Pendulum Clock’s

Presented To:

Sir Arshad Subhani

Presented By:

Malik Ghulam Murtza

Class/section:

(B.C.S/1ST SEMESTER)/B

Roll No:

9226

DEPARTMENT OF COMPUTER SCIENCE

GARRISON POSTGRADUATE COLLEGE [M]

Scheme of Presentation

The history of time

History of pendulum clock

What is pendulum clock

How pendulum clock work’s

Types of pendulum clock’s

Brief discussion on pendulum clock’s

Uses of pendulum clock’s

Conclusion

References

The history of time(before pendulum clock)

Augustine and time

• Time as the dramatic marker of being human

• Several ways to conceptualize time:

• The ‘time-lessness’ of God

• The time of humans, something that cannot be fully comprehended and that connects the inside/outside

• The measuring of time does NOT mean understanding time, but as humans this is the best we can do

Starting to measure time: the

sunclocks

Athanasius Kircher’s sunclock

11th Century in China: the Su-Sung

(waterclock)

14th century Europe: church-clocks,

no minutes

Clock in the Salisbury Cathedral, 1386

History of pendulum clock

Galileo and Huygens: the study of

the pendulum

Galileo is credited with coming up with the concept of

a pendulum as an tool for measuring time, having

studied its motion as early as 1582. Although he drew up

design plans for a pendulum clock, Galileo died in 1642

before he could actually build one.

Dutch mathematician and astronomer Christian

Huygens is the man who is actually credited with the

invention of the pendulum clock, in 1656.

Christian Huygens and the pendulum

clock (ca. 1650s)

• The pendulum swings left and right, and as it swings, it turns a wheel with teeth. The turning wheel turns the hour and minute hands on the clock

• On the first pendulum clocks, the pendulum used to swing a lot (about 50 degrees). As pendulum clocks were improved, the pendulum swung a lot less (about 10 to 15 degrees)

• The first pendulum clock with external batteries was developed around 1840. By 1906, the batteries

Pendulum clock

What is pendulum clock

1) A pendulum clock is a clock that uses a pendulum, a swinging weight, as its time-keeping element.

‘Or’

2) A clock regulated by a pendulum.

First pendulum clock of the world

(Pendulum clock conceived by

Galileo Galilee around 1637. The earliest known pendulum clock design, it was never completed)

How pendulum clock works

How pendulum clock works

(1)

Introduction

There is a pendulum that is

shown inside. this is the

mechanical pendulum

clock.

How pendulum clock works (2)

Parts of Pendulum clock

Parts of Pendulum clock

• Pendulum clocks have been used to keep time since

1656, and they have not changed dramatically since

then:

(1)There is the face of the clock, with its hour and minute

hand (and sometimes even a "moon phase" dial).

(2)There are one or more weights (or, if the clock is more

modern, a keyhole used to wind a spring inside the clock

-- we will stick with weight-driven clocks in this article).

• And, of course, there is the pendulum itself.

• In most wall clocks that use a pendulum, the pendulum

swings once per second. In small cuckoo clocks the

pendulum might swing twice a second. In large

grandfather clocks, the pendulum swings once every two

seconds.

How pendulum clock works (3)

A Weighty Subject

A Weighty Subject

• The idea behind the weight is to act as an energy storage device so that the clock can run for relatively long periods of time unattended. When you "wind" a weight-driven clock, you pull on a cord that lifts the weight. That gives the weight "potential energy" in the Earth's gravitational field. As we will see in a moment, the clock uses that potential energy as the weight falls to drive the clock's mechanism.

How pendulum clock works (3)

A Weighty Subject

So let's say that we wanted to use a fallingweight to create the simplest possible clock-- a clock that has just a second hand on it.We want the second hand on this simpleclock to work like a normal second hand onany clock, making one complete revolutionevery 60 seconds. We might try to do that,as shown in the figure on the right, simplyby attaching the weight's cord toa drum and then attaching a second handto the drum as well.

How pendulum clock works (3)

A Weighty Subject

• This, of course, would not work. In this

simple mechanism, releasing the weight

would cause it to fall as fast as it could,

spinning the drum at about 1,000 rpm until

the weight clattered on the floor.

• Still, it's headed in the right direction. Let's

say we put some kind of friction device on

the drum -- some sort of brake pad or

something that would slow the drum down.

This might work. We would certainly be

able to devise some scheme based on

friction to get the second hand to make

approximately one revolution per minute.

But it would only be approximate. As the

temperature and the humidity in the air

How pendulum clock works (3)

A Weighty Subject

• Property of pendulum

The period (the amount of time it takes for a pendulum to goback and forth once) of a pendulum's swing is related only tothe length of the pendulum and the force of gravity. Sincegravity is constant at any given spot on the planet, the onlything that affects the period of a pendulum is the length ofthe pendulum. The amount of weight does not matter. Nordoes the length of the arc that the pendulum swings through.Only the length of the pendulum matters.

