Question

describe an activity to show that sound cannot travel in vacuum?

Answer 1

The experiment is done by placing an electrical bell in the bell jar. ... However, the sound is not audible to our ears because of the vacuum inside the jar. This demonstrates that the soundwave cannot travel through vacuum. That is, a sound wave needs a material medium for its propagation.

Answer 2

experiment

take an electric bell and an airtight glass Bell jar

the electric bell is suspended inside the bell jar

the bell jar is connected to a vacuum pump as shown in above figure.


as the circuit of electric bell is completed by pressing the key the hammer of the electric bell is seen to strike the gong repeatedly and the sound of bell is heard .

now keeping the key pressed air is gradually withdrawn from the jar starting the vacuum pump .
it is noticed that the loudness of sound goes on decreasing as the air is taken out from the bell jar and finally no sound is heard when the entire air from the jar has been drawn out .

the hammer still is strikes but we are not able to hear the sound

this experiment proves that sound cannot travel in vacuum and it needs a material medium through which sound can propagate