书城教材教辅科学读本(英文原版)(套装1-6册)
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第25章 第一册(25)

Cups and saucers, plates and dishes, basins and jugs are made of clay; and so are bricks, tiles, chimneypots, and ?owerpots. We call these things earthenware. While the clay is moist and pliable, the men mold it into the proper shape for all these things, and then bake them in hot ovens till they are hard.

Clay-Its Uses

The children were called away before they could finish their chat about clay. They had to leave it till some other time.

The next evening Fred began by making a little rough basin with his piece of clay, just as he had seen teacher do. He then filled the little basin with water.

"I know what that is for." said Norah. "You want to prove that the moist clay is not porous."Fred then put a piece of dry brick into a basin, and filled the basin with water to the brim. They waited for a minute or two and then he said, "Look, Norah, some of the water has gone. What has become of it? It has not been spilt on the floor.""I suppose it has gone into the brick," said Norah. "That"s right," said Will. "Now what does thisshow?"

"If the brick has sucked up the water, it must be porous." said Norah.