Sound waves allow sounds to travel to our ears, but did you know they can also be used to find things when it's too hard to see? Sonar is the use of sound waves to navigate, locate things, and measure distances—often underwater. Readers dive deep into this topic through achievable text that explains this physics concept in a way that's easy for elementary learners to understand. Diagrams and full-color photographs aid in this educational reading experience, and a useful glossary includes terms to help readers strengthen their science vocabulary.