George 5. Hammond
University of California Sonta Cruz, 95060
Information Management and Original Thought in Chemical Education
I am especially honored to receive the ACS Award in Chemical Education because I entertained fantasies about becoming an educator long before I had any really concrete notions about becoming a chemist. I continue to derive great pleasure from presiding over a class or a research laboratory and observing that the students who are engaged in those activities with me are undergoing some kind of learning process. The fact that I continue to learn myself is an added bonus. Although I have acquired some credentials as a chemical educator, I still feel puzzled a t times as to what makes a successful enterprise in chemical education. A few years ago I made a modest proposal for restructuring undergraduate curricula in chemistry so as to group topics according to what seemed like more logical functional relationships. While some interesting experiments have been made along these lines most teaching is still done under the old titles: organic, inorganic, physical, analytical and biochemistry. Despite the fact that the organization still does not seem logical to me, the system works, more or less. During the Winter term which just ended I taught a large class in elementary organic chemistry for the first time in 15 years. I enjoyed the experience and my students learned-? good deal. Throughout the course I kept wondering ';.hy we were doing things as we did, why they seemed to work, and, especially, what could we have done better. I think that the course really had two important features. First, there was a strong attempt to correlate pieces of information to create patterns of chemical behavior. Second, I repeatedly asked students to test their creative ability by applying the behavior patterns to new situations. This approach is by no means new; i t is probahly the usual format for most courses in chemistry and physics and is common in modern courses in biology and earth science. To some extent it is probably also true of courses in many other disciplines, but I will not take the time to dwell on the extensibility of the principle. I would like to look in some detail a t the way pattern recognition works in chemical education. In a course in organic chemistry, we usually give very brief account of the historicallv structural oat- imoortant . terns associated with elementary composition and molecular weights of Dure com~ounds.This enormouslv. imoor. tant operation is usually capsulized to the extent that few students really understand the principles and we go on through most of the course asserting that compounds having various structures and names exist. We then talk about their physical and chemical properties and, in doing so, we try to establish patterns of physical and chemical properties. The basic vehicle in the search for patterns is structural formulas which we write on paper or blackboards or reproduce on the printed page. This system accepts a large group of patterns which were won with great labor over a period of roughly 100 years, between 1830 and 1930. We can ask whether or not the casual suhsumption of so many man years of scientific work is proper. I think that it is. There is really no good reason to drag our students through the gory details of why we believe that
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is a good formula for a compound that we call henzene and
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is a good formula for a compound known as tetrabydrofuran. We talk about the physical properties, such as ultraviolet or nmr spectra, or chemical properties, such as reactivity toward nitric acid or hydrochloric acid. Fundamentally, this is intended to help fit other compounds, having other easily deduced structural formulas, e.g.
into a coherent pattern. This is no trivial task, and one to which we should call our student's attention because the logical patterns relating compounds owning the three formulas are really rather tenuous. To do any useful job at all we require many information bits supplied by study of compounds other than benzene and tetrahydrofuran. I helieve methyl 5-nitrofurfuryl ether will react with nitric acid in a manner reminiscent of the behavior of benzene and with hydrochloric acid in a way that will remind one of the hehavior of tetrahydrofuran. Furthermore, I expect that in both cases the reactions will he much faster than those of the prototypical compounds. These are predictions, not facts known to me, and probahly not to anyone else. However, I will bet a t good odds that I am right. If the odds are changed in my favor, I would even undertake to predict the relative reactivities semiquantitatively, within limits to be defined in the wager. As a professor I face two problems. First, how on earth can I teach my students the correlation procedures which I use in generating the predictions? Second, would it be worth their time to learn of all the convolutions that I would put into the exercise? Obviously, methyl 5-nitrofurfury1 ether is not a very important material in the affairs of mankind or even chemical science. Furthermore, if my class and I put our all into understanding this micro-problem they and I both know that we would not be ahle to move on with great precision to prediction of the behavior of many other compounds that are not described in detail in the various textbooks and journals available to us. If the educational process in my class works very well, my students will he ahle to move in on a new objective compound with reasonable speed and will he ahle to make some kind of predictions concerning new substances. Given a structural formula, they would fit it to some kind
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The 1974 ACS Award in Chemical Education sponsored bv the Laboratory Apparatus and Optical Section of the Scientific Apnnratus Makers Association was oresented to Georee S.Hammand at t l w l(i:lh hlccling ot the ACS a t 1.0s Angeler in April uf thi- vmr. I'roies;or Hatntnmui ro-.nlthur t ~ fh~ehl\.Inn,n.ltlae urranit and general chemistry texts, and of an integrated undergraduate chemistry curriculum that eliminates classical divisions of the science and traditional organization of the subiect matter, is Vice Chancellor for Sciences and Professor of Chemistry at the Universitv of California at Santa Cruz. Possessed of unusual imagination and incisiveness. he has made sienificant contributions to ohvsical
