The Sound and Light unit provides students with an understanding of sound and light waves through the theme of the "Sunken Treasure," a continuous story line throughout the lessons. In Lessons 1-5, students learn about sound, and in Lessons 6-10, they explore the concepts of light. The first lesson introduces the concepts of longitudinal and transverse waves. Students then move on to the concepts of wavelength and amplitude in transverse waves. In the third lesson, students learn about sound through the introduction of frequency and how it applies to musical sounds. Next, girls and boys learn all about echolocation, what it is and how engineers use it to "see" things in the dark, or deep underwater. The last of the five sound lessons introduces acoustics, in which students learn how different materials reflect and absorb sound.