History of TimeHistory of Time

Prime Time Team:Prime Time Team:Gale, Jen, and ShirleyGale, Jen, and Shirley

Trip Through TimeTrip Through Time

• Can you measure the time of day by Can you measure the time of day by gazing at the sun’s shadow?gazing at the sun’s shadow?

• How does the flow of water aid in the How does the flow of water aid in the measure of time?measure of time?

• What did the Chinese burn to tell time?What did the Chinese burn to tell time?

• Let’s take a “Trip Through Time” to Let’s take a “Trip Through Time” to discover the answers to these ancient discover the answers to these ancient timekeeping secrets.timekeeping secrets.

TimelineTimeline1500 – 1300 BC1500 – 1300 BC

SundialsSundials• Egyptians measured the time of day by Egyptians measured the time of day by

using sundials. Sundials rely on the sun to using sundials. Sundials rely on the sun to tell time. These early timekeepers tell time. These early timekeepers discovered that hours are shorter in the discovered that hours are shorter in the winter and longer in the summer. winter and longer in the summer.

• Sundials can only be used during the day Sundials can only be used during the day to tell time.to tell time.

TimelineTimeline400 BC400 BC

Water ClocksWater Clocks• Discovered by the Greeks these clocks Discovered by the Greeks these clocks

measured time by observing the overflow of measured time by observing the overflow of water from a container. water from a container.

• Made of two containers, water drips from the Made of two containers, water drips from the higher container to the lower container. The higher container to the lower container. The point at which the water is collected raises a point at which the water is collected raises a floating device which triggers the pointer to floating device which triggers the pointer to mark the hour.mark the hour.

• These clocks worked better than the sundial These clocks worked better than the sundial because they were able to tell time at night.because they were able to tell time at night.

• In later years these clocks were adopted by the In later years these clocks were adopted by the American Indians.American Indians.

TimelineTimeline980 - 1000980 - 1000

• CandlesCandles

• The candle was used as the first alarm clock The candle was used as the first alarm clock by placing a nail into the side of the candle by placing a nail into the side of the candle wax, waiting for the wax to melt, and the wax, waiting for the wax to melt, and the eventually nail crashes into a pan.eventually nail crashes into a pan.

• The Chinese not only burned candles to The Chinese not only burned candles to mark time, but also burned incense as a mark time, but also burned incense as a measurement of timemeasurement of time

TimelineTimeline13701370

• BellsBells• King Charles V of France decided that all King Charles V of France decided that all

Paris church bells must ring at the same Paris church bells must ring at the same time as the Royal Palace. This stopped time as the Royal Palace. This stopped the ringing of bells during prayer time.the ringing of bells during prayer time.

• The name “Clock” originally meant “Bell.” The name “Clock” originally meant “Bell.”

TimelineTimeline14001400

• Mechanical ClocksMechanical Clocks• TheseThese clocks were built in Europe, using a clocks were built in Europe, using a

mainspring and balance wheel.mainspring and balance wheel.

• The problem with these clocks was that The problem with these clocks was that they would slow down when the main they would slow down when the main spring unwound. spring unwound.

• To eliminate this problem, a fusee, or spiral To eliminate this problem, a fusee, or spiral pulley, was invented.pulley, was invented.

• A fusee is a cone-shaped grooved pulley A fusee is a cone-shaped grooved pulley used with a barrel containing the used with a barrel containing the mainspring.mainspring.

TimelineTimeline1500 - 16001500 - 1600

• PendulumPendulum• In 1583 Galileo Galilei discovered that the rate of a In 1583 Galileo Galilei discovered that the rate of a

pendulum swing depends on its length.pendulum swing depends on its length.• Christian Huygens invented the pendulum clock around Christian Huygens invented the pendulum clock around

1656. 1656. • As the pendulum swings left to right, a wheel with teeth As the pendulum swings left to right, a wheel with teeth

turns the hour and minute hands.turns the hour and minute hands.• The second hand on the clock was developed at this time.The second hand on the clock was developed at this time.• This clock was more accurate than any previous clock This clock was more accurate than any previous clock

invented.invented.

