High School Chemistry Textbooks: Form and Function A SYMPOSIUM
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Introduction to the Symposium
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McMaster, Maryland. Stillwater, Project Synthesis. Dreyfus. Chem Com. What do all of these have in common? The commonality is change-a new direction for the teaching of chemistry. The following papers focus on me role of the textbwk in bringing aboul change. These papers were presented at the 7m Biennial Conference of Chemical Education. Stillwater. Oklahoma. as part of the symposium. High School Textbooks: Form and Function. Many questions have been raised during the past few years. Is change necessary? If so. what types of changes? Will publishers respond to a need for change? Read on for many thought-provoking answers.
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What Research Says and How it Can Be Used J. Dudley Herron Purdue University, West Lafayette, IN 47907
The content, organization, and development of chemistry texts is greatly influenced by research: market research. Such research typically asks what text is used currently, what topics are covered currently, what students are enrolled in the course currently, etc. The nature of the research almost guarantees that curriculum materials will not change, even if there is evidence that change would lead to greater learning for existing audiences or more appropriate courses for other audiences. Educational researchers are frequently criticized because the results of research seldom influences classroom activity. One reason it does not is that publishers, who produce the single most important tools for instruction, totally ignore that research and frequently produce text materials that perpetuate poor pedagogical practice. This article will present what research says about textbook construction and how these research findinns - should influence the development of chemistry texts. The Bottom Line Publishers are private cor~orationswhose major concern is to produce the maximum return on the capital invested. Teachers are public servants whose major concern is to produce the maximum learning on the part of their students. If the things that sell hooks are the things that teach students, the system works well; otherwise, the public loses. Several factors operate to produce less-than-optimal results. First, the costs of producing a hook are fixed costs. Producing one copy of a book costs almost as much as producing a thousand. Conseauentlv. ~ - - ~~~-~ " , it is more cost-effective to uroduce a single book which sells 12,000 copies than to produce3 hooks that sell 4.000 conies each. From the ~uhlisher'suoint of view it is better to produce compromise hooks that are acceptable for several dwerse erouns. . Teacher's interests are better served if there are several books designed for special groups of students. A second factor that affects the nature of hooks is the buyer. Teachers huv hooks: students use them. What makes a hook look good to teacher is not necessarily what makes it effective ~~
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Paper presented at the 7th Btennial Conference on Chemical Education. Stillwater,OK. August 8-12, 1982. 888
Journal of Chemical Education
for the student. But the teacher huys the book, so market research is aimed a t making the book attractive to the teacher. To the extent that teachers are sensitive to factors that make a hook an effective learning tool, pedagogically sound hooks will he demanded hv teachers and will he ~ r o v i d e dbv publishers. (In actual practice, a select group of teachers or lavnersons determine the a d o ~ t i o nof a hook in each state or &inunity and publishers ofien design hooks for particular state adoptions.) What Makes a Book Pedagogically Sound? Most teachers and authors operate as though learning is a process of absorbing information that exists externally; i.e., that we transfer information intact from one individual to another. This is not the case. Learning is a highly constructive process in which the information that we '.'readn or "hear" is constructed internallv and is influenced as much or more by what is already inside our heads as by what we are currently wrocessinr from the external source of information. This co&truction process is influenced by what is in our heads and what is accessed a t the time that new information is constructed. As an illt~strationconsider the following passage ( 1 ). pending on how much there is to do. If you have to go somewhere else due to lack of facilities that is the next step; otherwise, you are pretty well set. It is important not to overdo things. That is, it is better to do too few things at once than too many. In the short run this may not seem important, but complications can easily arise. A mistake can be expensive as well. At first, the whole procedure will seem complicated.Soon, however, it will become just another fact of life. It is difficult to foresee any end to the necessityfor this task in the immediate future, but then, one never can tell. After the procedure is completed one arranges the materials into different groups again. Then they can he put into their appropriate places. Eventually they will be used once more and the whole cycle will then have to be repeated. However, that is part of life.
