The Mechanics of Timekeeping

Abstract

THE MECHANICS OF TIMEKEEPING BY KATHERINE LIU THE DEVELOPMENT AND MECHANICS OF MEASURING TIME IN HUMAN HISTORY S ince the earliest human civilizations, humans have kept time in one form or another, either through water clocks, sundials, hourglasses or candle clocks. Though primitive, these early forms of clocks were the building blocks of modern timekeeping technology. However, even though time is such an essential part of our lives, many people do not understand the mechanics underlying clock function. Archaeological evidence has shown that the Egyptians and Babylonians began measuring time 5,000 years ago. They started by recording the length of a day by following the sun across the sky and noting the phases of the moon. 1 The Egyptians also created calendars that had 12 months with 30 days each. These calendars even included 5 extra days every year to estimate the solar year. The next form of time measurement came with the invention of the sundial. The sundial, which has been invented independently by all major cultures, works by indicating the time of day by the length and direction of a shadow cast by the sun’s light. But because such devices cannot work at night, the sundial’s counterpart, the water clock, was created to tell time during the night. The water clock is a basin of water that lets water drip from a small hole near the base of the basin. Lines were drawn inside the basin walls to denote sections of time so as the water level dropped, it would gradually reveal lines above the water level, thereby indicating the time. 1 The earliest clocks, along with the sundial and water clock, are the hourglass and candle clocks. We often see these in films and animation to give an archaic setting. However, even these seemingly familiar and simplistic clocks are quite impressive in being able to accurately keep time even before the physics regarding water flow and planetary motion were understood. The candle clock works similarly to the water clock in that the wax of a candle is Berkeley Scientific Journal | FALL 2016 melted down and the height of the candle at different moments measure how much time has passed. 1 More modern forms of timekeeping include pendulums, pocket watches, and classroom clocks. These are still relatively simple compared to today’s digital clocks and beyond, but are equally interesting and important. Pendulums are quite distin- guished in function from clocks and pock- et watches in that they don’t have as many small components that aid it in telling time. The main parts of a pendulum are the rod and weight which together swing side to side in an oscillating motion. 2 To maintain the same oscillating rate, there are specific configurations not seen from the outside. But this does not prevent a pendulum clock from eventually lagging in timekeeping. So, occasionally, a clockmak- er or clock owner will need to reconfigure the cogs in a pendulum so they read time accurately. Pocket watches and clocks are unique from pendulums. Clock mechanics