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3500 BCE
Egyptians tell time
Ancient Egyptians used the shadows cast by the sun on obelisks to tell the time. -
1500 BCE
First believed water clock
No one is sure when the first water clock was invented, however, what is believed to be one of the first water clocks was excavated from the tomb of the Egyptian pharaoh Amenhotep I. -
400
Greek water clocks
Greeks have proven use of water clocks, using water flowing from a vessel to measure time. -
980
Burning Candles
Burning candles are used to tell the time. This phenomenon was started by Alfred the Great. -
1370
Bells
In France, it was decreed that all church bells must ring in unison with the bells in the Royal Palace, ending the ringing of church bells at prayer times. -
Mechanical clock
The first mechanical clock, using a mainspring, balance wheel, and pendulum was invented by Christian Huygens.. -
Telegraph
The telegraph was invented, allowing the transmission of time signals. -
Time Ball
The Time Ball is dropped at noon each day at the U.S Naval Observatory, allowing ships in the harbor to set their on-board clocks. -
Greenwich Meridian
London, England is accepted as the Prime Meridian (zero degrees longitude). This becomes the basis for time throughout the globe. -
Washington signal
A radio signal is transmitted from Washington D.C to help ships find longitude. -
Wristwatches
The first self-winding (automatic) wristwatch is invented by a British watch repairer, John Harwood. -
Atomic Clock
The National Bureau of Standards builds the first atomic clock, using ammonia. -
Definition of the second
One second is defined as 9,192,631,770 vibrations of the cesium atom. -
Digital wristwatch
The first digital Pulsar watch was invented by Hamilton Watch Co. founded by George H. Theiss.