I think you will agree that the passage is totally incomprehensible. However, you have requisite knowledge in your head
to make sense out of the passage if you access that information and place the passage in the appropriate context. The passage, you see, is about washing clothesT You may claim that this is a nice trick, but it has little to do with chemistry texts. To the contrary, it has everything to do with chemistry texts and the fact that texts are sold to chemistrv teachers rather than chemistrv students. When H chemistry teacher reads a text,ae or she habitually accesses a vast store of existing knowledge which is subconsciously used to make sense out of what is presented in the text. The presentation appears to he straightforward and clear, but the student lacks the relevant knowledge, or the vocabularv used fails to access the knowledge that outs the passage in context and the student finds 2 incoiprehensible. A great deal of information is being accumulated on common student understanding of chemical ideas through research in the United States, Israel, Australia, Germany, Yugoslavia, the Netherlands, and Great Britain. Textbooks could be vastly improved by consciously considering these data. Illustrations and Symbols Accessing existing information through verbal cues is not the only way to provide a meaningful context for new information. Illustrations, diagrams, experiments, and other devices can be used. The effect of an illustration is shown by another study by Bransford and Johnson (2). If the balloon popped, the sound would not be able to carry since everything would be too far away from the correct floor.A closed window would also prevent the sound from carrying since most buildines " tend to be well insulated. Since the whole ooeration depends on a steady flow of electricity,a hreak in the middle uf t h e wire would :tlrl, Cause prc,hlems 01 tl8UrSQ l t w fellow could shout, hut the human voice is not loud enough to carry that far. An additional problem is that a string could break on the instrument. Then there could be no accompaniment to the message. It is clear that the best situation would involve less distance. Then there would he fewer potential problems. With face to face contact, the least number of things could go wrong.
Again, the passage is incomprehensible, because we have no context in which to assimilate the information. The following picture provides a context. Now can you tell what the passage said? Probably not, be-
cause the context was provided after you had read the passage. Bransford and Johnson's research suggests that the context must be provided before the passage is read if it is to he effective. There is another point that must be made. This picture, like any illustration, is highly symbolic. You see a balloon, a loudspeaker, a man playing a guitar. However, the picture is only a pattern of lines. You have learned to interpret lines such as these through repeated exposure to similar representations. Now think for a moment about the symbolic representations that we use in chemistry books, i.e.,
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These representations are familiar to chemistry teachers, but students must learn to use them and authors must teach students to interpret the symhols. Perhaps even more importantly, you must consider how such symbols can be made to call forth images of atoms and molecules that can never be seen. How, for example, could you get students who have never seen a halloon, a musical instrument, or a loud speaker to make sense of the balloon picture? The importance of the constructive Drocess in learnine cannot be overestimated. I t seems to be our nature to try to incorporate new information into some meanineful context. This nrocess of twine to make things sensible i n lead to undektanding or t h u n d e r standing, depending on the context provided.
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"Reading Between the Lines" When you read, you read many things that are not actually written. This "reading between the lines" can be very beneficial when you make correct interpretations of a text, but i t can be harmful when you are mistaken. I t is interesting to consider just how extensive this "reading between the lines" can be. In a recent study by Finley (3) students were asked to read a passage from aphysicstext and then recall propositions that they had read in the text. All students recalled a substantial number of propositions that were not actually in the text. For some students, only 47% of the propositions recalled were actually in the text. Not all of these propositions were wrong, and they were not necessarily detrimental to learning, but it is important to note just how much of what students recall from reading the text is a result of constructions that thev make which are not actuallv in the text. To consider the nature of this construction. vou must first distinguish between "surface structure" and "deep structure" of a communication. Surface structure means that vou have in mind rhenctualsrimul~.In the figure, yousawun thesurface ~ all that was fvcuied onlv straight lines and curves. If t h was upon, thcpicture could have hardly helped with the reading passage that was presented. I t is only when the lines and curves were interpreted as balloons and people, and a particular situation that the picture is useful. There is semantic information in the picture that goes beyond surface features. There is a deep structure that provides meaning. The deep structure accessed by surface features varies from individual to individual. Consider a passage written in a foreign language, i.e., Aide-toi, le ciel t'aidera. Such a written phrase is not processed by a native in the way it is by a foreigner. The native gives little conscious attention to surface structure whereas the foreigner may be forced to give a great deal of attention to it. Certainly the semantic content ih deep structure is not the same. T o take the language example a hit further, singers often learn to sing in Italian, German, or another language. However. if von talk to them.. vou " find that thev have little or no knowledge of the language. They sing thewords processing the information a t the surface level. but do no orocessine a t a deep level. By contrast, a listener who knows'the langGge Volume 60 Number 10 October 1983
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may process the content of the words a t a deep, semantic level. Now consider chemistry. It is a foreign language. Terms that are new to the student are frequently used. If the student is overloaded, or fails to make the connection between the surface and deen structure. then the student begins to process the message at a surfacelevel, memorizing terms and phrases in much the same manner that an operasinger may memorize what is being sung. If the student good a t this surface processing, it is difficult to detect that little deep structure is heing formed in the process. Indeed, superficial questions that reauire recall of exact phrases, definitions or skills may actually promote superficial processing of the information contained in a text (4-6). ~~
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Omission and Commission
Learning new ideas is a particularly tricky business. New concepts are developed through a process of successive refinement. This development is seriously misled if inappropriate or insufficient exemplars of new concepts are provided. Consider the following anecdote. I recently visited a student teacher who was talking about acids. As part of the presentation he pointed out that acidsreact with metals to produce hydrogen gas and proceeded to place zinc in hydrochloric acid to illustrate this property. It was a typical presentation. However, it is a presentation that suggests that any metal will react with any acid to give hydrogen gas, and this clearly is not the case. As the student is processing this information and extrapolating from the information given to more general structures of understanding, the student is led toa misconception that will require attention later on.
