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It's summertime, and you're on vacation.
时值夏季,你正在享受假期。
You sit beside a quiet pond, fishing, trying to relax, trying to think about nothing at all.
你稳坐在一个安静的池塘旁钓鱼，想放松自己,试图让脑子放空一切。
You watch the leaves stirring, the water rippling in the sunshine, and the water bugs standing on the surface of the water.
你看到树叶随水波荡漾,湖水在阳光下泛起涟漪,还有水虫恣意站在水面上。
How do they--Rats! Now your brain's working again, wondering how those bugs do that.
它们是如何!现在你的大脑再次被拉回工作状态,想知道虫子是如何做到的。
Well relax, it's Moment of Science to the rescue.
好了，放松,又到了科学出马的时候。
Today we'll explain Standing on Water.
今天我们将解释水上漂。
There are two things involved in this trick:
这一所谓的“魔术”涉及两个环节:
one is a property of the water, and the other has to do with the bug's feet.
一是水的性质,另一点是这种虫子的脚。
Let's start with the water.
让我们先从水开始。
Water molecules naturally stick to each other, due to a strong chemical attraction between the individual molecules.
由于单个分子之间的强烈化学吸引力，水分子自然而然的互相紧密连接。
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.
在池塘表面, 当强大的引力以及水内部的吸引力互相作用最上层的水分子经历这一吸引力。
This creates what's called "surface tension"-a somewhat compressed layer of water molecules right at the pond's surface.
这就产生了所谓的“表面张力”，一种水分子在池塘表面的压缩层。
You can think of this layer as being like a tight film over the surface of the pond.
你可以将这一层想象成池塘水面一种非常紧密的膜。
How does this help the water bug?
这对水虫起到什么作用?
If the surface water stuck to its feet as well as it stuck to the water below, the bug would be pulled under.
如果支撑它脚部表面的水支撑水面以下,虫子就会被拉入水中。
As it turns out, the bug's feet are covered with waxy hairs that are "hydrophobic"--which means they chemically resist contact with water.
事实证明,脚部覆盖着蜡状毛的这种昆虫是恐水的—这意味着它们会化学抵抗与水接触。
This combination of strong surface tension and water-resistant feet is what lets our bug stand on the water, without even getting wet!
这种结合强大的表面张力及防水的脚部让我们的虫子站在水上,甚至没有淋湿!
On our next program, we'll learn how water bugs move across this surface.
在我们下一期节目中,我们将了解水虫如何跨越这一表面。
Meanwhile, get back to your fishing!
与此同时,继续享受你的钓鱼吧!
