May 18, 2021 1:02 PM
A clock is a device which measures, maintains and indicates time. It is one of the oldest inventions in history and fulfilled a great need for humans to measure intervals of time shorter than a day, a lunar month and a year.
The history of timekeeping dates back to approximately 2000 BCE, when ancient civilizations observed the Moon and Sun as they moved across the sky. This eventually led to the development of timekeeping devices. The ancient Egyptians were one of the first civilizations to devise a way to track time by dividing the day into two 12-hour periods. The Egyptians used obelisks (a tall, four-sided monument which tapers at the top in a pyramid formation) to mark the sun's rays by reading the shadow it made. They also used sundials and developed water clocks, which were later adopted by the Chinese, the Persians and the Greeks.
Europe sparked a change in timekeeping methods during the 13th century to repetitive oscillatory processes, like the swing of pendulums, which could provide more accurate results than methods relying on movements in nature, such as the sundials use of shadow position on a flat surface. A major advancement occurred upon the invention of the verge escapement, which involves a mechanical linkage in watches and clocks that gives impulses to the timekeeping element and methodically releases the gear train to move forward in order to advance the clock's hands. Verge escapements were used from the late 13th century until the 19th century in pocket watches and clocks. The invention of the mechanical escapement mechanism is important because it is what makes an all-mechanic clock possible.
Sir Francis Ronalds, an English scientist and inventor, was the first in history to invent an electric clock. It was powered with dry piles, which is a high voltage battery with a long life, however its electric properties varied due to the weather. Alexander Bain was the first to invent and patent a clock powered by electric current in 1840. Although Bain's clock did employ a pendulum to measure time, as was customary in the standard clocks of the time, he took revolutionary step of powering it with electric current instead of the traditional method of using springs or weights. It was not until 1906 that the first self-contained battery-operated clock was invented.
Electricity is used in a master clock system to give direct impulses to the pendulum, which in turn causes the clock's gear train to move or to lift a lever after it has imparted an impulse to the pendulum. This pendulum operates a light count wheel that turns through the pitch of one tooth every double swing and is arranged to release a lever every half minute. The lever gives an impulse back to the pendulum and is then restored to its original position by an electromagnet. Electric master clocks of this nature are good timekeepers since the electricity-based impulses can be given symmetrically as the pendulum passes through its middle position and the interference with its motion is small.
In 1929 the single greatest contribution to precise time measurement occurred when quartz crystal was initially applied to timekeeping. A quartz clock includes a ring of quartz about 2.5 inches in diameter, which is suspended by threads and enclosed in a heat-insulated chamber. Electrodes are attached to the surfaces of the ring and connect to an electrical circuit in such a manner that helps to sustain oscillations.
Since the frequency of vibration (100,000-hertz) is too high for time measurement, it can be reduced by a process known as frequency division, or demultiplication. This procedure works by applying the frequency division process to a clock dial-connected synchronous motor through mechanical gearing.
The timekeeping element in modern clocks and watches is a harmonic oscillator, a physical object (resonator) that vibrates or oscillates at a particular frequency. This object can be a pendulum, a tuning fork, a quartz crystal or the vibration of electrons in atoms as they emit microwaves.
Horology is the study of the measurement of time, and often refers specifically to the study of mechanical time-keeping devices. A horologist specializes in the art and science of timekeeping, and often designs, builds and repairs watches.
Peter Henlein, a clockmaker of Germany in the early to mid-1500's, is often considered to be the inventor of the watch. He was one of the first to craft a small portable clock in 1511, which was often worn as a pendant or attached to clothing. The mainspring which made portable clocks possible, is often attributed to him. A mainspring is a spiral torsion spring of metal ribbon used as a power source in mechanical watches, some clocks and other timekeeping mechanisms. Winding the timepiece, by turning a knob or key, stores energy in the mainspring by twisting the spiral tighter, which allows its subsequent force to turn the clock's wheels as it unwinds, until it requires another winding.
A horologist will study and familiarize themselves with each component of a watch, down to the most minuscule pieces in the timekeeping mechanism. Most who enter the specialization of horology attribute it to a passion and dedication to the study of watches. The intensive training required to receive this complex technical knowledge and hands-on experience from watchmaking school and/or apprenticeship nearly demands this dedication and life-long passion.