Professor Robert B. Laughlin, Department of Physics, Stanford University

Seung Sae Hong December 10, 2007 (Submitted as coursework for Physics 210, Stanford University, Autumn 2007) Fig. 1: A schematic for Huygens' pendulum clock. This figure is currently under a free license as stated here. The Clock from Mechanical Periodicity Christiaan Huygens, a Dutch scientist, invented the pendulum clock in 1657[1]. Until his invention of the accurate clock, the matter of timekeeping hindered advances in many fields of science and expeditions. An accurate timekeeping method can enable the precise measurement in Physics, as well as the applications in daily life. In addition, the Europe was entering "the age of exploration," which required explicit time measurement for the maritime voyage[2]. Although Galileo Galilei studied the mechanism of the pendulum and conceived the pendulum clock concept, no clock using the periodicity of pendulum was demonstrated. The problem to realize a clock from the physical concept was the period of pendulum varies when the pendulum makes...