-
3500 BCE
Obelisks
Tall 4-sided structures that were used to tell time based on their shadows -
1500 BCE
Sundials
Shadow clocks first used by ancient Egyptians -
600 BCE
Merkhet
Handheld Egyptian shadow clocks that allowed telling time when the sun was down. -
325 BCE
Waterclock
A type of clock that measured time by passing water through a small hole. -
25 BCE
Vituvius' Ten Books on Architecture
Vitruvius describes >13 styles of sundials across Greece, Italy and Asia Minor. -
Dec 24, 1088
Song Dynasty Astronomical Clock
Water driven complex mechanism designed by Su Song in China. -
Pendulum Clock
Christiaan Huygens invented the first pendulum clock. This clock would keep time accurately to one minute per day. -
Quartz Clock
First clock developed by passing an electric current through quartz and counting the vibrations to determine 1 second. -
Atomic Clock
The first atomic clock used the vibrations of caesium atoms to determine 1 second.