How do you make a cup phone?

Poke a small hole on the bottom of two styrofoam cups (make sure that the whole is in the center of the cups), thread a long string through the cups (be sure that the top of the cup is pointing out). Tie a knot at both ends of the string so that the cups will not fall off.

When you are talking into the cup, keep the string tight so the person that is listening can hear.