托福聽力分為對話和講座兩個部分，其中對話主要場景為大學(xué)校園生活中會遇到的問題等情境，而講座則是對實(shí)際大學(xué)課堂場景的還愿。通常托福聽力講座部分會涉及各類學(xué)科話題領(lǐng)域，考生如果對相關(guān)領(lǐng)域的背景知識、重要概念一無所知，理解起來往往會略顯吃力;而如果考生對于一些常考話題類別的學(xué)科詞匯、重點(diǎn)知識有所涉獵，對托福聽力理解則會大有裨益。光學(xué)是比較生僻的學(xué)科領(lǐng)域，卻在托福聽力講座部分多次考察到，下面我們來了解一下光學(xué)相關(guān)聽力考點(diǎn)與背景知識，希望對各位的托福聽力備考有所幫助。

Introduction：

Spectroscopy

復(fù)色光經(jīng)過色散系統(tǒng)(如棱鏡、光柵)分光后,被色散開的單色光按波長(或頻率)大小而依次排列的圖案,全稱為光學(xué)頻譜。光譜中最大的一部分可見光譜是電磁波譜中人眼可見的一部分, 在這個波長范圍內(nèi)的電磁輻射被稱作可見光。光譜并沒有包含人類大腦視覺所能區(qū)別的所有顏色,譬如褐色和粉紅色。

Background information：

Spectroscopy and spectrography are termsused to refer to the measurement of radiation intensity as a function ofwavelength and are often used to describe experimental spectroscopic methods.Spectral measurement devices are referred to as spectrometers,spectrophotometers, spectrographs or spectral analyzers.

Daily observations of color can be relatedto spectroscopy. Neon lighting is a direct application of atomic spectroscopy.Neon and other noble gases have characteristic emission frequencies (colors).Neon lamps use collision of electrons with the gas to excite these emissions.Inks, dyes and paints include chemical compounds selected for their spectralcharacteristics in order to generate specific colors and hues. A commonlyencountered molecular spectrum is that of nitrogen dioxide. Gaseous nitrogen dioxidehas a characteristic red absorption feature, and this gives air polluted withnitrogen dioxide a reddish brown color. Rayleigh scattering is a spectroscopicscattering phenomenon that accounts for the color of the sky.

Spectroscopic studies were central to thedevelopment of quantum mechanics and included Max Planck's explanation ofblackbody radiation, Albert Einstein's explanation of the photoelectric effectand Niels Bohr's explanation of atomic structure and spectra. Spectroscopy isused in physical and analytical chemistry because atoms and molecules haveunique spectra. As a result, these spectra can be used to detect, identify andquantify information about the atoms and molecules. Spectroscopy is also usedin astronomy and remote sensing on earth. Most research telescopes havespectrographs. The measured spectra are used to determine the chemicalcomposition and physical properties of astronomical objects (such as theirtemperature and velocity).

Knowledge points：

1. 光譜學(xué)是指測量作為波長的輻射強(qiáng)度,它經(jīng)常被用來描述實(shí)驗(yàn)光譜方法。

2. 二氧化氮是一種常用的分子光譜。氣態(tài)的二氧化氮具有吸收紅色的特征,因此被二氧化氮污染的空氣呈現(xiàn)紅褐色。

3. 光譜可以用來確定物體的化學(xué)成分和物理特性。

Vocabulary prediction：

Substance 物質(zhì)

Spectroscopy 光譜學(xué)

Zinc 鋅

Pigment 顏料

Test Point – TPO5L3

What is Spectroscopy? Well, the simplestdefinition I can give you is that Spectroscopy is the study of the interactionbetween matter and light. Now, visible light consists of different colors orwavelengths, which together make up what's called spectrum, a band of colors,like you see in a rainbow. And all substances, all forms of matter, can be distinguishedaccording to what wavelength of light they absorb and which ones they reflect.It's like, m, well, every element has, what we call, its own spectralsignature. If we can read that signature, we can identify the element. Andthat's exactly what spectroscopy does.

Now, Laser Spectroscopy, which is the focusof your assignment, works by measuring very precisely what parts of thespectrum are absorbed by different substances. And it has applications in a lotof different disciplines. And your assignment will be to choose a disciplinethat interests you, and devise an experiment.

Knowledge points

1.最簡單的對光譜學(xué)的理解是,光譜學(xué)是研究物體和光的相互作用的學(xué)科。可見光是由不同顏色的波長組成的,這些合起來叫做光譜,像我們看到的彩虹一樣,有不同的顏色。

2.所有形式的物質(zhì)可以根據(jù)它們對不同波長的光的吸收和反射來被區(qū)分。每一個元素都有它特有的光譜特征。我們可以通過不同的光譜特征來辨別不同的物質(zhì)。

以上就是關(guān)于托福聽力講座光譜學(xué)相關(guān)考點(diǎn)和知識的梳理分享，托福聽力能力提升的關(guān)鍵在于加強(qiáng)練習(xí)與反思，各位TOEFLer一定要注意在備考托福聽力的過程中保證高效且持續(xù)的精聽泛聽訓(xùn)練，聽力水平提升之后托福聽力分?jǐn)?shù)自然也會獲得上漲。