How Clocks Work
The invention of the mechanical clock in the 13th century initiated a change in timekeeping methods from continuous processes, such as the motion of the gnomon's shadow on a sundial or the flow of liquid in a water clock, to repetitive oscillatory processes, like the swing of a pendulum or the vibration of a quartz crystal, which were more accurate. All modern clocks use oscillation.
Although the methods they use vary, all oscillating clocks, mechanical and digital and atomic, work similarly and can be divided into analogous parts. They consist of an object that repeats the same motion over and over again, an oscillator, with a precisely constant time interval between each repetition, or 'beat'. Attached to the oscillator is a controller device, which sustains the oscillator's motion by replacing the energy it loses to friction, and converts its oscillations into a series of pulses. The pulses are then added up in a chain of some type of counters to express the time in convenient units, usually seconds, minutes, hours, etc. Then finally some kind of indicator displays the result in a human-readable form.
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Famous quotes containing the words clocks and/or work:
“Weighing the steadfastness and state
Of some mean things which here below reside,
Where birds like watchful clocks the noiseless date
And intercourse of times divide,”
—Henry Vaughan (1622–1695)
“Men should not labor foolishly like brutes, but the brain and the body should always, or as much as possible, work and rest together, and then the work will be of such a kind that when the body is hungry the brain will be hungry also, and the same food will suffice for both; otherwise the food which repairs the waste energy of the overwrought body will oppress the sedentary brain, and the degenerate scholar will come to esteem all food vulgar, and all getting a living drudgery.”
—Henry David Thoreau (1817–1862)