Gears are wheels with teeth. You can use gears to slow things down or speed them up, to change direction, or to control several things at once. The gears, when placed together, have to be fitted into the teeth. Each gear in a series reverses the direction of rotation of the previous gear. The smaller gear, will always turn faster than the larger gear and in doing so, turn more rounds. You can find gears near the back wheels of cars and motorcycles. Trains also have gears. The train is how the miners got around or they used it when they move supplies.