Secret of Cicada Sound

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Secret of cicada sound revealed, according to reports in ScienceDaily 30 May 2013 and ScienceNOW 4 June 2013. Anyone who lives in a region where cicadas emerge en masse in early summer knows what an ear-splitting din they can make. A team of U.S. Naval researchers has been investigating how such a small creature can make such a loud sound. Derke Hughes, a research engineer at the Naval Undersea Warfare Center in Newport, Rhode Island, and colleagues used microcomputed tomography to study the structure and movement of the cicada’s sound producing organ, the tymbal.

The tymbal consists of a thin membrane with thick sections called ribs. To make their sound, the cicada uses muscles to pull the membrane so the ribs are pulled inwards and buckle. This produces a sharp click. The muscles then relax, allowing the ribs to snap back, which produces another click. The cicada can repeat this action 300 to 400 times per second, producing the characteristic high pitched drone. Researchers suggest the volume of the sound is enhanced because the cicadas have two tymbals, and the sound waves from each can combine to produce higher wave peaks. According to ScienceNOW, “The cicadas may be artfully using this effect to pump their volume to deafening levels without expending as much energy as if a single tymbal had to do it alone”.

Cicadas produce sound to attract mates. Naval engineers think that cicada sounds may help them design devices that use little power, but can produce loud sounds for sonar and underwater communication.

ScienceDaily

Editorial Comment: Making loud sounds by using two tymbals may be an artful use of the physics of sound production, but the cicadas didn’t think that up. Neither did they design noisemaking tymbals. If naval engineers are able to build a low powered but loud sound producing device using the same principles as the cicada tymbals it will be because they used their understanding of the physics of sound production and propagation, and can intelligently apply it using creative design. God’s a genius … go on … admit it… He thought of all this first, as well as inventing all the laws of physics and that would make it possible. (Ref. sound engineering, insects, arthropods, acoustics)

Evidence News 3 July 2013

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