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of a classification scheme and would use this to define analogies which would, in turn, he useful in some kind of literature search for the hehavior of analogous substances. This is a creative use of pattern recognition in chemistry. The orincinle can also he reversed bv devising structures khich are likely to generate'desired, iseful propon erties. Much of what we teach in chemistry can be justified mainly because it is, or should he, helpful in defining and recoenizine oattems of chemical behavior. Consider mo" lecular quantum mechanics as an example. Students in science heein in the eighth made to learn something about the quant;m mechanical model of the hydrogen atom. If they stay in the mainstream of chemical education they will hear about the hydrogen atom over and over again, well on into graduate courses in theoretical chemistry. We can question whether or not this repetition is worthwhile. The lower educational levels, or at least through the first three years of the usual university course, tend to confuse and irritate students because at each level they hear a different version of the quantum mechanical model. I have been asked by a number of students, "Why don't they tell us the right version in the first place, rather than changing the story every year?." This is a valid question generated by a common style of pedagogy. The principal justification for continued reference to the hydrogen atom is that the concepts and language used in the discussion of hydrogen are of great value in discussion of the behavior patterns of other atoms and molecules. The reason that the model for the hydrogen atom varies a t each reintroduction is that the nature of the derived correlation scheme will vary; a t any rate I think this should be the case. For example, a principal use of the ideas in most high school chemistry courses is to serve as a tool for discussion of the periodic properties of the elements whereas I suppose that'a principal burpose of most courses in elementary physical chemistry is to lay the basis for making quantitat:lvd predictions about the behavior of large molecules. For the first purpose an aesthetically acceptable modification of the Bohr atomic model is quite adequate. Quantitative work requires real wave functions, or at least some kind of parameterization of matrix elements. It appears to me that we may do students a disservice, not in changing the models, but in failing to identify the value of a particular version of the model in some kind of correlation process. Comparison of the correlation styles of organic and inorganic chemists is interesting. The basic objectives of education in the two fields should be similar and I believe that most inorganic chemists would say that establishing useful patterns of hehavior of pure and impure inorganic compounds is a principal object of their teaching just as I conceive it to he an object of teaching organic chemistry. If we accept this as a reasonable approximation, we have to he puzzled by the assertion that jnorganic chemists cannot teach organic chemistry and vlce versa. Although there are individual exceptions to this generalization, we must admit that there is some truth to the premise. We may also learn something of pedagogical value if we ask why the situation exists. Does the difference between organic and inorganic chemistry arise because there is a vast difference between the property ranges exhibited by organic and inorganic materials? I think not, although it probably seemed that way a hundred years ago when the differentiation between the two branches of chemistry began. The properties of sodium chloride, a "typical" inorganic compound, are certainly different from those of acetone, a "typical" organic compound. However, we have now acquired sufficient sophistication to realize that these two materials a r e h y no means typical of the large classes of materials to which they are assigned. Organic and inorganic compounds hoth show enormous ranges of physical and chemical proper-
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ties. It is true that no organic material is likely to become a candidate for use as a ceramic, hut this is also true of most inorganic substances. As we learn more and more about biological chemistry we come to realize that nature has not discriminated between organic and inorganic chemistry in the evolution of living systems. The continuity between the reaction chemistry of carbon compounds and that of phosphates, transition metallic elements, and so on has acquired a role in biochemistry which has been systematically denied by classical organic and inorganic chemists. On balance, I think that we are now at a point in chemical science where this separation loses more than it eains in the teachine of chemical science. ?he "organic-inorganicw dichotomy has been created by the evolution of different stvles of information processing. for purposes of pattern recognition. Basically this is because inoraanic chemistry started with sodium chloride and organic chemistry staked with acetone. The nature of the physical universe is such that the fields have really fused but many people are uncomfortable because of the historically based difference in styles. It is a curious fact that different people see different things when they look at the formula of hemoglobin. Some see the Fe's and remember the correlative route leading from the sodium chloride and others the C's, or the intersection of straight lines in the formula, and relate hemoglobin to acetone. Since neither sodium chloride nor acetone is a verv useful immediate model for hemoglobin, the whole process seems a hit ridiculous. However. the existing- correlations are better than none at all, and very few people would recommend that hemoglobin be considered by itself independent of any conceptual context. There might be some real merit in trying to begin a new system of chemical correlation beginning with hemoglobin. I doubt that this will be done because chemists would probably spend a century in debate as to whether hemoglobin or the nucleic acids would he the best starting point for the new system. However, it is easy to guess that any such exercise would not regenerate organic and inorganic chemistry in their present forms. 