Below are ideas for extending this topic beyond the activity & exploration you just completed.

• Lesson Assessment and Answer Key
• Activity: Make music that only you can hear.
• Activity: Make your paper cup telephone work around corners.
• Discussion/Activity: Send a message without words.

If you need to be convinced that sound can actually travel through a string, try this activity from San Francisco’s Exploratorium. With a string and a spoon, you can make amazing music that only you can hear.

Suppose you have a paper cup telephone that’s working great in the hall, where the string is straight. Then your friend ducks into a room and the string has to go around a corner. The phone stops working!

Can you figure out how to get it working again? This is a tough engineering challenge. Think about what changes when you go around a corner. What might be stopping the vibrations from traveling down the string?

If you want to see solutions that other people have come up with, check this site.

Suppose you keep making the string on your paper cup telephone longer and longer. At some distance, you can hear your friend talking — but you can’t tell what they are saying.

Can you think of a way to send a message when your friend can hear you, but can’t understand the words? Can you use a pattern of sounds to send a message without words?

If you’d like to see our ideas on how to do this, you’ll find them here.

We gave one idea away in the title! The telegraph invented by Samuel Morse uses Morse code to communicate with two sounds — dots and dashes. Can you make two sounds that your friend can tell apart through the long string? If you can, you can communicate with Morse code. Learn more about Morse code here.

Here’s another idea. You can communicate using a tap code, like this one. Using this code, a pattern of taps can be translated into letters.