Gr 2–5—This series urges budding experimenters to enjoy activities in physics, biology, observational astronomy, and even psychology. The approach is somewhat free form, with the overall design and step-by-step instructions tending to be sketchy. The materials are easy to find and constructions simple to build (with some major exceptions, such as colored light bulbs and diffraction gratings in Color, and a squirrel-proof bird feeder in Animals—good luck with that!). Schematic diagrams with each experiment are often very helpful in interpreting the directions. There is plenty of both easy and hard-won satisfaction to be earned from this offering, with an average of nine to 12 numbered activities, suggestions for multiple experiments, and inset lists of ideas for science fair-worthy projects. VERDICT Good choices for classroom collections, likely to please informal experimenters more than those who require rigorous direction.