Could a raft be powered only by soap? Is an empty bottle truly empty? What exactly is a paper squawker—and can you build one with household items? Physics is a science of action; it's the study of how energy and matter are affected by new conditions acting on them. This book, presented by Scientific American, explores many aspects of physics, from mass and balance to Boyle's law, all in language accessible for young scientists. Step-by-step instructions guide readers through each project while thoughtful questions and background and observations sections engage them further with the science concepts included.