英國學生科學讀本 Lesson 35 蒸汽往上冒(2)

There would soon be an explosion; the kettle would be burst open. It is in this way that boiler explosions are often caused. When there is too much steam in a boiler, and it cannot get out, it presses against the sides of the boiler, until at last the boiler bursts.

很快，就會發(fā)生爆炸，將水壺炸開。鍋爐經(jīng)常發(fā)生爆炸，就是這個原因。鍋爐里蒸汽太多，又出不來的時候，蒸汽就會緊緊壓在鍋爐壁上，直到最后把鍋爐炸開。

To prevent these accidents, every boiler has a safety-valve, or an opening through which the steam can escape when its pressure begins to get too great. It is only when something goes wrong with the safety-valve thatan explosion occurs.

為了避免這種事故，所有的鍋爐都裝著安全閥，這是一個開口，當蒸汽的壓力太大的時候，就能通過這個開口逃出去。只有在安全閥出問題的時候，才會發(fā)生爆炸。

Steam requires seventeen hundred times more room than the water from which it is formed. One kettle full of water would make enough steam to fill seventeen hundred kettles.

一份水變成的蒸汽，需要1700份這么多水的空間才能盛下。一把盛滿水的水壺，里面的水變成的蒸汽，可以盛滿1700個水壺呢!

It is heat that makes steam take up so much more room than water. The heat drives the tiny pieces of which water is made further and further away from each other.

是什么讓蒸汽占的地方，比水多了這么多呢?是熱量。熱量讓水分子之間的距離越來越遠。

This power of steam is a very good thing when it is properly used. It is this pressure that does the work in all steam-engines, and that sets their parts in motion.

如果用得合適，蒸汽的力量是一件非常好的事情。所有的蒸汽機，利用的都是這種力量。它們要靠蒸汽的力量，來推動部件運動。

The first really good steam-engines were made by James Watt, about a hundred years ago. It was by noticing the steam making the lid of a kettle dance and rattle, that he first began to think of the great power of steam.

最早一批實用的蒸汽機，是詹姆斯·瓦特在大約100年前制造的。瓦特當初看到了蒸汽推動水壺的蓋子跳舞，發(fā)出響聲，才開始思考蒸汽的強大力量。
 

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