Shadow clock



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tarix13.06.2022
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Shadow clock

Shadow clock Hourglass Water clock Incense clock Time ball

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Shadow clock

  • Shadow clock-one of a handful of portable timepieces known from ancient Egypt, this fragment is from the type that told time by measuring the length of the sun’s shadow. Preserved here is the block with a sloping face with a series of parallel and oblique lines engraved on its face to mark off the time. The original piece would also have had a perpendicular block set up in front of the sloping face to serve as a gnomon and cast a shadow.

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The ancient Egyptians were one of the first cultures to widely divide days into generally agreed-upon equal parts, using early timekeeping devices such as sundials, shadow clocks, and merkhets. Obelisks were also used by reading the shadow that they make.The clock was split into daytime and nighttime, and then into smaller hours.

Hourglass


Hourglass is a device used to measure the passage of time . It comprises two glass bulbs connected vertically by a narrow neck that allows a regulated flow of a substance from the upper bulb to the lower one . Typically , the upper and lower bulbs are symmetric so that the hourglass will measure the same duration regardless of orientation . The specific duration of time a given hourglass measures is determined by factors including the quantity and coarseness of the particulate matter , the bulb size , and the neck width .
History: The origin of the hourglass is unclear . Its predecessor the clepsydra , or water clock , is known to have existed in Babylon and Egypt as early as the 16th century BCE .

Water clock

A water clock or clepsydra is any timepiece by which time is measured by the regulated flow of liquid into or out from a vessel , and where the amount is then measured .

Water clocks are one of the oldest time measuring instruments . The bowl - shaped outflow is the simplest form of a water clock and is known to have existed in Babylon , Egypt and Persia around the 16th century BC . Other regions of the world , including India and China , also have early evidence of water clocks , but the earliest dates are less certain . Some authors , however , claim that water clocks appeared in China as early as 4000 BC . Water clocks were also used in ancient Greece and ancient Rome , described by technical writers such as Ctesibius and Vitruvius .

Incense clock

The incense clock is an Indian timekeeping device that was popularised in China during the Song Dynasty ( 960-1279 ) and spread to neighboring East Asian countries such as Japan and Korea . The clocks ' bodies are effectively specialized censers that hold incense sticks or powdered incense that have been manufactured and calibrated to a known rate of combustion , used to measure minutes , hours , or days . The clock may also contain bells and gongs which act as strikers . Although the water clock and astronomical clock were known in China , incense clocks were commonly used at homes and temples in dynastic times .

Time ball

Time ball or timeball is a time - signalling device . It consists of a large , painted wooden or metal ball that is dropped at a predetermined time , principally to enable navigators aboard ships offshore to verify the setting of their marine chronometers . Accurate timekeeping is essential to the determination of longitude at sea .

The fall of a little ball was in antiquity a way to show to people the time . Ancient Greek clocks had this system in the main square of a city , as in the city of Gaza in the post - Alexander era , and as described by Procopius in his book on Edifices . Time ball stations set their clocks according to transit observations of the positions of the sun and stars . Originally they either had to be stationed at the observatory , or had to keep a very accurate clock at the station which was set manually to observatory time .


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