Paper Cup Phone
Make a paper cup phone and learn how sound waves travel.
What You Need
- 2 paper cups with a hold in the bottom
- 1 metre piece of sting
- Tape
Guide:
Safety Notes
Ensure you are familiar with Let's Talk Science's precautions with respect to safe virtual outreach to youth.
What To Do
To make the paper cup phone
- Take one cup and put one end of the piece of string through the cup starting at the bottom.
- Tape about 2.5 cm of string to the bottom of the inside of the cup.
- Take the second cup and put the other end of the string through the cup starting at the bottom.
- Take about 2.5 cm of string to the bottom of the second cup.
To test the paper cup phone
- Place the top of the cup over your ear.
- Have your partner take the other cup and walk as far away as they can without pulling the string out of either cup.
- Have your partner talk into their cup while you have your cup over your ear. Can you hear your partner talking through the cup over your ear? If not, tighten the sting a little more and try again.
- Test out what happens if the sting isn't tight. For example, have your partner walk a little closer to you so the string sags in the middle a bit. Can you hear your partner now?
- What happens if you stay on one side of a door and your partner is on the other side of the door. Don't close the door tight- leave space for the string to pass through.
Discovery
Sound energy travels in waves, The waves need to travel through something (like air or water). When you pull the string tight on your phone, the sound waves can travel easily along the string and the person with the cup to their ear hears what was said into the cup at the other end of the string. If the string is loose or someone touches the string, the sound waves spread out as they travel and the person with the cup to their ear doesn't hear what was said.
Test our your phone with different types of string, with shorter or longer pieces of string, or with larger paper cups!
Guide:
What's Happening?
Sound energy travels in waves, The waves need to travel through something (like air or water). When you pull the string tight on your phone, the sound waves can travel easily along the string and the person with the cup to their ear hears what was said into the cup at the other end of the string. If the string is loose or someone touches the string, the sound waves spread out as they travel and the person with the cup to their ear doesn't hear what was said.
Investigate Further
Test our your phone with different types of string, with shorter or longer pieces of string, or with larger paper cups!