【精英翻譯】的部落格

Let’s Go Fly a Kite

飛翔吧！風箏

精英翻譯社轉自https://paper.udn.com/udnpaper/POH0061/354606/web/

Flying a kite is a common childhood pastime. Even if you haven’t done it yourself, you’ve probably at least seen it. But have you ever stopped and wondered how the fun activity actually works? What is it that keeps that colorful cloth aloft?

放風箏是常見的兒時消遣活動。即使你自己沒放過風箏，你八成至少有看過。但你有沒有停下來想過，這種有趣的活動實際上是怎麼運作的呢？是什麼讓這塊鮮豔的布料持續在天上飛？

If your answer to that last question is “the wind,” you are on the right track. It’s much more complicated than that, though. A kite that flutters steadily in the air with little effort from the person holding onto the string is a working example of the basic principles of aerodynamics, or the science of flight. Whether you are talking about a kite, a bird, or an airplane, the science is the same. The upward force that pushes a kite into the air and keeps it there is called lift. This is achieved when the air pressure underneath the kite, or a wing, is higher than the air pressure above it. That difference in pressure is the result of a difference in air speeds; fast-moving air is lower in pressure and slow-moving air is higher. The design of a kite is angled so that wind passing underneath it is slowed down, resulting in lift. Of course, you have to remember that the kite, though fairly light, still weighs something, so the force of the lift must be equal to a kite’s weight in order for it to fly.

針對上面最後一個問題，如果你的答案是「風」，你就想對了。不過實情要複雜得多。拉著風箏線的人不費吹灰之力、卻能使風箏在空中穩定飛揚是空氣動力學（也就是飛行的科學）基本原理的實例。無論你說的是風箏、鳥，或是飛機，背後的科學都一樣。將風箏推上天，並讓它留在空中的向上力稱為升力。當風箏（或是翼面）下方的氣壓高於其上方的氣壓時，就會形成升力。那種壓力差是空氣速度差異造成的結果；快速流動的空氣壓力較低，而慢速流動的空氣壓力較高。風箏的設計有斜角，因此通過下方的風會減速，導致升力形成。當然你必須記得，風箏儘管相當輕，卻還是有些重量，所以升力的力量必須等同風箏重量，風箏才飛得起來。

Once you have your kite in the air, then thrust (the force that pushes the kite forward) and drag (the force that pushes back against the kite) come into play. If you want to keep the kite steady, then these two forces must also be equal. Now, grab a kite and give it a try.

一旦你把風箏放上天空，接下來推力（將風箏往前推的力量）跟阻力（將風箏往後推的力量）就會開始發揮作用。如果你想穩住風箏，那麼這兩股力量也必須相同才行。現在就拿一只風箏，試著放放看吧。