1 helieve something" of value can be learned from ~ - that ~ what has happened in the confluence of organic and inoreanic chemistrv. We certainlv learn that there is no sinale way of processing chemical information. Two systems have brought organic and inorganic chemists together in such areas as biochemistry and orgauometallic chemistry. Entrants from hoth sides can make real contributions and some useful cross fertilization is occurring, albeit more slowly than seems desirable. I also believe that we should give thought to the postulate that there should he other information processing systems, perhaps much more powerful than those that have been developed by the evolutionary process of the past 150 years. One matter that concerns me is the realization that heavy emphasis on certain "fundamentals" such as deduction of molecular structure from data for molecular composition and molecular weight has disappeared from courses in organic chemistry. As I said earlier, I believe this is appropriate. My question is, "How many other topics .in the course that I have just finished should be given similar treatment?." Surely some of the detailed discussions of reaction chemistry could he capsulized in much smaller packages and still leave students with knowledge of those subject areas as effective as they now have. One source of reluctance in doing this is the fact that I use well-studied reactions, such as nucleophilic aliphatic substitution, as a vehicle for developing useful quasitheoretical correlation methodology. This is a feature which I would like to preserve hut I could do so using some other group of reactions which are not now as ready to be summarized in small packages. An appropriate choice might he reactions or organometallic compounds containing atoms of the transition elements. This would effect a ~
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Volume 51, Number 9. September 1974 / 559
merger of the organic and inorganic systems in a currently attractive area since chemists from many traditional disciplines are now interested in the many catalytic processes involving such compounds. Even such a minor perturbation of the education process meets with a lot of skepticism. For example, I suspect that there are people who would maintain that there is a peculiar distortion of the minds of organic chemists which allows them to think effectively in terms of s and p atomic orbitals and molecular orbitals compounded from them, but completely excludes comprehension of d orbitals. I cannot accept this conclusion hecause I am old enough to remember when most organic chemists felt that orhitals of any kind were a mischievous device of sadistic physical chemists. Some of those same people have now developed great skill in propounding very complex arguments using orbital symmetry concepts. Over a rather brief period people have come to accept concepts which once seemed very foreign to them. Surely it can happen again so I believe that chemists in general probably underrate their competence to make major changes in their teaching practices. If a principal purpose in chemical education is to process information and fit it to useful patterns we should pay attention to the rapidly evolving field of information science. I do not claim to know the field, but I have heen learning something about it, and am impressed with the prospects. New, powerful methods of analysis are being developed. These will enable people to do many dimensional, nonlinear analyses in ways incredibly more effective than any we have now. Unfortunately, the expansively inclined information theorists tend to turn most of their attention to modeling complex biological and social systems. This is fine, hut it leaves unattended the potentially more manageable matrix of chemical information. This is a pity because one of our problems is that we already have far more chemical information than anyone knows how to manage. The digestion of current knowledge and evaluation of the pros-
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pects of proposed research for extending the power of the knowledge hank could probably he upgraded by use of techniques of information theorists. Fortunately, this is heainnina to happen even before I give my official permission. some inteiesting work is beginning i o appear, introducing the subject of "Pattern Recognition in Chemistry.'' Ohvio&lv it will hecome ~ossihle.bv shrewd use of computers, to look a t many variable problems in chemical reactivity and seek hidden correlative patterns. I can see, for example, that all of the work that I did some years ago seeking and interpreting linear free energy relationships was a very crude exercise in pattern recognition. Obviously, the linear analytical methods that I used so laboriously are now totally outdated. If I were to reenter the field using pattern recognition techniques, I could probably extract far richer results from old data and he much smarter in planning to gather new information. I occasionally encounter those who maintain that they will leave the field when chemistry becomes an information science. This is the old fear of man being swallowed by his computers. The computer is seen as destroying the individual genius that characterizes creative work in chemistry. I doubt that this will he true. If Leibig had been told of a day when elementary analysis would he mechanized and most structures assigned on the basis of nmr and mass spectrometry, he would prohahly have been repelled by the prospect of all the real chemistry being done by machines rather than by people. It, of course, turns out that chemists have been freed to do their creative work in areas which now seem far more significant than any which were accessible to Leihig. I predict that chemists in the future will look hack to the 1970's and wonder how those poor devils could have possibly been content with their plodding methods for seeking patterns in the dark with their eyes closed. Part of the responsihility of chemical educators in the 1970's should be to alert our students to the prospects and start them on their way with the conviction that they will surely look a t things differently than we now do.
