In the search for alternative energy sources there’s one form of energy you don’t hear much about, which is ironic because I’m referring to sound energy. Sound energy is the energy produced by sound vibrations as they travel through a specific medium. Speakers use electricity to generate sound waves and now scientists from Korea have used zinc oxide, the main ingredient of calamine lotion, to do the reverse – convert sound waves into electricity. They hope ultimately the technology could be used to convert ambient noise to power a mobile phone or generate energy for the national grid from rush hour traffic.
Piezoelectrics are materials capable of turning mechanical energy into electricity, and can be substances as simple as cane sugar, bones, or quartz. Much research in this field has been focused on transforming the movement of a person running, or even the impact of a bullet, into a small electrical current, but although these advanced applications are not yet available in consumer products, scientists have been using piezoelectric materials in environmental sensors and speakers for years.
The Korean researchers were interested in reversing this process however. “Just as speakers transform electric signals into sound, the opposite process – of turning sound into a source of electrical power – is possible,” said Young Jun Park and Sang-Woo Kim, authors of the article in journal Advanced Materials.