in this issue Improving Classroom Performance The underlying assumption of every article in the Journal is that it will in some way improve classroom performan-ither by the teacher or by his or her students. Diverse articles can fulfill this expectation: everything from reviews of the latest research that will add interest and currencv to a lecture to snecific discussions of how to teach difficit concepts. The iormer is exemplified by the article on the AIDS virus by Volker (page 3). With a topic that is right out of the evening news, this review article shows how research into the biochemistry of the virus may lead to a method for controling its growth and maturation. This research is particularly interesting because it both illustrates some basic enzyme chemistry and also may lead to a cure for those alreadv infected with the disease. Since so many people are infeited with the AIDS virus worldwide, this article will he of interest to anyone trying to keep up with this timely subject. A less dramatic hut equally interesting review is Dbawale's summary (page 12) of the many uses of the thiosulfate ion in medicine and industry. This information should enliven any discussion of oxoanion chemistry. The problem of finding better ways to present classroom materkd can be approaihed in several ways. One can look at the material itself to see if concepts and terminology can be sim~lifiedor streamlined. One can find new wavs of oresenting the traditional concepts in classroom presentations. And one can lwk at how students actually think and learn and modify content, approach, and, possibly, expectations to better fit reality. Several articles in this issue provide a new way of Iwking at chemical concepts. Imyanitov (page 14) examines classification of chemical reactions and finds that, in the various subdiscinlines. similar reactions are oiten classified differently- for ekample, the terms "substitution", "transfer", and "oxidation-reduction" could each be used for chemically equivalent reactions, depending on the chemist describing them. He suwests that this unnecessarily confuses &dents and crezes an artificial separation in chemistry. Dumon, Lichanot, and Poquet (page 29) tackle a similar overabundance of terminology in kinetics. They suggest that using the reaction advancement
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Journal of Chemical Education
ratio x instead of the extent of reaction 6 will simplify and unify the description of a chemical reaction and avoid student confusion. The more theoretical concepts of physical chemistry are particularly difficult for students to grasp, and teachers continue to explore new ways to presenting them. BenZvi, Silberstein, and Mamlok (page 31) discovered that the traditional way of introducing heat concepts resulted in good performance on calculation problems on standardized tests, but when they tested for undentanding they found manv students still could not distineuish between such basicconcepts as "heat" and "temperaturem.They then developed a whole new way of introducing thermodynamics and found a vast improvement in student performance. Ludwig (page 28) offers a way of presenting the Heisenberg and deBmglie principles so that students have more insieht into wave-narticle dualitv and how the two principles relate. Developing successful new approaches like those above often is denendent on understanding how neode develo~ mentally ;nd how they learn new c>ncep
