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Topic: Water clock

	Water clock - Wikipedia, the free encyclopedia
		While never reaching the level of accuracy based on today's standards of timekeeping, the water clock was the most accurate and commonly used timekeeping device for millennia, until it was replaced by the more accurate pendulum clock in the 17th century.
		Through the centuries, water clocks were used for timing lawyer's speeches during a trial, labors of prostitutes, night watches of guards, sermons and masses in church, to name only a few.
		This outflow water clock was built in honor of Amenhotep I by Amenemhet, an 18th dynasty dignitary.
	en.wikipedia.org /wiki/Water_clock (2017 words)

	Clock - Wikipedia, the free encyclopedia
		The clock in its most common modern form (in use since at least the 14th century) displays the hours, minutes, and sometimes seconds that pass over a twelve or twenty-four-hour period.
		Mains power clocks count the 50 or 60 hertz periods of their AC power power supply, which is steered for long-term average frequency stability by power generating companies for this purpose.
		An ideal clock is a scientific principle that measures the ratio of the duration of natural processes, and thus will give the time measure for use in physical theories.
	en.wikipedia.org /wiki/Clock (1775 words)

	No.72: The First Clocks
		The problem is that the mechanical clock seemed at first to be a mere improvement on the older water clock, which had been around for well over a thousand years.
		The balance wheel on a watch or the pendulum on a grandfather's clock is an escapement -- a mechanism that ticks in a steady rhythm and lets the gears move forward at a steady rate in little equal jumps.
		Water clock inaccuracies had bottomed out at around 15 minutes a day, and that's about as well as the first mechanical clocks did.
	www.uh.edu /engines/epi72.htm (491 words)

	[No title] (Site not responding. Last check: 2007-10-21)
		The stick would float perpendicular to the surface of the water, and when the hole at the base of the urn was unplugged, the passage of time was measured as the stick descended farther into the urn.
		Water was continually poured into the vessel (B), with the overflow escaping from a pipe (I).
		The anaphoric clock was both a clock and a calendar, illustrating the both the time of day and the progression of the sun along the ecliptic.
	www.perseus.tufts.edu /GreekScience/Students/Jesse/CLOCK1A.html (2982 words)

	Clocks and Ctesibius
		The level of water sinks and its height is a measure of the time passed since it was full of water.
		The floating valve is the predecessor of the floating ball in the upper chamber of the toilet.
		More accurate mechanical clocks using falling weights instead of water appeared in the fourteenth century, and the ingredients for the modern clock were in place when Galileo described the pendulum in the sixteenth century.
	www.mlahanas.de /Greeks/Clocks.htm (1231 words)

	Gale Schools - Sci Try - Water Clock (Site not responding. Last check: 2007-10-21)
		The height of the water in the bottom container indicates the amount of time that has passed since the clock was started.
		One challenge in designing an accurate water clock relates to the rate at which the water flows or drips out of the container.
		In a container of water, all the water pushes downwards, causing pressure on the water at the bottom.
	www.galeschools.com /sci_try/water_clock.htm (1016 words)

	Delightful Machines - Bernard Gitton's Liquid Science
		The clock is suspended (apparently, from an examination of the picture) in the atrium of the museum.
		Water will flow from the glass through the tube and into the sink until the level of water in the glass reaches the level of the output end of the tube (or the input end, of course, but we assume that you ensure that this does not happen).
		The Time-Flow Clock illustrated on the cover of this issue is not identified within, but it is the 2.3 meter high clock installed at the Cité des Sciences, La Villette, Paris.
	www.marcdatabase.com /~lemur/dm-gitton.html (6129 words)

	James Designs - Professional water features
		The Vortex Water Clock was first developed as a commission for the reception area of the award-winning headquarters for Wessex Water in Bath, England.
		In Feng Shui, moving water is felt to be one of the most effective ways of increasing the energy of a specific space or room or building.
		The water is always in a state of flux – a balance between the pumped flow and the effects of vortical motion under the influence of gravity.
	www.jamesdesigns.co.uk (1855 words)

	Mystical-WWW : Clocks and History
		An inherent problem with the water clock was that they were not totally accurate, as the system of measurement was based on the flow of water either into, or out of, a container which had markers around the sides.
		It is known that water clocks were common across the Middle East, and that these were still being used in North Africa during the early part of the twentieth-century.
		These clocks appear to have been plagued by the same problem as that of the 'water clock', that of regulating the mechanisms and maintaining the accurate time.
	www.mystical-www.co.uk /time/clocks.htm (2595 words)

	Halfbakery: Static drippy water clock
		Water droplets are let out and small wires pull the drop in one general direction with static electricity(whatever time it is).
		The overall appearance is water drops magically being flung outwards, and landing near the lip of the dish.
		In fact, if the falling water powered the mechanics, then this clock wouldn't need to be plugged in, but meerly "wound" up by pouring water in a dish at the top.
	www.halfbakery.com /idea/Static_20drippy_20water_20clock (554 words)

