In Pursuit of Chemical Literacy: A Place for Chemical Reactions Douglas Bond Riverside City College, 4600 Magnolia, Riverside, CA 92506 I t has been six years since the publication of A Nation a t Risk(1). In the intervening years, the shock waves from this critique of American education have swept through every discipline and spawned additional studies of the educational process and its problems. Because of the important role that science and technology play in our contemporary economy and society, science education has not escaped scrutinv and within the chemical community such stu&es as the Yankworth report (2) have called for renewed efforts on behalf of science and chemical education at all levels from elementary to college. Survevs such as that conducted bv the National Assess~ ~ ment o f ~ d u c a t i o n aProgress l over a period of years show a decline in math and science skills hv academicallv able teenagzrs. Other surveys of adults suggest that the-knowledge and understandina of science amone the citizenrv is not what we would like it to he. In discusiing these results, the term scientific literacy (3)or illiteracy is used to describe the general state of knowledge of the Literacy, in its most common usage, is defined as the ability to read and write. These are hasic skills and the absence of one or hoth is considered to be a handicap in an industrialized society. Are there basic scientific skills whose absence handicaps (in part or full) the ability of individuals to function in our society? If so, which of these falls within the realm of the chemical sciences, and is there also a chemical literacy? ~ t u d i e i a i m i n gto assess the degree of literacy generally frame questions in terms of knowledae of scientific models and pr&iples. Does the person beingevaluated have a basic understanding of atomic theory, the mole concept, radioactivity, and other fundamentals of chemistry? t a c h science has similar yardsticks for evaluating the people's awareness of the important models and concepts of t h a t discipline. These evaluations suggest that creating literacy is a process of exposing a group of people to importantmodeis of science in a pedagogically logical fashion (with as little trauma as possible). But we mav be reinforcine the attitudes that turn i f f a significant nugber of studenis, because studies show that most students are alreadv turned off to science in elementary school and that by the middle school years, they do not want any more.' We have been discussine methods of teaching, altering the order of presentation o r topics, and offering courses for special groups (chemistry for artists, poets, etc.), yet we still see the same prohlems discussed in our journals (4). Several vears ago. I made substantial chanees in a course that I teach to nhscience and allied health students in an effort to change the a ~ ~ r o a to r hreachine srientific literacv. There were several e&ts that led up tb these changes of which the greatest was dissatisfaction with the course as then being taught.
A second fador was teen-age children who had taken or were taking high school chemistry. The oldest child took chemistrv while we were livine in Eneland where the curriculum was significantly differeit fromihat taken by the younger children in the United States. There was a heavier emphasis on "actual" chemistry, and endless complaints were heard about havine to learn all of the reactions. properties. and methods of for the compound^ ofsulfur; nitrogen, etc., as well as some of the basic concepts. I t was very descriptive and much like the courses that many would like to hring back. contrast, a younger child was taking a much more prin~ -In cipler-oriented approach and was also hating it for the lack of connection with reality. As the chemical education literature debated the differences and pros and cons of chemical orinci~lesversus descriotive chemistrv. the home e x ~ e r i ince was saying that neiiher were excitkg to students. ' The final catalyst was a remark made by DerekDavenport a t the Project SERAPHIM Powwow I. In the process of reporting on his group's work, Derek made the insightful comment that a student finishing a chemistry course should be able to make some kind of prediction as to whether a chemical reaction would proceedor not, assuming that there were no subtleties involved. As innocuous as the statement sounds, it came as a revelation, because it is not altogether clear from most courses taught inour department that this is an ultimate objective. A practicing chemist does not need to be told that chemistry is the study of chemical phenomena, but except for an introductory statement in the first section of the first chapter (or perhaps the preface), one would be hard pressed to know this from the content of an introductory chemistry course. Indeed, many of the current approaches t o teachina chemistry are driven more by the nekd to get through the book, but the hooks are written primarily to teach skills and concepts required to understand and do chemistry. Thus, we use a pedagogical model whose premise is that the skills necessary to d o chemistry and chemical literacy are the same. This gives a false impression of what chemistry is and what it tries to do. Examination of the textbooks that are commonly used in introductorv courses shows that most s ~ e n dthe first (or sometimes second) chapter discussing measurement. ~ h k n measurement is not the first topic, i t is usually preceded by a short introduction to chemistry and the nature of matter. Students are then exposed to the metric system and to the methods of converting one unit of measurement to another. Almost without exception, this involves dimensional analysis and the impression given to the student is that this is-a math course. With all due respect to Lavoisier who established the importance of measurements and recognizing the importance of mathematics in chemistry, this is the wrong impression to give students; it is the wrong way to start a chemistry course; and it does not lead to chemical literacy.
