Sound requires a medium to travel? Justify experimentally.
Sound requires medium for propagation and it can be proved by the following experiment: 1) Take a bell jar and suspend an electric bell in it. 2) The the bell jar is connected to a vacuum pump. Till the air is in the bell jar, the sound of the electric bell is louder. 3) Now, with the help of vacuum pump, pump out the air gradually 4) Now as air is pumped out, the sound of the bell gets fainter and fainter. 5) Now, when the bell jar is completely vacuumed no sound is heard. 6) This shows that air is required for propagation of sound.
