Harvesting Energy From Walking (broadcast Friday, February 8th, 2008)

In this energy harvesting mode, the device is programmed to engage only during the end of the swing phase, producing electrical power while simultaneously assisting the knee flexor muscles in decelerating the knee. The mask and mouthpiece measure the metabolic cost or "effort." The cabling and computer engage and disengage power generation and measure the amount of generated power. (Credits: © Science) See More Videos

Researchers have built a device resembling a knee brace that can generate usable amounts of electrical energy as a person walks. The brace, described in an article in the journal Science, harvests the energy lost when a human brakes the knee after swinging the leg forward to take a step. Last year, scientists created a backpack frame that translated the up-and-down motion of a frame mounted backpack to electrical energy. Other researchers are studying ways to harvest energy from footsteps by means of piezoelectric devices mounted i the soles of shoes. In this segment, Ira talks to one of the creators of the new knee-mounted device about harvesting energy from human movement. Teachers, find more information about using Science Friday as a classroom resource in the Kids' Connection.