The problem doesn't seem to be how science is taught but what it seems to be. Many of the students argue that all of this effort in the teaching of science is being directed toward introducing the true meaning of science and its method to the nonscience student. At the same time, say these students, the scientist himself is incapable of any hut the emptiest platitudes when he strays from his own specialty. His statements are vague generalities: to render human nature more beautiful, nobler, and more harmonious; to assure the triumph of peace, liberty, and reason; to eliminate the cultural lag. At the same time, however, it is impossible to have confidence in men who lack the faculties of criticism, discrimination, judgment, and option. It may be that the scientist has opted for arrogance a t the expense of that other ingredient, humility. Perhaps it will be concluded that man must strive for more than Seahorg's Post Office, reclamation project, and a science laboratory as an integral part of every state. When the social sciences, the humanities, the heritage of man's spirit, and the flourishing state of Twentieth Century science all work together, only then will the imbalances of each one he corrected and the vigor of each enhanced. Science must address itself to the problems of society in ways other than mere statement of the second law of thermodynamics. Young scientists must be made to realize a h a t has been the philosophy and history of science, what science can do, how far it can lead us, and what it is that makes science a cultural force. The scientist must be involved and make the nonscientist aware of this involvement. One of the students quoted Joseph Wood Krutch who said, "(He) is willing to consider the possibility of man being saved from the present perilous state by philosophy, religion, sensibility, or anything that depends upon the free functioning of the human intellect and spirit. Rut (he) will not be saved by propaganda, manipulation, and conditioning. These latter techniques can only t.ransform us into well behaved puppets; that would not be salvation but thc damnation of an eternal death."
Chemical Transport and Zirconium
To the Editor: With reference to the recent article in THIS JOURNAL^ on "Chemical Transport Reactions" I would like to draw attention to a very recent paper2 which discusses the purification of zirconium by the Van Arkel filament method. Until recently the maximum observed in the rate of deposition of zirconium has been thought to be due to the formation of involatile lower iodides, which reduced the concentration of halogen in the gas phase, thus lowering the rate of deposition of metal via zirconium tetraiodide.
It now seems likely that the mechanism causing the maximum is a change in the pressure dependency of the iodine diffusion coefficient. At low temperatures the rate of metal deposition is proportional only to the pressure of iodine at the filament, but as the temperature rises, the rate becomes proportional to the total pressure +t the filament (iodine plus zirconium tetraiodide). This suggestion is important in that it uses a simple mass transfer explanation instead of a relatively complex chemical one, particularly since the conditions required to produce the lower iodides3 are far removed from those used in the Van Arkel process.
Negative Catalyst
T o the Editor: I n the July issue of THIS JOURNAL (45, 477, (1968)), J. A. Young and J. G. Malik, in an answer to a chemical query regarding the difference between a negative catalyst and an inhibitor, explain that "the negative catalyst would be like an inert substance, substantially ineffective." This conclusion of the aforesaid authors seems to be based upon the mechanistics of the action of a catalyst which they have invoked in order to differentiate between a (positive) catalyst and a negative catalyst. Thus they conclude that "a negative catalyst would be a substance which when present in a reacting system provided a new path for the formation of products from reactants, but which path has a higher energy of activation than the energy of activation for the reaction mechanism which takes place between and among the reactants alone. So a negative catalyst would not slow down a reaction; the reactants would merely react to form products in the same manner, in the presence or absence of such a negative catalyst." Although there seems to be no inconsistency in the arguments of Young and Malik, their mechanistic (and not the prevailing phenomenological) approach is liable to cause some confusion. For example, according to Paul H. Emmett ["Encyclopedia in Chemistry" (2nd ed.), Editors: CLARK,GEORGEL., AND HAWLY,GESSNER G., Reinhold Publishing Gorp., New York, 1966, p. 1871 "One common theory of the action of negative catalysts is that they combine with and remove from the system traces of positive catalysts, or they combine with intermediates in a chain reaction in such a way as to break the reaction chain" which will obviously result in the retardation of the reaction. Identical views have been expressed by E. Abel ["Proceedings of the International Congress on CataVolume 46, Number 3, March 1969
