Read and download NCERT Class 9 Science Sound in NCERT book for Class 9 Science. You can download latest NCERT eBooks chapter wise in PDF format free from Studiestoday.com. This Science textbook for Class 9 is designed by NCERT and is very useful for students. Please also refer to the NCERT solutions for Class 9 Science to understand the answers of the exercise questions given at the end of this chapter
NCERT Book for Class 9 Science Chapter 12 Sound
Class 9 Science students should refer to the following NCERT Book Chapter 12 Sound in Class 9. This NCERT Book for Class 9 Science will be very useful for exams and help you to score good marks
Chapter 12 Sound NCERT Book Class 9
SOUND
Everyday we hear sounds from various sources like humans, birds, bells, machines, vehicles, televisions, radios etc. Sound is a form of energy which produces a sensation of hearing in our ears. There are also other forms of energy like mechanical energy, heat energy, light energy etc. We have talked about mechanical energy in the previous chapters.
You have been taught about conservation of energy, which states that we can neither create nor destroy energy. We can just change it from one form to another. When you clap, a sound is produced. Can you produce sound without utilising your energy? Which form of energy did you use to produce sound? In this chapter we are going to learn how sound is produced and how it is transmitted through a medium and received by our ear.
12.1 Production of Sound
Activity _____________12.1
• Take a tuning fork and set it vibrating by striking its prong on a rubber pad. Bring it near your ear.
• Do you hear any sound?
• Touch one of the prongs of the vibrating tuning fork with your finger and share your experience with your friends.
• Now, suspend a table tennis ball or a small plastic ball by a thread from a support [Take a big needle and a thread, put a knot at one end of the thread, and then with the help of the needle pass the thread through the.Touch the ball gently with the prong of a vibrating tuning fork (Fig. 12.1).
• Observe what happens and discuss with your friends.
Activity _____________ 12.2
• Fill water in a beaker or a glass up to the brim. Gently touch the water surface with one of the prongs of the vibrating tuning fork, as shown in Fig. 12.2.
• Next dip the prongs of the vibrating tuning fork in water, as shown in Fig. 12.3.
• Observe what happens in both the cases.
• Discuss with your friends why this happens.
Fig. 12.1: Vibrating tuning fork just touching the From the above activities what do you conclude? Can you produce sound without a vibrating object? In the above activities we have produced sound by striking the tuning fork. We can also produce sound by plucking, scratching, rubbing, blowing or shaking different objects. As per the above activities what do we do to the objects? We set the objects vibrating and produce sound. Vibration means a kind of rapid to and fro motion of an object. The sound of the human voice is produced due to vibrations in the vocal cords. When a bird flaps its wings, do you hear any sound? Think how the buzzing sound accompanying a bee is produced. A stretched rubber band when plucked vibrates and produces sound. If you have never done this, then do it and observe the vibration of the stretched rubber band
12.2 Propagation of Sound
Sound is produced by vibrating objects. The matter or substance through which sound is transmitted is called a medium. It can be solid, liquid or gas. Sound moves through a medium from the point of generation to the listener. When an object vibrates, it sets the particles of the medium around it vibrating. The particles do not travel all the way from the vibrating object to the ear. A particle of the medium in contact with the vibrating object is first displaced from its equilibrium position. It then exerts a force on the adjacent particle. As a result of which the adjacent particle gets displaced from its position of rest. After displacing the adjacent particle the first particle comes back to its originalposition. This process continues in the medium till the sound reaches your ear. The disturbance created by a source of sound in Fig. 12.3: Both the prongs of the vibrating tuning fork dipped in water.
the medium travels through the medium and not the particles of the medium. A wave is a disturbance that moves through a medium when the particles of the medium set neighbouring particles into motion. They in turn produce similar motion in others. The particles of the medium do not move forward themselves, but the disturbance is carried forward. This is what happens during propagation of sound in a medium, hence sound can be visualised as a wave. Sound waves are characterised by the motion of particles in the medium and are called mechanical waves.
Please refer to attached file for NCERT Class 9 Science Sound
NCERT Class 9 Science Matter In Our Surroundings |
NCERT Class 9 Science Matter In Our Surroundings Questions |
NCERT Class 9 Science Is Matter Around Us Pure |
NCERT Class 9 Science Is Matter Around Us Pure Questions |
NCERT Class 9 Science Atoms And Molecules |
NCERT Class 9 Science Atoms And Molecules Questions |
NCERT Class 9 Science Structure Of The Atom |
NCERT Class 9 Science Structure Of The Atom Questions |
NCERT Class 9 Science The Fundamental Unit Of Life |
NCERT Class 9 Science The Fundamental Unit Of Life Questions |
NCERT Class 9 Science Tissues |
NCERT Class 9 Science Tissues Questions |
NCERT Class 9 Science Diversity In Living Organisms |
NCERT Class 9 Science Diversity In Living Organisms Questions |
NCERT Class 9 Science Motion |
NCERT Class 9 Science Motion Questions |
NCERT Class 9 Science Force And Laws Of Motion |
NCERT Class 9 Science Force And Laws Of Motion Questions |
NCERT Class 9 Science Gravitation |
NCERT Class 9 Science Gravitation Questions |
NCERT Class 9 Science Work And Energy |
NCERT Class 9 Science Work And Energy Questions |
NCERT Class 9 Science Sound |
NCERT Class 9 Science Sound Questions |
NCERT Class 9 Science Why Do We Fall Ill |
NCERT Class 9 Science Why Do We Fall Ill Questions |
NCERT Class 9 Science Natural Resources |
NCERT Class 9 Science Natural Resources Questions |
NCERT Class 9 Science Improvement In Food Resources |
NCERT Class 9 Science Improvement In Food Resources Questions |
NCERT Class 9 Science Solutions and Answers |
NCERT Book Class 9 Science Chapter 12 Sound
The above NCERT Books for Class 9 Science Chapter 12 Sound have been published by NCERT for latest academic session. The textbook by NCERT for Chapter 12 Sound Science Class 9 is being used by various schools and almost all education boards in India. Teachers have always recommended students to refer to Chapter 12 Sound NCERT etextbooks as the exams for Class 9 Science are always asked as per the syllabus defined in these ebooks. These Class 9 Chapter 12 Sound book for Science also includes collection of question. Along with Science Class 9 NCERT Book in Pdf for Chapter 12 Sound we have provided all NCERT Books in English Medium for Class 9 which will be really helpful for students who have opted for english language as a medium. Class 9 students will need their books in English so we have provided them here for all subjects in Class 9.
You can download the NCERT Book for Class 9 Science Chapter 12 Sound for latest session from StudiesToday.com
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