The How and Why Library How Things Work Author:Childcraft Chapters include 1.There's More To A Door Than You Think — 2.Pipes You See, Pipes You Don't, 3.It's Heat 4.Clocks and Watches 5.Things That Make Sounds 6.Things That Make Music 7.Mirrors, Lenses and Prisms 8.Things That Help Us Extend Our Reach 9.Batteries, Cells and Generators 10.Plugs Sockets and Switches 11.Saws, Hammers and Other Tools 12.Mac... more »hines That Make Work Easier 13.Wheels, Wings and Other Things 14.The Power That Makes Things Go 15.Things To Steer With 16.Brakes and Drags« less