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The Horn of Jericho: An Acoustical Cannon

With a giant glass pipe, a slice of ceramic cut from a diesel exhaust system, and a strip of toaster wire, I built an acoustical cannon: The Horn of Jericho. It is the brainchild of Dr. John Wight, a research scientist at Corning Incorporated, and it is probably unique. It is a vast enlargement of a test tube-sized design, distributed as a $14 kit by Penn State.

The setup has no moving parts. There is no speaker; in fact, nothing is mechanically driving the air, which is what makes this effect interesting. Air passing back and forth through the channels of the ceramic resonates, driven by the temperature difference across the ceramic. One side of the ceramic is heated by toaster wire and the other is cooled by zip lock bags filled with iced water. (The glass pipe itself keeps the electrical wiring and the water safely separate.) As long as the temperature difference is maintained, the pipe shakes with a deep, pure tone that can be felt several rooms away! (For more science, read about thermoacoustics.)

The video is a quick visual tour. The sound does not do justice to the sheer volume of the rumble.

Video Sweep of the Horn of Jericho…

an acoustical cannon

More pictures…

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