A hands-on STEM buddy for the Make Some Noise! breakout. Build a cup-and-string phone and send your voice across the room using sound — then make it work even better.
🎯 The problem
How can you talk to a friend far away without shouting? Build a string phone that carries your voice along a string using sound. The string vibrates and carries the sound to the other cup!
Big question: Does the string phone work better when the string is loose or pulled tight?
🧰 What you need
2 paper or plastic cups
A long piece of string or yarn (a few big steps long)
A pencil or a paper clip to help poke a small hole and hold the string
A friend or a partner
⚠️ Safety: ask a grown-up to help poke the small hole in the bottom of each cup.
🔁 Be an engineer
Ask: How can I send my voice to a friend across the room?
Imagine: How will the sound travel? (Along the string!)
Plan: Poke a small hole in the bottom of each cup for the string.
Build: Thread the string through both cups and tie a knot or use a paper clip inside so it stays.
Test: Walk apart until the string is tight. One person talks into a cup while the other listens.
Make it better: Try it with the string loose, then tight. Which one works better?
📊 What happened?
String
Could you hear? (yes / no / a little)
Loose string
Tight string
🗣️ Tell about it
Did the string phone work better loose or tight?
Why do you think so? (Try the words sound, vibrate, and string.)
📞 Meet a STEM job — Engineer & Inventor. Alexander Graham Bell invented a way to send voices far away — the telephone! Engineers use sound to help people talk across the world. (Grade 2 scientists to meet: Alexander Graham Bell, Marie Daly, Mario Molina, Jane Goodall.)
TEKS for this challenge
2.8(A) sound is made by vibrating matter · 2.8(C) design a device that uses sound to communicate over a distance · 2.1(B) plan & do a simple test · 2.1(G) make a model · 2.2(D) tell if a design works. Aligned to, not reproduced from, the official TEKS — confirm before adoption.