Simple Electrical Devices

School Library Journal

Gr 7-10 The same basic concepts of electromagnetism are presented here from the standpoint of their historical development as are introduced from the view of everyday experience in The First Book of Electricity (Watts, 1977) by Sam and Beryl Epstein. Both are for beginners, introducing fundamental relationships and stopping short of presenting strict mathematical formulas. Gutnik's chronological perspective on magnetism, static electricity, and early electrical devices (leyden jar, voltaic pile) leads into a discussion of electric circuits, both series and parallel. One outstanding feature of this primer is its style of smoothly integrating text, projects, and illustrations so that they all carry the discussion forward without interrupting each other. Almost all of the many projects can be completed with easily obtainable equipment and relate directly to the concepts presented. The section on electric cells and batteries includes projects on series and parallel circuits, as well as the construction of a simple galvanometer. The incandescent light is explained, and students learn how to fashion their own working model. Two projects demonstrate how to devise two-way telephones, and although they both work on non-electrical principles, they do offer some fun. The concluding chapter on electronic devices follows the progression from vacuum tubes to solid state transistors and microchips. Extensive glossary. Dennis Ford, Canandaigua Junior Academy Lib . , N.Y.