SlideShare a Scribd company logo
1 of 23
Download to read offline
CHAPTER - 12
$OUND
CLA$$ :- IX -A
MADE BY :- HITE$H MEENA
$CHOOL :- GLT.$ARA$WATI BAL MINDIR.!!!
कारणाभावात् कायार्याभाव: |
न तु कायार्याभावातु कारणाभाव: ||
(vaiseshikadarshaanam 1.2)
There is no effect possible without a cause.
But the absence of effect does not means the
absence of causes.
The text also substantistes the above fact with
an example:Applying a force (less than needed
to overcome friction ) will not make a body
move.In the case , (The force ) is present but
not the effect (Motion)
1) Production of sound :-
Sound is produced due to the vibration of objects.
Vibration is the rapid to and fro motion of an object.
Eg :- The sound of human voice is produced due to the
vibration of the vocal cords.
A stretched rubber band when plucked vibrates and
produces sound.
Activity :- Strike the prongs of a tuning
fork on a rubber pad and bring it near
the ear. We can hear a sound. If a
suspended table tennis ball is touched
with the vibrating prong, the ball is
pushed away repeatedly. This shows
that the prong is vibrating and
vibrating objects produces sound.
Thread
Vibrating
tuning fork
Table tennis
ball
2) Propagation of sound :-
The sound produced by a vibrating object travels through a
medium to a listener. The medium can be solid, liquid or gas.
When an object vibrates, the particles around the medium vibrates.
The particle in contact with the vibrating object is first displaced from
its equilibrium position. It then exerts a force on the adjacent particle
and the adjacent particle is displaced from its position of rest. After
displacing the adjacent particle the first particle comes back to its
original position. This process repeats in the medium till the sound
reaches the ear.
The disturbance produced by the vibrating body travels through the
medium but the particles do not move forward themselves.
A wave is a disturbance which moves through a medium by the
vibration of the particles of the medium. So sound is considered as a
wave. Since sound waves are produced due to the vibration of
particles of the medium sound waves are called mechanical waves.
Propagation of sound through air :-
Air is the most common medium through which sound travels.
When a vibrating object moves forward, it pushes and compresses the
air in front of it forming a region of high pressure called compression
(C). The compression moves away from the vibrating object. When the
vibrating object moves backward, it forms a region of low pressure
called rarefaction (R). As the object moves to and fro rapidly, it
produces a series of compressions and rarefaction in the air which
makes the sound to propagate in the medium.
A vibrating object producing a series of compressions (C)
and rarefaction (R)
C C C CRR R R
3) Sound needs a medium to travel :-
Sound is a mechanical wave and needs a medium for propagation.
Sound travels through solids, liquids and gases. Sound does not travel
in vacuum.
Activity:-
Suspend an electric bell in an air tight bell jar. Connect the bell jar to
a vacuum pump. If the switch is pressed, we can hear the sound of the
bell. If air is pumped out through the vacuum pump, we cannot hear the
sound of the bell. This shows that sound needs a medium to travel and
sound cannot travel in vacuum.
Bell jar
Electric bell
Cork
4) Sound waves are longitudinal waves :-
Sound propagates in a medium as a series of compressions (C) and
rarefactions (R).
In these waves the particles move back and forth parallel to the
direction of propagation of the disturbance. Such waves are called
longitudinal waves.
There is another kind of waves called transverse waves. In these
waves the particles oscillate up and down perpendicular to the
propagation of the direction of disturbance.
Activity :- Stretch a slinky and push and pull it alternately at one end.
If you mark a dot on the slinky, the dot moves back and forth parallel to
the direction of the propagation of the disturbance.
C C CR R R
5) Characteristics of a sound wave :-
Sound wave can be described by its frequency, amplitude and speed.
Sound can be graphically represented as a wave. There is changes in
the density and pressure as sound moves in a medium.
Compressions are the regions of high pressure and density where
the particles are crowded and are represented by the upper portion of
the curve called crest.
Rarefactions are the regions of low pressure and density where the
particles are spread out and are represented by the lower portion of the
curve called trough.
The distance between two consecutive compressions (crests) or two
consecutive troughs is called wave length. It is represented by the
symbol . (Greek letter lamda). Its SI unit is metre (m).
compression rarefaction
Crest
Troug
h
λλ
PressureorDensity
λ
i) Frequency of sound wave :-
When sound is propagated through a medium, the density of the
medium oscillates between a maximum value and a minimum value.
The change in the density of the medium from a maximum value to a
minimum value and again to the maximum value is one oscillation.
The number of oscillations per unit time is called the frequency of
the sound wave.
It is represented by the symbol ٧ (Greek letter nu).
Its SI unit is hertz (Hz).
ii) Time period of sound wave :-
The time taken for the change in the density of the medium from a
maximum value to a minimum value and again to the maximum value
is the time period of the sound wave.
Or
The time taken for one complete oscillation in the density of the
medium is called the time period of the sound wave.
It is represented by the letter T.
The SI unit is second (s).
Frequency and time are represented as follows :-
٧ for one oscillation
1 1
T = ---- or ٧ = ----
٧ T
iii) Amplitude of sound wave :-
The magnitude of the maximum disturbance in the medium on either
side of the mean value is the amplitude of the sound wave.
Or
The amplitude of sound wave is the height of the crest or tough.
It is represented by the letter A.
The SI unit is the same as that of density or pressure.
Wavelength and Amplitude
The wavelength is the distance between the "crests" of two waves that are next to
each other. The amplitude is how high the crests are.
Wavedisturbance
iv) Pitch and loudness of sound :-
