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3000 BCE
Obelisk
Early Egyptians told time by the shadow cast by the sun on an stationary object, the obelisk. -
Period: 3000 BCE to
The History of Telling Time
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1500 BCE
Water Clock (Clepsydra)
The early Greeks and Egyptians designed a water clock. It used the flow of water to measure time. The water reaching certain lines drawn on the container showed that a certain amount of time had passed. -
1500 BCE
Burning Rope
In ancient China, people tied knots at regular intervals on a rope and burned it to show passage of time. -
520 BCE
Candles
People used notches in candles to represent periods of time. How much time passed depended on how many notches had been burned since the candle was lit. -
300 BCE
Sundial
By 300 BCS, the Babylonians started using a sundial with a 12-hour clock face. -
1000
Hourglass
By the 11th century, Europeans used the hourglass, which could be used day or night. -
1300
Mechanical Clocks
These clocks used physics principles of weights and balances to mark out increments of time over a 12-hour period. Unfortunately, they weren't very accurate yet. -
1400
Watches
Timepieces that people could wear or carry appeared in Italy. They measured time through a system of coiled springs. -
Pendulum Added to Mechanical Clocks
Scientists and inventors in Europe discovered the adding a pendulum greatly increased a clock's accuracy and preciseness. It could also now record minutes and seconds as well as hours. -
Standard Time
Standard time was a way for people from all over the world to standardize to meet common needs. Standard time divides the earth from top to bottom into 24 equal time zones. -
Digital Clock
The first digital clock was invented. -
Atomic Clock
The atomic clock is the most accurate time-keeping device invented so far. The materials have changed since it was first developed in the 1940s. -
Universal Time Coordinate
This was a new, highly accurate system that was adopted around the world as the official measure of time for the planet.