Other problems occur as individuals attempt to construct knowledge in a sensible way as closely related ideas are simultaneouslv" nresented. The student should. and usuallv . does, try to integrate the information presented. He or she mav have difficultv sewaratina what does go together with present molarity, molality, normality, mole fraction, or other concentration terms one after the other. For an experienced chemist who has a well-formed concept of concentration, this may cause little difficulty, hut for the beginning student who is struggling with the underlying concept, concentration, the various exemplars are easily confused. From the student's viewpoint, it is thus preferable to present the concept of concentration using a single example such as molarity. The other concentration terms could then he presented a t some other time when the earlier concept is well established. Process Information
As knowledge is constructed in our heads, we use many logical operations or processing strategies that have proven useful in the past. Once we become accustomed to using these logical operations, we do so subconsciously and thus have difficulty imagining that there was ever a time when we did not use these operations.
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It is sufficient to say that science textbooks rely heavily on what Piaget describes as formal operations; however, many students have not developed the facilities necessary to process such logic. As a result, many relationships that are perfectly transparent to the teacher and to some students are impossibly opaque to other students. Authors and teachers must be sensitive to this problem and prepare materials that can he understood by the intended audience. As the understanding of how these logical operations is expanded, textbooks must be written to foster such development. It IS Time
Research unfortunately has had little influence on the writing of chemistry texts, and chemical education suffers because of this. It is probably unrealistic to expect high school the cla&oom functioning. It is not unreasonable for puhlishers to keep abreast of such research-even to do it-and to use the results of this research to improve the products that they sell. Puhlishers defend oresent oractices hv that thev "renortinr . produce what the public wants. They are sensitive to the marketplace. This is undoubtedly true, hut it does not excuse the industry, and educators should no longer tolerate the cavalier attitude that has been seen. The automobile industry is no longer &wed to place unsafe cars in the hands of willing buyers, even though there is ample evidence that the public is more interested in speed and style than in safety. The oharmaceutical industrv is not allowed to market untested drugs, even though there is a ready market for them. Farmers are not allowed to water down milk, even though they could increase their profits by doing so. It is time for the publishing industry to pay attention to the research that shows how it can produce a better product, and it is time for teachers to expect publishers to provide evidence of the effectiveness of their wares before they are sold in the market. The influence of the textbook on chemistry learning is far too important to he left totally a t the mercy of the marketplace.
Literature Cited (1) Bransford. J. D. and Johnson, M. K., Conteatualprorequisitea for understanding: Some investigations uf comprehension and recall. Journal 01 VtibolLtoiningond Vedol Rehouior, 11,711-26 11972). (2) Branshrd, J. D. and Johnson. M. K.. Consideratiom ofsomeprnblem~ofcomprehension. In W. G.Chase (Editor), "Vbuai information piocessing."AcademicPreas,New Ymk. IS72
(3) F i n l ~ y F. , M., Students' recall from science teat. Journal 01 R ~ s ~ a i cinh Science Teaching, (19821. (4) Rolhkopi, E. 2 , Leaning from written materials: An exploration of the control of inspection behavior by test~likeevents. American Educolionai Rrseoich Journal, 3, 241-49 (1966). 151 . . Ruthkoof. E. 2..The conceot of mathemaeenic activities. Reuirlu of Educoiioml R c ~ seorci,bo,325-36 w o i . (6) Rolhkopf, E. 2.. Structural text features and the control of processes in learning from written materials.In J. E. Carroll m d R 0. Freedle (Editors), "Languagecomprehension andthe AmuisitlonufKnuwledge. V. H. Winston andSons, Washingfon,DC, 1972.
