Chinese Invasion Alarm

posted: 04/11/12
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As seen in "MythBusters: Chinese Invasion Alarm"
Hemera Technologies/Thinkstock


Explanation: Leave it to a high-school science class to send the MythBusters toward one of their most surprising findings yet.

The students inquired about an ancient Chinese invasion alarm that supposedly alerted villagers of approaching armies that were invading by tunneling in the ground. Two-hundred-liter pots with goat skins stretched across the tops like drums served as the alarm bells to broadcast vibrations from deviant diggers. To get the system to work, Chinese villagers dug shafts in the ground and lowered the pots into them at strategic points around the territory, stationing guards in the holes to listen for any enemy burrowing.

MythBusters Kari Byron, Tory Belleci and Grant Imahara — with some additional help from Jamie Hyneman and Adam Savage — re-created the archaic alarm to see if the drums could really keep track of any treacherous tunneling. Inside an abandoned mine, Kari and Adam camped out next to their drum-like ceramic pots. Up above, Tory and Jamie simulated the picking sounds of an invading army preparing to tunnel beneath an enemy city.

Amazingly, Kari's keen ears detected the faint vibrations from Tory and Jamie's hammering in the distance. The sound waves apparently struck the pottery drum just hard enough to produce a soft sound.

Since no physical proof of the ancient alarm system exists, the myth earned only a plausible finding, but the drumbeats Kari heard were music to the MythBusters' ears.

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