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water clocks and sun dials
water clocks and sundials were both earlier forms of keeping track of time that donot have known inventors.water clocks use the flow of water in or out of a marked container.The earliest found water clock was made around 1500bcand foundin the tomb of Ahmotep in Egypt.Sundials use the suns position to decide what time it is.The earliest sundial was made in 3500bc.http://www.ancient-origins.net/ancient-technology/ancient-invention-water-clock-001818 ttp://www.britannica.com/technology/sundial -
Oct 7, 1250
mechanical clock
Mechanical clocks differed from earlier methods of time keeping in that they had something called an escapement. This idea was first thought of by the French architect Villard de Honnecourt 1250. The escapement allowed for the internal gears to move at steady pace and worked based on the laws of inertia. http://www.uh.edu/engines/epi1506.htm -
pendulum clock
Christiaan Huygens in 1656 created the first pendulum clock. This clock was based off of galileos earlier principles of a pendulum. As stated in the name this clock started the use of pendulums in clocks making them more precise. but this clock does not work at sea. http://www.infoplease.com/ipa/A0855495.html
http://www.time-for-time.com/timeline.htm -
The Shortt Free Pendulum Clock
william harrisison shortt invented this clock. The difference between the shortt clock and the original pendulum clock was that the short clocks was that it's pendulum swung in a vacum filled copper tank. this lessens the aerodynamic drag on pendulum which provides less variation on the swing of the pendulum.
http://www.clockvault.com/heritage/ -
quartz clock
Warren Marrison built the first quartz clock. Quartz crystal was used to differentiate this clock from the rest. Quartz can generate an electrical feild and vibrate when put in a proper electrical circut.The clock could now use the vibrations of the quartz crystal. This allowed a more reliable replacement of earlier escapements and pendulums http://inventors.about.com/od/cstartinventions/a/clock.htm#quartz
http://www.infoplease.com/ipa/A0855498.html -
Atomic clock
The first atomic clock was built in in 1949 by the NBS. this clock uses atomic particles as its scource of vibrations. The first atomic clock was powered by the vibrations of amonia particles. All atomic clocks are based on a technique that Isidor Rabi suggested called atomic beam magnetic resonance. This technique was made in 1930 and surpasses quartz watches as far as precission goes.
http://science.howstuffworks.com/atomic-clock4.htm