TimelineTimeline17001700

• NavigationNavigation• In 1714 the British Parliament offered a In 1714 the British Parliament offered a

cash reward to anyone that could invent cash reward to anyone that could invent an accurate clock for use at sea.an accurate clock for use at sea.

• In 1759 John Harrison built a tiny pocket In 1759 John Harrison built a tiny pocket watch that only lost 5 seconds in 6 ½ watch that only lost 5 seconds in 6 ½ weeks.weeks.

TimelineTimeline18001800

•InventionsInventions• The telegraph was invented in 1839. This invention The telegraph was invented in 1839. This invention

allowed instant transmission of time signals. allowed instant transmission of time signals. • In 1840 the first battery clock used an electrical In 1840 the first battery clock used an electrical

impulse to operate the dials of a master clock.impulse to operate the dials of a master clock.• Throughout the 1850s regional time zones were Throughout the 1850s regional time zones were

established. established. • Twenty-five countries accepted Greenwich, Twenty-five countries accepted Greenwich,

England as the Prime Meridian. Eventually, the England as the Prime Meridian. Eventually, the Prime Meridian became the base of time Prime Meridian became the base of time throughout the world.throughout the world.

TimelineTimeline18001800

• InventionsInventions• In the early 1800’s Eli Terry mass-produced In the early 1800’s Eli Terry mass-produced

interchangeable parts for clocks. This made interchangeable parts for clocks. This made clocks affordable to all people.clocks affordable to all people.

• 1886 R.W. Sears Watch Co. sold watches 1886 R.W. Sears Watch Co. sold watches across America.across America.

TimelineTimeline19001900

• Modern TimepiecesModern Timepieces• In the early 1900’s women wore the wrist watch In the early 1900’s women wore the wrist watch

while men only used pocket watches. Because of while men only used pocket watches. Because of the war, soldiers needed to tell time quickly. As a the war, soldiers needed to tell time quickly. As a result wrist watches became a socially accepted result wrist watches became a socially accepted fashion for men.fashion for men.

• In 1928 W.A. Marrison of Bell Labs built the first In 1928 W.A. Marrison of Bell Labs built the first quartz watch. quartz watch.

• Quartz is a type of crystal that vibrates when you Quartz is a type of crystal that vibrates when you apply an electrical charge and pressure. This apply an electrical charge and pressure. This vibration moves the clock’s hands at a constant vibration moves the clock’s hands at a constant rate and is very precise.rate and is very precise.

• Quartz was later used to make wrist watches.Quartz was later used to make wrist watches.

TimelineTimeline19001900

•Modern InventionsModern Inventions• In 1945 Physicist Isador Rabi experimented with In 1945 Physicist Isador Rabi experimented with

building a clock using atoms. This method was building a clock using atoms. This method was known as atomic-beam magnetic resonance.known as atomic-beam magnetic resonance.

• In 1949 the first atomic clock using ammonia was In 1949 the first atomic clock using ammonia was built.built.

• In 1967 the first atomic clock using the cesium In 1967 the first atomic clock using the cesium atom was built. Time no longer depends on atom was built. Time no longer depends on astronomical bodies. astronomical bodies.

• For every 1.4 million years, the clock will off by 1 For every 1.4 million years, the clock will off by 1 second.second.

TimelineTimelineTriviaTrivia

• Daylight Savings Time/War TimeDaylight Savings Time/War Time• Although Ben Franklin originally had the Although Ben Franklin originally had the

idea in 1784, daylight savings time was idea in 1784, daylight savings time was not adopted in the U.S. until World War I. It not adopted in the U.S. until World War I. It was a way to save fuel needed to produce was a way to save fuel needed to produce electric power.electric power.

• In 1966 Congress established the Uniform In 1966 Congress established the Uniform Time Act. Daylight savings time was Time Act. Daylight savings time was implemented throughout the nation.implemented throughout the nation.

• ½ a billion watches are sold each year.½ a billion watches are sold each year.