Dating cuckoo clocks
Devices operating on several physical processes have been used over the millennia.Some predecessors to the modern clock may be considered as "clocks" that are based on movement in nature: A sundial shows the time by displaying the position of a shadow on a flat surface.A major stimulus to improving the accuracy and reliability of clocks was the importance of precise time-keeping for navigation. The development of electronics in the 20th century led to clocks with no clockwork parts at all.The timekeeping element in every modern clock is a harmonic oscillator, a physical object (resonator) that vibrates or oscillates at a particular frequency.The Greek and Roman civilizations are credited for initially advancing water clock design to include complex gearing, which was connected to fanciful automata and also resulted in improved accuracy.These advances were passed on through Byzantium and Islamic times, eventually making their way back to Europe.Instead, water clocks in ancient societies were used mainly for astrological reasons.These early water clocks were calibrated with a sundial.
The next development in accuracy occurred after 1656 with the invention of the pendulum clock.
A sundial shows the time by displaying the position of a shadow on a (usually) flat surface, which has markings that correspond to the hours.
With the knowledge of latitude, a well-constructed sundial can measure local solar time with reasonable accuracy, within a minute or two.
Both the candle clock and the incense clock work on the same principle wherein the consumption of resources is more or less constant allowing reasonably precise and repeatable estimates of time passages.
In the hourglass, fine sand pouring through a tiny hole at a constant rate indicates an arbitrary, predetermined, passage of time. Water clocks, also known as clepsydrae (sg: clepsydra), along with the sundials, are possibly the oldest time-measuring instruments, with the only exceptions being the vertical gnomon and the day counting tally stick.
This object can be a pendulum, a tuning fork, a quartz crystal, or the vibration of electrons in atoms as they emit microwaves.