WHAT IS SOUND? 



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which follow the use of our voices, for withou: sound 

 means without voice. You will be glad, now, to get a little 

 information about sound in its relation to human beings. 



What is sound ? We know in a general way that we 

 make sounds by means of certain cords in our throats, 



Enjoying life at home. 



called the vocal cords, and that sounds affect our ears, which 

 in turn communicate them to the brain, and we get the 

 sensation we call sound. But this does not explain how 

 sound originates. 



Experiment. To show that sound is due to vibration. 



Materials: Tuning fork. Pith ball on end of a thread. Glass of water. 



Method and Results: Strike the prong of a tuning fork on a block of wood. 

 Rest the handle end against the table. Let the pith ball suspended by 

 the thread come in contact with the prong. Result ?* Strike the 

 prong again and touch the surface of the water with it. Result? 

 Pluck a stretched string. Touch with the pith ball. Result? 



Conclusion: Do these bodies produce sound except when they are vi- 

 brating? How does a body produce sound? 



