Can sound travel through a vacuum? Describe an experiment to explain your answer.

No, sound cannot travel through a vacuum.

It is shown by the following experiment:

1. Take an electric bell and an air-tight glass jar connected to a vacuum pump. Suspend the electric bell inside the jar.
2. Connect the bell to a battery through a switch.
3. On pressing the switch bell starts ringing and a sound is heard.
4. Now start the vacuum pump. It withdraws the air from the jar.

We will notice that as the air from the jar is evacuated the sound gradually becomes more and more feeble. After sometime when no air is left within the jar, no sound is heard. But we can notice the hammer of the electric bell is striking the gong.

This shows that sound cannot travel in vacuum because when there is air in the jar, we can hear the sound but when air is evacuated from the jar through vacuum pump, we cannot hear the sound although the bell is vibrating.