	Water clock at opensource encyclopedia (Site not responding. Last check: 2007-10-21)
		Water clocks were among the earliest timekeepers that didn't depend on the observation of celestial bodies.
		Later named clepsydras ("water thieves") by the Greeks, who began using them about 325 BCE, these were stone vessels with sloping sides that allowed water to drip at a nearly constant rate from a small hole near the bottom.
		More elaborate and impressive mechanized water clocks were developed between 100 BCE and 500 CE by Greek and Roman horologists and astronomers.
	www.wiki.tatet.com /Water_clock.html (554 words)

	science web page\water clocks (Site not responding. Last check: 2007-10-21)
		Water slowly dripping from a bowl or some other form of container has been used to measure time for many centuries.
		Either by having a bowl drip water through a small hole and the hours would be shown by the falling level of the water measured against a scale marked in the inner surface.
		The water clock frame is made from the various pieces of wood.
	www.horizon.ab.ca /barnwell/grade6/water_clocks.htm (447 words)

	Clock a History - Timekeepers (Site not responding. Last check: 2007-10-21)
		This cylinder water clock was used by the Romans.
		The Candle was used as an Alarm Clock by putting a nail into the wax, whenever the candle wax melted down to the nail then the nail would fall into a tin pan and make a noise.
		A synchronous electric motor being used in a clock is wholly dependent on the frequency stability of the AC current which is supplied by the power company.
	users.commspeed.net /k6xf/clock.htm (3749 words)

	© The Children's Museum of Indianapolis
		Designed by French physicist and artist Bernard Gitton, the water clock was procured by the museum in 1989 with a contribution from Mr.
		The clock, which is 26.5 feet tall, uses 70 gallons of a solution of water, methyl alcohol and food coloring.
		The water clock works on three basic principles of physics: energy cannot be destroyed only changed; gravity pulls objects down to the lowest possible level; and water seeks its own level.
	www.childrensmuseum.org /themuseum/waterclock.htm (478 words)

	NASAexplores 5-8 Lesson: Water Clocks (Student Sheets)
		Water clocks have been in use in one form or another for more than 3,000 years.
		First used in Egypt and Babylonia, water clocks were brought across the Mediterranean by the Greeks.
		Sun clocks were good for telling the time of day, but water clocks could be used easily to measure the length of shorter intervals of time.
	www.nasaexplores.com /show_58_student_st.php?id=02122080550 (370 words)

	Water Clock (Site not responding. Last check: 2007-10-21)
		Water traveled from the higher container to the lower container through a connecting tube.
		While these clocks weren't totally reliable, they worked indoors, at night, and on cloudy days, so they were more useful than the sundial, the only other clock in use at the time.
		Water clocks were common across the Middle East, and were still being used in North Africa during the early part of the twentieth century.
	www.scholastic.com /schoolage/activities/k_2/waterclock.htm (370 words)

	Rees's Clepsydra 1819 (Site not responding. Last check: 2007-10-21)
		It is absolutely necessary that the arbor should fit the central square hole so well as to prevent the escape of water from the drum, otherwise the instrument would continue to gain velocity, till at length it would no Ionger afford a true indication of time.
		Varignon has given a geometrical and general method of determining the scale for a clepsydra, whatever may be the shape and magnitude of the vessel.
		We think, however, that the mechanism is nearly as complex as that of a clock itself and consequently prefer a water-clock, such as that made by Perrault in the year 1699, where a pendulum is used as the regulator, and water only as the first mover.
	www.ubr.com /clocks/pub/clep/clep.html (976 words)

	Time
		This manner of timing, a crude water clock, is still in use but nowadays mainly for goods 'on hire'.
		Water clocks also lend themselves to extension into other areas of science, technology and maths.
		Water pressure from the model clock could then lead on to a study of simple hydraulics and pneumatics.
	www.zetnet.co.uk /sea.jnp/earth.4/time.htm (1372 words)

	No. 120: Su-Sung's Clock
		The Chinese, of course, had their own version of the water clock, and the Sung dynasty improved on it during the 11th century.
		But it was hard for water clocks to do all these things, because a float indicator riding on a water surface didn't exert enough force to drive a lot of extra machinery.
		His huge clock stood 40 feet high and was powered by a special water wheel.
	www.uh.edu /engines/epi120.htm (506 words)

	Rough Science . Rough Science Adventure . Water Quality Control Center \| PBS
		To determine if the water has a high or low mineral content, test the hardness of the water in a soap solution.
		Distilled water is "soft." We can use it as a measure of the hardness-the mineral content-of the "island water." In hard water the salts (magnesium and calcium) interact with soap to form a scum that will not form bubbles (soap foam).
		Water is full of plants and animals that are too small to see with the naked eye.
	www.pbs.org /weta/roughscience/discover/waterquality.html (1510 words)

