Crossword clues for water clock
water clock
The Collaborative International Dictionary
Water clock \Wa"ter clock`\ An instrument or machine serving to measure time by the fall, or flow, of a certain quantity of water; a clepsydra.
Wiktionary
alt. 1 A device for measuring time by letting water flow out of a container, usually through a tiny aperture. 2 A clepsydra. n. 1 A device for measuring time by letting water flow out of a container, usually through a tiny aperture. 2 A clepsydra.
WordNet
n. clock that measures time by the escape of water [syn: clepsydra, water glass]
Wikipedia
A '''water clock ''' or clepsydra ( Greek κλεψύδρα from κλέπτειν kleptein, 'to steal'; ὕδωρ hydor, 'water') is any timepiece in which time is measured by the regulated flow of liquid into (inflow type) or out from (outflow type) a vessel where the amount is then measured.
Water clocks, along with sundials and hourglasses, are likely to be the oldest time-measuring instruments, with the only exceptions being the vertical gnomon and the day-counting tally stick. Where and when they were first invented is not known, and given their great antiquity it may never be. 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.
Some modern timepieces are called "water clocks" but work differently from the ancient ones. Their timekeeping is governed by a pendulum, but they use water for other purposes, such as providing the power needed to drive the clock by using a water wheel or something similar, or by having water in their displays.
The Greeks and Romans advanced water clock design to include the inflow clepsydra with an early feedback system, gearing, and escapement mechanism, which were connected to fanciful automata and resulted in improved accuracy. Further advances were made in Byzantium, Syria and Mesopotamia, where increasingly accurate water clocks incorporated complex segmental and epicyclic gearing, water wheels, and programmability, advances which eventually made their way to Europe. Independently, the Chinese developed their own advanced water clocks, incorporating gears, escapement mechanisms, and water wheels, passing their ideas on to Korea and Japan .
Some water clock designs were developed independently and some knowledge was transferred through the spread of trade. These early water clocks were calibrated with a sundial. While never reaching a level of accuracy comparable to today's standards of timekeeping, the water clock was the most accurate and commonly used timekeeping device for millennia, until it was replaced by more accurate pendulum clocks in 17th-century Europe.
A water clock, also known as a clepsydra, uses a flow of water to measure time. If viscosity is neglected, the physical principle required to study such clocks is the Torricelli's law. There are two types of water clocks: inflow and outflow. In an outflow water clock, a container is filled with water, and the water is drained slowly and evenly out of the container. This container has markings that are used to show the passage of time. As the water leaves the container, an observer can see where the water is level with the lines and tell how much time has passed. An inflow water clock works in basically the same way, except instead of flowing out of the container, the water is filling up the marked container. As the container fills, the observer can see where the water meets the lines and tell how much time has passed.
The Water Clock, also known as The Giant Water Clock, is in the permanent collection of The Children's Museum of Indianapolis located in Indianapolis, Indiana, United States. The modern water clock is located in the Sunburst Atrium of The Children's Museum, and is adjacent to the Grand Staircase leading up to the second floor. It was created by French scientist and artist Bernard Gitton in 1988, the same year that the museum acquired it.
The artistic timepiece is the largest water clock in North America.
Usage examples of "water clock".
A water clock would function correctly at a different latitude if it told only constant hours, but not if it measured different hours in summer and winter.
Then the water clock on the Temple of Small Gods would trigger the big bronze gong.
The circle was surrounded by Roman numerals and strange objects: a piece of string, a water clock, a rusty knife, a dragon-shaped silver bracelet, a gold ring, a metal brazier full of burning charcoal, a glass vial, a small mound of earth, a stone.