'They are probably as turned offto English, history, and physical education.
Some Premises As a basis for working toward an improved literacy among the local populace, we start with the hypothesis that a chem-
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The Seeds of Change
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ically literate person is one who is curious about chemical phenomena and makes a n effort .. toward satisfvine ." that curiosity. If this person isachemist or chemistry student, he or she will regard the need to satisfv this curiositv as more or less a full-time effort. Those who are not chemists may find that fullfillment soread less intenselv, and over a lone oeriod of time, either from formal classes,-reading in newspapers, books, and magazines, or through private conversations. There are some scientific values or attitudes that must be part of this curiosity that give some meaning to the search and that make i t possible to deal with the uncertainties that will arise. These involve the following types of scientific thought trains:
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(1) The answer to a question may not be obtainable at the present time for one reason or another. (2) An explanation given previously appears to he untenable in light of new observations.We will need to develop anewh~woth..
esis.
(3) An explanation of chemical phenomenon given previously is not
capable of shedding light on a new, hut related phenomenon; however, it appears to be valid for the older phenomenon. The original idea needs to he extended. (4) How can an established concept be applied to other chemical phenomena? Does it have practical applications? Since first imnressions are often imoortant in formine opinions, we might consider what first impression we would like students to have of chemistry. This will vary from one instructor to another, but using the hypothesis stated above, students should see chemical ~henomenaand be curious enoughabout what they see to tiy to understand the chemistry. Thus, the first two units of the revised course were designed to maximize the number of demonstrations to make as favorable a first impression as possible. Indeed, many students have said that, to them, this is real chemistry. There is more to this than the excitement of explosions, dramatic color changes, etc. There is something happening during a demonstration that is the key to bringing about chemical literacv: oeonle beine curious. Curiosity must 6e initiatediy observation, but that curiositv must then cause a more thoroueh observation. These obs&ations, will, in turn, generate questions, to which we will seek answers. Later, when the student has more exoerience, he or she may chance to see again an earlier experiment, and the added maturity will give rise to observations not seen previously or perhaps to questions not asked. The Science Museum in London has an excellent section for children with manv demonstrations of ohvsical ohenomena on a "hands-on" 1;asis. I t is a madhouse with youngsters runnine inall directions nushine as manv buttons as oossible to see Ghat will happen A d th& running on to the nkxt. I t is unknown how manv actuallv ask oertinent ouestions about what is happening, but extrapolating from a sample of 20 minutes of observation, the numher is probably quite small. Thus, demonstrations are not enough and neophytes seem to need direction in those earls weeks of study. I t is not the intention of the author t o discuss the revised class in detail, but rather to discuss some elements of the revision and their impact on chemical literacy. The table shows the structure of the course that, with few exceptions, does not look verv innovative. There are other masters to serve, particularly the institutionally imposed requirement of reachine the end of the semester in aooroximatelv the same placeand having "covered" roughly the same material as instructors teaching other sections of the course. The Course Students hate learning terms and vocabulary, so what we do is to try to develop the necessity for a well-defined and precisevocabulary. For each of the demonstrations, we ask a pair of students to come up and write their observations on the hoard. Their language is often amhiguous; however, with
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class involvement, precision is developed, and much of what would have been a dull presentation of terms becomes a group learning experience. Units of measurement come up in the same way. The early introduction of bulk matter comes first, i.e., the concepts of states of matter, homo- and heterogeneous, and mixtures, etc. The concept of a chemical compound is also introduced in this unit. At this time, the term is defined and we show that compounds have both names and formulas. Studentsare given both the names andnumbers of each type of element present and are expected to write the formulas. There is no concern about order of the elements in the formula or valences or any of the rest. In unit 2 they see names and formulas of compounds again as we start writing chemical reactions. This is their first encounter with the fact that sodium reacts with a single chlorine, while magnesium needs two to form a compound. Even more unsettling is the fact that there are two different compounds, and