Fri, Apr 11, 2008 page20

• Weekend Science: Writing secret messages with lemon juice 週末科學: 用檸檬水製作無字天書

  Welcome to Weekend Science! Every Friday, 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《週末科學版》！我們每週五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！

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  Have you ever wanted to write a secret message that only your friends can read? You can do so using a lemon, milk, vinegar or orange juice.

  What you will need:

  One or more of the following: lemons, milk, orange juice or vinegar

  

  照片︰MICHAEL KEARNEY

  PHOTO: MICHAEL KEARNEY, TAIPEI TIMES

  A heat source, such as a 100-watt light bulb

  White paper

  Cotton swabs

  Glasses

  Water

  ▲ Cut one of the lemons and squeeze some of its juice into a cup. Mix in some water.

  ▲ Put some milk, orange juice and vinegar into separate cups and mix them with water.

  ▲ Put only water into another cup. This will be your control.

  ▲ Dip a cotton swab into one of the cups, and use it to write on a piece of paper. Label the piece of paper so you know what kind of “ink” you used to write on it.

  ▲ Do the same with all your other kinds of “ink.” Use a different cotton swab for each one.

  ▲ Let the pieces of paper dry until you can’t see your message.

  ▲ Have a friend hold the piece of paper up to the light bulb. The message should appear. Note that you need to use a hot enough light bulb. Be careful not to burn yourself or the paper. Have an adult help you with this part. Don’t forget to record what happens in your Science Journal.

  (MICHAEL KEARNEY, STAFF WRITER)

  你曾經想要寫下一個只有你的朋友可以看到的秘密訊息嗎？你只要使用一顆檸檬、牛奶、醋或柳橙汁就可以做到囉。

  所需材料︰

  一個或多個下列物品：檸檬、牛奶、醋或柳橙汁

  一個加熱源，如一百瓦的燈泡

  白紙

  棉花棒

  玻璃杯

  水

  ▲ 切一顆檸檬，把汁擠到一個杯子裡，再加水攪拌。

  ▲ 分別將牛奶、柳橙汁和醋倒入三個不同的杯子裡，再加水攪拌。

  ▲ 再拿一個杯子裡面只裝水，這是你的對照組。

  ▲ 把一根棉花棒放到其中一杯裡蘸濕，然後用它在紙上寫字；在紙上標記你所使用的「墨水」種類，以免混淆。

  ▲ 使用不同種類的「墨水」重複上述步驟，每次都要換一根棉花棒。

  ▲ 等紙上的墨水乾到看不見所寫的訊息。

  ▲ 請一個朋友把紙放到一個燈泡前面，你剛剛寫的訊息應該就會顯現出來。注意！燈泡一定要夠熱才行，另外請小心不要燙到自己或是燒到紙張；請一個大人從旁協助這個步驟。別忘了在《科學日誌》裡記錄下結果。

  （翻譯︰袁星塵）

  Publication Notes

  VOCABULARY 今日單字

  1. watt n. 瓦特 (wa3 te4) 2. light bulb n. phr. 燈泡 (deng1 pao4) 3. cotton swab n. 棉花棒 (mian2 hua1 bang4) 4. squeeze v.t./v.i. 擠壓 (ji3 ya1) 5. control n. 對照組 (dui4 zhao4 zu3) 6. ink n. 墨水 (mo4 shui3) 7. consume v.t./v.i. 飲用 (yin3 yong4) 8. bubble n. 氣泡 (qi4 pao4) 9. carbon dioxide n. phr. 二氧化碳 (er4 yang3 hua4 tan4) 10. dilute v.t. 稀釋 (xi1 shi4) 11. weaken v.t./v.i. 使變脆弱 (shi3 bian4 cui4 ruo4)

  Publication Notes

  Science Journal 科學日誌

  In your Science Journal you should record how well each of the “inks” works. Also try to figure out how much water to add to each substance to dilute it so that the message disappears when it dries but appears when heat is added. 在你的《科學日誌》中，你應該要記錄每種「墨水」顯現的效果如何。另外，試著自己找出每種物質要分別加入多少水稀釋，才能讓訊息在紙乾了的時候消失，而在熱源照射下又會出現。

  Publication Notes

  WHAT'S THE SCIENCE? 科學原理

  The lemon juice, milk, vinegar and orange juice all weaken the paper. Even after they dry, the paper is still weakened. When you apply a heat source to the places you wrote, those areas turn brown first. Careful, they’ll also be the first places to burn. Note that when you apply the heat source to the paper you wrote on using only water, there is very little change. The paper hasn’t been weakened much, so it doesn’t turn brown easily. 檸檬汁、牛奶、醋和柳橙汁都會讓紙變脆弱，即使乾了後也一樣。當你用熱源照射你寫字之處時，那裡會先變焦黃；小心，那裡也會是最先燒起來的地方。 注意：你用清水寫字的紙張在熱源下沒有什麼變化，因為紙張並沒有變得比較脆弱，所以也不太容易變焦黃。

  Publication Notes

  FURTHER IDEAS 進階點子

  Lemons can also be used to make a tasty drink similar to the sodas you buy at the grocery store. Besides lemons, all you need is baking soda, sugar, a spoon and a cup. Have an adult help out to make sure your homemade drink is safe to consume. First wash your hands and a cup. Squeeze lemon juice into the cup. Add an equal amount of drinking water and then some baking soda. The bubbles that form when you add the baking soda are carbon dioxide bubbles ­— the same kind of bubbles that are in soda you buy at the store. Add sugar until the drink is how you like it. 檸檬也可以用來製作可口的飲料，就像你從雜貨店買來的汽水一樣，除了檸檬，你還需要準備小蘇打粉、糖、攪拌匙和一個杯子。請一個大人從旁協助，以確保你自製的飲料可以安全飲用。首先，先把你的手和杯子洗乾淨，把檸檬汁擠到杯子裡，加入等量的飲用水後，再加入一點點小蘇打粉。當你加入小蘇打粉時，產生的氣泡是二氧化碳氣泡──和市面上汽水裡的氣泡一樣。 依照個人喜好加入適量的糖。

  Publication Notes

  NEXT WEEK 下週預告

  For next Friday’s experiment you will need the following special items: an empty Pringles can and aluminum foil. 下週五的科學實驗，你需要特別準備以下的東西︰一個品客洋芋片空罐和鋁箔紙。
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