It is possible to keep track of the time without the help of any sort of
devices. All one need do is look up at the position of the Sun, and it can give
a fair estimate of the time of day. One can also examine the stars at night to
give an estimate of the time when you can no longer see the Sun.
Sundial
In order to keep more accurate track of the time, however, men have sought
to build devices for the purpose. The first device used to keep track of the
time was the sundial. First used in Mesopotamia ca. 3500
BCE, it was comprised of a rod or plate that was affixed to a disc. The Sun
would cast a shadow from the rod onto the disc, telling the Sun’s position and
thus the time of the day.
Water Clock
Another early developed timekeeping device was the water clock. Its exact
origins are unknown, but water clocks have been found dating as far back as
1500 BCE in ancient Egypt.
The device works by allowing water to pass through a small aperture of the
clock at a certain rate. By watching this flow of water you will be able to
tell what time it is, even at night as it was not based upon the Sun. Water
does not always flow at a consistent rate, however, so this device was not
perfectly accurate.
Hourglass
The origins of the hourglass are not exactly certain. They might have been
used as early as the 11th century CE, although we do not have assured evidence
of their existence until the 14th century. Hourglasses are composed of a single
piece of glass which is separated into two bowls. There is a narrow opening
allowing sand to fall from one bowl to the other. The amount of time taken for
all of the sand to fall from the top to the bottom would be about an hour, or
whatever amount of time the hourglass maker wanted to keep track of.
Mechanical Clock
It is also in the 14th century that we see the first mechanical clocks being
developed. Although very crude in design, these devices were the first able to
accurately measure a consistent unit of time. The original mechanical clocks
ran on a system of falling weights. Mechanical clocks are still in use today.
In the 16th century, a new development arose. This was the mechanical clock,
which was run on a coil mainspring. It allowed individuals to carry the time
with them for the first time in the history of the world. The watch is a vital
element in the lives of people today, and mechanical clocks are still in use.
Pendulum Clock
The pendulum clock was invented in the middle of the 17th century by a Dutch
physicist named Christiaan Huygens (1629-95). The passing of time was based on
the natural swing of a pendulum, which would give an even more accurate showing
of the time than the mechanical clock.
Quartz Clock
The development of the clock has been a constant struggle to create the most
accurate clock possible. In 1927, a man by the name of W.A. Marrison invented
the quartz clock.
When exposed to an electronic field, quartz vibrates at a constant
ultrasonic frequency that would provide the frictionless beat needed to operate
the clock. It was the most accurate clock yet invented, and could keep time to
the thousandth of a second.
Atomic Clock
The quartz clock was beat for accuracy in 1948 with the atomic clock. It
keeps track of time by monitoring the vibrations of a caesium atom, and is able
to keep track of time to the billionth of a second.