CLOCKS
THROUGH TIME
It
was probably around 3,000 years ago that people first
began making things to
help them measure the passage of
time.
Having observed that shadows move
around trees as the sun moves
across the sky, someone drew a circle
and put a stick in the centre. As the sun passed overhead,
he marked even divisions
on the circle as the shadow of the stick crossed it.
Then people could tell which part of the
day it was by noticing which marks
on the circle the shadow fell across.
These circles were called "sundials". Later, they were made of stone and metal
to last longer.
Of
course, a sundial did not work at night or
on cloudy days, so men kept
inventing other ways
to keep track of time. One invention
was a striped candle. Each stripe took
the same amount of time to melt.
If each stripe melted in about an hour, about three hours would have passed
when three stripes melted.
A water
clock was another way to tell time. A container had
a line with a number beside
it for every hour. It also had a tiny hole
in the bottom. The container was filled
with water that dripped through
the hole. When the water level reached the first line, people
knew that an hour had passed. Each time the water level fell to another line,
one more hour had passed.
Candles
and water clocks helped people
know how much time had gone by. But candles had to be remade,
and water clocks had to be refilled. So, after glass
blowing was invented, the hourglass
came into use. Glass bulbs were joined by
a narrow tunnel of glass, and
fine, dry sand was placed
in the top bulb.
The hourglass was easy to use, but it had to be turned
over every hour so the sand could flow again.
It
was about 600 years ago that the first clock with a face and
an hour hand was made. One of
the first such clocks was built for a king of France
and placed in a tower of the royal palace.
The clock did not show minutes or
seconds.
Usually it did not even show the correct hour! Since there were on planes or trains
to catch, however, people were not concerned
about knowing the exact time.
Gradually,
clocks began to be popular. They still did not keep
correct time, but they were unusual,
and they could be beautifully decorated. One clock was in the shape
of a cart with a horse and driver.
One of the wheels was the face of
the clock.
Watches came into use as soon as clocks
were made small enough to be carried.
These did not always tell the correct time, either.
They were often put into beautiful watchcases,
which were made to look like anything the owner
wanted.
The
pendulum
clock was
invented in 1657. This was the beginning of the style
of clocks we call "grandfather clocks"
which were enclosed in tall wooden
boxes.
Pendulum
clocks showed the hours more exactly than
earlier clocks since the weight on the pendulum could be moved
up or down to make the clock go faster or slower . About forty years
later, minute and second
hands were put on some clocks. Grandfather clocks are
very much in demand again today. They are usually very expensive,
however, and require more space than
other styles of clocks.
As
people began to go to more places and
do more things, they were more interested knowing
the correct time. By 1900, almost every house had
a clock, and nearly every well-dressed gentleman wore
a watch on a chain tucked
in his vest pocket.
Today,
of course, we have electric
clocks that keep giving the
right time until they are unplugged
or the electricity goes off. Scientists have invented
clocks that look like large machines
and tell the correct time to a split second.
The
most modern electric clocks for home use
do not have faces or hands. These clocks are called digital
clocks, and they tell the time
with a set of numerals which appear
in a little window.
The seconds are counted
off like the tenths of
a mile on the odometer of
a car.
Many
electric clocks are combined with radios,
which can sometimes be set to turn on automatically.
Thus, instead of an alarm ringing in
your ear in the morning,
you can hear soft music
playing when it is time to get
up. Some clocks will even start the
coffee
maker!
Although
clocks and watches play an important part in people's
lives in industrialized countries,
time is still regarded in very different ways in
different parts of the world.
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