hence, formulas for the combination of iron and chlorine. There are many questions about this, and they cannot be answered because the students have not encountered oxidation state. Conventional pedagogy is to delay the presentation of formulas until bonding and oxidation state have been learned, but they will he seeing formulas in the laboratory anyway, so there is no leeitimate reason t o hesitate. Students are told thacthe basis for these phenomena will be discussed in units 6 and 7, and that if they cannot wait, thev should read chaoters 8and 9 in the text.'l'he ooint here is not formulas, or oxidation states, but a fundamental value of doine science (it1 in our list above): exolanations of chemical phenomeGa are not always available a h e n we want them. What we must learn, scientist and nonscientist alike. is that questions must be lodged in the mind, and the search continued. Someday, somehow, maybe as a result of a concentrated search, perhaps fortuitously, an answer may be found, a light may go on. I n unit 4, we look a t compounds again, this time in more depth; attempting t o classify them, much as we did with the elements in unit three (periodic table). In our first classification, we consider the distinction between covalent and ionic comnounds. Normallv. the concent of ionic and covalent boniing is taught first, and then 'the concept of ionic and covalent compounds follows. However, it is difficult to observe ionic and covalent bonds, hut relatively simple to demonstrate the difference (in a simple-minded way) between ionic and covalent compounds. We use two tests here: solubility in water and the ability of the solution (if the substance dissolves) to conduct an electric current. Substances that do not dissolve are immediately classified as covalent. Soluhle substances are then tested to determine if they conduct an electric current. The conductors are classified as ionic and the nonconductors as covalent. Students ask a number of questions a t this point, including: (1) "Why do ionic compounds conduct a current in Course Units of Instruction
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Classilicat on 01 Mmer lnrrw~cton to Chemical Change PerlWIc C assitieat;on ol Elements CIas~ifl~ati~n of Compounds Structure of the Atom Chemlcal Bondlng Performing Chemlcal Reactions States of Matter Chemlstry in Solution Dynamics of Chemical Change Measurement and Control of Acidity Organic Chemistry Nuclear Chemistry
solution and covalent compounds not?", and (2) "Why do all ionic compounds dissolve in water whereas only some of the covalent compounds do?" They also begin to form some hypotheses about the types of elements in each type compound. In addition t o an empirical exposure to some facts, we are reinforcing the scientific values here, most notably the first, but also the second. The auestions cannot he answered a t this time because of alack df information about the electronic structure of matter. Althoueh the criticism could he made that we are confusing the &dents and cluttering their minds with facts that must he unlearned. we have in fact. already made the discusaion of bonding clearer tor them because they are aware of the diveraent behavior of chemical substances.- hey are aware that-there are probably two types of bonding because thene are two types of compounds. Furthermore, the discussion of the polar covalent bond will be much less abstract because the students have already seen differences in the behavior of covalent compounds. But value number two is also emphasized, because in unit 9.. thev. will learn that not all ionic comoounds dissolve in water (in fact, a suhstantial number). Thus, an operating hvoothesis must he thrown out and a new one souebt. Thev nbw ask the same question about ionic compoundsthat they asked about covalent, and fortunatelv, - . thev - are not likelv to get an answer; not in chemistry class for majors or nonmajors, not in their undergraduate education, and perhaps they may never know. Although it is unsettling, to them, they learn that scientists havenot solved or explained every prohlem that has been encountered. Compounds are also classified as t o whether they are acids, bases, or salts, or none of these, and students learn that many compounds can be classified in two different ways; that there is more than one way of looking a t the same phenomena. The simple definition that we give of an acid also allows us to emphasize our third value. The Arrhenius definition serves well for many common acids and bases. However, in unit 11, we will need to extend and modify this definition. The students understand and accept more easily the concept of extending ideas (such as the definition of an acid) much more easily when the first definition is accepted for a period of time as an operating hypothesis, and then the second (Bronsted) is presented. The addition of new information causes the student t o see the distinction better and to think about the differences and reasons for the change. We have already mentioned that the first exposure to reactions comes in unit 2. We do some demonstrations and then write chemical equations for each. At this point, the reactions are of fairly simple combination, decomposition, and replacement types. Thus, thev are tauaht verv earlv to write chemical equiiions, first