In yet another Olympian feat of measurement, researchers at Commerce's National Institute of Standards and Technology (NIST) recently calibrated a tape that will be used to measure out the distance of this summer's Olympic marathon—a distance of 26 miles 385 yards—to 1 part in 1,000.
Measurement is a vital aspect of the Olympic Games. Officials measure the height of jumps, the speed of races, and the mass of weights to determine who wins a medal and who goes home. The marathon is no different. Because of the difficulties in measuring out the distance, the International Association of Athletic Federations (IAAF) only recognized best times and didn't begin awarding world records for marathons until 2004 when a method using a device called a Jones Counter was officially recognized as sufficiently accurate.
Developed by a father-son duo in the early 1970s, the Jones Counter is a simple geared device that counts the revolutions of a bicycle wheel. To calibrate the device, course measurers lay out a calibrated measuring tape at least 30 meters in length. Once they have determined the number of revolutions that equal that distance—and a couple of successively longer distances—they follow painstaking procedures for laying out the rest of the course. The measurements, which can take hours to complete, will ensure that the shortest distance a runner will run will be at least the required distance and no more than about 40 meters over, corresponding to an error of about one part in 1,000. Full story