Sonar is a technology that uses sound waves to detect objects underwater and measure distances. Here's how it works: a device sends out pulses of sound that travel through the water. When these sound waves hit something like a submarine, a whale, or the ocean floor, they bounce back as echoes. By measuring how long it takes for the echo to return, sonar can determine how far away the object is and even what shape it has.

Submarines use sonar to navigate in the dark depths where no light reaches. Ships use it to avoid underwater hazards and to map the seafloor. Fishermen use sonar to locate schools of fish. Scientists use it to study marine life and explore shipwrecks thousands of feet below the surface.

Interestingly, bats and dolphins use their own natural form of sonar called echolocation. They make clicking sounds and listen to the echoes, building a sound picture of their surroundings. Human sonar technology was inspired by observing how these animals navigate in darkness.

Without sonar, exploring and understanding the ocean, which covers more than 70% of Earth's surface, would be much harder.