in &rds andihen withch&ical symbols. Balancing of the equations comes shortlv after. Unlike language, where the student has years to practice all of the nuances and forms, we have only a semester, so that it is i m ~ o r t a nto t heein to translate intochemical terms what is being observed. In unit 4, we return to eauations, addine acid-base to the store of reaction types that the students must know. Here, students also learn that reactions disolav that can . . oatterns be classified. These patterns allow us to predict products when only the reactants are known. In unit 6, the students have finally been exposed to nomenclature and formula writing, and it is now possible t o give problems where the right side of the reaction is completely blank. Students must determine which compound is formed and what its formula is. For many this is not a trivial operation. If you ask a student what salt is formed from the Na+ and C1- ions, he or she will say NaCI. But if you ask the same student what salt is formed from the reaction of Na2C03 and HCI, they may well reply Na2C1. In unit 9 (solution chemistry), this process is reviewed and
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the concept is extended to net ionic eauations. The conceDt of weak a i d strong acids is also encointered here and s k dents observe that reactions in which a weak acid is formed are much more viable than those in which a strong acid is formed. This prompts still more questions that prepare the way for our discussion, in unit 10, of thermodynamics. At the end of this unit, the student should have some elementary idea of what drives a simple chemical reaction toward or to completion. Although there are three units following unit 10, we have, in fact, reached one of the major goals of the course in this unit. Desdte this, we must emohasize that i t is not the abilitvof the stident ti predict the outcome of a postulated reaction that makes him or her chemicallv literate. I t is the encounter with chemical phenomenon along the way that generates first curiosity, then questions, and finally a search for answers to those questions, that fosters literacy. Evaluation How effective is the course and concept? We present no statistical comoarison of the new aonroach with the tradi~~~~~-~~ ~ - - ~ - ~ tional course that demonstrates that students are more curious, that thev have adooted the basic values. and that thev are, therefor;, more litkrate. Indeed, there is probably no quantitative method of evaluatine curiositv. One qualitative measure that gives some indication is the "problem"of questions. We have given some examples of the kindsof questions that arise in thesecond unit and later. Far from being a problem, students are showing that they are capable of asking serious questions about the nature of chemical phenomena and of being seriously interested in the answers. Chemistry is of greater interest than is apparent from the surveys of attitudes. Indeed, most students leave with positive attitudes toward the course and chemistry alike. Many have said that they liked discovering answers. A possible criticism of this approach is that what we are describing really belongs in the laboratory. This is the place to explore chemistrv from a more exoerimental m i n t of v i e w . ~ h i smay he tr"e, but it doesn't happen t h e r e . & ~ o of st the time is spent illustrating concepts and developing laboratory skills and, in fact, students are likely to be more involved in a search for correct answers than in a search for new questions. We have already pointed out that lay ohservers often need to have curiosity sharpened and honed. We have also already alluded to another potential criticism: that of the learning and unlearning of ideas and information. Unfortunately, any other view of science is untenable. We are all learning and unlearning. Ideas that were accepted five sears ago have since been modified or oerhaos evei discarded altogether. Can we say that nonscientiks understand science when thev have never had t o discard and regroup? The major problem is the student's expectation of a made at the endof the course. The grade, of coirse, is based on one or more evaluation devices called tests, and these have been rather traditional in content. The net result is to focus the student's efforts on skills (u,hich must be learned) and on knowledge " of facts. models. and theories. We have not found a way to measure curiosity on a written exam or t o assess the demee to which students have a d o ~ t e dthe basicvalues. The stidents have an implicit understanding of this and their study is directed toward mastery of skills. When the course is over, the students will continue to encounter chemical phenomena whether they like i t or not. Chemistry is in the newspapers, magazines, and nightly news programs. I t figures in politics and economics and is an import& part of air cultuie. The literate person now uses his chemistry background as a base to seekunderstanding of these phenomena and their key features. This may require additional learning, and i t is this continuing interest in science that constitutes literacv. Thus. chemical literacv is not a product, it is a state of "mind; lt is not achieved, it is ~
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Volume 66 Number 2 February 1989