The pitch of sound (shrillness or flatness) depends on
the frequency of vibration.
If the frequency is high, the sound has high pitch and if
the frequency is low, the sound has low pitch.
Wavelength, Frequency, and Pitch
Since the sounds are travelling at about the same speed, the one with the shorter wavelength
will go by more frequently; it has a higher frequency, or pitch. In other words, it sounds higher.
The loudness of sound depends upon the amplitude of
vibration.
If the amplitude is bigger, the sound is loud and if the
amplitude is smaller, the sound is soft.
Amplitude is Loudness
The size of a wave (how much it is "piled up" at the high points) is its amplitude. For
sound waves, the bigger the amplitude, the louder the sound.
v) Speed of sound :-
The speed of sound is different in different media. The speed of
sound is more in solids, less in liquids and least in gases.
The speed of sound also depends on the temperature of the medium.
If the temperature of the medium is more, the speed of sound is more.
Speed of sound in different media at 250
C.
Relationship between
Speed (v), frequency
(٧) and wave length
(λ)
Speed = wave length x
frequency
v = λ x ٧
State Substance Speed in m/s
Solid Aluminium 6420
Steel 5960
Iron 5950
Brass 4700
Glass 3980
Liquid Water (Sea) 1531
Water (Distilled) 1498
Ethanol 1207
Methanol 1103
Gas Hydrogen 1284
Helium 965
Air 346
Oxygen 316
Sulphur dioxide 213
6) Reflection of sound :-
Like light, sound gets reflected at the surface of a solid or liquid and
follows the laws of reflection.
i) The angle of incidence is equal to the angle of reflection.
ii) The incident ray, the reflected ray and normal at the point of
incidence all lie in the same plane.
Activity :- Take two pipes of the same length and arrange them on a
table near a wall or metal plate. Keep a clock near the open end of one
pipe and try to hear the sound of the clock through the other pipe by
adjusting the position of the pipe.
Now measure the angles of incidence
and reflection. Then lift the second
pipe and try to hear the sound.
It will be seen that the angle of
incidence is equal to the angle of
reflection. The incident ray, the
reflected ray and normal all lie in
the same plane.
7a) Echo :-
If we shout or clap near a reflecting surface like tall building or a
mountain, we hear the same sound again. This sound which we hear is
called echo. It is caused due to the reflection of sound.
To hear an echo clearly, the time interval between the original
sound and the echo must be at least 0.1 s.
Since the speed of sound in air is 344 m/s, the distance travelled by
sound in 0.I s = 344 m/s x 0.1 s = 34.4 m
So to hear an echo clearly, the minimum distance of the reflecting
surface should be half this distance, that is 17.2 m.
b) Reverberation :-
Echoes may be heard more than once due to repeated or multiple
reflections of sound from several reflecting surfaces. This causes
persistence of sound called reverberation.
In big halls or auditoriums to reduce reverberation, the roofs and
walls are covered by sound absorbing materials like compressed fibre
boards, rough plaster or draperies.
c) Uses of multiple reflection of sound :-
i) Megaphones, horns, musical instruments like trumpets, shehnais
etc. are deigned to send sound by multiple reflection in a particular
direction without spreading in all directions.
ii) Doctors listen to sounds from the human body through a
stethoscope. The sound of heartbeat reaches the doctor’s ears by
multiple reflection.
iii) Generally the ceilings of cinema halls and auditoriums are curved
so that sound after multiple reflection reaches all parts of the hall.
Sometimes a curved sound board is placed behind the stage so
that
sound after multiple reflection spreads evenly across the hall.
8) Range of Hearing :-
Human beings can hear sound frequencies between 20
Hz and 2000 Hz.
Sound whose frequency is less than 20 Hz is called
infrasonic sound. Animals like dogs, elephants, rhinoceros,
whales etc. produce and hear infrasonic sound.
Sound whose frequency is more than 2000 Hz is called
ultrasonic sound. Animals like dolphins, bats, rats
propoises etc. produce and hear ultrasonic sound.
Bats use reflection of ultrasonic sound waves to detect an
obstacle or its prey.
9) Uses of ultrasonic sound :-
i) Ultrasonic sound is used to clean objects like electronic
components. The components to be cleaned are kept in a
cleaning solution and ultrasonic waves are sent into the
solution. Due to the high frequency, the dirt particles get
detached from the components.
ii) Ultrasonic sound is used to detect cracks in metal
blocks. Ultrasonic waves are sent through the metal
blocks and if there are cracks, the waves are reflected
back and the cracks can be detected.
iii) Ultrasonic sound is used in ultra sound scanners for
getting images of internal organs of the human body.
iv) Ultrasonic sound is used to break small stones formed in
the kidneys into fine grains so that they are removed
through the urine.
10) SONAR :-
Sonar stands for Sound Navigation And Ranging. It is a device which
uses ultrasonic waves to measure distance, direction and speed of
underwater objects.
Sonar has a transmitter and a detector installed in ships. The
transmitter produces ultrasonic sound waves which travel through the
water and after striking the object in the sea bed is reflected back to the
detector.
The distance of the object can be calculated by knowing the speed of
sound in water and the time taken between the transmission and
reception of ultrasound.
If the time taken for the transmission and reception of ultra sound is t
and the distance travelled is 2d by the ultra sound, then 2d = v x t
or d = v x t
2
11) Structure of the human ear :-
The outer ear called pinna collects the sound waves. The sound
waves passes through the ear canal to a thin membrane called eardrum.
The eardrum vibrates. The vibrations are amplified by the three bones
of the middle ear called hammer, anvil and stirrup. The middle ear then
transmits the sound waves to the inner ear. In the inner ear the sound
waves are converted into electrical signals by the cochlea and sent to
the brain through the auditory nerves. The brain then interprets the
signals as sound.
Hammer
Anvil
Stirrup Cochlea
Pinna
SOUND

