時差N小時:水上漂 Standing on Water

It's summertime, and you're on vacation.

時值夏季,你正在享受假期。

You sit beside a quiet pond, fishing, trying to relax,trying to think about nothing at all.

你穩(wěn)坐在一個安靜的池塘旁釣魚，想放松自己,試圖讓腦子放空一切。

You watch the leaves stirring, the water rippling inthe sunshine, and the water bugs standing on thesurface of the water.

你看到樹葉隨水波蕩漾,湖水在陽光下泛起漣漪,還有水蟲恣意站在水面上。

How do they--Rats! Now your brain's working again, wondering how those bugs do that.

它們是如何!現(xiàn)在你的大腦再次被拉回工作狀態(tài),想知道蟲子是如何做到的。

Well relax, it's Moment of Science to the rescue.

好了，放松,又到了科學(xué)出馬的時候。

Today we'll explain Standing on Water.

今天我們將解釋水上漂。

There are two things involved in this trick:

這一所謂的“魔術(shù)”涉及兩個環(huán)節(jié):

one is a property of the water, and theother has to do with the bug's feet.

一是水的性質(zhì),另一點是這種蟲子的腳。

Let's start with the water.

讓我們先從水開始。

Water molecules naturally stick to each other, due to a strong chemical attraction between theindividual molecules.

由于單個分子之間的強烈化學(xué)吸引力，水分子自然而然的互相緊密連接。

At the pond's surface, the uppermost water molecules experience this attraction as a strongpull toward each other, and downward from the water beneath them.

在池塘表面, 當(dāng)強大的引力以及水內(nèi)部的吸引力互相作用最上層的水分子經(jīng)歷這一吸引力。

This creates what's called "surface tension"-a somewhat compressed layer of water moleculesright at the pond's surface.

這就產(chǎn)生了所謂的“表面張力”，一種水分子在池塘表面的壓縮層。

You can think of this layer as being like a tight film over the surface of the pond.

你可以將這一層想象成池塘水面一種非常緊密的膜。

How does this help the water bug?

這對水蟲起到什么作用?

If the surface water stuck to its feet as well as it stuck to the water below, the bug would bepulled under.

如果支撐它腳部表面的水支撐水面以下,蟲子就會被拉入水中。

As it turns out, the bug's feet are covered with waxy hairs that are "hydrophobic"--which meansthey chemically resist contact with water.

事實證明,腳部覆蓋著蠟狀毛的這種昆蟲是恐水的—這意味著它們會化學(xué)抵抗與水接觸。

This combination of strong surface tension and water-resistant feet is what lets our bugstand on the water, without even getting wet!

這種結(jié)合強大的表面張力及防水的腳部讓我們的蟲子站在水上,甚至沒有淋濕!

On our next program, we'll learn how water bugs move across this surface.

在我們下一期節(jié)目中,我們將了解水蟲如何跨越這一表面。

Meanwhile, get back to your fishing!

與此同時,繼續(xù)享受你的釣魚吧!