英文科學(xué)讀本 第三冊(cè)·Lesson 02 Some of the Uses of Water

Lesson 02 Some of the Uses of Water

Now that we know something of the properties of water, said Fred, "we can talk about a few of the uses to which it is put. What do you think is the most important use which we make of water, Norah?"

I should say, replied Norah, "that its chief use is for drinking purposes."

Quite right, said Fred. "We could not live long without drink of some sort, and although we do not always drink water, yet all drinks are made of water."

Yes, added Willie, "and animals and plants, as well as ourselves, require water or they would die."

We must not forget, too, that our food has to be cooked and prepared with water.

Then think of the great use we make of water in washing ourselves and our dirty clothes, and in cleaning our houses. Teacher says it is the natural cleanser. We cannot be healthy and happy unless we are clean. Dirt brings disease, and the worst enemy of dirt is water.

Now, I want you, said Fred, "to imagine what would happen if the water, instead of being colorless, tasteless, and odorless, had a taste, smell, and color of its own."

Picture to yourself our shirts and collars, everything we wear, as well as our floors and tables, and every article of our food, colored red or blue, through being washed or prepared in red or blue water.

Think of the taste of our food too. It would take the same flavor and the same smell as the water in which it was cooked.

Water is useful for all these purposes simply because it is colorless, tasteless, and odorless.

I have just been thinking, said Willie, "of what teacher told us about the water cisterns. You know water is very absorbent, and will suck up and hold gases."

Teacher told us that all rotting or decaying matter in dustheaps and manure heaps gives off bad gases. These bad gases would be sure to find their way into any water that was near, and we could not drink such water without being made very ill.

The cistern which holds the water for drinking and cooking our food should be kept as far as possible from rubbish and manure heaps, and bad smells of all kinds.

There is one great use of water, said Fred, "that depends upon its being absorbent. Just think of the fishes and other animals that live entirely in the water. These animals all require air. Without air they would die."

But how can they get air in the water, Fred? said Norah. "Do they come up to the top every time they want to breathe?"

No, said Fred, "they do not. Many of these creatures never come to the surface of the water at all. Yet they breathe freely, because there is plenty of air in the water."

The water is absorbent. It is constantly sucking in air all over its surface. It is this air which the fishes and other creatures breathe.

SUMMARY

Water is the natural drink of man and all animals. It is the natural cleanser. We cook and prepare our food with water. Water absorbs gases. Fishes can breathe in water, because it contains air. Drinking water should be kept from bad smells of all kinds.