What is color? - Colm Kelleher

顏色是什麼？ - Colm Kelleher

譯者: FU SHIUNG KE 審譯者: Audrey Her

One of the most striking properties about life is that it has color.

所有生命最醒目的特質是它有顏色。

To understand the phenomenon of color, it helps to think about light as a wave.

要理解色彩這一現象，將光想作為波會有幫助。

But, before we get to that,

但，在此之前，

let's talk a little bit about waves in general.

我們先來談談“波”的概念。

Imagine you're sitting on a boat on the ocean watching a cork bob up and down in the water.

想象你正在海上，坐在一艘船上 看著軟木塞在海裡上下擺動著。

The first thing you notice about the motion is that it repeats itself.

對於這個動作你第一個注意到的事 是它自己一直重覆著。

The cork traces the same path over and over again... up and down, up and down.

軟木塞沿著相同的路徑， 一次又一次地，上下擺動。

This repetitive or periodic motion is characteristic of waves.

這個重覆或週期的動作是“波”的特徵。

Then you notice something else...

然後你注意到另外一些事情...

using a stopwatch, you measure the time it takes for the piece of cork

使用秒錶，測量一塊軟木塞

to go over its highest position down to its lowest and then back up again.

在其最高位置下降到最低位置， 然後再回到最高位置， 如此一來回所需的時間

Suppose this takes two seconds.

假設需要兩秒鐘。

To use the physics jargon, you've measured the period of the waves that cork is bobbing on.

用物理術語來說，你測試到 讓軟木塞載浮載沈的波浪的週期，

That is, how long it takes a wave to go through its full range of motion once.

這個週期指的是一個波 從最低點到最高點全程波動所需要的時間。

The same information can be expressed in a different way by calculating the wave's frequency.

同樣的數據資料可以透過計算波的頻率來表示。

Frequency, as the name suggest, tells you how frequent the waves are.

頻率，就如這名詞所指，意指波浪多常擺動。

That is, how many of them go by in one second.

也就是說，一秒鐘有多少個波產生。

If you know how many seconds one full wave takes,

如果你知道一個完整的波需要花多少時間，

then it's easy to work out how many waves go by in one second.

然後就可以容易地算出 一秒鐘之內產生了多少“波”。

In this case, since each wave takes 2 seconds, the frequency is 0.5 waves per second.

在這種情況下，由於每個波時間 2 秒，頻率是每秒 0.5 波。

So enough about bobbing corks... What about light and color?

講夠了那上上下下波動的軟木塞了... 那光和顏色是怎麼一回事呢？

If light is a wave, then it must have a frequency. Right?

如果光是一種”波“， 那它勢必會有一個頻率。 對吧？

Well... yes, it does.

嗯...是的，它有頻率。

And it turns out that we already have a name for the frequency of the light that our eyes detect.

事實上我們對於眼睛可偵測的光頻 已經都給它安上名號了，

It's called color.

它叫做顏色。

That's right. Color is nothing more than a measure of how quickly the light waves are waving.

對。顏色不過就是光波波動的頻率。

If our eyes were quick enough, we might be able to observe this periodic motion directly,

如果我們的眼睛能夠趕上光波， 我們可能能夠直接觀察此週期運動，

like we can with the cork and the ocean.

就像我們能觀察軟木塞在海洋中波動。

But the frequency of the light we see is so high,

但我們所看見的光頻是如此之高，

it waves up and down about 400 million million times a second,

每秒鐘這波上下波動約400億億次，

that we can't possibly see it as a wave. But we can tell, by looking at its color, what its frequency is.

我們無法以波的形勢見到它。 但我們可以透過觀察它的顏色而知道它的頻率。

The lowest frequency light that we can see is red and the highest frequency is purple.

我們肉眼可以見最低頻率光線是紅色；高頻率是紫色。

In between all the other frequencies form a continuous band of color, called the visible spectrum.

在紅色與紫色之間， 其他頻率形成一個色彩的相續頻 稱為可見光譜。

So, what if you had a yellow pencil sitting on your desk?

所以，如果你有一枝黃色鉛筆在桌上？

Well, the sun emits all colors of light, so light of all colors is hitting your pencil.

嗯，太陽會發出包含所有顏色的光， 這光照在你的鉛筆上。

The pencil looks yellow because it reflects yellow light more than it reflects the other colors.

鉛筆看上去是黃色因為它反射黃色 比反射其它的顏色還要多

What happens to the blue, purple and red light?

那藍色、 紫色、 紅色光又怎樣呢？

They get absorbed and the energy they are carrying is turned into heat.

它們被吸收而且它們所攜帶的能量被轉化為熱量。

It is similar with objects of other colors.

其他顏色的物件也是如此。

Blue things reflect blue light, red things reflect red light and so on.

藍色的東西反映藍光，紅色的東西反射紅光，等等。

White objects reflect all colors of light,

白色物件反映所有顏色的光，

while black things do exactly the opposite and absorb at all frequencies.

然而黑色的東西完全相反，並吸收所有的頻率。

This - by the way - is why it's uncomfortable to wear your favorite Metallica t-shirt on a sunny day.

因為這個道理，你明白為什麼在一個晴朗的天 穿你最喜歡 Metallica 樂團的 t-shirt 是多麼不舒服的事。