时差N小时 雨滴的多种形状

When it's raining, it may seem that every raindrop is the same—same size, same basic shape, same wetness. But if you could compare and measure raindrops, you'd find that they're not all the same size or shape. In fact, raindrops vary from one to six millimeters in diameter and come in all sorts of shapes. When they first fall from clouds, raindrops are surprisingly large—in rare cases, some are as wide across as a baseball. So what happens to break these monster drops into many smaller drops of different sizes?

下雨时，似乎每一滴雨都是一样的——一样的大小，一样的基本形状，一样的湿润。但如果你能比较和测量雨滴，就会发现它们的大小、尺寸并不完全相同。实际上，雨滴的直径从一毫米到六毫米不等，形状和尺寸也各不相同。当雨滴第一次从云端落下时，它们出奇的大——在很少见的情况下，某些雨滴甚至会宽如棒球。那么是什么让这些“怪兽”雨滴破碎成许多大小不一的小雨滴呢？

Scientists used to think it was the result of drops colliding and splintering as they fell. But one study has found that although individual large drops do indeed break up into smaller shards¹, it has nothing to do with mid² air collisions. Instead, drops shatter all on their own. French scientists observed the phenomenon when they used a high speed camera to capture drops falling from a nozzle to simulate rainfall.

过去，科学家认为这是由雨滴在下落过程中相互碰撞、不断分裂所致。但一项研究发现，大雨滴确实分裂成为较小的碎片，但这与半空中的碰撞无关。实际上，雨滴是自动破裂的。法国科学家观察到这一现象，他们用喷嘴模拟降雨，用高像素的相机捕捉到了水滴下落时的镜头。

As it falls from the nozzle or cloud, the drop flattens³. Then it seems to inflate⁴ like a balloon. Finally, after a few milliseconds, the upward pressure of air causes the drop to explode into hundreds of watery⁵ bits. The researchers created mathematical models to demonstrate that the shattering of individual drops explains why raindrops come in different sizes. Now, math is always useful—but to really get a sense of how raindrops shatter, you have to see it up close.

随着水滴从喷嘴或云端不断下降，雨滴趋于平缓。然后，它们像气球一样膨胀。最后，几毫秒过后由于空气的上行压力，雨滴爆炸成上百个小水滴。单个雨滴的爆炸解释了为什么雨滴的大小各异，研究人员还创建了数学模型来加以说明。现在，数学总是能派上用场——但想要真正了解雨滴是如何分裂的，你必须近距离观察它。

1 shards   

n.（玻璃、金属或其他硬物的）尖利的碎片( shard的名词复数 )

参考例句：

• Eyewitnesses spoke of rocks and shards of glass flying in the air. 目击者称空中石块和玻璃碎片四溅。 来自辞典例句
• Ward, Josh Billings, and a host of others have survived only in scattered shards of humour. 沃德、比林斯和许多别的作家能够留传下来的只是些幽默的残章断简。 来自辞典例句

2 mid   

adj.中央的，中间的

参考例句：

• Our mid-term exam is pending.我们就要期中考试了。
• He switched over to teaching in mid-career.他在而立之年转入教学工作。

3 flattens   

变平，使（某物）变平( flatten的第三人称单数 )； 彻底打败某人，使丢脸； 停止增长（或上升）； （把身体或身体部位）紧贴…

参考例句：

• After Oxford the countryside flattens out. 过了牛津以远乡村逐渐平坦。
• The graph flattens out gradually after a steep fall. 图表上的曲线突降之后逐渐趋于平稳。

4 inflate   

vt.使膨胀，使骄傲，抬高（物价）

参考例句：

• The buyers bid against each other and often inflate the prices they pay.买主们竞相投标，往往人为地提高价钱。
• Stuart jumped into the sea and inflated the liferaft.斯图尔特跳到海里给救生艇充气。

5 watery   

adj.有水的，水汪汪的；湿的，湿润的

参考例句：

• In his watery eyes there is an expression of distrust.他那含泪的眼睛流露出惊惶失措的神情。
• Her eyes became watery because of the smoke.因为烟熏，她的双眼变得泪汪汪的。