More Related Content

What's hot (18)

Sound Waves Explained
Sound Waves ExplainedSound Waves Explained
Sound Waves Explained
 
Sound
SoundSound
Sound
 
Sound&resonance
Sound&resonanceSound&resonance
Sound&resonance
 
Sound wave
Sound waveSound wave
Sound wave
 
Sound for class 9 physics
Sound for class 9 physicsSound for class 9 physics
Sound for class 9 physics
 
Sound Waves
Sound Waves Sound Waves
Sound Waves
 
Study of sound
Study of soundStudy of sound
Study of sound
 
Sound
SoundSound
Sound
 
Chapter 16
Chapter 16Chapter 16
Chapter 16
 
Sound
SoundSound
Sound
 
SOUND
SOUND SOUND
SOUND
 
Sound Waves
Sound WavesSound Waves
Sound Waves
 
Waves and Sound
Waves and SoundWaves and Sound
Waves and Sound
 
propogation of sound (CLASS 9 ICSE)
propogation of sound (CLASS 9 ICSE)propogation of sound (CLASS 9 ICSE)
propogation of sound (CLASS 9 ICSE)
 
Sound - Chapter 12 NCERT Science for KV Students
Sound - Chapter 12 NCERT Science for KV StudentsSound - Chapter 12 NCERT Science for KV Students
Sound - Chapter 12 NCERT Science for KV Students
 
Sound wave for Dummies
Sound wave for DummiesSound wave for Dummies
Sound wave for Dummies
 
Waves and sounds
Waves and soundsWaves and sounds
Waves and sounds
 
Ppa6 Lecture Ch 12
Ppa6 Lecture Ch 12Ppa6 Lecture Ch 12
Ppa6 Lecture Ch 12
 

Similar to SOUND

12sound-201208075306.pdf..................
12sound-201208075306.pdf..................12sound-201208075306.pdf..................
12sound-201208075306.pdf..................VishwatejNalawade1
 
chapter sound for class 9 ppt
chapter sound for class 9 ppt chapter sound for class 9 ppt
chapter sound for class 9 ppt Arpit Meena
 
Sound And It's Applications | Science PPT | Pritam Priyambad Sahoo
Sound And It's Applications | Science PPT | Pritam Priyambad SahooSound And It's Applications | Science PPT | Pritam Priyambad Sahoo
Sound And It's Applications | Science PPT | Pritam Priyambad SahooPritamPriyambadSahoo
 
New microsoft office power point presentation (3)
New microsoft office power point presentation (3)New microsoft office power point presentation (3)
New microsoft office power point presentation (3)swpuri319
 
SOUND and its properties.pptx
SOUND and its properties.pptxSOUND and its properties.pptx
SOUND and its properties.pptxSYED MASOOD
 
5sound-181206142548.pd
5sound-181206142548.pd5sound-181206142548.pd
5sound-181206142548.pdPraveen0073
 
Physics copy-120407040751-phpapp01
Physics copy-120407040751-phpapp01Physics copy-120407040751-phpapp01
Physics copy-120407040751-phpapp01MznaSaif
 

Similar to SOUND (20)

sound
soundsound
sound
 
i AM YEDA
i AM YEDAi AM YEDA
i AM YEDA
 
12sound-201208075306.pdf..................
12sound-201208075306.pdf..................12sound-201208075306.pdf..................
12sound-201208075306.pdf..................
 
