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Make your 1st String Telephone

“Necessity may be the mother of invention, but the play is certainly the father.” Today, we are surrounded by technology, but the young ones are unaware as to which root invention was these tools invented. Making string telephones is a great way to teach children about sound waves and how traditional telephone works.


While speaking, our vocal cords make molecules in the air vibrate. Those vibrating air molecules make other air molecules around them vibrate, and so on it continues, which is how sound travels through the air.


  • 2 Plastic Cups

  • Long Cotton String

  • Scissor


  1. Make a small hole in the center of the bottom of each cup

  2. Thread each end of the string through the holes in the cups

  3. Tie knots in each end to prevent the string from pulling back through the cups

  4. Hold one cup for yourself and hand over the other to your partner and speak in the cup from a distance and the other one keeps it near their ears

Learning Opportunity:

  • Sound is made up of sound waves or rather vibrations

  • These waves are generated by objects vibrating

  • The waves are made of microscopic building blocks called molecules.

  • Sound waves can travel through water, air, and solid objects as vibrations

  • The size and shape of sound waves determine the kind of sound heard

  • Sound waves are used in a variety of important ways by animals and humans

  • Animals, such as bats, can use echolocation and sound wave vibrations to locate objects in their paths

  • Humans use sound waves to share important ideas and feelings

Time Required: 10 minutes

Cost: NIL

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