A ‘clock’ is an instrument used to specify, record, and manage time. The word ‘clock’ comes from the French word “cloche” meaning bell, came into use when timekeepers were kept in bell towers in the Middle Ages. Historians do not who or when mankind “invented” a time-keeping device or a “clock”. Probably thousands of years ago when someone stuck a stick in the ground and saw a shadow of the sun move across the ground, known as the sundial. (Cummings, 1997-2012).
After the Samarian culture left little knowledge behind, the Egyptians were next to divide their day in two parts. A vertical stick, or obelisk that is used to cast a shadow is known as a sundial. They were used as early as 3500 B.C.. Another shadow clock or sundial, possibly the first portable timepiece, came into use around 1500 B.C. to measure the passage of hours. As the sun moves from east to west, the shadows predict the time of the day. They also showed the year's longest and shortest days when the shadow at noon was the shortest or longest of the year. The Greeks used a sundial called “pelekinon”. These sundials are marked to predict time accurately throughout the year. They built a more accurate sundial based on their knowledge of geometry. An ancient Egyptian sundial from the 8th century and a Greek sundial are still in existence today.
Water clocks along with sundials are known to be the oldest time-measurements devices. The bowl-shaped outflow is the simplest form of a water clock and is known to have existed in Babylon and in Egypt 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. (Cowan, 1958) Ctesibius or Ktesibios or Tesibius (Greek: Κτησίβιος) (fl. 285–222 BC) was a Greek inventor and mathematician in Alexandria, Ptolemaic Egypt. (As of 2008, 1768–2010) He improved the...
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