Sun, Feb 03, 2008 - Page 14 News List

Sunday Science: Cup phones 週日科學:傳聲筒

Welcome to Sunday Science! Every Sunday, we're going to guide you through some cool experiments that you can do at home. It's a good idea for you to keep a record of what you do in a Science Journal. That way you can record what you learn, compare results and maybe use them to design new experiments! Have a look at the Science Journal box for some ideas to get you started. Remember to always ask a grown-up's permission before trying out an experiment.




Cup phones 傳聲筒

This week we're going to use two cups and some string to make a telephone that you can use to tell secrets to your friends!

What you will need:

Two disposable cups (You can make more than one set of cup phones. Try using cups that are different sizes and made from different materials, such as cardboard, plastic or tin. If you use tin, be careful of sharp edges.)

A long (about 4m to 5m) piece of string




★ Clean out the cups and poke a small hole in the bottom of each one. The hole should be just big enough to poke the string through.

★ Put one end of the string through one of the cups. Tie it to a paperclip so the string won't be able to go back through the hole (the paperclip should be inside the cup). Attach some tape around the hole to close it up.

★ Do the same with the other cup.

★ Take one of the cups and have a friend take the other. Stand apart, with one person holding one of the cups up to his or her ear and the other talking into the other one. Make sure the string is taut. Don't forget to record your findings in your Science Journal.(michael kearney, staff writer)








★ 將每個杯子清潔乾淨後在底部戳一個小洞,這個洞只要大到可以把線穿進去即可。

★ 將線的一端穿過一個杯子,然後綁上迴紋針,讓線不致溜出杯洞(迴紋針應在杯內)。在杯洞口封上膠帶。

★ 另一個杯子也如法炮製。

★ 你拿一個杯子,你的朋友拿另一個杯子,兩人站遠一點,一個人將杯子靠近她或他的耳朵,另一個對著杯子說話,線必須要拉緊才行喔。別忘了把自己的發現寫在《科學日誌》中!



Vibrating objects create sound waves. When you speak into one of the cups, your vocal chords vibrate to create sound waves. Sound waves are compression waves, which means they move by the compression of a fluid. First they move through the air in the cup, then they move along the length of the string. Next they move through the air in the cup on the other end and into your friend's ear. Once the waves reach your friend's ear, they cause your friend's eardrum to vibrate. These vibrations are eventually changed into nerve signals that your friend's brain can detect.

Note that if the string isn't taut, the vibrations die out before they are able to travel the length of the string. And if you hold onto the string, the vibrations won't be able to pass.



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