Sonar

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A sonar machine

Sonar is a machine that uses underwater sound waves to find other objects in the sea. A sonar can work by sending out sound and listening for echoes (active sonar), like a radar, or by listening for sound made by the object it is trying to find (passive sonar).

The basic parts of an active sonar are:

Active sonar was first used in 1917 by Paul Langevin. The word SONAR was created during the Second World War as an acronym for Sound Navigation and Ranging.[1] This acronym replaced the British acronym ASDIC. The word is now thought by many people as a regular word, no longer as an acronym.

References[change | change source]

  1. "What is sonar?". oceanservice.noaa.gov. 2013. http://oceanservice.noaa.gov/facts/sonar.html. Retrieved 30 December 2013.