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lysis" Editor: FARKAS, ADELBERT, Philadelphia, Pennsylvania, 1956, Academic Press Inc., New York, 1957, p. 3301 and Edward L. King ["Catalysis" Editor: EMMETT, PAULH., Reinhold Publishing Corp., New York, 1955, Vol. 2, p: 4471. The reason for this discrepancy seems to be quite apparent. A negative catalyst is generally considered to be a substance that acts opposite to a (positive) catalyst; Young and Malik, however, consider the mode of action of a negative catalyst in providing an alternate path to the reaction with a higher activation energy (in cont,rast to a catalyst that provides an alternate path to the reaction with a lower activation energy). Abel, Emmett, and King, on the other hand, consider the mode of action of a negative catalyst to slow down the reaction irrespective of the mechanism involved in doing so. Also if we agree to the view expressed by Young and Malik, it is difficult to think of a mcchanism by which a negative catalyst can provide an alternate path to a reaction with a higher energy of activation. HAKAM SINGH K. L. MITTAL U X I V E R ~ TOFY SOUTHERN CALIFORNIA Los ANGELES,90007
T o the Editor: The point of controversy expressed by Professors Singh and Mittal seems to me to be philosophical-and worth further comment. Semantically, it hinges upon the significance of the word, negative. Thus, if we define a catalyst as a substance which by its action provides a reaction path of lower activation energy, then it is reasonable to define a negative catalyst oppositely, in terms that describe a reaction path of higher activation energy. And, as Professor Mittal says, "it is difficult to think of (such) a mechanism." Therefore, defined in this way, negative catalysts do not exist, effectively. On the other hand, if we define a catalyst as a substance which promotes the rate of a reaction, with respect to specified products, then it is reasonable to define a negative catalyst oppositely, as a substance which retards the rate of production of those products. This is substantially Professors Singh and Mittal's position; and, given their premise-definition, I agree. However, it seems to me to be proper to define anything in terms of its essence, rather than operationally, whenever this is possible. An operational definition is indeed useful, but always restricted to a specific (from which it derives its utility). So, I prefer to retain my position on this question. I hope that this further discussion will clarify the issue. Too often, teachers tell students that a negative catalyst is a substance which "raises the energy of activation," and Professors Singh and Mittal and I do all agree that such a statement is preposterous.
Uncertainty [Principle]
T o the Editor: My compliments to Hutchinson [J. CHEM.EDUC.,45, 600 (1968)l for his article on the relationship of science and scientific education to the world around us. I fnlly support the statement that abstraction readily transforms from servant to master [because] we don't fnlly accept the limitation of an abstraction. But can we get a deeper insight into this problem? Is it probable that it is of vital importance to human beings to have a feeling of an unambiguous orientation, and that because of this we often deny the limitation of an abstraction? I guess there must be something to this because many great scientists appear to evade the problem. I am often surprised at the random mixing of "interaction'' and "no interaction" in science. This erratic mixing seems to be generally accepted. An example: An interaction between elements (components) always appears to involve the impossibility of measuring one or more qualities of an element. Nevertheless we say that elements (atoms) interact, and that (at the same time) each element has one or more measurable qualities (a mass, a charge, etc.). This appears to be contrary to the laws of logic. We make trouble by operating (at the same time) with entirety (interaction) and "real" [incorruptible] individual particles. Although this inconsistency appears to lead to great difficultiesin communication (example: thermodynamics), and also seems to make it easy for men of fashion to "take over" more and more of scientific education, the major contributors to science seem to avoid the problem. Why? My explanation: Nearly all of us feel, that something important is lost, if we obey [only] the laws of thought. But what do we lose? By obeying the laws of thought, and by accepting, for example, that our moon, our earth, and our atoms interact, it is difficult to avoid relating their "qualities" to experimental operations. In fact, a reasonable communication in these and similar cases seems to be possible only by relating qualities to operations; we cannot retain the "well known" qualities of individual elements, e.g., our "familiar" [unaltered] atoms. I n this way, we lose images which we have had for centuries. I n their place we get operationally defined qualities (e.g., the operational definition of pH). Since these are related to experimental operations, limitation of the definitions may be expected. Is this too much to human beings to see beyond these limitations? Perhaps this also leads to that which we no more can state, i.e., that we are free, and that we (at the same time) interact with our surroundings? I t appears to be of fundamental importance to elucidate these difficulties. Is it possible to remove them? Have we to accept that even in science feelings are prior to reasoning? Is this the "real" hindrance to more profound understanding of the scientific language, and to a deeper insight into other problems, which are important to all of us?? BJORNBERGTHORSSON THETECHNICAL UNIVERSITY OF DENMARK COPENHAGEN
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Journal of Chemical Education
