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Narrator:Listen to part of a lecture in a chemistry class.
獨白:請聽化學課的一部分。
Professor:Okay. I know you all have a lot of questions about this lab assignment that's coming out
教授:好的，我知道你們對此次的實驗作業都有很多問題，
so...I'm gonna take a little time this morning to discuss it.
因此今天早上我將花點時間跟你們討論一下。
So, you know the assignment has to do with Spectroscopy, right?
那么，你們已經知道此次作業是有關光譜學，是吧？
And your reading should help you get a good idea of what that's all about.
你們通過閱讀應該能夠很好了解這一 概念。
But, let's talk about Spectroscopy a little now just to cover the basics.
但是，我們還是將一些基本要點過一遍吧。
What is Spectroscopy?
什么是光譜學呢？
Well, the simplest definition I can give you is that Spectroscopy is the study of the interaction between matter and light.
嗯，我能給你們的最簡單的光譜學定義就是關于物和光之間相互作用的研究。
Now, visible light consists of different colors or wavelengths, which together make up what's called spectrum, a band of colors,
這樣，可見光擁有不同顏色或者波長，而一起構成我們做說的光譜。光譜是一條五顏六色的緞帶，
like you see in a rainbow.
就像你在彩虹中看到的一樣。
And all substances, all forms of matter, can be distinguished according to what wavelength of light they absorb and which ones they reflect.
而所有的物質和物質形式都可以根據其吸收的光的波長和其反射的光來加以區分。
It's like, um, well, every element has, what we call, its own spectral signature.
它就像，嗯，每種元素都有我們所說的本身的光譜簽名。
If we can read that signature, we can identify the element.
如果我們可以讀懂，我們就可以知道是什么元素。
And that's exactly what spectroscopy does.
這正是光譜學的作用所在。
Now, Laser Spectroscopy, which is the focus of your assignment,
激光光譜學是你們作業中的重點，
works by measuring very precisely what parts of the spectrum are absorbed by different substances.
它能非常精確地測量光譜中哪一部分被不同的物質吸收。
And it has applications in a lot of different disciplines.
該門學科在很多不同學科中都有用武之地。
And your assignment will be to choose a discipline that interests you, and devise an experiment.
你們的任務就是要選擇一門你感興趣的學科然后進行實驗。
For example, I'm gonna talk about art.
我們就來談談藝術。
I'm interested in the art and to me it's interesting how spectroscopy is used to analyze art.
我對藝術很有興趣，我對光譜學是怎么應用在對藝術的分析上的問題感興趣。
Er... let's say a museum curator comes to you with a problem.
呃。。比如一位博物館館長需要你解決一個問題。
She's come across this painting that appears to be an original-let's say, a Rembrandt.
比如說，她碰到一幅貌似是真跡的油畫，出自倫布蘭特之手。
And she wants to acquire it for her museum.
她想收購這幅畫放到自己博物館展出。
But she's got a problem:she's not absolutely certain it's an original.
但她遇到了一個問題:她不確定這是否為真跡。
So, what do you do?
那你該怎么做呢？
How do you determine whether the painting's authentic?
你怎么判定這幅畫是否是真跡呢？
Okay. Think about the scientific process.
好的，想想科學的方法。
You've got the question:Is the painting a Rembrandt?
你現在的問題是:這是倫布蘭特畫的嗎？
So first, you'll need to make a list of characteristics the painting would have to have to be a Rembrandt.
那么首先，你將需要列出這幅畫作具有的倫布蘭特畫作的特征。
Then you have to discover whether the painting in question has those characteristics.
然后你必須看這幅有爭議的畫是不是具有這些特征。
So first of all, you'll need to know the techniques Rembrandt used when he applied paint to canvas-his brushstrokes, how thickly he applied his paint.
首先，你要了解倫布蘭特在帆布上畫畫時會使用的技巧，他的畫風，他用的顏料的情況。
So you'd need to work with an art historian who has expert knowledge of Rembrandt's style.
