Grade 5-7-This colorful, hands-on guide introduces a number of different branches of science. The projects range from the fairly simple (clay pot wind chimes, pinwheel helicopter) to the complex (model grist mill, powered model boats, xylophone). The detailed instructions include a list of materials needed and explanatory line drawings. The activities are divided into four sections: air, water, earth, and fire. Extensive informational sidebars explain the principles involved. Attractive, full-color photographs show a variety of actively involved, enthusiastic kids. However, only 8 of the 50 projects listed in the contents have a "needs adult help" symbol