Question

explain the experiment sound needs material medium for propagation

Answer 1

* take a jar with a lid ( preferably a rubber cork) and with a small opening at one side

*place a small Bell with a gong inside the jar and turn it on. it makes a sound

*now, fix a vacuum pump in the small opening of the jar and suck all the air out of the jar with the vacuum pump

*now turn the Bell on

you will not hear any sound although the Bell is turned on

this process that sounds needs a material medium for propagation