Describes the "coordinated polymeric model," which yields more accurate energy calculations than the "ionic model" for compounds which exhibit considerable covalency. The dichotomy between ionic and covalent bonding is thus largely broken down for solids which are nonmolecular in the crystalline state. (MLH)

Discusses the importance and difficulties of teaching basic quantum theory. Presents a discussion of wave-particle duality, indeterminacy, the nature of a quantized state of a system, and the exclusion principle. (MLH)

Presents a summary and comparison of various views on the concepts of mass and weight. Includes a consideration of gravitational force in an inertial system and apparent gravitational force on a rotating earth. Discusses the units and methods for measuring mass and weight. (GS)

Outlines the basic engine design and nomenclature, develops some relations between the state parameters of the rubber-band system, defines engine efficiency, and compares the Archibald engine with the Carnot engine. (GS)

Describes the construction, function, and applications of heat pipes. Suggests using the heat pipe to teach principles related to heat transfer and gives sources for obtaining instructional kits for this purpose. (GS)

This manual provides numerous experiments for college-level microbiology students illustrating the basic principles in phage, tissue culture, and animal virology. (CS)

The goal of this study was to provide information and ideas that would contribute to the improvement of elementary school science facilities. Specific purposes were to (1) examine existing facilities in a group of selected schools, (2) arrange data so that others might use it to evaluate their facilities, (3) prepare a guide that could be used in…

In this volume there are reviews of books, children's books, and films, as well as a comprehensive list of book and film reviewers. Trade books, textbooks, and reference books are reviewed. Books and films which are intended for students in elementary and secondary school and in the first two years of college are reviewed. All instructional…

Equipment needed for teaching the New South Wales (Australia) Natural Science course in grades 3-6 is listed. A general list needed for all grades is supplemented by lists of materials needed specifically for each grade. Whenever possible materials available from students' homes are listed, and many examples of improvised equipment are given.…

Presents data on the readability of periodicals and textbooks commonly used by students studying school agriculture. (GS)

Elodea is an attractive plant, well suited for classroom aquaria. This article describes the collection, care, and maintenance of this plant. (BB)

A description and plans for a working model to demonstrate rotational slope failure are presented. (MR)

Describes a method of producing photographs of X-ray diffraction patterns using Kodak X-ray film. (SL)