<^Tools That Use Sound> You can find many different kinds of tools that use sound - they’re all around us! Musical instruments, for instance, are an extremely common sound “tool”. Also common are the tools of sound engineers - microphones, speakers, tape recorders, and other electronic devices for recording and reproducing sounds.
Sometimes geophysicists will set off a small explosion on or just below the earth’s surface. The explosion sends sound <#5675,6><!waves> into underground layers of rock. The waves are reflected off the layers of rock and back toward the surface in certain patterns. A machine displays these patterns so the scientists can analyze them and tell whether or not the rocks are likely to contain oil or mineral deposits.
Acoustical engineers work to control sound and noise. They develop insulation for buildings and mufflers for car engines, and they also design concert halls and auditoriums so that they will be good at focusing and reflecting sounds out to the audience.
Commercial fishermen use <#5659,5112><!sonar> to detect schools of fish far below the water’s surface. The sonar sends sound waves into the water. These waves bounce off the schools of fish and <#5683,5><!echo> back toward the surface. The fishermen then drop their nets or fishing lines to catch the fish! Navies also use sonar to locate submarines and other underwater objects.
