College Physics (4th Edition)

Many speed skaters in the 1998 Winter Olympics shaved remarkable amounts of time--about one second per lap--off previous records. Most experts attribute much of the savings to the use of a new kind of skate invented by Dutch researchers in biomechanics. Christine Witty, shown on our cover, won the bronze medal in the 1500-meter race using such a skate. This skate is designed to increase the amount of time the skate is in contact with the ice, and therefore to lengthen the skater's stride and the amount of work done by the skater's leg muscles, without also causing the skate to dig into the ice, which would increase friction and decrease speed and stability. Hinged at the toe, the blade releases from the boot toward the end of the stride and then returns to the boot with a "clap" sound when the foot lifts off the ice-hence the new skate has been dubbed the "clap skate." The Dutch researchers who invented it, however, call it the "slap skate" because it allows skaters to "slap on" additional work with each stride. Homer Levi Dodge (1896-1994), shown skating at top right with his wife, Margaret, on the Iowa River in 1921, probably would have been keenly interested in the clap skate. A physics professor, Dodge was an active researcher, primarily focusing on applied physics, and was involved in several conservation efforts and outdoors activities. Dodge was also very interested in physics education. In 1930 he helped found the American Association of Physics Teachers (AAPT). He became the organization's first president and was instrumental in setting up its journal, now known as the American Journal of Physics.