英國學(xué)生科學(xué)讀本 Lesson 64 紅色金屬--銅(2)

Copper can be rolled or hammered out into thin sheets, and so we say that it is malleable. It can also be easily drawn out into wire, and for this reason we call it ductile. Sheet copper is much used for covering the bottoms of ships, and for making kettles and saucepans and many other household articles.

經(jīng)過碾壓與捶打，人們就可以把銅制成薄片。因此，我們說，這種金屬具有可鍛性。通過拉伸，人們就可以獲得銅線，因此我們說銅具有延展性。銅片可以用于覆蓋船底以及制造水壺、燉鍋與其他居家物品。

Copper is a good conductor of electricity—that is, it allows electricity to pass along it very easily. When electric lights or electric bells are put up, copper wire is always used. The cables which are placed on the bottom of the sea to carry telegraph messages from one country to another have copper wires running through them.

銅是很好的導(dǎo)電介質(zhì)，也就是說，電流可以輕易通過這種金屬。人們在電燈與電鈴中總會使用到銅線。用于在不同國家之間傳送電報(bào)信息的海底電纜也使用到了銅線。

Copper does not rust or tarnish so quickly as iron when exposed to the air. But if we heat a piece of sheet copper in a clear fire, we shall find that the surface turns black, from the copper rust which forms all over it.

與鐵相比，如果暴露在空氣之中，銅并不會那么快生銹與褪色。然而，如果我們使用明火對銅片進(jìn)行加熱，那么就會發(fā)現(xiàn)其表面從銅銹處開始變黑。

Copper is harder than lead, for we cannot scratch it with our finger-nail as we can scratch lead. But it is not so hard as iron, for it is easily scratched by an iron nail. Copper takes on a fine polish, and the surface of a piece of clean and polished copper is very bright.

銅的硬度比鉛要高，因?yàn)榕c鉛不同，我們無法用指甲在銅的表面刮出痕跡。不過它的硬度又比不上鐵，因?yàn)槲覀兛梢杂描F釘輕松地在銅的表面留下刮痕。銅的拋光性很好，一塊經(jīng)過拋光的純銅表面能夠呈現(xiàn)明亮的光澤。

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