Make a toy telephone and explain your observation
Answers
Sound waves are created when sounds make vibrations in the air. In this activity, your voice vibrates the air inside the cup, which are then transferred to the bottom of the cup. The bottom of the cup passes the sound waves to the string, and so on to the other cup. You can hear surprisingly far using a string telephone if help the right way!
If the string is kept tight, the sound waves will travel. If the string is loose, the sound is less. This is because the lose string causes the vibrations to travel all around rather than directly down the string. Try experimenting with different lengths of string, types of string, and types of cups to see which produces the best sound over the longest distance.
Old landline phones were created using the same principle as a string telephone. The sound waves are turned into an electrical signal that can travel much farther than a simple string.