Aristotle was a wise philosopher, but his use of intuitive reasoning misled him in examining the motion of objects. In this lively program, simple experiments and dramatic dialogues with Aristotle, Galileo, and Sir Isaac Newton illustrate how our understanding of motion and gravity has evolved. Students can see how Galileo separated motion into its horizontal and vertical components and how Newton, with his Law of Universal Gravitation, demonstrated that orbits are elliptical and why the Moon does not fall to Earth—but is falling. Produced by the Open University. (25 minutes)