	Come Together Community
		It was a bowl with a hole in a bucket of water; the sinking of the bowl marked the passage of time.
		PROBLEMS: In order for a water clock to work properly, someone had to keep an eye on it; to make sure that no pebbles were in the bowl to increase talking time.
		This type of clock was the first one to not be dependent on the weather.
	groups.msn.com /ComeTogetherCommunity/timezones.msnw (1028 words)

	Long Now: Projects: Clock
		Peter Gabriel, the musician, thinks the clock should be alive, like a garden, counting the seasons with short-lived flowers, counting the years with sequoias and bristlecone pines.
		The idea of hiding the clock to preserve it has a natural corollary, but it takes Teller, the professional magician, to suggest it without shame: "The important thing is to make a very convincing documentary about building the clock and hiding it.
		The only clocks that have ever really survived over the long run (like the water clock of Su Sung, or the giant hourglass of Uqbar) have survived in books, drawings, and stories.
	www.longnow.org /projects/clock (1434 words)

	Science NetLinks: Building a Water Clock
		In the first part of the activity, the class will investigate how a water clock works and the effect of one of its variables on its ability to be an accurate timepiece.
		Tell students: Early water clocks were stone vessels with sloping sides that allowed water to drip at a nearly constant rate from a small hole near the bottom.
		Other water clocks were bowl-shaped containers that slowly filled with water at a constant rate.
	www.sciencenetlinks.com /lessons.cfm?BenchmarkID=11&DocID=2 (1392 words)

	Long Now > Projects > Clock > Principles
		With occasional maintenance, the clock should reasonably be expected to display the correct time for the next 10,000 years.
		It should be possible to determine operational principles of the clock by close inspection.
		It should be possible to build working models of the clock from table-top to monumental size using the same design.
	www.longnow.org /projects/clock/principles (248 words)

	Medieval Clocks (Site not responding. Last check: 2007-10-21)
		In the period that clocks of this type were used the day was devided into 12 daylight 'hours' and 12 dark 'hours'.
		This is also a greek water clock, called a clepsedra (water thief) Rasing and lowering D would allow more or less water to flow into F to adjust for the differnt lenght of the hour during differnt seasons Again I'm making educated guesses.
		Hezekiah and the water clock, illustration II (IV) Kings 20.1-11 with it's 'moralizing' equivalent, Doubting Thomas, from the Bible Moralisee: Paris c.1235-45 (MS Bodl.
	jim-diana-hart.home.att.net /clock.html (444 words)

	Water Clock by Furuya-Labrats
		section of the river floating above itself, the Water Clock / Prosthetic Stomach is a Decomposition Chamber and Environmental Metabolizer, a slowly deteriorating record of the event and a climatic transformer.
		n exhibition subject travelling between places and retaining their traces, the Water Clock is a mysterious floating beacon at night and a bristling exhibition chamber during the day, displaying artifacts of the route in suspended time, in decaying time, in travelling time, in instantaneous time.
		n instrument of amplification, both of the momentary and the impercepatably slow, the device of the floating Water Clock is a collector of the environment, an artificial metabolizing system ingesting its surroundings to be recreated in an alternate form.
	www.atomicsky.com /cow/groups/clock/clock.html (230 words)

	Neowin.net > Real Goods really offers real water-powered clock (Site not responding. Last check: 2007-10-21)
		The only water clock I know of is at the Children's Museum here in Indianapolis and unless technology has come that far to reduce the size of this (which has to be upright, mind you), then I totally doubt it.
		Water molecules are polarized, giving them a slight charge at opposite ends.
		Of course it's not really powered by water; you pour a little water inside and it serves as the electrolyte in a primitive battery (well, techically just one single cell, not a battery, but that's a fine distinction).
	www.neowin.net /forum/lofiversion/index.php/t273712.html (624 words)

	Water Clocks
		(“water thief”) by the Greeks, who began using them about 325 B.C., these were stone vessels with sloping sides that allowed water to drip at a nearly constant rate from a small hole near the bottom.
		Since the rate of flow of water is very difficult to control accurately, a clock based on that flow can never achieve excellent accuracy.
		clepsydra - clepsydra or water clock,ancient device for measuring time by means of the flow of water from a...
	www.factmonster.com /ipka/A0855491.html (495 words)

	Ancient Egypt Water Clocks (Site not responding. Last check: 2007-10-21)
		It is a instrument for measuring time by the flow of water through a small orifice.
		Hours were marked on the sides of either sides of the bowl that received the water.
		It was much better than wasting land using shadow clocks, and it was used in three different countries.
	www.up140.jacksn.k12.il.us /Egypt99/Sullivan/water.htm (357 words)

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