It was a beauty, roaring down Quentin Road right in front of Fremd High School late Wednesday morning: a red car, a cool red car, with a woman driver wearing sunglasses.
The physics students flew into action.
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A couple youths huddled in the shade along the sidewalk and fiddled with the adjustments on a laptop computer. The computer was connected to an ultrasonic transducer, a little metal box on a slim metal pole set in the grass and aimed at the traffic.
The physics part-the reason why they got to be outside on a stunning sunny morning rather than inside in a 1 1/2-hour physics class-has to do with how the sound from the transducer will hit the car and bounce back. The computer will eat up that information, taking into account time and distance, and spit out the speed of the car. With a little calculation, the first team had the number for the red car: 36 m.p.h.
Now for the pro.
Hidden deeper in the shade, Palatine police officer John Saurmann aimed his $3,800 portable laser device at the same car. His machine registered 38 miles per hour.
The laser device uses light to do a similar bouncing job against a car. And the Police Department’s radar device, which he also brought along, uses microwaves. The sound, which gets more high-pitched as a car goes faster, advises a police officer of a speeding car.
“But after eight hours with one of these machines, you can tell from just the sound who is speeding. Before I even look, I can guess the speed correctly within 1 mile per hour,” Saurmann mentioned-twice-to the 16- and 17-year-olds.
Robert Grimm, chairman of the science department at Fremd, was pleased with the accuracy of the student experiment. “We’re within a few miles per hour of the police,” he said.
After the students calculated the speed of a car, other students relayed the information by walkie-talkie down the sidewalk to other students holding signs that would alert the anonymous driver: “Your Speed is 36 M.P.H.”
A quick analysis Wednesday showed that 48 percent of the 101 cars that passed were speeding. But only 8 percent were 5 or more miles per hour over the limit.
As the students charted data on clipboards, Sauermann turned his ear to the side as if he had been hit with a painfully pitched tone.
“That’s 73!” the officer said as he reached into his jacket for a little book and a white Firebird rushed by him down Quentin. “I’m getting that guy.”