Clocks from early to modern civilization

1. CLOCK

2. CONTENTS
• Introduction
• How Do People in early civilisation tell time
• Clocks of Modern Civilisation
• Time Display Methods
• Various Designs of clock

3. Introduction
• Clock is a device that tells the time.Some clock can give the date as
well as time and also other information.
• The word clock is derived ultimately from the Celtic words clagan
and clocca meaning “bell".
• It is one of the Oldest Human Inventions,meeting the need to
consistently measure intervals of time shorter than the natural units:
the day, the lunar month, and the year.
• Clocks use different ways to measure time.Ancient clock use
sun,sand, water,candle and Modern clock use some mechanical or
electromechanical machine for measuring time.
• The evolution of the technology of clock continues today.
• The study of clock i.e., timekeeping is known as Hormology.

4. How Do People in Early Civilisation
Tell Time
Devices that early civilisations used to tell the time are:
• Sundials
• Water Clock
• Candle Clocks
• Incense Clocks
• Hourglass clock

5. Sundial Clock
• Sundial shows time by displaying the
position of sun shadow on a flat surface
which has marking corresponds to hour.
• Ancient Egyptians invent it.
• It is widely used in ancient times.
• Sundials continued to be used to monitor
the performance of clocks of modern era.
• These early timekeepers also discovered
that hours are shorter in the winter while
longer in the summer.
• But sundials work only when the sun
shines,which encourage the use of other
technique for measuring and displaying
time.

6. Water Clock
• Water clock is any timepiece in
which time is measured by the
regulated flow of water either into
or out from a vessel.This vessel
has marking that are used to show
the passage of time.
• Where and when they first
invented is not known.
• This clock remove the cons of
sundial as it works day as well
as night.

7. The candle and incense clock work on the same
principle to tell time but the consumption of resources
is more or less.
Candle Clock:
• A candle clock has consistent spaced markings on
it .When it is burned the candle becomes lower and
lower, where the top of the candle at any given
point tells the time,how many hours have passed.
• It is usually used approximately 1400 years ago
to tell time at night.
Incense Clock:
• An incense clock was an incense stick with
calibrations,sometimes threads with weights attached
at given intervals.The weights would drop onto a
platter,signifying that a certain time had elapsed.
• Sticks of incense with different scents were also used,
so,that hours were marked by a change of fragrance.
Candle & Incense Clock

8. Hourglass Clock
• Hourglass clock mark passage of time without
respect to reference time or useful for
measuring hour.That’s why it is called hourglass
clock.
• It contain two glass bulbs connected
vertically by narrow neck that allows a regulated
trickle of material (Historically sand) from the
upper bulb to the lower one.That’s why it is also
known as sand clock in ancient times.
• Today the material used in most bulbs was a
combination of "powdered marble, tin/lead
oxides, burnt eggshell”.
• It is reused by inverting the bulbs once the
upper bulb is empty.
• sand-glass was invented at Alexandria about 150
BC.

9. Clocks Of Modern Civilisation
• Spring-Driven clock
• Pendulum Clock
• Electronic clock
• Quartz clock
• Bedol water clock
In Modern Civilisation Various mechanical and Electro-
mechanical equipments are used to tell time. Various clocks of
modern civilisation are:

10. Spring-Driven Clock
• Spring-driven clocks appeared during the 15th
century. It wound up with a key.
• This clock contain:
• A dial or hands: which indicate the time.
• Spring: is its timekeeping element which is a
harmonic oscillator(Device that generate current
by non electrical means).
• Timekeeping gears: drive the different hands
around clock face.
• Working: When Clock is wound up with key it twist
the mainspring tighter and stores energy in it.This
energy turns set timekeeping gears, which drive the
different hands around clock face over certain period
of time. Winding the clock again twist the spring back
up, storing more energy to turn gears that are then
stopped.
• The disadvantage of it is :when the wound spring
starts to get to the end of its stored energy the second
hand slows down until the spring is wound back up.
Dial
Spring
Gears