chapter sound for class 9 ppt
chapter sound for class 9 ppt chapter sound for class 9 ppt
chapter sound for class 9 ppt
 
CLASS 9 _ SOUND.pptx
CLASS 9 _ SOUND.pptxCLASS 9 _ SOUND.pptx
CLASS 9 _ SOUND.pptx
 
Sound And It's Applications | Science PPT | Pritam Priyambad Sahoo
Sound And It's Applications | Science PPT | Pritam Priyambad SahooSound And It's Applications | Science PPT | Pritam Priyambad Sahoo
Sound And It's Applications | Science PPT | Pritam Priyambad Sahoo
 
Ppt on sound
Ppt on soundPpt on sound
Ppt on sound
 
Sound 1
Sound 1Sound 1
Sound 1
 
New microsoft office power point presentation (3)
New microsoft office power point presentation (3)New microsoft office power point presentation (3)
New microsoft office power point presentation (3)
 
SOUND and its properties.pptx
SOUND and its properties.pptxSOUND and its properties.pptx
SOUND and its properties.pptx
 
Introduction to Audiography/Sound
Introduction to Audiography/SoundIntroduction to Audiography/Sound
Introduction to Audiography/Sound
 
ch 12 sound.pdf
ch 12 sound.pdfch 12 sound.pdf
ch 12 sound.pdf
 
Sound ppt
Sound pptSound ppt
Sound ppt
 
Ch5 wave motions and sound
Ch5 wave motions and soundCh5 wave motions and sound
Ch5 wave motions and sound
 
lec 10.pptx
lec 10.pptxlec 10.pptx
lec 10.pptx
 
sound class 9 physics
sound class 9 physicssound class 9 physics
sound class 9 physics
 
5sound-181206142548.pd
5sound-181206142548.pd5sound-181206142548.pd
5sound-181206142548.pd
 
Physics copy-120407040751-phpapp01
Physics copy-120407040751-phpapp01Physics copy-120407040751-phpapp01
Physics copy-120407040751-phpapp01
 
noise (1).ppt
noise (1).pptnoise (1).ppt
noise (1).ppt
 
Sound and waves grade 6 pps
Sound and waves grade 6 ppsSound and waves grade 6 pps
Sound and waves grade 6 pps
 

More from Poonam Singh (20)

Diabetes
DiabetesDiabetes
Diabetes
 
Polynomials
PolynomialsPolynomials
Polynomials
 
Advertising
Advertising Advertising
Advertising
 
old age
old ageold age
old age
 
Chemistry
ChemistryChemistry
Chemistry
 
Diabetes mellitus
Diabetes mellitusDiabetes mellitus
Diabetes mellitus
 
WATER CRISIS “Prediction of 3rd world war”
WATER CRISIS “Prediction of 3rd world war”WATER CRISIS “Prediction of 3rd world war”
WATER CRISIS “Prediction of 3rd world war”
 
Issue of Shares
Issue of SharesIssue of Shares
Issue of Shares
 
My experience my values 7th
My experience my values 7thMy experience my values 7th
My experience my values 7th
 
Solid
SolidSolid
Solid
 
Smart class
Smart classSmart class
Smart class
 
S107
S107S107
S107
 
S104
S104S104
S104
 
Mera anubhav meri siksha 7th
Mera anubhav meri siksha 7thMera anubhav meri siksha 7th
Mera anubhav meri siksha 7th
 
S103
S103S103
S103
 
S102
S102S102
S102
 
S101
S101S101
S101
 
Projectile motion
Projectile motionProjectile motion
Projectile motion
 
Mansi
MansiMansi
Mansi
 
Gravitation
GravitationGravitation
Gravitation
 

Recently uploaded

Beauty Amidst the Bytes_ Unearthing Unexpected Advantages of the Digital Wast...
Beauty Amidst the Bytes_ Unearthing Unexpected Advantages of the Digital Wast...Beauty Amidst the Bytes_ Unearthing Unexpected Advantages of the Digital Wast...
Beauty Amidst the Bytes_ Unearthing Unexpected Advantages of the Digital Wast...DhatriParmar
 
Narcotic and Non Narcotic Analgesic..pdf
Narcotic and Non Narcotic Analgesic..pdfNarcotic and Non Narcotic Analgesic..pdf
Narcotic and Non Narcotic Analgesic..pdfPrerana Jadhav
 
Team Lead Succeed – Helping you and your team achieve high-performance teamwo...
Team Lead Succeed – Helping you and your team achieve high-performance teamwo...Team Lead Succeed – Helping you and your team achieve high-performance teamwo...
Team Lead Succeed – Helping you and your team achieve high-performance teamwo...Association for Project Management
 
How to Make a Duplicate of Your Odoo 17 Database
How to Make a Duplicate of Your Odoo 17 DatabaseHow to Make a Duplicate of Your Odoo 17 Database
How to Make a Duplicate of Your Odoo 17 DatabaseCeline George
 
