mething new from the pwt Solids "The Teaching of Crystal Geometry in t h e Introductory Course," R. L. Livingston, J. CHEM. EDUC., 44, [7], 367-381 (1967). Crystal structure has become an important topic in general chemistry courses. In his article, Livingston outlines an approach to the teaching of crystal structure a t the elementary level. He considers only a few of the simplest types of crystals. He introduces terminuk~gy first by constructing a one-dimensional lattice, then a two, and, finally, a three-dimensional lattice. As his example, the author presents the cubic crvatal. both the face-centered and the body-centered forms.
JOSEPH
Edited by: S. SCHMUCKLER
Chairman of Science Education Temple University 345 Ritler Hall Philadelphia. PA 19122
several tubes containing just the mercury columns be prepared in advance to save time during the actual demonstration with the class.
Evaporation Rate "Evaporation Rate: A Beginning Chemistry Experiment," H. I. Feinstein a n d C. Walters, J. CHEM. EDUC.,49, [Z], 135 (1972).
.~
.
This exneriment is suitable for a chemistrv student.. earl" in his or her experience in chemistry. "The procedure described for determining evaporation rate of a solvent requires only the simplest of apparatus and techniques, a rapid weighing balance, and some common solvents." ~
~
the notation used in describing crystals A good follow-up demonstration of lowest energy configuration i n crystal form is given in t h e article: "Dynamic Model of a Crystal Lattice," R o b e r t T h e Science Teacher, February 1975, p. 63.
E. Burr,
Phase Change "Freezing Curves for Salol (Phenyl Salicylate)," P a t t y Laswick, J. CHEM. EDUC., 49, [a], 537 (1972).
H.
Laswick has developed an interesting experiment which introduces the thermodynamics of phase transition. The title material which freezes a t 40-43-C. can be used easily and safely with a warm water bath. In addition, Laswick describes other interesting phenomena associated with the experiment such as supercoolingand the observing of "beautiful" crystal growth using a microscope.
Electrolytic Conductivity "Electrolytic Conductivity Apparatus," Joseph S. Schmuckler a n d Robert C. Schenck, J. CHEM. EDUC., 33, [lo], 506 (1956). "A simple, effective apparatus which demonstrates the conductivity of salts when fused in the solid state, in solution, and in varying degree of dilution."
A "Take-Home" Experiment "Which Freezes Faster, H o t o r Cold Water?" R o b e r t James, T h e Science Teacher, 39 ( J a n u a r y 1977).
K.
A clue to the answer lies in the variables. Herein is an excellent "take-home" experiment. Anticipate good classroom discussion!
Vapor Pressure "Vapor Pressure Determination; An Elementary Experiment," E d w a r d T. Radley, J. CHEM. EDUC.,37, [I], 35 (1960). "The approximate vapor pressure of low bailing liquids, such as benzene, chloroform, ethylacetate, and carbon tetrachloride may be estimated bv measurine the increase in leneth of an air column
than the cross section, the volume of a trapped gaseous column is proportional to its length. The procedure described by Radley is fairly simple to follow and the mathematics associated with the suggested calculations are well within the levelof a highschoolor freshman college chemistry course. The experiment can be done as a demonstration using an overhead projector and a clear plastic rule. Data can then be obtained by the whole class a t once. This recommendation is made since the chemicals cited by Radley are considered potentially hazardous by today's standards, and it is felt that Radley's work should not be disregarded. In a well-ventillated area, there should be no problem in using the experiment as a lecture-demonstration. I t is further suggested that 62 / Journal of Chemical Education
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 l o when the topic is taught in a typical high school c~rriCuIum. Joseph S. Schmuckler is currently me chairman of the Department of Education and a Professor of Chemistry at Temple University. He was formerly a chemislry teacher at Haverford Township Senior High School in Pennsylvania where he taught for 15 years. Dr. Schmuckler received his BS degree in 1952. MS degree in 1954. and PhD in 1968 from the University of Pennsylvania. His numerous awards in recognition of his dedication to teaching and chemical education include his receiptof the Amwican Chemiwl Society James Bryant Conant Award in High School Chemishy Teaching in 1968. That year he also received the MCA and Chemical industries Council awards. He is one of the coauthors to the Silver Butdetl Company program in chemistry and was an original participant and contributw tothe CHEM Study Program for High School Chemistry; he has published articles in journals in science and science education.
a
LA
