【英语时差8,16】水上漂

It's summertime, and you're on vacation. You sit beside a quiet pond, fishing, trying to relax, trying to think about nothing at all. You watch the leaves stirring, the water rippling¹ in the sunshine, and the water bugs³ standing⁴ on the surface of the water.  How do they--Rats! Now your brain's working again, wondering how those bugs do that. Well relax, it's Moment of Science to the rescue. Today we'll explain Standing on Water.

There are two things involved in this trick: one is a property of the water, and the other has to do with the bug²'s feet. Let's start with the water.

Water molecules⁵ naturally stick to each other, due to a strong chemical attraction between the individual molecules. At the pond's surface, the uppermost water molecules experience this attraction as a strong pull toward each other, and downward from the water beneath them. This creates what's called "surface tension"--a somewhat compressed layer of water molecules right at the pond's surface. You can think of this layer as being like a tight film over the surface of the pond.

How does this help the water bug? If the surface water stuck to its feet as well as it stuck to the water below, the bug would be pulled under. As it turns out, the bug's feet are covered with waxy⁶ hairs that are "hydrophobic"--which means they chemically resist contact with water. This combination of strong surface tension and water-resistant feet is what lets our bug stand on the water, without even getting wet!

On our next program, we'll learn how water bugs move across this surface. Meanwhile, get back to your fishing!

1 rippling   

起涟漪的，潺潺流水般声音的

参考例句：

• I could see the dawn breeze rippling the shining water. 我能看见黎明的微风在波光粼粼的水面上吹出道道涟漪。
• The pool rippling was caused by the waving of the reeds. 池塘里的潺潺声是芦苇摇动时引起的。

2 bug   

n.虫子；故障；窃听器；vt.纠缠；装窃听器

参考例句：

• There is a bug in the system.系统出了故障。
• The bird caught a bug on the fly.那鸟在飞行中捉住了一只昆虫。

3 bugs   

adj.疯狂的，发疯的n.窃听器( bug的名词复数 )；病菌；虫子；[计算机]（制作软件程序所产生的意料不到的）错误

参考例句：

• All programs have bugs and need endless refinement. 所有的程序都有漏洞，都需要不断改进。 来自《简明英汉词典》
• The sacks of rice were swarming with bugs. 一袋袋的米里长满了虫子。 来自《简明英汉词典》

4 standing   

n.持续，地位；adj.永久的，不动的，直立的，不流动的

参考例句：

• After the earthquake only a few houses were left standing.地震过后只有几幢房屋还立着。
• They're standing out against any change in the law.他们坚决反对对法律做任何修改。

5 molecules   

分子( molecule的名词复数 )

参考例句：

• The structure of molecules can be seen under an electron microscope. 分子的结构可在电子显微镜下观察到。
• Inside the reactor the large molecules are cracked into smaller molecules. 在反应堆里，大分子裂变为小分子。

6 waxy   

adj.苍白的；光滑的

参考例句：

• Choose small waxy potatoes for the salad.选些个头小、表皮光滑的土豆做色拉。
• The waxy oil keeps ears from getting too dry.这些蜡状耳油可以保持耳朵不会太干燥。