- 2 paper cups
- Pin or pin
- about 1.5m of string
- 2 paper clips
Use a pin to make a hole in the bottom of each mug.
Pull the string through the holes through both cups. Make sure the bottoms of the cups are facing each other.
Tie a paper clip at each end of the string
Pull the string so hard with your friend that the paper clips hit the bottom of the mugs.
Take turns talking into the mug and listening by placing the mug over your ear.
The sound travels through the air in waves. When you speak, the mug picks up sound waves, after which they move the string along with your friend’s mug.
This can also be done when several mugs are connected by string. Make another landline phone out of two mugs and tie the phones together to get a landline phone for four.