Vaccines are substances that help protect people from diseases and they have been proven to save lives. So why has something that should reassure people become so controversial? This useful and timely book looks at the facts, viewpoints, and perspectives surrounding vaccines and how they became a crossroads between science and individual rights.

This exciting title introduces readers to the concept of a wave and the patterns and properties common to both light and sound waves. Clear text and detailed diagrams combine to demonstrate the cause-and-effect relationships involved in the properties of amplitude, wavelength, and frequency. A link to interactive activities online plus an activity in the book allow readers to explore key concepts close up by creating their own wave models.