"Version: 20180401"--Title page verso."A Morgan & Claypool publication as part of IOP Concise Physics"--Title page verso.Includes bibliographical references.1. The continuum Universe -- 1.1. The right use of x[square] : describing a continuum2. Everything is a wave -- 2.1. Waves in what medium : waves made of what stuff? -- 2.2. Evidence for waves -- 2.3. Early clues to the size and nature of a…