A clock is a timekeeping device and a precision instrument for measuring and indicating time. Clocks are usually distinguished by the size of the internal unit. According to international practice, those with a diameter of more than 80 mm and a thickness of more than 30 mm are called clocks; those with a diameter of 37 to 50 mm and a thickness of 4 to 6 mm are called pocket watches; those with a diameter of less than 37 mm are called watches; Those with a diameter of no more than 20 mm or a movement area of ??no more than 314 mm2 are called women’s watches. The watch is one of the smallest, sturdiest and most precise machines ever invented by man.

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Many people always think that clocks originated abroad. In fact, Chinese clock technology was first introduced to Europe, and Europeans later produced clocks with sophisticated craftsmanship. When it comes to Chinese clocks, many people may first think of sundials, water clocks, etc. However, these ancient timekeeping tools cannot be called clocks in the strict sense, but can only be called timers.

There is a record in the Swiss World Watch Journal that "the escapement used in modern mechanical clocks originated from the invention of Su Song in ancient China." Joseph Needham, the famous British historian of science and technology, said, "Su Song invented the clock Since the combination of mechanical and astronomical observation instruments,

it has been completely successful in principle. He was six centuries ahead of Robert Hooke. For example, together with Pei and Hooke, he was considered by the West to be the inventor of astronomical clocks seven centuries earlier. Half a century." In 1099, Su Song, the Prime Minister of the Northern Song Dynasty, presided over the construction of a water-borne instrument similar to a modern clock, with an error of only one second per day.

Reference source; Baidu Encyclopedia-Watch