Clocks- during the 1300’s Clocks were invented during the 1300s. Galileo, an Italian scientist, discovered the pendulum in 1581. The pendulum greatly improved the constant movement of the hands or bells of a clock. The average error with the pendulum varied only by seconds each day. Before this error was from 10 to 15 minutes a day. During the 1600s the metallic gear, or toothed wheel, and the use of the screw in assembling the clocks were first used.