mnething new from the bwt
Edited by: JOSEPH S. SCHMUCKLER Chalrman of Science Education Temple Unwerslty 345 Rmer Hall Phdadelphla, PA 19122
Molecular Structure
Molecular Geometrv
"Size of a Molecule-or What's i n a Shape?" Michael J. Demchik, and Virginia C. Demchik, J. CHEM. EDUC.,48, [ l l ] , 770-771 (November 1971).
"Molecular Architecture," L. Carroll King, T h e Science Teacher, 27-34 (September 1966).
The authors of the article feel that the accuracy sacrificed in the lahoratorv orocedures shown in several contemoorarv hieh school lab level." The experimental procedure suggested by the Demchiks first determines V = *r2/h of a monolayer af oleicaeid in alcohol on water. Then the procedure is repeated using a very dilute solution of HC1 to give the second dimension. The method of calculation is completely outlined for the teacher.
One of the mare useful articles to he published on molecular geometry was done by Carroll King, who was one of the major contributors to chemical education in the CHEMS program. King presents excellent tables for different classification schemes. He develops an historical approach that can refresh or initially teach interesting information related to structural theory. He further states a set of postulates as the basis of a theory of molecular architecture. King describes the use of a model, easily constructed, that this reviewer has used successfullysince he fint learned to use it as a student in King's classes. It was good to meet an old friend and teacher, and to bring his work to the fore for you, the reader.
"Left-handed a n d Right-handed Molecules-Louis Pasteur's Resolution of Racemic Acid," George P. Kauffman, Chemist r y , 50 [3], 14-18, (April 1977). In the form of a dialogue between Dr. Namffuak B. Egroeg (Dr. George Kauffman spelled backwards) and a young student, Albert Chemist, skillfully tells the story of the history of the work leading up to Pasteur's workon optical activity of molecules. Pasteur's work with salts of dextro- and levo-tartrate is easily duplicatable and Kauffman gives a reference to a lab experiment he and Meyers wrote-"The Resolution of Racemic Acid: A Classical Stereochemical-Experiment for the Undergraduate Labratmy," J. CHEM.EDUC., 52,777 (1975). This article and the associated lab experiment are excellent references that will allow students to repeat the work of a great scientist--in this case. Pasteur. It should help give students the feeling that science is a human endeavor.
Aufbau Principle "Atomic 'Cities;' "Neil Radtke, T h e Science Teacher, 45 [I], 3 5 (January 1978).
In an attempt to introduce students to atomic structure and the Aufoau principle, Radtke uses a familiar analogy. People are electrons, houses are orhitals, and there are four types of houses, neighborhoods are energy levels, and the city is the atom
Chemical Forces "A Classical Electrostatic View of Chemical Forces," H. H. Jaffe, J. CHEM. EDUC., 40 [12], 649-651 (December 1963). Jaffe reviews the different types of forces in the formation of chemical comoounds usine a classical electrostatic aooroach. He discusses ionic crystals, molecular crystals, extended lattice crystals, and metallic crystals. He relates his treatment to quantum meehanies.
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Growing Crystals "Thin-Layer Crystal Growing," Eugenia Keller, Chemistry, 51 [7],29-30, (September 1978). "Crvstals are solids comoosed of ions. atoms. or molecules arraneed in rematine three-dimensional oatterns called unit cells. Onlv 14 are six such crystal systems." Keller, in this "Lab Bench," describes in good detail procedures for growing and observing crystal growth. She suggests methods involving the microscope and camera. This reviewer has used techniques described bv Keller dona with a ohotomierooroiector (and ~olarizina film) to allow a whole cl&s to observe crysth Gowth.
This feature includes annotations of articles from previous issues of the JOURNAL. and other science teaching journals. Topics will be presented in the issue prior to when the topic is taught in a typical high school CurriCuiUm. . J o s e ~ hS. Schmuckier is currentlv the chairman of the Department of ~duc&on and a Professor of Chemistry at Temple University. He was formerly a chemistry teacher at Haverford Townshio Senior Hioh School in Pennsvlvania where he taught for 15 years. Or. Schmuckler received his BS degree in 1952, MS degree in 1954, and PhD in 1966 from the University of Pennsylvania. His numerous awards in recoanition of his dedication toteachinoand
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awards. He is one d the c+authors to the Silver Burden Com~anvDrooram n cnemisly and bas an a r q m pan clpant and contr out& lome &EM S14f Program tor Hogn Scnooi Cnem slry: he has p.o shedartcics n purna s n scence ana sc ence earcat.on
Volume 58
Number 11
November 1981
959
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