Do you know how to make something that can tell whether the $20 bill in your wallet is a fake? Or how to generate battery power with simple household items? Or how to create your own home security system? Science-savvy author Cy Tymony does. More than a simple do-it-yourself guide, this quirky collection uses run-of-the-mill household items and easy-to-follow instructions to build useful devices that are sure to amaze friends and family alike! A favorite reference tool for 16 years, this new revised edition is better equipped than ever as a practical tool to build useful devices and a resource guide for the next generation of makers.