How pendulum clock works (4)

Experement

If you not convinced from previous discussion then I would like to perform a experiment as:

Experiment Time:

As we stated on the previous page, the only thing affecting the period of a pendulum is the length of that pendulum. You can prove this fact to yourself by performing the following experiment. For this experiment you will need:

• A weight

• A string

• A table

• A watch with a second hand (or a numeric seconds display on a digital watch)

How pendulum clock works (4)

Experiment

For the weight you can useanything. In a pinch, a coffee mugor a book will do -- it doesn't reallymatter. Tie the string to the weight.Then suspend your pendulum overthe edge of the table so that thelength of the pendulum is about 2feet, as shown inside:

How pendulum clock works (4)

Experiment

Now pull the weight back about a foot and

let your pendulum start swinging. Time it

for 30 or 60 seconds and count how many

times it swings back and forth. Remember

that number. Now stop the pendulum and

restart it, but this time pull it back only 6

inches initially so it is swinging through a

much smaller arc. Count the number of

swings again through the same 30- or 60-

second time period. What you will find is

that the number you get is the same as the

first number you counted. In other words,

the angle of the arc through which the

pendulum swings does not affect the

pendulum's period. Only the length of the

How pendulum clock works (4)

Experiment

Once someone noticed this fact aboutpendulums, it was realized that you coulduse the phenomenon to create anaccurate clock. The figure below showshow you can create aclock's escapement using a pendulum.

In an escapement there is a gear withteeth of some special shape. There isalso a pendulum, and attached to thependulum is some sort of device toengage the teeth of the gear

How pendulum clock works (4)

Experiment

One thing to keep in mind is thatpendulums will not swingforever. Therefore, oneadditional job of the escapementgear is to impart just enoughenergy into the pendulum toovercome friction and allow it tokeep swinging as shown infigure again:

How pendulum clock works (4)

Experiment

• So, let's say that you create an escapement. If you gave theescapement gear 60 teeth and attached this gear directly to theweight drum we discussed above, and if you then used apendulum with a period of one second, you would havesuccessfully created a clock in which the second hand turns atthe rate of one revolution per minute. By adjusting thependulum's length very carefully we could create a clock withvery high accuracy.

• However, while accurate, this clock would have two problemsthat would make it less-than-useful:

(1)Most people want a clock to have hour and minute hands as well.

(2)You would have to wind the clock about every 20 minutes.Because the drum makes one revolution every minute, theweight would unwind to the floor very quickly. Most people wouldnot like a clock that had to be rewound every 20 minutes!

How pendulum clock works (5)

Gearing Up!

• The problem of having to rewind every 20 minutes is easy to solve.you can create a high-ratio gear train that causes the drum to makeperhaps one turn every six to 12 hours. This would give you a clockthat you only had to rewind once a week or so. The gear ratiobetween the weight drum and the escapement gear as shown in thediagram below:

How pendulum clock works (5)

Gearing Up!

You can see that, even though all the gears in a clock make it lookcomplicated, what a pendulum clock is doing is really pretty simple.There are five basic parts:

• Weight or spring - This provides the energy to turn the hands of theclock.

• Weight gear train - A high-ratio gear train gears the weight drum wayup so that you don't have to rewind the clock very often.

• Escapement - Made up of the pendulum, the anchor and theescapement gear, the escapement precisely regulates the speed atwhich the weight's energy is released.

• Hand gear train - The train gears things down so the minute and hourhands turn at the right rates.

• Setting mechanism - This somehow disengages, slips or ratchets thegear train so the clock can be rewound and set.

Types of pendulum clock’s

Types of pendulum clock’s

No : Type of pendulum clock’s No: Type of pendulum clock’s

1 Musical pendulum clock 2 Ignatz flying pendulum clock

3 Horolover flying pendulum

clock

4 Crazy flying pendulum clock

5 LEGO pendulum clock 6 Phun pendulum clock

7 Paper pendulum clock 8 Panthoen pendulum clock

9 Swinging pendulum clock 10 Rotary pendulum clock

11 Hangman pendulum clock 12 Warriors pendulum clock

13 Home made LED pendulum

clock

14 Weird pendulum clock

15 Beuco pendulum clock 16 Elvis pendulum clock

17 Charlie chaplin pendulum

clock

18 Bernoux conical pendulum clock

19 Small bentima pendulum

clock

20 Vortex pendulum clock

Conclusion!

oFrom Augustine’s reflections on time:

oTime as the dramatic marker of being human

oTime is fundamentally impossible to comprehend, but…

o It can be measured!

oHistory of measuring time

o In a sense, time is a HUMAN creation

oRelationship between human and technology as an important aspect of the ‘history of time’

References!

The major source of collection of this data is collected

through INTERNET through following web sides:

o WWW.Answer.com

o WWW.Wikipedia.com

o WWW.Webopedia.com

o WWW.Webanswers.com

o WWW.How stuff work?.com

o WWW.mypptsearch.Ppt search engine

o WWW.mypdfsearch.Pdf search engine