书城教材教辅科学读本(英文原版)(套装1-6册)
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第128章 第二册(45)

"Well," said Fred, "after it had been through this hole, it was forced into a smaller one, and drawn through it, then through a still smaller one, and so on, each hole being smaller than the last.""I think I can understand it all now," said Norah. "Every time the iron was drawn through a hole, it became thinner and longer, until at last it made a great length of this thin wire. But is all wire made like this, Fred?""Yes, dear," said her brother, "all wire is drawn out through holes in a steel plate in the same way.

"Teacher gave us a name for metals which can be drawn out into wire. They are said to be ductile. Ductile means able to be drawn out. They are ductile because they are tough or tenacious, and hold firmly together.""Whenever you see," added Will, "a piece of wire, Norah, you will be able to say at once, "This metal must be ductile and tenacious, or it could not have been drawn out into wire." "SUMMARY

Some metals can be drawn out into wire. We say they are ductile. They must be very tough or tenacious, to hold together while they are being drawn out.

Iron Ore