The following are some landmarks in the history of telling the time.
1500 -1300 BC Sundials are used in Egypt as the earth rotates,
the gnomon - the upright part of the sundial - casts
shadow which moves to indicate the time.
1325 The first clock with a dial is installed in Norwich Cathedral, England
1350 The oldest known surviving alarm clock is made in wurzburg, Germany.
1364 Clocks are first used in people's homes.
1665 The first watches with minute and second hands are made.
1880 The first practical wristwatches are made for the German navy.
1949 The first atomic clocks is built in the USA.
1969 Quartz wristwatches are first sold in Japan.
2008 PARCS(Primary Atomic Reference Clock in Space). a super-accurate
laser-cooled caesium atomic clock, is tested on the international
Space Station(see image above).
Comments
Post a Comment