Question

Describe an experiment to show that sound cannot travel through vacuum.

Answer 1

Take a container with a tightly held lid. Make a hole at the bottom of the container. Now, connect a vacuum pump to this hole with a rubber tube. Make sure that there is no gap between hole and tube. The vacuum pump is used to extract air from the container.
Put a cell phone inside the container and close it with the lid. Now call the number of the cell phone so that it rings. We can hear the sound clearly. Extract the air from the container by switching on the vacuum pump. Again, call the number of the cell phone. This time no sound is heard because there is no air (medium) to help the propagation of sound. This experiment shows that sound cannot travel through vacuum.