| MIT replay of alleged Greek trick |
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21 October 2005, for Science In 213 B.C.E., Archimedes made a "death ray," an ingenious set of mirrors that concentrated the sun's rays onto a Roman fleet, setting the ships aflame and staving off the siege of Syracuse—or so the story goes. The Discovery Channel's show Mythbusters last year declared this story "busted" after an unsuccessful attempt to replicate the trick. But mechanical engineer David Wallace of the Massachusetts Institute of Technology in Cambridge thought it doable, so this month he assigned it as an exercise to his product-design class. Students built an oak replica of a Roman warship and carefully aligned 127 mirrored tiles, a total of 12 square meters, to focus light on one spot 30 meters away. Sure enough, after about 10 minutes of sunlight, the planks burst into flame. Although successful, the experiment "demonstrated just how impractical the mirrors are," because they wouldn't work if the ships moved, says Chris Rorres, a mathematician and Archimedes scholar at the University of Pennsylvania, Kennett Square. Archimedes, famous for his weapons, would most likely have used oversized crossbows to rain pots of a flammable liquid called "Greek fire" onto the ships, he says. |