The History of the Pendulum

SS Component Option 1: Historical Connections.

In the first century, the pendulum was used by Chinese scientist Zhang Heng of the Han dynasty. It's original purpose was to sway and activate a series of levers after being disturbed by a distant earthquake. Depending on the lever activated, a ball would fall into a different "toad's mouth", indicating the direction of the earthquake. During the Renaissance, large pendulums were used as power sources for large machinery - saws, bellows, pumps, etc. Leonardo da Vinci made several speculations about the uses of pendulums, although timekeeping was not among them.

Seismograph Sketch. 2012. Infographic. granitestudio.org, Luoyang. Web. 13 Nov 2013. <http://www.shkp.org.cn/kply/shdzkpg/h000/h16/img200609180329411.jpg>.

In 1602, the Italian scientist Galileo Galilei was the first to study the properties of pendulums, with his first report of his research held in a letter to Guido Ubaldo dal Monte. His interest in the topic was sparked, according to his protegee, Vincenzo Viviani, by the swinging motion of a chandelier. It was Galileo who discovered isochronism - the period of the pendulum is approximately independent of the amplitude or width of the swing - , the property of pendulums which make them such good timekeepers. He was also the first to utilize the pendulum in simple timing apparatuses. One of Galileo's physician friends invented a device which measured a patient's pulse, called a pulsilogium. In 1641, Galileo sent the first designs for the pendulum clock to Vincenzo, who began constructing it, but did not complete it before Galileo's death in 1649.

Marey, Etienne. Sphygmograph in used. 1885. Infographic. sciencemuseum.org.uk, London. Web. 13 Nov 2013. <http://www.sciencemuseum.org.uk/hommedia.ashx?id=10000&size=Small>.

English scientist Robert Hooke studied the conical pendulum, which consisted of a pendulum that was free to swing in two dimensions, with the weight rotating in an elliptical fashion. Hooke used this motion to analyze the orbital paths of the planets, and suggested that the components of orbital motion consisted of inertial motion along a tangent direction plus an attractive motion n the radial direction, which played a part in colleague Isaac Newton's formulation of the law of universal gravitation.