Sun, Feb 17, 2008 page14

• Making a paper dragonfly and paper airplane 自製紙竹蜻蜓和紙飛機

  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！

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  This week we're going to make a paper dragonfly and a paper airplane. We're going to use these to demonstrate how helicopters, planes and even most birds are able to fly!

  本週我們要來做紙竹蜻蜓和紙飛機，我們要利用這個機會來說明直昇機、飛機，甚至大多數鳥類的飛行原理！

  What you will need:

  

  Paper

  Scissors

  A paperclip

  

  To make the paper airplane:

  ★ Take a look at the picture below. Fold a piece of paper in half lengthwise to make a center crease.

  ★ Unfold the paper. Fold the two upper corners of the paper to the center crease, and then fold the folded corners to the center crease.

  

  照片：Michael Kearney

  PHOTO: MICHAEL KEARNEY, TAIPEI TIMES

  ★ Fold the paper in half again lengthwise, and then fold the two wings down.

  To make the paper dragonfly:

  ★ Take a look at the picture to the right. You need to copy it on to a piece of paper. You can make it bigger if you like. Cut along the dotted lines and fold along the solid lines. First fold A and B down in different directions to make the paper dragonfly's blades. Next fold C and D over in opposite directions, and then fold E up and attach a paperclip to make a stable base.

  Don't forget to record what happens in your Science Journal.

  (MICHAEL KEARNEY, STAFF WRITER)

  所需材料︰

  紙

  剪刀

  迴紋針

  紙飛機的製作步驟：

  ★ 參照下方圖示。將長方形紙「直立」對摺，中央會出現一條摺痕。

  ★ 把紙攤開，將上面兩個紙角摺向中央線，然後再將摺出來的折角摺向中央線。

  ★ 再把紙縱向對摺一次，然後把摺起的兩個機翼放下。

  紙竹蜻蜓的製作步驟：

  ★ 參考右側圖示。你必須把圖示複印到一張紙上，你可以依個人喜好放大，然後沿著虛線剪開，再沿實線摺疊；先將A和B處朝不同方向摺下，做成紙竹蜻蜓的槳翼，然後將C和D處反摺交疊，最後將E處向上折起，再用一根迴紋針固定基底即可。

  別忘了把結果記錄在《科學日誌》中。

  （翻譯︰袁星塵）

  For your information

  WHAT'S THE SCIENCE? 科學原理

  Airplanes need lift to fly, and the wings help give them lift. To understand how, first you need to know Newton's third law of motion, which states that for every action there is an equal and opposite reaction. Airplane's wings are shaped in such a way that they push a lot of air downward when speeding through the sky. Pushing air downward is the action. The reaction is that the wing is pushed upward. Another explanation for how airplanes get lift makes use of Bernoulli's principle, which states that as the speed of a fluid (either liquid or gas) increases, its pressure decreases. When a wing travels through air, the wing's shape causes air to travel more quickly over its top than its bottom. This causes the pressure of the air above the wing to be less than the pressure of the air below the wing. The result is lift. To produce lift, helicopters rotate their blades and airplanes move their wings through air. As the paper dragonfly falls, it rotates, which produces lift and causes it to float to the ground. There's also a push upward on the paper airplane, which helps it to fly when you throw it. 飛機飛行需要抬升力，而機翼能提供飛機飛行需要的抬升力。想要了解原理何在，首先你得先認識牛頓的第三運動定律：凡有物體受力作用，就一定會有一個大小一樣、方向相反的反作用力存在。飛機機翼的形狀便是依此設計，飛機在飛行時，機翼會把大量空氣向下推擠；將空氣下壓是作用力，機翼被向上推升就是反作用力。 我們也可以用柏努利定律來解釋飛機飛行的原理，柏努利定律說明流體（液體或氣體）的速度增加時，它的壓力就會減少。飛機飛行時，機翼的形狀讓機翼上方的氣流流速較下方來得快，因此機翼上方的壓力會較下方的壓力小，這就是為什麼飛機會被推升的原因。 直昇機靠著螺旋槳旋轉而飛起，飛機則靠著改變機翼與氣流接觸的角度來產生升力。 紙竹蜻蜓掉落時會旋轉，旋轉提供了上升的力量，使得紙竹蜻蜓能慢慢飄落到地面；紙飛機也有上推力，因此你丟出的紙飛機才會飛在空中。

  For your information

  VOCABULARY 今日單字

  1. dragonfly n. 蜻蜓 (qing1 ting2) 2. fold v.t/v.i. 對摺 (dui4 zhe2) 3. lengthwise adj. 縱長的 (zong4 chang2 de5) 4. crease n. 摺痕 (zhe2 hen2) 5. dotted adj. 點狀的 (dian3 zhuang4 de5) 6. solid adj. 實心的 (shi2 xin1 de5) 7. blade n. 葉片 (ye4 pian4)，槳翼 (jiang3 yi4) 8. Bernoulli's principle n. phr. 柏努利定律 (bo2 nu3 li4 ding4 lu4) 9. reaction n. 反作用力 (fan3 zuo4 yong4 li4) 10. rotate v.t./v.i. 旋轉 (xuan2 zhuan3)

  For your information

  SCIENCE JOURNAL 科學日誌

  What do you know about flight? Have you ever heard of Bernoulli's principle? The explanation in the "what's the science?" section isn't the whole story. Try searching the Internet for more information about how planes are able to fly. 你對飛行了解多少？你曾聽過「柏努利定律」嗎？今天的「科學原理」並沒有講解得太細，你可以到網路上搜尋更多飛機飛行原理的資料。
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