Pendulums

1. Pendulums By: Nahdir Austin Honors Physics Period 2

2. History of the Pendelum • First used in the Han dynasty’s seismometer device by scientists Zhang Heng. • Tenth century Egyptian astronomer Ibn Yunis used a pendulum for time measurement. • Leonardo da Vinci made many drawings of the motion of pendulums. • Italian scientist Galileo Galilei was the first to study the properties of pendulums, beginning around 1602. • Most accurate time keeping device up until the 1930’s, when the quartz was invented.

3. Period of oscillation • A pendulum is a weight suspended from its pivot so it can move freely. • When released the restoring force combined with the pendulum's mass causes it to oscillate about the equilibrium position, swinging back and forth • Period: Time for one complete cycle, a left and right swing. • Swing periods of a simple gravity pendulum is dependent on its length, acceleration of gravity, and its amplitude. • The property of isochronisms is the reason why pendulums are good for timekeeping. • Isochronisms: regardless of the amplitude of oscillation the period of pendulums of equal length is constant. • They are directly effected by the acceleration of gravity, which is constant. • Since the force of gravity slightly differs throughout the earth, pendulums need to be adjusted when moved to a new area.

4. Uses of the Pendulum • Used as a gravimeter to measure local gravity. • Used in seismometers, which measures earth’s tremors. • They are an important factor for Schuler tuning, which is used in guidance systems of planes and ships • Some religions use pendulum motion at religious ceremonies such as The swinging incense burner called a censer.