Question

Prove that
1.Sound needs a medium for propagation
2.Sound travels in liquid
3.Sound can travels through solids.

Answer 1

1 Hang an electric bell inside a jar connected to a vaccum pump.

Switch on yhe bell . Can you hear it ? Yes! Now switch on the vaccum pump to take out the air from the jar. What happens to the sound of the bell? The sound become feeble and finally you may not hear the sound . Thus proved sound need medium to travel.

2 Fill a balloon with water. Hold it near you ear. Now keep a watch gently to the other side of the balloon. Do you hear the sound? Yes!! Thus proved sound can travel through liquids.

3 Take a long metal rod. Keep it on a flat surface such as a table. Bring yoir ear close to one end of rod. Ask your friend to gently strike the other end of the rod by hammer. Do you hear the sound ? Yes !! Thus proved sound travel through solid.

Hope my answer help.