英文科學讀本 第一冊·Lesson 03 Solids

Lesson 03 Solids

You know what happens, Norah, when I pour water on the table.

Oh yes, replied Norah; "it flows about, because it is a liquid."

Now I will put this stone on the table. Will the stone flow away too?

No, said Norah, "it will stand where you place it."

Then would it be right to call the stone a liquid? said Fred.

No, it cannot be a liquid, for all liquids flow.

We know we can't pick up water, said Fred. "It would run through our fingers, and fall in drops on the floor.

But we can pick up the stone without spilling any of it.

Yes, said Willie, "and we might shake the stone ever so long, but we could not shake drops from it, as we did from the water in the brush."

I say, Will, said Fred, "wasn't it funny when teacher shook the saw-dust into the basin, and asked one of the boys to pick out the piece of wood?"

Yes, said Will, "but there was no piece of wood in the basin, for the little bits of saw-dust do not run together, as the drops of water do."

I think, said Norah, "I can tell you something else. Water and all other liquids have no proper shape. But if we look at this stone, this brick, or this piece of wood, we can see that each of them has a shape of its own."

We know that, when we put some water into the basin, it spreads out to fill it, said Fred.

Yes, said Norah, "it takes the shape of the basin, and it keeps a level surface."

Now watch, while I put this brick into the basin. Does it spread out to fill the basin, Norah?

No, said Norah.

Does it take the shape of the basin?

No.

Teacher gave us the proper name for things like the brick and the piece of wood, said Willie. "We call them solids."

Solids are bodies that do not flow, do not break up into drops, have a shape of their own, and do not take the shape of the vessel which holds them.

SUMMARY

Solids do not flow about, and do not fall away in drops, as water does. They do not take the shape of the vessels which hold them, but have a shape of their own.