Gr 7 Up-Sonneborn covers gravitational force, electromagnetic force, electromagnetism at work, and strong and weak forces. The writing is clear and easy to read. A final chapter discusses the unification of forces. Viegas begins by explaining kinetic and potential energy and the history of their discoveries. Mechanical energy, momentum, and the laws of energy are also presented. Willett introduces readers to the nature of light and of the atom. The ultraviolet catastrophe, the photoelectric effect, and line spectra are also addressed. These titles provide basic introductions to their respective topics and are especially useful for reluctant readers or those new to the topics. The layouts are open and appealing and include well-captioned photographs and simple diagrams.-Maren Ostergard, Bellevue Regional Library, WA Copyright 2005 Reed Business Information.