Cup String Instruments

Learn about sympathetic vibration by making your own string instrument.

What you need

  • 3 pieces of string, each 4 feet long (1 needs to be a different kind of string)
  • 2 different plastic cups
  • 2 large paper clips
  • Paper towels
  • Water

Here’s what you do

  1. Tie a 4 foot piece of string to a table leg.
  2. Pull it tight and pluck it.
  3. Repeat this with a different kind of string.

Does it make a sound? What does it sound like to you? How are the strings different?

  1. With the two different kinds of string, slide the string between your thumb and index finger

Does it make a sound? Is it quiet or loud? How would you describe the sound for the two strings?

  1. Untie the strings from the table leg.
  2. Carefully poke a hole in the bottom of the two different cups.
  3. Put the loose end of your string through the hole in the cup from the bottom and then tie the string to a paperclip inside the cup. Use the same string for each cup.
  4. Pull the string so that the paperclip is on the bottom of the cup.
  5. Hold one cup so that the string is loose and slide it between your thumb and index finger.

Is the sound similar to the sound it made without the cup? 

  1. Next, fold a paper towel into quarters and use water to wet the towel.
  2. Pinch the string with the wet towel and slide the towel down the length of the string.

How is this sound different?

  1. Now tie the string to a table leg again and pull the cup so that the string pulls very tightly against the table leg.
  2. Pluck the string. If you have a friend, have them pinch the string at different points while you pluck.
  3. Repeat this with the other cup.

What does it sound like now? How do the different cups and different strings compare?