那么你要請教一名對倫布蘭特畫風有專業了解的藝術歷史學家。
You'd have to know when he created his paintings,
你要知道他什么時候創作，
um... what pigments he used,
嗯，用什么顏料創作，
in other words, what ingredients he used to make different colors of paint, because the ingredients used in paints and binding agents plus varnishes, finishes, what have you, have changed over time.
換句話說，就是他使用什么材料畫出不同的顏色，因為繪畫中使用的顏料和粘合劑會隨著時間而改變。
Since you're trying to verify that's a Rembrandt, the ingredients in the pigment would need to have been used during Rembrandt's lifetime-in the 17th century.
由于你試圖證明這是倫布蘭特的真跡，其顏料中使用的材料就必須是倫布蘭特那個年代，即十七世紀，所使用過的顏料。
And that's where chemistry comes in.
這時候化學知識就會派上用場。
You've got to find out what's in those pigments, learn their composition, and that requires lab work-detective work really-in a word, Spectroscopy.
你要了解顏料的成分，而這需要做實驗，探測性實驗，一句話，用光譜學才能得知。
So, how do we use Spectroscopy?
那么我們怎么利用光譜學呢？
Well, we put an infrared microscope-a spectroscope-on tiny tiny bits of paint.
嗯，我們使用紅外線顯微鏡，一個分光鏡，來觀察油畫上的細微之處。
And using ultraviolet light we can see the spectral signature of each component part of the pigment.
而使用紫外線，我們可以看到顏料上每一部分的光譜簽名。
Then we compare these signatures with those of particular elements like zinc or lead, to determine what the pigment was made of.
然后我們將這些簽名符號和鋅和鉛等一些特別的元素進行對比來判定顏料是什么組成的。
So, you can see why this type of analysis requires a knowledge of the history of pigments, right?
這樣，你就知道為什么這種研究需要關于顏料使用史的知識了對吧？
How and when they were made?
它們如何制成，何時制成？
Say we determined a pigment was made with zinc, for example.
比如我們判定某一種顏料是由鋅構成的。
We know the spectral signature of zinc.
我們知道鋅的光譜簽名，
And it matches that of the paint sample.
它和顏料樣本相符合。
We also know that zinc wasn't discovered until the 18th century.
我們也知道直到18 世紀鋅才被發現。
And since Rembrandt lived during the 17th century, we know he couldn't have painted it.
而倫布蘭特生活在十七世紀，我們就知道他是不可能用鋅作畫的。
Now, Spectroscopy has a very distinct advantage over previous methods of analyzing our works, because it's not invasive.
現在，光譜學比起以前的解析作品的方法優異更為明顯，因為它不會對原作造成損害。
You don't have to remove big chips of paint to do your analysis, which is what other methods require.
你不需要毀掉一部分油畫來進行分析，而其他方法則必須這樣做。
All you do is train the microscope on tiny flecks of paint and analyze them.
你所做的就是；練習使用顯微鏡對準油畫上的小小斑點，進行分析。
Now a word or two about restoration.
現在簡單講講儲藏方法。
Sometimes original art works appear questionable or inauthentic because they've had so many restorers add touchup layers to cover up damage, damage from the paint having deteriorated over time.
有時候藝術品真跡看起來是贗品是因為很多修護人員加上很多層保護膜覆蓋油畫上的損害。畫作上損壞的地方經久日衰。
Well, spectroscopy can review the composition of those touchup layers too.
而光譜學也可以檢查這一層附加上去的物質成分。
So we can find out when they were applied.
我們因此可以知道是什么時候加上去的一層東西。
Then if we want to undo some bad restoration attempts,
而如果我們想避免一些錯誤的修復嘗試，
we can determine what kind of process we can use to remove them to dissolve the paint and uncover the original.
我們能通過判定修復過程中哪一步會溶解畫作和掩蓋真跡的痕跡。
