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.

歡迎閱讀《週日科學版》!我們每週日都要為你介紹可以在家中進行的有趣科學實驗。你可以在《科學日誌》中記錄自己做了哪些活動,這樣就可以將所學的紀錄下來,比較這些結果,也許還可以利用它們來設計新的實驗!先看一下《科學日誌》的點子再開始吧。展開實驗之前,記得要獲得大人許可喔!

照片︰MICHAEL KEARNEY

PHOTO: MICHAEL KEARNEY, TAIPEI TIMES

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

Paperclips

Scissors

Tape

★ 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)

本週我們要用兩個杯子和一些線來製作可以用來和朋友分享秘密的電話!

所需材料︰

兩個免洗杯(你可以做不止一組的傳聲筒,試著用不同大小或不同材質的杯子,例如紙杯、塑膠杯或罐頭。若使用罐頭,請留意銳利的罐口緣。)

一段長度約四到五公尺的線

迴紋針

剪刀

膠帶

★ 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!

(翻譯︰袁星塵)

WHAT'S THE SCIENCE? 科學原理

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.

震動的物體會產生聲波,當你對著杯子說話時,你的聲帶震動產生了聲波,聲波是一種壓力波,這表示它們隨著流體的壓力而傳播。首先,聲波會穿透杯中的空氣,然後它們透過那段線傳遞,接著他們又傳到另一端杯子中的空氣,最後才傳到你朋友耳裡。聲波一傳到你朋友耳裡,會使你朋友的耳膜震動,震動最後會轉換為大腦偵測的到的神經信號。

注意,當線不是緊繃時,震動會在傳送到末端途中就消失;若你握著這段線,震動也無法通過。


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