Take three plastic tubes two with same and small size and the other of large size. now attach these three tubes in Y shape. now attach paper cups on three ends of the Y shape tube. now stethoscope is ready.....
U - shape tube is like that of the letter Y but the only difference is it will be in the shape of U at the centre. This activity can be even done with the help of a plastic tube as well. U - shaped tube is available in the market.

1)Take three paper cups of same size and a U - shaped tube.
2)Attach the three cups to each end of the U - shaped tube that is
one to the right end, other to the left end and another to the centre end.
3)Place the centre end on the chest of the person and the other two ends to your ears.
4)Now your paper cups stethoscope is ready.