NCERT Solutions for Class 9 Science, Chapter 12 - Sound

In this chapter, you’ll study ‘Sound’ and various terms related to sound. So, what is ‘Sound’ exactly? A sound is a form of energy or a pressure wave created by a vibrating object, which travels through any medium, such as water, seafloor or air. We hear various sounds throughout the day such as bells ringing, children shouting, music playing, chanting, teacher teaching, and more. In NCERT Solutions for Class 9, Science, Chapter 12, you’ll study some interesting characteristics of sound, various mediums used by sound to travel, sound waves, the reflection of sound, range of hearing, ultrasound, its uses and structure of the human ear.

In-depth knowledge of this chapter will help you to have a clear understanding of the topic ‘Sound’ and various terms and applications related to it.

Let’s take a look at topics and sub-topics of Class 9 Science Chapter 12, Sound

12.1 Production of Sound

12.2 Propagation of Sound

  12.2.1 Sound needs a medium to travel

  12.2.2 Sound waves are longitudinal

  12.2.3 Characteristics of a sound wave

  12.2.4 Speed of sound in different media

12.3 Reflection of Sound

12.3.1 Echo

12.3.2 Reverberation

12.3.3 Uses of multiple reflections of sound

12.4 Range of Hearing

12.5 Applications of Ultrasound

12.5.1 Sonar

12.6 Structure of Human Ear

In Class 9 Science Chapter 12, you will learn – 

Section 12.1 – In this section, you’ll learn how sound is produced with the help of some very interesting activities. You’ll also study various ways and mediums through which you can produce sound. You’ll also come across vibration and how it helps in producing sound.

Section 12.2 – In this section, you’ll study what is the propagation of sound, how does sound travel, what are the significant characteristics of the sound wave and how does the speed of sound vary in different media.

Section 12.3 – In this section, you’ll learn what is a reflection of sound, what is an echo, how it occurs, what is reverberation, applications of various reflection of sound in designing megaphones, stethoscope, horns, the ceiling of concert halls, and more.

Section 12.4 – In this section, you’ll study the range of hearing in human beings and animals such as dogs, rhinoceroses, whales, elephants, dolphins, bats, moths, and more.

Section 12.5 – In this section, you’ll learn what is ultrasound and its applications, what is Sonar, how it works, its applications and what is echo-ranging.

Section 12.6 – In this section, you’ll acquire knowledge about the structure of the human ear, how do we hear, auditory parts of the human ear such as the outer, middle and the inner ear.

In this chapter, you are provided with several diagrams, activities and examples with their solutions for a clear understanding of Sound. To know more about NCERT Solutions for Class 9 Chapter 12 you should explore the exercises mentioned in this chapter. You can also download the Sound Class 9 Solutions PDF, solved by our science experts.