书城教材教辅科学读本(英文原版)(套装1-6册)
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第34章 第一册(34)

"Oh, this is luck," said Fred, "I"ll ask him for a piece of his putty, and then we can have a chat about it.""Did you see the man rolling the putty about in his hands, Norah?" he asked, as soon as they sat down.

"Yes," said Norah, "and I knew at once that putty must be a pliable substance.""Quite right," said Fred. "Now I will show you some of the things we have learned about putty to- day. Look, I will make it into a little cup, and then fill it with water, just as teacher did."The children watched it for some time, and then Willie said, "I am sure Norah can tell us all about it now.""Yes," said Norah, "the water stands in the cup, as it stood in the cup of moist clay. The putty is not porous-water will not pass through it.""Quite right," said Will. "Teacher told us to say that putty is waterproof.""Now let me have a turn," said Fred. "But what a mess our hands are in. How this putty sticks to our fingers.""I say, Fred," said Will, "do you think Norah can tell us why the workman was glad to have sticky putty? We know, don"t we?""Why, I suppose it is because he wants it to stick fast to the wood of the windowframe." said Norah.

"That"s my clever little sister once more." said Fred.