Editorially speaking - Journal of Chemical Education (ACS Publications)

Discusses common "Santa Claus concepts" or misconceptions in introductory chemistry. Keywords (Audience):. High School / Introductory Chemistry. Keywo...
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EDITORIALLY S P E A K I N G

Santa Claus may seem to be an odd topic for remarks in September, but here he is. Let's see what happens to our ideas about the old boy in the white beard and red suit during the two decades of our lives from four t,o t,went,y-four; then let's see what, happens to some of the ideas our students get about chemical concepts during about twenty weeks of their early lives as chemists. To the toddler, Santa is very real. He does not even need definition; he is. I t does not occur to the small child to wonder about t,he relationship bet,ween Santa's girth and the chimney dimensions. Not even the mult,iplicity of impersonations clouds the simple image. Then sophistication sets in. The first grader knows, and he can be bombadc in proving, that "there ain't, no Santy Claus." Adolearenee calms him down on the subject, but all his very logical use of information increases his disdain of the earlier fantasy. Then finally as an adult he becomes a parent. When a new generation of toddlers appears, Santa reemerges as a mighty, profound idea. The famous letter to Virginia is not juvenile literature. I t speaks to the mature, experienced person who reads more than a definition in so many words. Santa Claus is an idea, not a person. So it is, by analogy, with many of the ideasehemistry teachers will be trying to plant in youngminds, ~t~arting in September. How many "Santa Claus concepts" there are in introductory chemistry! Acids and bases, oxidation and reduction, electronic structure, tit,ration and equivalence, and equivalent weight are examples. Let us examine a few. Earliest definitions should make sense to the inexperienced. The first acid a neophyte chemist knows about is something which turns litmus red and neut.ralizes an hydroxide. So with t~hebase a t the "Santais-a-jolly-man" level. It does something: it neutralizes an acid. But if "base" means "OH somewhere

in the formula," disillusionment is sure to set in when he finds that CaO, Na,COi, and even acetate ion will neutralize acids. Then he is in the crucial "Thereain't-no-Santa Claus" stage. He needs to have some broader view to make sense out of a lot of additional information. I t is not enough merely to shatter his earlier image; a replacement is needed. The BronstedLowry conceptual scheme for acid-base phenomena correlates even the subtler observations such as amphoterism of some hydrated cations with his increasingly more sophisticated appreciation of structural features. Finally, the mature adult view of "Santa" is the Lewis picture which makes even the Bronsted acids and bases appear to be simplified special cases of a far more inclusive pattern of phenomena. The Santa parallel also fits the process of developing a full appreciation of redox. "Combination with oxygen" for oxidation can last only a short time. Soon "increase in positive oxidation number" is needed as a replacement. "Loss of electrons" comes along next. Finally an appreciation of t,he distinction between onthe-paper balancing of an equation and the in-thebeaker mechanism of the reactioii signifies having attained adulthood. The analogy points up some important warnings for the teacher. Allowing a child to hold on to juvenile views may be comfortable but is ludicrous. Almost equally silly is an attempt to force a child's mind to appreciate an adult idea. Balanced between is a gradual growt,h in presentation from the simple to the complex, from the isolated to the all-inclusive. So it is with the beginning chemistry student and the major concepts of chemistry. Furthermore, once the growt,h has started and is sympathetically nurtured, it can be gratifyingly rapid. Santa Claus in September? All year long, too!

Volume 38, Number

9, September 1967

/ 433