Gears; mechanical components with teeth on their rim that can continuously mesh to transmit motion and power. They are interlocking toothed mechanical parts. The diameter of a large gear is twice that of a small gear. If the large gear is stationary, how many rotations does the small gear make as it completes one revolution around the large gear? Conversely, if the small gear is stationary, how many rotations does the large gear make as it completes one revolution around the small gear? When the large gear is stationary and the small gear completes one revolution around it, the small gear rotates once. When the small gear is stationary and the large gear completes one revolution around it, the large gear rotates one and a half times, i.e., one full rotation at 240°, one and a half rotations at 360°, two full rotations at 480°, and three full rotations at 720°.