provocative opinion Chemical Education: An Obsession with Content Mawin Gold California State University, Chlco, CA 95929 It is not my novel discovery that college chemistry texts for science majors have grown to he so massive as to overwhelmall hut the best students. Chemicaleducators have for the oast 10 or so vears written about the "knowledee exdosio;", the transition of General Chem into P. he& or "haby" P. Chem, the gradual squeezing out of descriptive chem from the first-year course, etc. I t is hard to say how much agreement there is on this subject. Judging from the articles published in this Journal, one might conclude that the ahove beliefs are widespread; however, those who are satisfied with the status quo don't tend to write about it. Regardless of who thinks what, the reality is that nothing much is changing, i.e., the status quo continues to prevail. This is clear from several observations: college texts continue to he enormous and startlingly similar; bigh school texts continue to resemble modified college texts; and, a t least in California. colleee chemistrv instructors have clearlv sent the message to ihe bigh s c ~ o o l sregarding preparation for college chemistrv: the messaee. embodied in a recent report, is that we shall Lave "busin& as usual". But more on this later. Content vs. Cognltlon I believe that the fundamental problem in chemistry instruction (both high school and college) is an obsession with content. A corollary is that logical thinking is given little attention, either because it is (1)deemed less important, (2) assumed to be "included" in the chemistry content, or (3) there is simnlv no time. A recent article hv Kraicik and Yagerl made'some excellent points about thissubject and is "must" readine for all chemical educators. Some (not all) of these points may he summed up as follows: 1. Regular (not high ability) students,would profit more if the high
school chem course were aimed at developing intellectual and learning skills such as reading, writing, proportional reasoning, eambinatarial reasoning, deductive logic, making sense of data, drawing inferences, using mathematical skills, and using information and evidence to make decisions. 2. In order to give more time to the above, the number of topics covered must he drastically reduced (my emphasis). 3. Evidence indicates that college instructors would rather have high school students develop the skills in (1) than learn such tradition concepts as electron structures, molecular shapes, etc. After 24 years of teaching college-level general chemistry for science majors, Ican only second the ahove andsay, "well spoken!" My feeling is that most students deal with most college chemistry topics on a recall or rote basis. This is not surprising; if the groundwork for using intellectual skills has not been laid, then rote memory must be relied upon. This is especially true if the student is expected to deal with the large number of topics typically found in high school texts. Add to this the fact that meaningful science instruction is virtually absent in grades K-8, and we should not be sur780
Journal of Chemical Education
prised that college students find general chemisGy so difficult. I am one of those college instructors who doesn't want his students to he inundated by an unmanageable quantity of chemical content that characterizes the traditional high school course. If teachers believe that this is what we in the colleges "want", they will feel obliged to cover this topic and that topic, and that other topic too because i t is so "important" (and oh yes, we can't omit this one because i t is also so important, and they should "know" about this too, and so on-we in the colleges do the very same thing). But the high school teachers are carrying out what they perceive to he their mission, and their mission is clearly spelled out in the texts that they use and in the expectations that we in the colleges talk about. In other words, chemical educators in the colleges are calling the shots, and they need to he good ones. I think we are off the mark. Some Thlngs I Would Like My Students To LearnlNot Learn In High School Chemlstry To he a hit more specific, let me mention just a few things that I don't want mv students to deal with in high school chemistry, and a few things that I do wish they would deal with. Don't: learn to solve gas law problems using the equation P V = nRT. Plugging into an equation that has been memorized has little or no pedagogical value. Whether or not the student gets the right answer is unrelated to hisher ability to conceptualize P V T relations in gases. Don't: memorize quantum numbers, orbital shapes and nomenclature, etc. Such concepts are far too abstract for this level, and, furthermore, there is little or no opportunity in the rest of the course (even in college) to build upon this material. In other words, there is no logical development of ideas, no relating of concepts. The college science majors can deal with these subjects later on; there will he time. The others gain nothing at all. Do: Gach about>^^ relations in gases from a framework that involves physical intuition and spatial concepts. As an example, consider solving this problem: Find the density of oxygen gas at 3.0 atm and 400 K. Letting n = g/ MW and plugging into the ideal gas equation we have g/V = P X MWIRT = 3.0 X 32.010.082 X 400 = 2.9 g L
a correct solution that conveys no feeling about the effect of Por T on gas density. On the other hand, if we remind studenw that st STI', the density of oxygen = R'LO g122.4 I., and since \'is inversely proportional to Pand directly proportional to T , then the density is 32.0 g ~ ( 2 2 . x 4 1.013.0 x 4 ~ 1 2 1 3=) 2.9 ~
gn.
' Krajcik. J. S.; Yager. R. E. J. Chem. Educ. 1987, 8 4 . 4 3 3 .
From a pedagogical point of view, the second approach is much more sat6f;ing. ft deals with density as a concept,one which is more difficult for students than we sometimes realize. Wecan ask thestudent to"pictureWwhat happens to the v & n e of the mole a t S T P as
