Gr 3-5-The first two chapters in each title are nearly identical, although there are occasional changes in the photographs and the examples used to define the concepts work" and machines. Subsequent chapters feature a specific simple machine and provide directions for basic experiments that children can accomplish, with the occasional exception, on their own, using easily located items. Final chapters explain that simple machines are everywhere. On the whole, the texts provide clear explanations and the experiments add a significant degree of interest. The color photographs are crisp and clear, as are the diagrams. Serviceable additions where the topics are a part of the curriculum. (c) Copyright 2011. Library Journals LLC, a wholly owned subsidiary of Media Source, Inc. No redistribution permitted.