Like last year's Secret Life of School Supplies, this directs kids through simple, un-glamorous investigations that explore the properties of everyday materials. The first section deals with household cleaners: testing their relative emulsifying ability, demonstrating how sulphur tarnishes silver and then how early photographers worked with silver compounds, and finally comparing the melting points of different waxes to determine their relative purity. The next chapter explores the basic elements of paint; and another brings together, under the title ""connectors,"" an analysis of the composition of ropes and a mixing of kitchen ingredients to make glue. Next comes a study of tools and their mechanical advantages that is more familiar from an old-fashioned elementary school physics class. The last chapter stretches the ""hardware"" umbrella to include an exploration of electricity. It's an odd combination, but possibly an intriguing one for kids with a desire to ""do science"" and a still-unfocused curiosity. As always, Cobb's readers know why they are going through certain motions and what it all means; they'll come out with a habit of mind they can carry over to all the other ordinary things around them.