James H. Williams, Jr. and the world's largest yo-yo, 1974
James Henry Williams, Jr. '67, SM '68, professor of mechanical engineering, led a group of 10 students in building "the world's largest yo-yo" during MIT's Independent Activities Period (IAP) in 1974 and tested it from the Cecil and Ida Green Building (54), the tallest on campus.
When the 35-pound contraption, made of two bicycle wheels, was ready, Williams took it to the roof of a 21-story building at MIT. He anchored the cord to an I beam, hooked up a motor which jerked the line rhythmically like a finger and let the yo-yo drop. The wheels, revolving up to 1,000 times a minute, reached a speed of more than 80 miles an hour. Then, the yo-yo climbed more than two-thirds of the way back up the 400-pound-test-weight nylon cord.
The scientific principle involved, according to Williams, is the conversion of the potential energy of a poised yoyo into kinetic energy and vice-versa. “I am interested in the dynamics of toys,” says Williams, “because they have lots of subtle and sophisticated aspects in a kinetic sense. Besides, too many technical people cultivate their gardens too tightly.”
After high school, Williams himself worked as a machinist in a shipbuilding yard in his native Newport News, Va. Then he went back to school and has earned two MIT degrees, a Cambridge doctorate and an award for outstanding undergraduate teaching. He lives with his wife, Karen, a poet, and his 5-year-old son, “J.T.,” in an MIT dorm where he is the house master. He is an intramural football and basketball player and a flutist.
Williams’ inspired students now want to build a giant Frisbee and sail it across the Charles River with, yoicks, the professor aboard. “It’s too dangerous,” he says...
Williams was offered $5,000 for the yo-yo by a Las Vegas casino (“I feel sensitive about selling it”), and laughed off suggestions that he drop it from Canada’s tallest structure, Toronto’s 1,800-foot Canadian National Tower. “There were all sorts of radio and TV offers,” he says wearily.