英文科學(xué)讀本 第一冊(cè)·Lesson 11 A Piece of Clay

Lesson 11 A Piece of Clay

Will and I have had a rare run since we left school, said Fred. "We had a lesson on a piece of clay today, and we wanted to find some clay for ourselves. Well, we came at last upon some men digging, and we got some clay from them. Here it is. Now we will settle down for our chat.

I told you, Fred began, "that the men were digging this clay out of the ground. Teacher gave us a name for the clay, because it is dug out of the ground. Clay is a mineral."

Will has a piece of dry clay. My piece is moist; it was only just now dug up. We will look at Will's piece first. You can tell Norah all about it, Will.

Will put his piece of dry clay into a saucer, with a little water in the bottom. When he asked Norah to take the clay out of the saucer, the water was all gone.

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

Clay is a mineral; it is dug out of the ground. Dry clay is porous; it absorbs water. Moist clay is not porous; it will not absorb water. Moist clay is pliable. We can mold it into any shape we please.