BIOCHEMISTRY-CARBOHYDRATE METABOLISM CHAPTER 2.pptx
BIOCHEMISTRY-CARBOHYDRATE METABOLISM CHAPTER 2.pptxBIOCHEMISTRY-CARBOHYDRATE METABOLISM CHAPTER 2.pptx
BIOCHEMISTRY-CARBOHYDRATE METABOLISM CHAPTER 2.pptxSayali Powar
 
MS4 level being good citizen -imperative- (1) (1).pdf
MS4 level   being good citizen -imperative- (1) (1).pdfMS4 level   being good citizen -imperative- (1) (1).pdf
MS4 level being good citizen -imperative- (1) (1).pdfMr Bounab Samir
 
Employablity presentation and Future Career Plan.pptx
Employablity presentation and Future Career Plan.pptxEmployablity presentation and Future Career Plan.pptx
Employablity presentation and Future Career Plan.pptxryandux83rd
 
Congestive Cardiac Failure..presentation
Congestive Cardiac Failure..presentationCongestive Cardiac Failure..presentation
Congestive Cardiac Failure..presentationdeepaannamalai16
 
4.11.24 Poverty and Inequality in America.pptx
4.11.24 Poverty and Inequality in America.pptx4.11.24 Poverty and Inequality in America.pptx
4.11.24 Poverty and Inequality in America.pptxmary850239
 
Integumentary System SMP B. Pharm Sem I.ppt
Integumentary System SMP B. Pharm Sem I.pptIntegumentary System SMP B. Pharm Sem I.ppt
Integumentary System SMP B. Pharm Sem I.pptshraddhaparab530
 
Tree View Decoration Attribute in the Odoo 17
Tree View Decoration Attribute in the Odoo 17Tree View Decoration Attribute in the Odoo 17
Tree View Decoration Attribute in the Odoo 17Celine George
 
Scientific Writing :Research Discourse
Scientific  Writing :Research  DiscourseScientific  Writing :Research  Discourse
Scientific Writing :Research DiscourseAnita GoswamiGiri
 
4.9.24 Social Capital and Social Exclusion.pptx
4.9.24 Social Capital and Social Exclusion.pptx4.9.24 Social Capital and Social Exclusion.pptx
4.9.24 Social Capital and Social Exclusion.pptxmary850239
 
How to Uninstall a Module in Odoo 17 Using Command Line
How to Uninstall a Module in Odoo 17 Using Command LineHow to Uninstall a Module in Odoo 17 Using Command Line
How to Uninstall a Module in Odoo 17 Using Command LineCeline George
 
Oppenheimer Film Discussion for Philosophy and Film
Oppenheimer Film Discussion for Philosophy and FilmOppenheimer Film Discussion for Philosophy and Film
Oppenheimer Film Discussion for Philosophy and FilmStan Meyer
 
ICS 2208 Lecture Slide Notes for Topic 6
ICS 2208 Lecture Slide Notes for Topic 6ICS 2208 Lecture Slide Notes for Topic 6
ICS 2208 Lecture Slide Notes for Topic 6Vanessa Camilleri
 
Transaction Management in Database Management System
Transaction Management in Database Management SystemTransaction Management in Database Management System
Transaction Management in Database Management SystemChristalin Nelson
 

Recently uploaded (20)

Beauty Amidst the Bytes_ Unearthing Unexpected Advantages of the Digital Wast...
Beauty Amidst the Bytes_ Unearthing Unexpected Advantages of the Digital Wast...Beauty Amidst the Bytes_ Unearthing Unexpected Advantages of the Digital Wast...
Beauty Amidst the Bytes_ Unearthing Unexpected Advantages of the Digital Wast...
 
Narcotic and Non Narcotic Analgesic..pdf
Narcotic and Non Narcotic Analgesic..pdfNarcotic and Non Narcotic Analgesic..pdf
Narcotic and Non Narcotic Analgesic..pdf
 
Team Lead Succeed – Helping you and your team achieve high-performance teamwo...
Team Lead Succeed – Helping you and your team achieve high-performance teamwo...Team Lead Succeed – Helping you and your team achieve high-performance teamwo...
Team Lead Succeed – Helping you and your team achieve high-performance teamwo...
 
