书城教材教辅科学读本(英文原版)(套装1-6册)
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第178章 第三册(3)

"And you are quite right," said both the boys. "Water is a colorless liquid.""Now," Fred continued, "look through the tumbler of water, and then through the milk. Can you see this ball through the milk?""No."

"Can you see it through the water?"

"Yes, I can see it through the water, but not through the milk.""Remember, then, that water is transparent, milk is opaque. Water is a colorless transparent liquid. Milk is a white opaque liquid.""And remember, Norah," said Will, "that we learn these properties of water through our eyes, by the sense of sight.

"Now, suppose we made you shut your eyes, and tell the names of various liquids, such as tea, vinegar, cocoa, coffee, brine, by smelling and tasting them, could you do it?""Oh yes, I am sure I could." said Norah.

"Then shut your eyes, and tell us the name of thisone by first smelling it and then tasting it." said Fred.

"I can neither smell nor taste anything." said Norah.

"Now open your eyes and see what the liquid is," said her brother. "You see it is water. Water has neither odor nor taste. We say it is an inodorous and tasteless liquid, but we learn this through two other senses-the sense of smell and the sense of taste."SUMMARY