History of Time
Prime Time Team:
Gale, Jen, and Shirley
Trip Through Time
• Can you measure the time of day by gazing at
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the sun’s shadow?
How does the flow of water aid in the
measure of time?
What did the Chinese burn to tell time?
• Let’s take a “Trip Through Time” to discover
the answers to these ancient timekeeping
secrets.
Timeline
1500 – 1300 BC
Sundials
• Egyptians measured the time of day by using
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sundials. Sundials rely on the sun to tell time.
These early timekeepers discovered that
hours are shorter in the winter and longer in
the summer.
Sundials can only be used during the day to
tell time.
Timeline
400 BC
Water Clocks
• Discovered by the Greeks these clocks measured
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time by observing the overflow of water from a
container.
Made of two containers, water drips from the
higher container to the lower container. The point
at which the water is collected raises a floating
device which triggers the pointer to mark the hour.
These clocks worked better than the sundial
because they were able to tell time at night.
In later years these clocks were adopted by the
American Indians.
Timeline
980 - 1000
• Candles
• The candle was used as the first alarm clock by
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placing a nail into the side of the candle wax,
waiting for the wax to melt, and the eventually
nail crashes into a pan.
The Chinese not only burned candles to mark
time, but also burned incense as a measurement
of time
Timeline
1370
• Bells
• King Charles V of France decided that all
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Paris church bells must ring at the same time
as the Royal Palace. This stopped the ringing
of bells during prayer time.
The name “Clock” originally meant “Bell.”
Timeline
1400
• Mechanical Clocks
• These clocks were built in Europe, using a
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mainspring and balance wheel.
The problem with these clocks was that they
would slow down when the main spring
unwound.
To eliminate this problem, a fusee, or spiral
pulley, was invented.
A fusee is a cone-shaped grooved pulley used
with a barrel containing the mainspring.
Timeline
1500 - 1600
• Pendulum
• In 1583 Galileo Galilei discovered that the rate of a pendulum
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swing depends on its length.
Christian Huygens invented the pendulum clock around 1656.
As the pendulum swings left to right, a wheel with teeth turns
the hour and minute hands.
The second hand on the clock was developed at this time.
This clock was more accurate than any previous clock invented.
Timeline
1700
• Navigation
• In 1714 the British Parliament offered a
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cash reward to anyone that could invent an
accurate clock for use at sea.
In 1759 John Harrison built a tiny pocket
watch that only lost 5 seconds in 6 ½ weeks.
Timeline
1800
• Inventions
• The telegraph was invented in 1839. This invention
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allowed instant transmission of time signals.
In 1840 the first battery clock used an electrical
impulse to operate the dials of a master clock.
Throughout the 1850s regional time zones were
established.
Twenty-five countries accepted Greenwich, England
as the Prime Meridian. Eventually, the Prime Meridian
became the base of time throughout the world.
Timeline
1800
• Inventions
• In the early 1800’s Eli Terry mass-produced
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interchangeable parts for clocks. This made
clocks affordable to all people.
1886 R.W. Sears Watch Co. sold watches
across America.
Timeline
1900
• Modern Timepieces
• In the early 1900’s women wore the wrist watch while
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men only used pocket watches. Because of the war,
soldiers needed to tell time quickly. As a result wrist
watches became a socially accepted fashion for men.
In 1928 W.A. Marrison of Bell Labs built the first
quartz watch.
Quartz is a type of crystal that vibrates when you
apply an electrical charge and pressure. This vibration
moves the clock’s hands at a constant rate and is very
precise.
Quartz was later used to make wrist watches.
Timeline
1900
• Modern Inventions
• In 1945 Physicist Isador Rabi experimented with
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building a clock using atoms. This method was known
as atomic-beam magnetic resonance.
In 1949 the first atomic clock using ammonia was
built.
In 1967 the first atomic clock using the cesium atom
was built. Time no longer depends on astronomical
bodies.
For every 1.4 million years, the clock will off by 1
second.
Timeline
Trivia
• Daylight Savings Time/War Time
• Although Ben Franklin originally had the idea
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in 1784, daylight savings time was not adopted
in the U.S. until World War I. It was a way to
save fuel needed to produce electric power.
In 1966 Congress established the Uniform
Time Act. Daylight savings time was
implemented throughout the nation.
• ½ a billion watches are sold each year.