two plastic cups, some string, paper clips, sharpened pencil for poking holes
1. With the pencil, carefully poke a small hole in the bottom of each plastic cup.
2. Tie the paper clip to one end of the string.
3. Thread the other end of the string through the hole in the bottom of one of the cups. Be sure to thread it from the inside of the cup. The paperclip will keep the string from going all the way through the hole.
4. Then thread the string through the hole in the second cup, but this time do it from the outside of the cup.
5. Tie the second paper clip to the other end of the string. The paper clip should be inside the cup, just like the first paper clip.
6. Then, pull the cups so that the string is tight and have one person talk into the cup while the other person holds the cup to their ear.
When we put the string through the cups and pulled tight, we could hear the other person. It sounds like an echo and really felt like a real telephone.
- 끈과 종이컵으로 돈이 필요없는 전화기를 만들어 통화를 할 수 있게 된다. 끈을 팽팽하게 했을 경우와 다른 종류의 수화기(ex. can)을 이용하여 실험을 해 본다.