TY_Chronology-Unit_Aisling_White-1

Time
Chronology and Horology
Transition Year
Unit 1

Coláiste Chú Chulainn

Irish Museum of Time –
Waterford

Aims for this Unit
• Writing a clear, accurate and easy to follow method
• Identifying factors that affect a phenomenon
• Identifying common experimental errors
• Practicing graphing accurately and clearly

History of Timekeeping
Why is time divided into 12 hours?
A. The
Using
number
the
10 had
thumb,
not even been
and
invented
pointing
yet. Key numbers
to each
like
of
0 were
not the invented three for a finger long time as bones number systems on each developed finger slowly in among
ancient turn, civilisations. it is possible for people to count on
B. There their were fingers 6 main times to of 12 day on – Dawn, a single Morning, Midday, hand. Afternoon,
Evening, Night. By dividing the time between these 6 time periods in two, the
The Ancient Babylonians adopted this
day was split into 12 sections.
from the Sumerians, who were using it as
C. An
early
ancient people
as 3500
used parts
BC.
of their body to count, and the easiest part was
divided into twelve useful sections.

Easiest method to measure the time?

Making a sundial
Method:
- Mark where the shadow falls on your paper plate.
- Round to the nearest hour and label the shadow.
- Return an hour later, place the sundial in the exact same
space and place a new mark.
Things to think of:
What are the shortcomings of this method?

What other ways were used to tell time?

Water clocks
• Greek inventor and mathematician Ctesibius invented the
first artificial automatic self-regulatory system by designing
an improved water clock or clepsydra (water thief).
• Ctesbius's clepsydra (try saying that five times fast) kept
more accurate time than any clock invented until 1656.

Candle CLocks
• A thin candle with consistently spaced marking that, when
burned, indicates the passage of periods of time.
• While no longer used today, candle clocks provided an
effective way to tell time indoors, at night, or on a cloudy
day.

hourglass
• An hourglass has two glass bulbs connected by a narrow neck that allows a
regulated flow of a substance (historically sand) from the upper bulb to the lower
one.
• Hourglasses were very popular on-board ships, as they were the most
dependable measurement of time while at sea.
• The motion of the ship while sailing did not affect it
• Temperature changes don’t cause evaporation/condensation

“TIME”LINE

WAIT!
Christiaan huygens
Keep in mind! Christiaan’s father was an incredibly rich and influential
diplomat, who was friends with Galileo, Descartes and Mersenne.
Christiaan was individually tutored by some of the finest minds in
• Dutch mathematician, physicist, engineer, astronomer, and inventor
Europe and went to very expensive, prestigious colleges.
• In physics, Huygens made ground-breaking contributions in optics
and mechanics, while as an astronomer he is chiefly known for his
studies of the rings of Saturn and the discovery of its moon Titan.
At 25, Christiaan was able to move home to live in the family palace, no
job required.
• As an engineer and inventor, he improved the design of telescopes
and invented the pendulum clock, a breakthrough in timekeeping and
the most accurate timekeeper for almost 300 years.
Sometimes incredibly talented physicists just had a LOT of free
time/money on their hands! Being “naturally talented” is not the reason
for their success!!

Pendulums
What factors affect how
long it takes for one full
swing?

Experiment: Pendulum investigation
•What variables do we have? (independent, dependent, controlled?)
•How many variables can we change at a time?
•What errors can we predict?
•How can we measure the time taken for one full swing as accurately as
possible?

Does Mass Affect the period of a pendulum?
Mass of Pendulum Bob
Time Taken for 1 pendulum swing

Does angle Affect the period of a pendulum?
Angle of Incline
Time Taken for 1 pendulum swing

Does string length Affect the period of a pendulum?
Length of String
Time Taken for 1 pendulum swing

Making a good graph
❑ Title of Graph
❑ Axis Labels
❑ Accurate Scale
❑ Careful data points
❑ Best Fit Line
Make sure you use a sharp pencil and a long ruler, and
take up the whole sheet of graph paper – no minigraphs!