听力文摘：轻轻地,它缩水了

Sublimation¹

升华现象

Sublimation on this moment of science.

今天我们的节目要讲的是：升华现象。

Pop quiz, everybody put away your books, and keep your eyes on your own radio.

各位，请放下你们手中的书本，专心听收音机，我们来做一个突击测验。

You fill the ice tray up to the rim² and put it in the freezer. The ice that results will be

用水将冰格填得满满的，漫过冰格的边缘，然后再将冰格放到冰箱的制冷室里，最后结成的冰会：

a. at the rim b. over the rim c. under the rim. Answer? It depends.

a. 刚好齐边 b. 边缘以上 c. 边缘以下 答案是？要看情况而定。

I know, you hate that. But it does depend —it depends on how long you wait before checking on the ice again. My guess would be that most folks chose answer b: over the rim. That is correct, if you checked on the ice trays after only a couple hours. That's because water expands when it turns into ice, as you know if you ever put a soda³ bottle in the freezer and came back to find it exploded all over the fish sticks.

我明白，你们不喜欢这样的答案。但是，实际情况确实如此——答案取决于你要过多长时间去查看。我猜，很多人都会选择b选项：边缘以上。如果你在放入制冷室仅两个小时之后去查看的话，这个答案就是正确的。这是因为水在变成冰的时候会膨胀。就像大家所知道的，如果将一瓶汽水放在制冷室中，回头去看的时候会发现，汽水已经炸开了，整个制冷室中到处都是汽水。

But if you were to leave the ice tray untouched for a couple of months, you might find the ice to be under the rim, or lower than the water was.

但是，如果你将冰格放在制冷室中，好几个月都不动它的话，你会发现，冰在边缘以下，或是低于你之前装的水的高度。

Huh? Didn't we just say water expands when it freezes? Initially⁴, yes. But frozen water can do something else as well: it can sublimate⁵. To sublimate is to go from one state to another without passing through the usual intermediary state.

哈？我们刚刚不是才说了水在变成冰的时候会膨胀吗？最开始的时候，会。但是冷冻之后的水也会有其他的变化：升华。升华也就是物质不经中间状态直接从一个状态转变成另一个状态。

By adding heat, ice can be melted into liquid water, which can be evaporated. That's three states: solid, liquid, gas. But given enough time, ice can also turn into a gas without melting first! When your ice cubes seem to have shrunk, it's because they are sublimating⁶: the frozen water is slowly evaporating off the cubes, without ever actually melting.

通过加热，冰可以化成液态水，液态水可以被蒸发为水蒸气。这是三个状态：固态，液态，气态。但是，如果时间足够的话，冰可以在不被融化的情况下转变为气态。如果你的冰“缩水”了，那是因为被升华了：在没有被融化的情况下，固态水以非常缓慢的速度在蒸发着。

Will this work in any freezer? Next time.

这种现象在任何的制冷器中都会出现吗？下次再谈。

1 sublimation   

n.升华，升华物，高尚化

参考例句：

• Presently, entrepreneurship, innovation and excellence-creating are the sublimation of the spirit. 在新的历史条件下，“创业创新创优”的三创精神是新时期江苏人文精神的升华。 来自互联网
• Luleng deems that public will is a sublimation of human's free volitions. 摘要卢梭认为，公意就是人类自由意志的升华。 来自互联网

2 rim   

n.(圆物的)边，轮缘；边界

参考例句：

• The water was even with the rim of the basin.盆里的水与盆边平齐了。
• She looked at him over the rim of her glass.她的目光越过玻璃杯的边沿看着他。

3 soda   

n.苏打水；汽水

参考例句：

• She doesn't enjoy drinking chocolate soda.她不喜欢喝巧克力汽水。
• I will freshen your drink with more soda and ice cubes.我给你的饮料重加一些苏打水和冰块。

4 initially   

adv.最初，开始

参考例句：

• The ban was initially opposed by the US.这一禁令首先遭到美国的反对。
• Feathers initially developed from insect scales.羽毛最初由昆虫的翅瓣演化而来。

5 sublimate   

v.(使)升华，净化

参考例句：

• We need sublimate water for our experiment.我们的实验需要纯净化的水。
• Her sublimate future husband will be tall,dark,and handsome.她理想化的未来丈夫将是身材高大，皮肤浅黑，相貌英俊。

6 sublimating   

v.（使某物质）升华( sublimate的现在分词 )；使净化；纯化

参考例句：