed, sodium ion and chloride ion are essential nutrients. Large amounts of either, however, can be
Conservation of Energy
harmfill .........
It is important to consider chemical rhange when we want todispose of toxic wastes. Sometimes it is possible tochange wastes to less harmful forms. For example, we do not have to dump chlorinated organic solvenrs on the ground or into the waters. We can incinrrate them. Prooerlv . " dune. incineration transforms these solvents into carbon dioxide, water, and hydrogen chloride, presumably less harmful forms of matter. Even HCI is rather easily removed from the effluent by scrubbing. Why are people opposed to incineration of such solvents? Perhaps because they do not know the difference between chemical change (burning) and physical change (volatilization). They fear that the chlorinated compounds will be vaporized and rain down upon them. Not all wastes can be disposed of by incineration as, for example, those containing heavy metals. Most are toxic in all forms, and disposal really means indefinite containment in a landfill or other repository. Entropy If matter is conserved, how can we ever run out of an element? How, for instance, can we ever run out of copper? The answer is that we will not run out. There will be very nearly the same number of copper atoms aboard Planet Earth a thousand years from now as there are today. However, we may have spread those copper atoms so widely in the environment that it will be too exoensive to eather them again into useful concentrations. \Vhs does romer alwavs eet more ex~ensive?(There are periodic ups and downs i n prices, but the general trend is always up). Because as resources get scarcer, we must obtain it from lower grade ores or from more distant areas. When Europeans first came to North America, there were areas where they could pickup nuggets of pure native copper. Now we mine the tailings of former mines for their 0.1% coDDer content. T o get copper out of low-grade ore takes a 1% of energy and causes a lot of pollution. The pollution can be controlled, but that takes energy and materials. You cannot get something for nothing. What can we do? We can look for a more efficient process. There is now a method for extracting copper from ore by using a chelating agent. This method presumably uses less energy than roasting the ore, and the formation of sulfur dioxide is avoided. Even a t the high school level-or earlier-we can intro-
766
Journal of Chemical Education
Another important princiole is the law of conservation of energy. ~pplicationoithis I&to dieting was described previously ( 3 ) .If energy is ronsewed, how could we have an energj crisis? ~ n e r g yis conserved, all right, but it can be changed from one form to another. In any spontaneous change, the energy winds up in a less useful form. And in every change some of the energy is lost as heat. Again, a simple yet powerful natural law-has enormous prart&al applirations. It places considerable restraint on what we can do to "sohe the energy crisis." To convert coal to (more convenient~gaseous or l~quidfuels requires that we forfeit a part of the eneras of the coal. To useelertricirv to oroduce hvdrogen for use-as a fuel requires that we fbrfeit a part i f the electrical energy as waste heat. And we have already surrendered a major part (-60%) of the energy of the coal or uranium that we used to generate the electricity. We frequently hear scientists propose hydrogen as the fuel of the future, often without seriously considering where the energy will come from to produce the hydrogen. I am sure the& scientists know the laws of thermodynamics; they just don't seem to realize that they have practical application ComposRion, Structure, and Properties Another law of considerable importance is that of constant composition and its corollaries. U ~ o electrolvsis. n . . water alwaysforms two parts by volume ofhydrogen and one of oxygen. But the law of constant composition is more than just the basis for chemical formulas. compounds also have constant properties. Water is always wet. Pure water freezes at 273 K and boils a t 373 K (under 1 atm of pressure). You can put a little carbon dioxide and a few minerals in i t and call it Perrier's and sell it for a lot of dollars. You can put other substances in it, but the basic stuff is still water. A given comoosition and structure defines a set of nronert i e s . ~ i t r a t eion has certain properties. We could discuss its oxidizin~potential, solubilitv oarameters. etc. We could discuss i t s r i l e as a plant nutrient. It matters not whether nitrate ions come from a chemical factory or cow manure. The formula NO; not only designates acertain composition, it also represents a set of properties. These properties are as invariant as the composition. Vitamin C is ascorbic acid, a chemical compound. Its properties do not depend on its source, advertising claims, or our wishes. Aspirin is acetylsalicylic acid. I t has a nice set of desirable propertiesantiowetic. analeesic. - . anti-inflammatorv. .. and anticoaeul a n t a n d some that are undesirable-it promotes bleedTng and causes alleraic reactions in some neoole. . . The desirable and undesirableproperties are inseparable. Indeed, the anticoagulant action may be desirable-it mav decrease the chance of a second stroke or heart attack-; undesirablepromoting bleeding from a wound or aggravating an ulcerdepending on the circumstances. In more basic terms, knowing that aspirin is aspirin can save the consumer a lot of money.
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