Cite an experiment to show that sound needs a material medium for its propagation.

Answer

To prove that sound needs a medium for propagation, we do the Bell Jar experiment

bell-jar-experiment.png

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In this experiment -

  • We take an electric bell and an airtight glass jar
  • The electric bell is suspended on the glass jar
  • And the glass jar is connected to a vacuum pump from the bottom
  • Now, we switch on the bell
  • We can hear the sound bell. 
  • Now start the vacuum pump. The air inside is pumped out gradually
  • And we can observe that the sound becomes fainter and fainter.
  • Eventually, when there is no air inside the jar, we cannot hear the sound of the bell

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Thus, when vacuum is created in the glass jar, then the sound of ringing bell cannot be heard.

This shows that sound needs a medium for propagation and cannot travel through vacuum.

  1. Class 9
  2. Chapter 12 Class 9 - Sound (Deleted)

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CA Maninder Singh
CA Maninder Singh is a Chartered Accountant for the past 11 years and a teacher from the past 11 years. He teaches Science, Accounts and English at Teachoo