How to Make a Duplicate of Your Odoo 17 Database
How to Make a Duplicate of Your Odoo 17 DatabaseHow to Make a Duplicate of Your Odoo 17 Database
How to Make a Duplicate of Your Odoo 17 Database
 
BIOCHEMISTRY-CARBOHYDRATE METABOLISM CHAPTER 2.pptx
BIOCHEMISTRY-CARBOHYDRATE METABOLISM CHAPTER 2.pptxBIOCHEMISTRY-CARBOHYDRATE METABOLISM CHAPTER 2.pptx
BIOCHEMISTRY-CARBOHYDRATE METABOLISM CHAPTER 2.pptx
 
MS4 level being good citizen -imperative- (1) (1).pdf
MS4 level   being good citizen -imperative- (1) (1).pdfMS4 level   being good citizen -imperative- (1) (1).pdf
MS4 level being good citizen -imperative- (1) (1).pdf
 
Employablity presentation and Future Career Plan.pptx
Employablity presentation and Future Career Plan.pptxEmployablity presentation and Future Career Plan.pptx
Employablity presentation and Future Career Plan.pptx
 
Congestive Cardiac Failure..presentation
Congestive Cardiac Failure..presentationCongestive Cardiac Failure..presentation
Congestive Cardiac Failure..presentation
 
4.11.24 Poverty and Inequality in America.pptx
4.11.24 Poverty and Inequality in America.pptx4.11.24 Poverty and Inequality in America.pptx
4.11.24 Poverty and Inequality in America.pptx
 
Integumentary System SMP B. Pharm Sem I.ppt
Integumentary System SMP B. Pharm Sem I.pptIntegumentary System SMP B. Pharm Sem I.ppt
Integumentary System SMP B. Pharm Sem I.ppt
 
INCLUSIVE EDUCATION PRACTICES FOR TEACHERS AND TRAINERS.pptx
INCLUSIVE EDUCATION PRACTICES FOR TEACHERS AND TRAINERS.pptxINCLUSIVE EDUCATION PRACTICES FOR TEACHERS AND TRAINERS.pptx
INCLUSIVE EDUCATION PRACTICES FOR TEACHERS AND TRAINERS.pptx
 
Tree View Decoration Attribute in the Odoo 17
Tree View Decoration Attribute in the Odoo 17Tree View Decoration Attribute in the Odoo 17
Tree View Decoration Attribute in the Odoo 17
 
Scientific Writing :Research Discourse
Scientific  Writing :Research  DiscourseScientific  Writing :Research  Discourse
Scientific Writing :Research Discourse
 
4.9.24 Social Capital and Social Exclusion.pptx
4.9.24 Social Capital and Social Exclusion.pptx4.9.24 Social Capital and Social Exclusion.pptx
4.9.24 Social Capital and Social Exclusion.pptx
 
How to Uninstall a Module in Odoo 17 Using Command Line
How to Uninstall a Module in Odoo 17 Using Command LineHow to Uninstall a Module in Odoo 17 Using Command Line
How to Uninstall a Module in Odoo 17 Using Command Line
 
Oppenheimer Film Discussion for Philosophy and Film
Oppenheimer Film Discussion for Philosophy and FilmOppenheimer Film Discussion for Philosophy and Film
Oppenheimer Film Discussion for Philosophy and Film
 
Plagiarism,forms,understand about plagiarism,avoid plagiarism,key significanc...
Plagiarism,forms,understand about plagiarism,avoid plagiarism,key significanc...Plagiarism,forms,understand about plagiarism,avoid plagiarism,key significanc...
Plagiarism,forms,understand about plagiarism,avoid plagiarism,key significanc...
 
Spearman's correlation,Formula,Advantages,
Spearman's correlation,Formula,Advantages,Spearman's correlation,Formula,Advantages,
Spearman's correlation,Formula,Advantages,
 
ICS 2208 Lecture Slide Notes for Topic 6
ICS 2208 Lecture Slide Notes for Topic 6ICS 2208 Lecture Slide Notes for Topic 6
ICS 2208 Lecture Slide Notes for Topic 6
 
Transaction Management in Database Management System
Transaction Management in Database Management SystemTransaction Management in Database Management System
Transaction Management in Database Management System
 

