Gr 2-4-A collection of quick, simple projects that use materials most kids will have around the house. Grouped into such subject areas as gravity, water, and light, most have just a few steps to follow. Instructions, illustrated by black-and-white drawings, are easy to understand and always note when adult help is needed. Each procedure is followed by an explanation of what should have happened and why. At times these explanations involve concepts that children might not easily grasp from the experiment alone. A description of light rays and focal points, for instance, is hard to follow without elaboration or diagrams. In another case, molecules are introduced as ``...the smallest particles of a substance that can exist on their own,'' which is accurate, but not the clearest way to describe them. Some activities are so predictable that reading about them can substitute for performing them. Other projects are more intriguing, such as using oil, water, and sunshine to make a rainbow, or creating a simple sand clock. The book is not terrifically exciting; its strength is that youngsters will be able to use it successfully on their own, and in many cases will learn a bit about science in the process.-Steven Engelfried, West Linn Library, OR