书城教材教辅科学读本(英文原版)(套装1-6册)
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第22章 第一册(22)

"Oh, I know." said Norah. "The dry clay is just like the sponge; it sucks up, or absorbs the water. It must be porous.""Dry clay is porous," said Will, looking pleased, "and it absorbs water through its pores."Fred now put his piece of clay in the saucer of water, but after waiting some time, they saw that none of the water was gone out of the saucer. He poured some more water on the clay, but it only rolled off into the saucer.

"This is very funny," said Norah. "Isn"t the moist clay porous too?""No, sister, moist clay is not porous; it does not absorb water," said Fred.

"Now look, Norah," added Fred, "and I will show you something else about this moist clay. Watch me while I work it up in my hands. I can make all sorts of things with it. This would do for a saucer; now let us break up the saucer, and mould or shape the clay into a little basin. See, it is done.

"Teacher says that things, which can be molded into all sorts of shapes like this, are said to be pliable," added Fred. "Don"t forget this word, Norah.""I suppose," said Norah, in reply, "the dough with which mother made the meat pie today is pliable, for I saw her work it up in her hands."SUMMARY