NCERT Book Class 8 Science Chapter 10 Sound

SOUND

H
ow do you come to know that a Sound plays an important role in our
‘period’ is over in your school? lives. It helps us to communicate with
You come to know easily that one another. We hear a variety of sounds
someone is at your door when he knocks in our surroundings.
or you hear the sound of the doorbell. Make a list of sounds you hear in
Most of the time you can make out that your surroundings.
someone is approaching you by just In the music room of your school you
hear the sounds produced by musical
hearing the foot steps.
instruments like flute, tabla,
You might have played a game called
harmonium, etc. (Fig. 10.1).
hide and seek. In this game a person is How is sound produced? How does it
blind-folded and has to catch the travel from one place to another ? How
remaining players. How is the blind- do we hear sound? Why are some sounds
folded person able to guess which player louder than others? We shall discuss
is closest to her? such questions in this chapter.

Tabla

Sitar

Flute
Harmonium

Fig. 10.1 : Some musical instruments