PURPOSE: To demonstrate conservation of energy in a very dramatic way.
DESCRIPTION: The instructor backs up against the backdrop, holds the pendulum bob up to his or her chin, and releases it. Because of conservation of energy the bob will swing across and return to its original position adjacent to the instructor's chin, but without hitting his or her chin. Despite the wariness of the students, the pendulum bob cannot rise to a height greater than its original height, and the instructor is safe.
REFERENCES: (PIRA 1M40.10)
EQUIPMENT: Bowling ball pendulum, crane from Machine Shop.
SETUP TIME: 15 min.
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