The Body Takes in Oxygen and Gives off Carbon Dioxide身体吸入氧气并排出二氧化碳

I-14 / 014

The Body Takes in Oxygen and Gives off Carbon Dioxide

Joseph Priestley was a scientist. Joseph Priestley discovered oxygen. He put a lighted candle in a glass jar. He covered the jar. The flame of the candle went out.

Next, he put a mouse in a jar with a lighted candle. He covered the jar. The candle flame went out, and the mouse died.

The scientist thought, “The candle and the mouse needed the same gas.”

“What spoiled the air?” he wondered.

He tried something else. He placed a small growing plant in a glass jar. He covered the jar. After ten days, the plant was still alive!

Next, Joseph Priestley put a mouse in with the plant and covered the jar. Both the mouse and the plant stayed alive!

He had to be sure. He took the plant from the jar and left the mouse. The mouse died. His thoughts were right.

The animals and the lighted candle both needed the same gas. What was that gas? It was oxygen.

In your studies about plants, you learned that plants gave off oxygen. The mouse needed oxygen from the plant.

You may ask, “Would it be better if all the air were oxygen?” It made the mouse so lively that it soon was tired.

You need nitrogen in the air to make the oxygen weaker.

Your blood is always moving. The blood takes oxygen to all parts of your body. When the blood takes the air back to the lungs, the air has changed. There is a lot more carbon dioxide in that air. This air goes from the lungs to the windpipe. It goes up the windpipe and out through the nostrils. We breathe out carbon dioxide.

必背词汇

练 习

1. Answer each statement with Yes or No.

(1) All living creatures need oxygen.__________

(2) It is better to breathe through your mouth.__________

(3) The blood is always moving to all parts of the body._________

(4) Joseph Priestley discovered oxygen.___________

(5) We breathe out carbon dioxide.___________

2. Complete the puzzle.

Finish the puzzle by using the clues below.

Down

1 The tube that carries oxygen to the lung

2 To make

3 The part of our body that takes in oxygen and gives out carbon dioxide

4 The gas that our lungs take from the air

Across

5 The gas that is mixed with oxygen in the air we breathe

6 The air we breathe out from our lungs

7 Openings in the nose

译 文

身体吸入氧气并排出二氧化碳

约瑟夫·普里斯特利是一名科学家，他发现了氧元素。他曾把一根点燃的蜡烛放进一个玻璃罐中。盖上盖子后，蜡烛熄灭了。

接着，他把一只老鼠和一根点燃的蜡烛都放在罐中。盖上盖子后，蜡烛灭了，老鼠也死了。

这位科学家想：“老鼠和蜡烛需要同一种气体。”

“是什么东西使空气变质了？”他很好奇。

他又尝试了别的实验。他把一小株正在生长的植物放入罐中，盖上盖子。10天后，植物仍然活着！

接下来，约瑟夫·普里斯特利把一只老鼠和这株植物一起放入罐中，并盖上盖子。结果，老鼠和植物都活着！

为了进一步确认，他把植物拿出罐外，把老鼠留在罐中，结果老鼠却死亡了。这证实了他的想法是对的。

老鼠和点燃的蜡烛都需要同一种气体。这种气体究竟是什么呢？那就是氧气。

通过对植物的研究，你们了解到植物会释放氧气，而老鼠需要植物释放出来的氧气。

也许你会问：“如果空气中只有氧气，是不是会变得更好呢？”如果是这样，老鼠就会由于过于兴奋，而很快就会变得疲惫了。

我们需要氮气来稀释空气中的氧气。

血液在体内循环流动，它把氧气带到身体的各个部分。当血液把气体带回肺部时，气体已经发生了变化。此时，气体中的二氧化碳含量会增加。该气体从肺部进入气管，之后经鼻孔排出，这样我们便呼出了二氧化碳。

练 习

1. 判断下列句子是否正确。

(1) ____________ 所有的生物都需要氧气。

(2) ____________ 用嘴呼吸会更好。

(3) ____________ 血液在身体各部位循环流动。

(4) ____________ 约瑟夫·普里斯特利发现了氧元素。

(5) ____________ 我们呼出二氧化碳。

2. 完成字谜。

根据下列线索，完成字谜。

纵向

1 将氧气送入肺部的管子

2 制造

3 我们身体中吸入氧气及呼出二氧化碳的部分

4 肺部从空气中吸入的气体

横向

5 我们呼吸的在空气中与氧气混合的气体

6 我们从肺部排出的气体

7 鼻子的出口

答 案

1. (1) Yes (2) No (3) Yes (4) Yes (5) Yes

2. (1) windpipe (2) create (3) lungs (4) oxygen(5) nitrogen (6) carbon dioxide (7) nostrils