the presence of empty orbitals available for bonding (while 2d orhitals do not exist, 3d orhitals are present in third- and later-period elements).
The Tao ol Chemistry
To the Editor: As one who has used Taoist thought and its concomitant symbol of the T'ai Chi in my teaching for more than two decades (1-3), I was particularly gratified to read E. R. Scerri's excellent article "The Tao of Chemistry" [1986,63, 1061. As Oriental ideas are incorporated into Occidental thought and as the proportion of Oriental students in our chemistry classes increases, the use of bhese Eastern concepts has become a striking and effective way of presenting fundamental scientific conceots as well as of inteeratine Eastern thought into western science as advocated,>or examole, hv the Chinese-American biochemist R. G. H. Siu (4).
The familiar T'ai Chi symbol, which appears on the South Korean flag and is representative of the ultimate unity, consists of a circle divided into two complementary teardrops-one white (Yang, positive, active, masculine) and one black (Yin, negative, passive, feminine). The sigmoid
Thirty spokes share the wheel's hub; It is the center hole that makes it useful. Shape clay into a vessel; It is the space within that makes it useful Cul dour5 and wi!nduws fur 3 r w m ; I t is the holes uhich make it u+tful. 'I'herrt'orr profit culnrr trom ahat is there; ~sefulnessfrornwhat is not there (7). Literature Cited
1. Kauffman, G. B. "An Introduction to the Art ofSeientifie &search: A Porsond view", 2. 3.
4. 5.
6. 7.
The 1973 California State Uniwraity and Colleges Outstanding Profesror Award Lecture; excerpted in J. Coll. Sri. Teaching 1973.3. 124. Ksuffman,G.B. Ann. Sci. 1979,36,395. Kauffman, G. B.J. Coll. Sci. Teaching 1980, lo, 23. Siu, R. G. H. The Too of Science: An Essoy on Weafsm Knvlvl~dgeand Eastern Wisdom; M.I.T.: Cambridge, MA. 1957. Feng, G.-F.; Kirk, J. Tni Chi-A way of Centering and I Ching; COII~FP: N ~ W~ o r k , 1970. . ...,n R.. Capra, F. The Too of Physics: Shamhhala: Berkeley, CA, 1875;pp EM.160. Tsu, Lao. Too Te Ching: Feng. G-F.; English, J.. Trans.: Vinfege: New Yolk. 1972;
George B. Kauffman
California State University. Fresno Fresna, CA 93740 Center for the History of Chemistry Resources
To the Editor:
line bisecting the circle conveys a sense of dynamic change and perpetual motion, which unifies what we in the West dualistiially consider as polar opposing forces but which the Taoist considers as harmonious complementary forces, a viewpoint reinforced by the dark spot in the light area and the light spot in the dark area. According to Jerome Kirk, the T'ai Chi can he regarded "as a kind of mathematical model of the universe [and] a fruitful conventional representation of reality, as are the equations of physics and chemistry . . . . . . . [it] served very much the same function in Chinese culture and science as has mathematics in Western science since the Renaissance" (5). Thus it is not surprising that Niels Bohr, who introduced the concept of complementarity to reconcile the wave and particle Giews of the electron, chose the T'ai Chi motif for his coat of arms with the inscription Contraria sunt cornplementa (Opposites are complementary) (6). As Linnaeus aptly observed, Natura non facit saltum (Nature makes no leap). The T'ai Chi symbol with its rejection of oooosites in favor of an all-embracine continuitv can be used ;;emphasize the fact that electrovaknt (100%ionic, 0%covalent) and covalent (100%covalent, 0% ionic) bonding are merely extreme endpoints on a continuum based on electroneaativitv differences between atoms (Faians's rules and the transitibn between ionic and covalent bonding). The resourceful and imaginative instructor will find numerous occasions on which the Tao and T'ai Chi can be used to drive home a chemical concept in a vivid, easily remembered manner. As a case in ooint., I use Lao Tsu's auotation in praise of emptiness to reinforce the important fact that third- and later-period elements can expand their octets and form more than four covalent bonds while the introductory (second-period) elements are limited to a covalency of four. This is due not to the presence of additional electrons but to
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188
Journal of Chemical Education
T o assist teachers interested in the history of chemistry, chemical eneineerine. and the chemical process industries. I would like to take this opportunity to liit for your readersa few of the resources availahle from the Center for the History of Chemistry (CHOC). CHOC's traveling exhibits are all accompanied by catalogs with the full text and many i~lustrationsisuitable for use as teaching guides or reading assignments. Now available are Joseph Priestley: Enlightened Chemist (1983), Scaling Up: Science, Engineering, and the American Chemical Industry (19841, and Polymers & People: An Informal History (1986). In addition to the exhibit catalogs, our publications include archival guides and introductions to the literature. Most useful for teachers are C o r ~ o r a t eHistorv and the . .
of Large ~ o l e i u l e (1986). s Our newsletter, CHOC News, provides information on the history of chemistry, chemical engineering, and the chemical process industries, including brief surveys of a variety of topics, book reviews, and notices of new hooks. CHOC News is availahle at no charge to individuals, as is a full publications list and additional information, by writing to CHOC Publications, Room BV, 215 South 34th Street, Philadelohia. PA 19104. CHOC itself holds a wealth of material-including photoe"r a.~ h and s oral histories-on topics ranaine - - from alchemy to biotechnology. We welcome inquiries and visits from science teachers. Bruce V. Lewenstein
Public Education Officer Center for History of Chemistry 215 South 34th Street Philadelphia, PA 19104
