In this revised and expanded edition, William Gurstelle shows ordinary folks how to build a dozen fun and impressively powerful launchers with inexpensive household and hardware store materials. This new edition includes three new projects along with diagrams, photographs, and fascinating science information. With a strong emphasis on safety, the book also gives tips on troubleshooting and describes each machine's historical origins as well as the science behind it. Workshop warriors and tinkerers at any skill level will love these new exciting DIY projects.