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pursued. How well we have succeeded a t this is unknown. That requires followup studies for which we have no resources. Summary
We have partially described one method of implementing a course for nonscience majors in which an early and repeated exposure to chemical riactions in tandemkith a set of scientific values is the key to approaching chemical literacy. This earlv introduction of chemical reactions and the re~ - -~ ~ peated eiposure has two purposes. First, it allows us to emnhasize the im~ortanceof chemical reactivitv in chemistryand gives an opportunity to teach the skills of chemistry repeatedlv. Second. and more imnortantlv. it demands that many concepts must he introduced earl& than is normal and a t a time when the required background is not completely in place. This, in turn, causes students to ask questions and to become curious, which we suggest is the crux of chemical literacy. If the sole purpose of a course is t o teach the skills of doing chemistry, the concepts outlined in this paper are not relevant or helpful. Students questions are substantially reduced and instruction is much more efficient when the prerequisite knowledge for a concept has previously been taught. But a carefully ordered curriculum that minimizes questions hides the real nature of chemistry and does not permit an approach to chemical literacy as weare defining it. Emphasizing chemical reactions is not the only way to anorokh chemical literacv. There are manv chemical nhenomena which do not ikolve changes in"structure that, nevertheless, are suitable for provoking curiosity. The author encourages other chemical educators to experiment with these and to begin a dialogue that will lead to better literacy among nonscience people and to an improved attitude toward chemistw and science amone the citizenrv. As important as terms are in understanding chemistry, thev are a means, not an end. In spite of the emphasis that we place on models and model building in chemistry and in other sciences, models are simply a mental construct to facilitate the understanding of chemical phenomena. At its core, science involves curiosity about the natural world, not a knowledee of models or terms. The models can chanee. hut curiosity-will always triumph and in combination wyth the scientific values. lead to an understandine of what we believe t o he correct today and an ability to ac&mmodate our revised picture 20 years from now. A recent article suggested an alteration of the freshman chemistrv curriculum to emphasize descriptive facts of chemistry (5). Sources, prepaiations, and reactions should he taught, not theories. There have heen many such calls in recentie&s, hut a principles-based course still continues to ~~~~~
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Journal of Chemical Education
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he widely taught. The danger in such a call for the ahandonment of theory is the same as a call for the teaching of theory only. Chemistry is not just theory or just fact; it is both. The criticism that many theories have exceptions (often many) is valid. This, however, should not stop us from teaching theories as generalizations of chemical phenomena. Such criticism merely pointsout that in the future, the theory may he scrapped or extended (the second and third of our scientific values) and may even provoke the student to ask relevant questions. The danger comes in extremes. The teaching of only facts neglects the idea that science can he organized, however imnerfectlv. In soite of their loonholes. manv theories are fo; the moment; adequate models of'our present ~ercentionof the world. The teachine of theorv- onlv - eives - a ialse impression that chemistry is answers, not questions. Chemical literacy will not occur when the coin lands with either the theorybr fact aide up. Only when it standson edge and both sides are visible can we approach chemical literacy. Several years ago, a group opposed to experimentation with animals carried out a widely reported raid on the animal lahs at the University of California, Riverside. Considerable damage was done, and the perpetrators were not caught. In a letter to the editor of the local newspaper, one supporter of the raid said that since the experiments served no practical purpose, no real damage was done because "all of these experiments have already been done, and all of the facts are known". It is unlikely that such ignorance will ever be wiped out, hut it is not necessary for such attitudes to be widespread or to influence adversely private and public decision-making process. Students currently leave our courses with knowledge of models and terms that have been presented as the last and final word, despite the fact that chemistry, like the other sciences, is not answers, but questions and a search for the answers. Acknowledgments
The author expresses appreciation to Riverside City College for a sabbatical leave, a portion of which was used to write this naner. He is also erateful to Paul Schlever and his research &o;p for generoushospitality and camaraderie and to Alan Reed and Timothy Clark for critically reviewing - the manuscript. Literature Clted 1. A Notian o t Riak! Tho Immrotiue for Edveotianol Reform: National Commiaaion on
