Search results
Results From The WOW.Com Content Network
The idea of using atomic transitions to measure time was first suggested by the British scientist Lord Kelvin in 1879, [204] although it was only in the 1930s with the development of magnetic resonance that there was a practical method for measuring time in this way. [205] A prototype ammonia maser device was built in 1948 at NIST. Although ...
This timeline of time measurement inventions is a chronological list of particularly important or significant technological inventions relating to timekeeping devices and their inventors, where known. Note: Dates for inventions are often controversial. Sometimes inventions are invented by several inventors around the same time, or may be ...
Detail of a cubit rod in the Museo Egizio of Turin The earliest recorded systems of weights and measures originate in the 3rd or 4th millennium BC. Even the very earliest civilizations needed measurement for purposes of agriculture, construction and trade. Early standard units might only have applied to a single community or small region, with every area developing its own standards for ...
Chronometry is derived from two root words, chronos and metron (χρόνος and μέτρον in Ancient Greek respectively), with rough meanings of "time" and "measure". [6] The combination of the two is taken to mean time measuring. In the Ancient Greek lexicon, meanings and translations differ depending on the source.
Similar methods of measuring time were used in medieval churches. [citation needed] The invention of the candle clock was attributed by the Anglo-Saxons to Alfred the Great, king of Wessex. The story of how the clock was created was narrated by Asser, who lived at Alfred's court and became his close associate. [2]
Unlike most other methods of measuring time, the hourglass concretely represents the present as being between the past and the future, and this has made it an enduring symbol of time as a concept. The hourglass, sometimes with the addition of metaphorical wings, is often used as a symbol that human existence is fleeting, and that the " sands of ...
There’s something almost magical about the way boomerangs arc through the air and return to the hand of the thrower. Watching them cut through the sky on their wide trajectories can provide ...
Before the coming of the railways in the 1840s, local time was displayed on a sundial and was used by the government and commerce. Before the invention of the clock the sundial was the only way to measure time. After the invention of the clock, the sundial maintained its importance, as clocks needed to be reset regularly from a sundial, because ...