英語(yǔ)聽(tīng)力文摘572 神奇的發(fā)光色彩？

A Magical Glow?

Have you ever wondered why fluorescent colors, like you see in highlighters or clothing dyes, for instance,seem so much brighter than other colors?

It’s because they seem to reflect more light than they receive! It may sound like a magic trick, but it makes sense if you think about the fact that the light you can see is only a small section of the larger spectrum of energy all around you.

Regular, non-fluorescent colors appear to our eyes when objects absorb some wavelengths of light, and reflect others. For example, a yellow pencil looks yellow because its paint reflects the wavelength of yellow light, and absorbs the other wavelengths. Fluorescent colors also reflect or absorb colors in the visible spectrum, but that extra glow in fluorescent colors comes from energy we humans don’t see,ultraviolet light.

Ultraviolet light, or UV, is just beyond visible violet in the spectrum. Its wavelength is too short to be visible to the naked eye, but you see it working when fluorescent colors glow! Regular dyes just absorb UV along with all the other wavelengths they don’t reflect, so you don’t see any evidence of it.

But, fluorescent dyes contain substances that respond to UV. Some of the molecules in these fluorescent dyes are excited by UV energy, and afterwards, as the energy level within these molecules decreases, they release part of that extra energy as visible light.

So fluorescent dyes turn invisible energy into visible light, and that’s how the magic trick works! They don’t reflect more energy than they receive, but they do reflect more visible light, converted from parts of the spectrum we can’t see.

　　神奇的發(fā)光色彩?

　　你想知道為什么熒光色，譬如你從熒光筆或服裝染料上看到的顏色，似乎比別的顏色更鮮亮嗎?

　　原因是這些顏色反射的光線比吸收的光線要多。這可能聽(tīng)起來(lái)像個(gè)魔術(shù)，但是如果你想到這樣一個(gè)事實(shí)，即可見(jiàn)光只是你周?chē)蠊庾V能量中的一小部分，那這就合理了。

　　當(dāng)物體吸收一些波段的光并反射其他光，我們就能看見(jiàn)一般的非熒光色。例如，黃色彩筆之所以看起來(lái)是黃色是因?yàn)樵摲N顏料反射黃色光波，并且吸收其他波段的光。熒光色也反射或吸收了光譜中的可見(jiàn)光，但是熒光色額外的光來(lái)自于人眼看不到的能量，紫外光。

　　紫外光，或稱作UV，頻率恰好在可見(jiàn)紫光之外。紫外光的波長(zhǎng)太短以至于無(wú)法用肉眼看到，但是熒光色發(fā)光的時(shí)候你就能看到它起的效果!一般的染料只是吸收紫外光和所有其他不反射的光，所以你看不到紫外光的存在。

　　但是，熒光染料含有對(duì)UV起反應(yīng)的物質(zhì)。這些熒光染料中的一些分子被UV的能量激活，然后隨著這些分子的能量水平降低，它們就會(huì)以可見(jiàn)光的形式釋放出一部分額外的能量。

　　所以熒光染料把不可見(jiàn)的能量轉(zhuǎn)換成了可見(jiàn)光，這就是魔術(shù)的奧妙所在!不是它們反射出的能量比接收的多，而是反射出了更多的可見(jiàn)光，這些多出來(lái)的可見(jiàn)光是從我們看不到的波段轉(zhuǎn)換來(lái)的。