Describe an experiment to show that sound can travel in a solid .

Take two empty ice-cream cups. make a small hole at the bottom of each cup and pass a long thread (about $20m$ long) through them. Tie a knot or match-stick at each end of the thread so that the thread does not slip out through the holes. This makes a toy -telephone . Now use the toy telephone as shown in figure and talk to your friend . You will be able to hear the sound of your friend . This shows that sound travels through the thread and reaches your ear. Thus , sound can travel through a solid.