Question

【題目】Easy floating

If you have ever been swimming in the ocean, you may have noticed that sea water is easier to float in than pool water. Here’s why:

You’ll need

Two clear bowls Food coloring Spoon Salt Two eggs

1. Fill bowls halfway with water.

2. Add 10 tablespoons of salt to one bowl, mix until it dissolves, and then add several drops of color.

3. Carefully put an egg into each bowl of water, and watch what happens.

What happens?

The egg in the plain water sinks. The egg in the salt water floats.

(If the salt water egg does not float well, mix more salt into the bowl. )

The water and salt particles (粒子) in the salt water bowl are closer together than plain water particles are. They press harder against the egg than the plain water particles do and the egg floats.

【1】The purpose of the experiment is to explain ________.

A. why the egg floats in the salt water

B. why people float more easily in the sea

C. how we can make the egg float in water

D. how the water and salt particles act together

【2】According to the text, if the egg in the salt water doesn’t float, which is the reason?

A. The water is too hot.B. The egg is not fresh.

C. The bowl is too small.D. The salt is not enough.

【3】Why does the egg float in the salt water instead of in the plain water?

A. The egg gets more pressure.B. The salt particles press harder.

C. The water particles are closer.D. The food coloring gives a force.

Answer 1

【答案】

【1】B

【2】D

【3】A

【解析】

這是一篇科普類閱讀。文章通過(guò)做實(shí)驗(yàn)的方法，解釋了為什么人們更容易漂浮在海水里。

【1】細(xì)節(jié)理解題。答案定位在第一段If you have ever been swimming in the ocean, you may have noticed that sea water is easier to float in than pool water.可知這個(gè)實(shí)驗(yàn)的目的是解釋為什么人們更容易漂浮在海里，故選B。

【2】推理判斷題。根據(jù)If the salt water egg does not float well, mix more salt into the bowl.（如果鹽水里的雞蛋不能很好地漂浮，在碗里加入更多的鹽。）由此可知如果雞蛋在鹽水中不漂浮，是因?yàn)辂}不夠，故選D。

【3】推理判斷題。答案定位在最后一段They press harder against the egg than the plain water particles do and the egg floats.（它們比普通的水粒子對(duì)雞蛋的壓力更大，雞蛋就會(huì)漂浮起來(lái)。）由此推斷出雞蛋浮在鹽水里而不是在白水里，是因?yàn)殡u蛋得到更多的壓力，故選A。