Make A Cup Phone
Make a simple cup phone using two paper cups and string to explore sound vibrations and communication over distance through hands on experimentation.
About this activity
Make a simple cup phone using two paper cups and string to explore sound vibrations and communication over distance through hands on experimentation.
What you need
Step by step
- 1
Step 1
Gather all your materials and place them on a clear table.
- 2
Step 2
Cut the string to about three meters long with the scissors.
- 3
Step 3
Use the pencil to poke a small hole in the center of the bottom of the first cup.
- 4
Step 4
Use the pencil to poke a small hole in the center of the bottom of the second cup.
- 5
Step 5
Push one end of the string through the hole in the first cup from the outside to the inside.
- 6
Step 6
Tie a big knot on the string close to the inside of the first cup so the string cannot slip back through.
- 7
Step 7
Push the other end of the string through the hole in the second cup from the outside to the inside.
- 8
Step 8
Tie a big knot on the string close to the inside of the second cup so the string cannot slip back through.
- 9
Step 9
Walk backward while holding one cup so the string pulls straight and becomes tight.
- 10
Step 10
Put a small piece of tape over each knot inside the cups to secure the knots.
- 11
Step 11
Trim any extra string close to the knots with the scissors.
- 12
Step 12
Test your cup phone by having a friend hold one cup to their ear while you speak a short message into the other cup.
- 13
Step 13
Share your finished creation on DIY.org
Fun facts
How do you make a cup phone?
To make a cup phone, poke a small hole in the bottom center of two paper or light plastic cups using a pencil or skewer. Thread a 10–20 foot (3–6 m) length of string through both holes and tie a knot or tape the string to the inside of each cup so it won’t pull back through. Walk apart until the string is taut; one person speaks into a cup while the other listens at the opposite cup. Keep the string tight and avoid touching it while talking.
What materials do I need to make a cup phone?
You need two paper or lightweight plastic cups, a length of non-stretch string or twine (around 10–20 feet or 3–6 meters), a pencil or skewer to make small holes, and tape or glue to secure knots if needed. Scissors can cut the string and a marker can decorate the cups. For safety, choose rounded scissors and supervise children when creating holes or using sharp tools.
What ages is this activity suitable for?
Making a cup phone suits preschoolers to elementary-age children (about 4–10 years) with adult help for cutting and hole-making. Younger children (3+) can join with close supervision while adults handle tools. Older kids and tweens enjoy experimenting with distance and materials independently. This activity supports fine motor skills, listening practice, and simple science experiments across these ages.
What are the benefits of making a cup phone?
A cup phone teaches basic sound-vibration and communication concepts through hands-on play, encouraging curiosity about how sound travels. It builds fine motor skills when threading string and tying knots, promotes cooperative play and listening, and invites simple experiments (vary string length or material). It’s low-cost and safe when supervised, making it an engaging STEM introduction for young learners.
Watch & Learn
Need help?
I can't find thin string—what can I use instead?
If you don't have the thin string, use about three meters of yarn, fishing line, or strong dental floss and still poke holes with the pencil so the substitute feeds through like the string.
The phone is quiet or crackly—how do I fix it?
If you can't hear well, make sure the string is pulled straight and tight (step 'Walk backward while holding one cup'), that each end has a big knot taped inside the cup, and trim any extra string so it doesn't rub against the cup walls.
How can I change this activity for different ages?
For younger kids have an adult pre-cut the three-meter string and poke the holes with the pencil while the child ties knots and adds tape, and for older kids increase the string length, test fishing line versus yarn, or build a three-person network.
How can we extend or personalize the cup phone once it's made?
Decorate the cups before using the pencil to poke holes, thread beads onto the string before tying the knots for a handle, or swap between paper and plastic cups to compare sound quality when you test the phone.