Trivia: What is the name of a sound-based system used to measure the ocean floor?
Correct Answer: SONAR
So why is this answer correct? : SONAR, the abbreviation for Sound Navigation and Ranging, uses sound to map and measure the ocean floor — as well as help submarines and military vessels determine their surroundings. Active SONAR measures distance by emitting sound waves, which bounce off anything in their path and alert the operator of obstacles. Passive SONAR does not emit sound but instead gathers sound from the environment around the vessel. While SONAR is a helpful system of measurement for the vastly unexplored ocean, you don’t want to be too close to an active SONAR transmission — the sound waves can be as loud as 235 decibels, about twice as loud as the average rock concert.