Sound is one example of wave motion and the ability to hear sound is based on the principle of resonance. In this chapter’s activities, you will learn about standing waves, resonance, and an interesting wave phenomenon known as the Doppler effect. Teacher background information, assessment, safety notes, references, additional resources, and a keyword glossary are provided. This book selection also includes the Table of Contents, Preface, Acknowledgments, About the Authors, An Introduction to Phenomenon-based Learning, Appendix, Credits, and Index.