Question

Describe an experimental arrangement showing that material medium is necessary for propagation of sound.

Answer 1

The experiment to show sound waves require a medium to transfer is as below:

1. Place a sounding alarm inside a closed jar with an outlet connected to vacuum pump. The set-up will be as below.

1. Connect the bell to a battery and allow it to ring.
2. While the bell is ringing, allow the vacuum pump to suck the air out of the jar.
3. As the air is emptied from the jar, we can observe that the volume of sound lowers.
4. Once the sir is completely emptied, the sound is completely cut off but the sounding bell is seen to be still ringing.
5. Thus, in this case air is necessary for the sound waves to travel

Thus, from the above experiment we can prove that sound waves need a medium to travel.