constant, or repetitive action
(or process) that will effective-
ly mark off equal increments
of time. For example, in the
old days before our battery-
driven, analog and digital
clocks and watches, “clocks”
included marking candles in
even increments, or using a
specific amount of sand in an
hourglass to measure time.
Second, there has to be a
way to keep track of the time
increments and easily display
the results. This eventually led
to the development of watch-
es, large clocks such as Big
Ben in London, England, and
even the clocks that count
down the New Year. The most
accurate clocks today are
atomic clocks, which use an
atomic frequency standard as
the counter.What was the driving force
behind the developmentof
accurate clocks?
The true driving force behind
accurate clocks began around
the 16th century in relation to
finding longitudinal measure-
ment. As countries began to explore the world, an accurate way of telling a ship’s posi-
tion became a critical problem. With one time standard around the world (and clocks
to tell those times), longitude, and thus position, could be determined. This would not
only mean an increase in exploration but also wealth for the sponsoring country.How was (and is) one second defined?
A second was once defined as 1/86,400 of a mean solar day. By 1956 this definition was
58 changed by the International Bureau of Weights and Measures to 1/31,556,925.9747 of
One of the most famous clocks on Earth is Big Ben in London,
England. Although today’s digital and atomic clocks are much
more accurate, the charm of an old-fashioned analog clock still has
its appeal. Lonely Planet Images/Getty Images.