11. Pendulum Clock
• It is invented in 1656 by Christiaan Huygens.It is also
wound up with key.
• Pendulum clock uses a pendulum(A weight on a rod)
as its timekeeping element.It is a harmonic oscillator as
it generate current by swings back and forth in a precise
time interval dependent on its length,which drive clock
entire mechanism.
• This clock generally contain: Power source: weight on
a rod ,Timekeeping gear ,Dial or hands.
• A dial and hands indicate the time.
• A weight stores energy ,that turn a set
timekeeping gears as weight falls,which then drive
the different hands around the clock face at, over
the day.Winding the clock raises the weight back up,
storing more energy to power the mechanism.
• In wall clocks pendulum swings once per sec. , in small
cuckoo clocks the pendulum swing twice a sec. & In
large grandfather clocks, it swings once every two sec.

12. Electrical & Quartz clock
Electrical Clock:
• The first experimental electric clocks were
constructed around 1840.
• Electrical clock is somewhat similar to mechanical
clock.The Only difference is that it is powered by
electricity instead of hanging weight or a
mainspring. These are used before quartz clocks.
Quartz Clock:
• The first quartz clock was built in 1927 by Warren
Morrison and J.W. Horton.
• This clock uses an electronic oscillator that is
regulated by a quartz crystal resonator(Which is in
shape of small fruit folk) to keep time. This resonator
creates a signal with very precise frequency ,that drive
clock sec. hand which then min. than hour hand.
• It provides analog as well as digital display.
• It is the world's most widely used timekeeping
technology, used in most clocks and watches,
computers and other appliances that keep time.

13. Bedol Water Clock
• Bedol Water clock is the first eco-friendly clock ,
as it work on 100% natural power means it requires
no battery or electricity to function.By simply
filling it with water and few drops of lemon,you
can enjoy up to 6 months of hassle free time.
• The secret of this clock of this clock functioning is
completely chemistry magic : Inside of this clock
contain electrolytic cell ,or 2 metal posts, one
copper and one zinc.
• An electrolyte is simply a liquid in which the
metals are suspended, adding the water and
few drops of lemon completes the electrolytic
cell, allowing current to flow and power the
clock,which conducts electricity and show time.
• The advantage of it is that it is pollution free &
since run solely on water,thus helping to reduce our
carbon footprint on planet.

14. Time display Methods
• Analog clocks
• Digital clocks
• Auditory clocks
• Word clocks
• Tactile clocks

15. Analog & Digital
Analog Clock:
• Analog clocks indicate time using angles.It has
fixed numbered dials(usually 12 and 24) and
moving hands of hours,minutes & seconds by
which clock with fixed dials(12) can serves not only
as a scale of 12 hours,but also 60 min. & 60 sec.
• Some clocks also contain nano second hand.
• Sundial clock is a type of analog clock.
Digital clocks:
• Digital clocks display a numeric representation of
time. Two numeric display formats are commonly
used on digital clocks: the 24-hour notation & the
12-hour notation with AM/PM indicator.
• Digital clocks use electronic mechanisms and LCD,
LED, or VFD displays to display time.
Today on smartphones analog and digital both clocks
are displayed.

16. Auditory and Word
Auditory clock:
• Auditory clocks present the time as sounds. The sound is either
spoken natural language, (e.g.), or as auditory codes (e.g. number of
sequential bell rings on the hour represents the number of the hour
like the bell Big Ben represent 9 o’clock here).
• It us used for convenience, distance, telephony or blindness.
Word Clock:
• Word clocks are clocks that
display the time visually using
sentences. E.g.:"It’s about three
o’clock."
• These clocks can be implemented
in hardware or software.

17. Projection & Tactile
Projection Clock:
• Some clocks include an optical projector that
shines a magnified image of time onto a screen or
a surface such as an indoor or ceiling wall.
• The digits are large enough to be easily read,
without glasses, by persons with moderately
imperfect vision.
Tactile Clock:
• These clocks are designed for blind.It contain such
displays that can be read by using the sense of
touch.
• It is similar to analog displays, but are constructed
so that hands can be felt without damaging them.

18. Various Designs of Clock

19. Don’t Watch
The Clock
Do
What It Does
Keep Going…

20. -Neha Gupta
“Thank You”