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"Water clocks" was the first device that didn't use the observation of the celestial bodies to calculate the passage of time.
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A Brief History of Clock
Clocks
At best, historians know that 5,000-6,000 years ago, great civilizations in the Middle East and North Africa started to examine forms of clock-making instead of working with only the monthly and annual calendar. Little is known on exactly how these forms worked or indeed the actual deconstruction of the time, but it has been suggested that the intention was to maximize time available to achieve more as the size of the population grew. Perhaps such future periods of time were intended to benefit the community by allotting specific lengths of time to tasks. Was this the beginning of the working week？
Sun Clocks
With the disappearance of any ancient civilization, such as the Sumerian culture, knowledge is also lost. Whilst we can only hypothesize on the reasons of why the equivalent to the modern wristwatch was never completed, we know that the ancient Egyptians were next to layout a system of dividing the day into parts, similar to hours.
"Obelisks" (tall four-sided tapered monuments) were carefully constructed and even purposefully geographically located around 3500 BC. A shadow was east as the Sun moved across the sky by the obelisk, which it appears was then marked out in sections, allowing people to clearly see the two halves of the day. Some of the sections have also been found to indicate the "year"s longest and shortest days, which it is thought were developments added later to allow identification of other important time subdivisions.
Another ancient Egyptian "shadow clock" or "sundial" has been discovered to have been in use around 1500 BC, which allowed the measuring of the passage of "hours". The sections were divided into ten parts, With two "twilight hours" indicated, occurring in the morning and the evening. For it to work successfully then at midday or noon, the device had to be turned 180 degrees to measure the afternoon hours.
Water Clocks
"Water clocks" were among the earliest time keeping devices that didn't use the observation of the celestial bodies to calculate the passage of time. The ancient Greeks, it is believed, began using water clocks around 325 BC. Most of these clocks were used to determine the hours of the night, but may have also been used during daylight. An inherent problem with the water clock was that they were not totally accurate, as the system of measurement was based on the flow of water either into, or out of, a container which had markers around the sides. Another very similar form. was that of a bowl that sank during a period as it was filled of water from a regulated flow. It is known that water clocks were common across the Middle East, and that these were still being used in North Africa during the early part of the twentieth-century.
Mechanical Clocks
In 1656, "Christian Huygens' (Dutch scientist), made the first "Pendulum(钟摆) clock", with a mechanism using a "natural" period of oscillation(振幅). "Galileo Galilei" is credited, in most historical books, for inventing the pendulum as early as 1582, but his design was not built before his death. Huygens' clock, when built, had an error of "less than only one minute a day". This was a massive leap in the development of maintaining accuracy, as this had previously never been achieved. Later refinements to the pendulum clock reduced this margin of error to "less than 10 seconds a day".
The mechanical clock continued to develop until they achieved an accuracy of "a hundredth-of- a-second a day", when the pendulum clock became the accepted standard in most astronomical observatories.
Quartz Clocks
The running of a "Quartz clock" is based on the piezoelectric property of the quartz crystal. When an electric field is applied to a quartz crystal, it actually changes the shape of the crystal itself, If you then squeeze it or bend it, an electric field is generated. When pla
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