SOUND

  • 1. CHAPTER - 12 $OUND CLA$$ :- IX -A MADE BY :- HITE$H MEENA $CHOOL :- GLT.$ARA$WATI BAL MINDIR.!!!
  • 2. कारणाभावात् कायार्याभाव: | न तु कायार्याभावातु कारणाभाव: || (vaiseshikadarshaanam 1.2) There is no effect possible without a cause. But the absence of effect does not means the absence of causes. The text also substantistes the above fact with an example:Applying a force (less than needed to overcome friction ) will not make a body move.In the case , (The force ) is present but not the effect (Motion)
  • 3. 1) Production of sound :- Sound is produced due to the vibration of objects. Vibration is the rapid to and fro motion of an object. Eg :- The sound of human voice is produced due to the vibration of the vocal cords. A stretched rubber band when plucked vibrates and produces sound. Activity :- Strike the prongs of a tuning fork on a rubber pad and bring it near the ear. We can hear a sound. If a suspended table tennis ball is touched with the vibrating prong, the ball is pushed away repeatedly. This shows that the prong is vibrating and vibrating objects produces sound. Thread Vibrating tuning fork Table tennis ball
  • 4. 2) Propagation of sound :- The sound produced by a vibrating object travels through a medium to a listener. The medium can be solid, liquid or gas. When an object vibrates, the particles around the medium vibrates. The particle in contact with the vibrating object is first displaced from its equilibrium position. It then exerts a force on the adjacent particle and the adjacent particle is displaced from its position of rest. After displacing the adjacent particle the first particle comes back to its original position. This process repeats in the medium till the sound reaches the ear. The disturbance produced by the vibrating body travels through the medium but the particles do not move forward themselves. A wave is a disturbance which moves through a medium by the vibration of the particles of the medium. So sound is considered as a wave. Since sound waves are produced due to the vibration of particles of the medium sound waves are called mechanical waves.
  • 5. Propagation of sound through air :- Air is the most common medium through which sound travels. When a vibrating object moves forward, it pushes and compresses the air in front of it forming a region of high pressure called compression (C). The compression moves away from the vibrating object. When the vibrating object moves backward, it forms a region of low pressure called rarefaction (R). As the object moves to and fro rapidly, it produces a series of compressions and rarefaction in the air which makes the sound to propagate in the medium.
  • 6. A vibrating object producing a series of compressions (C) and rarefaction (R) C C C CRR R R
  • 7. 3) Sound needs a medium to travel :- Sound is a mechanical wave and needs a medium for propagation. Sound travels through solids, liquids and gases. Sound does not travel in vacuum. Activity:- Suspend an electric bell in an air tight bell jar. Connect the bell jar to a vacuum pump. If the switch is pressed, we can hear the sound of the bell. If air is pumped out through the vacuum pump, we cannot hear the sound of the bell. This shows that sound needs a medium to travel and sound cannot travel in vacuum. Bell jar Electric bell Cork
  • 8. 4) Sound waves are longitudinal waves :- Sound propagates in a medium as a series of compressions (C) and rarefactions (R). In these waves the particles move back and forth parallel to the direction of propagation of the disturbance. Such waves are called longitudinal waves. There is another kind of waves called transverse waves. In these waves the particles oscillate up and down perpendicular to the propagation of the direction of disturbance. Activity :- Stretch a slinky and push and pull it alternately at one end. If you mark a dot on the slinky, the dot moves back and forth parallel to the direction of the propagation of the disturbance. C C CR R R
  • 9. 5) Characteristics of a sound wave :- Sound wave can be described by its frequency, amplitude and speed. Sound can be graphically represented as a wave. There is changes in the density and pressure as sound moves in a medium. Compressions are the regions of high pressure and density where the particles are crowded and are represented by the upper portion of the curve called crest. Rarefactions are the regions of low pressure and density where the particles are spread out and are represented by the lower portion of the curve called trough. The distance between two consecutive compressions (crests) or two consecutive troughs is called wave length. It is represented by the symbol . (Greek letter lamda). Its SI unit is metre (m). compression rarefaction Crest Troug h λλ PressureorDensity λ
  • 10. i) Frequency of sound wave :- When sound is propagated through a medium, the density of the medium oscillates between a maximum value and a minimum value. The change in the density of the medium from a maximum value to a minimum value and again to the maximum value is one oscillation. The number of oscillations per unit time is called the frequency of the sound wave. It is represented by the symbol ٧ (Greek letter nu). Its SI unit is hertz (Hz).
  • 11. ii) Time period of sound wave :- The time taken for the change in the density of the medium from a maximum value to a minimum value and again to the maximum value is the time period of the sound wave. Or The time taken for one complete oscillation in the density of the medium is called the time period of the sound wave. It is represented by the letter T. The SI unit is second (s). Frequency and time are represented as follows :- ٧ for one oscillation 1 1 T = ---- or ٧ = ---- ٧ T
  • 12. iii) Amplitude of sound wave :- The magnitude of the maximum disturbance in the medium on either side of the mean value is the amplitude of the sound wave. Or The amplitude of sound wave is the height of the crest or tough. It is represented by the letter A. The SI unit is the same as that of density or pressure. Wavelength and Amplitude The wavelength is the distance between the "crests" of two waves that are next to each other. The amplitude is how high the crests are. Wavedisturbance
