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A sensor that detects the formation of ice on aeroplane wings has been
developed by researchers at Penn State University. Ice disrupts the flow of air
over wings, making planes more difficult to fly. The device works by passing a
surface acoustic wave called a “Love wave” across the wing surface. A series of
ultra-thin piezoelectric components set in the wing monitor its frequency. When
water on the wing freezes, it changes the frequency of the Love wave. “We can
detect the ice before it has a chance to build up,” says Vijay Varadan, who led
the project. As soon as ice is detected, heating wires can be turned on to melt
it.