Short & Concise Class 8 Sound Notes

Firstly, let us see what we are going to study in this chapter. The overview of the chapter is very necessary for every student. This gives you an idea about the content we are going to study and can relate to our previous syllabus or chapters.

Class 8 Sound Notes
Sound Notes Class 8
Overview: Chapter 13 Sound

Let us first see what we are going to study-

Here is the list of topics we are going to discuss in this chapter 13 Sound.

  1. What is Sound?
  2. Sound Production
  3. Propagation of Sound
  4. Time Period
  5. Frequency
  6. Amplitude
  7. Characteristics of Sound
    1. Pitch
    2. Loudness
    3. Quality of Sound
  8. How Humans Speak
  9. Human Ear
  10. Noise and Music
  11. Causes, Effects, and Prevention of Noise Pollution
  12. Echo
  13. Application of Echo

Sound Notes Class 8 [Short and Concise]

What is Sound?

A sound is a form of energy that helps us to communicate with each other.

In other words, Sound is a mechanical wave (longitudinal) that is produced by a vibrating source.

Knowledge Booster:

A wave is a disturbance.

Longitudinal Wave: The type of wave in which particles vibrate in the direction of the motion of the wave.

For More About Longitudinal and Transverse Waves: Click Here to Read

Production of Sound

Sound is produced when the source vibrates or the object producing the sound vibrates.

Vibration: Vibration is the to and fro or back and forth motion. The best example is the motion of the pendulum about its mean central position.

Propagation of Sound

Now, let us talk about the propagation of sound waves.

What is propagation of sound?

The propagation of sound takes place in a medium. The propagation of sound takes place in solid, liquid, and gas.

The propagation of sound waves is faster in Solids than liquid and gas.



Amplitude meaning

The definition of Amplitude says it is the maximum displacement of a particle from its mean position.

Time Period

It is the time taken to repeat an event.


It is the number of events occurring in a second.

In other words, it is the number of waves (in this case sound wave) passing a fixed point in a unit time.

Frequency can also be defined as the number of cycles in unit time or one second.

Unit of Frequency: Hertz (Hz)

Note: per second (1/second) = Hertz

Characteristics of Sound

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