  • 13. iv) Pitch and loudness of sound :- The pitch of sound (shrillness or flatness) depends on the frequency of vibration. If the frequency is high, the sound has high pitch and if the frequency is low, the sound has low pitch. Wavelength, Frequency, and Pitch Since the sounds are travelling at about the same speed, the one with the shorter wavelength will go by more frequently; it has a higher frequency, or pitch. In other words, it sounds higher.
  • 14. The loudness of sound depends upon the amplitude of vibration. If the amplitude is bigger, the sound is loud and if the amplitude is smaller, the sound is soft. Amplitude is Loudness The size of a wave (how much it is "piled up" at the high points) is its amplitude. For sound waves, the bigger the amplitude, the louder the sound.
  • 15. v) Speed of sound :- The speed of sound is different in different media. The speed of sound is more in solids, less in liquids and least in gases. The speed of sound also depends on the temperature of the medium. If the temperature of the medium is more, the speed of sound is more. Speed of sound in different media at 250 C. Relationship between Speed (v), frequency (٧) and wave length (λ) Speed = wave length x frequency v = λ x ٧ State Substance Speed in m/s Solid Aluminium 6420 Steel 5960 Iron 5950 Brass 4700 Glass 3980 Liquid Water (Sea) 1531 Water (Distilled) 1498 Ethanol 1207 Methanol 1103 Gas Hydrogen 1284 Helium 965 Air 346 Oxygen 316 Sulphur dioxide 213
  • 16. 6) Reflection of sound :- Like light, sound gets reflected at the surface of a solid or liquid and follows the laws of reflection. i) The angle of incidence is equal to the angle of reflection. ii) The incident ray, the reflected ray and normal at the point of incidence all lie in the same plane. Activity :- Take two pipes of the same length and arrange them on a table near a wall or metal plate. Keep a clock near the open end of one pipe and try to hear the sound of the clock through the other pipe by adjusting the position of the pipe. Now measure the angles of incidence and reflection. Then lift the second pipe and try to hear the sound. It will be seen that the angle of incidence is equal to the angle of reflection. The incident ray, the reflected ray and normal all lie in the same plane.
  • 17. 7a) Echo :- If we shout or clap near a reflecting surface like tall building or a mountain, we hear the same sound again. This sound which we hear is called echo. It is caused due to the reflection of sound. To hear an echo clearly, the time interval between the original sound and the echo must be at least 0.1 s. Since the speed of sound in air is 344 m/s, the distance travelled by sound in 0.I s = 344 m/s x 0.1 s = 34.4 m So to hear an echo clearly, the minimum distance of the reflecting surface should be half this distance, that is 17.2 m. b) Reverberation :- Echoes may be heard more than once due to repeated or multiple reflections of sound from several reflecting surfaces. This causes persistence of sound called reverberation. In big halls or auditoriums to reduce reverberation, the roofs and walls are covered by sound absorbing materials like compressed fibre boards, rough plaster or draperies.
  • 18. c) Uses of multiple reflection of sound :- i) Megaphones, horns, musical instruments like trumpets, shehnais etc. are deigned to send sound by multiple reflection in a particular direction without spreading in all directions. ii) Doctors listen to sounds from the human body through a stethoscope. The sound of heartbeat reaches the doctor’s ears by multiple reflection. iii) Generally the ceilings of cinema halls and auditoriums are curved so that sound after multiple reflection reaches all parts of the hall. Sometimes a curved sound board is placed behind the stage so that sound after multiple reflection spreads evenly across the hall.
  • 19. 8) Range of Hearing :- Human beings can hear sound frequencies between 20 Hz and 2000 Hz. Sound whose frequency is less than 20 Hz is called infrasonic sound. Animals like dogs, elephants, rhinoceros, whales etc. produce and hear infrasonic sound. Sound whose frequency is more than 2000 Hz is called ultrasonic sound. Animals like dolphins, bats, rats propoises etc. produce and hear ultrasonic sound. Bats use reflection of ultrasonic sound waves to detect an obstacle or its prey.
  • 20. 9) Uses of ultrasonic sound :- i) Ultrasonic sound is used to clean objects like electronic components. The components to be cleaned are kept in a cleaning solution and ultrasonic waves are sent into the solution. Due to the high frequency, the dirt particles get detached from the components. ii) Ultrasonic sound is used to detect cracks in metal blocks. Ultrasonic waves are sent through the metal blocks and if there are cracks, the waves are reflected back and the cracks can be detected. iii) Ultrasonic sound is used in ultra sound scanners for getting images of internal organs of the human body. iv) Ultrasonic sound is used to break small stones formed in the kidneys into fine grains so that they are removed through the urine.
  • 21. 10) SONAR :- Sonar stands for Sound Navigation And Ranging. It is a device which uses ultrasonic waves to measure distance, direction and speed of underwater objects. Sonar has a transmitter and a detector installed in ships. The transmitter produces ultrasonic sound waves which travel through the water and after striking the object in the sea bed is reflected back to the detector. The distance of the object can be calculated by knowing the speed of sound in water and the time taken between the transmission and reception of ultrasound. If the time taken for the transmission and reception of ultra sound is t and the distance travelled is 2d by the ultra sound, then 2d = v x t or d = v x t 2
  • 22. 11) Structure of the human ear :- The outer ear called pinna collects the sound waves. The sound waves passes through the ear canal to a thin membrane called eardrum. The eardrum vibrates. The vibrations are amplified by the three bones of the middle ear called hammer, anvil and stirrup. The middle ear then transmits the sound waves to the inner ear. In the inner ear the sound waves are converted into electrical signals by the cochlea and sent to the brain through the auditory nerves. The brain then interprets the signals as sound. Hammer Anvil Stirrup Cochlea Pinna