Watch Gravity (1976) Official Trailer

In this spoof of public-school educational films, young Mary Jane asks the question, "What is gravity?" After asking various (dysfunctional) family members without success, she then asks Dr. Waxman of the Karl LaFong Foundation for Gravitational Research (motto: "heads in the clouds and feet on the ground"), who explains that gravity is caused by a substance named GR12. Unfortunately, the world is running out of GR12. The cartoon character Jiminy Gravity then explains (in song) how we can conserve gravity with such practices as sitting on the floor and carrying helium balloons.