托福听力分为对话和讲座两个部分，其中对话主要场景为大学校园生活中会遇到的问题等情境，而讲座则是对实际大学课堂场景的还愿。通常托福听力讲座部分会涉及各类学科话题领域，考生如果对相关领域的背景知识、重要概念一无所知，理解起来往往会略显吃力;而如果考生对于一些常考话题类别的学科词汇、重点知识有所涉猎，对托福听力理解则会大有裨益。光学是比较生僻的学科领域，却在托福听力讲座部分多次考察到，下面我们来了解一下光学相关听力考点与背景知识，希望对各位的托福听力备考有所帮助。

Introduction：

Spectroscopy

复色光经过色散系统(如棱镜、光栅)分光后,被色散开的单色光按波长(或频率)大小而依次排列的图案,全称为光学频谱。光谱中最大的一部分可见光谱是电磁波谱中人眼可见的一部分, 在这个波长范围内的电磁辐射被称作可见光。光谱并没有包含人类大脑视觉所能区别的所有颜色,譬如褐色和粉红色。

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. 光谱学是指测量作为波长的辐射强度,它经常被用来描述实验光谱方法。

2. 二氧化氮是一种常用的分子光谱。气态的二氧化氮具有吸收红色的特征,因此被二氧化氮污染的空气呈现红褐色。

3. 光谱可以用来确定物体的化学成分和物理特性。

Vocabulary prediction：

Substance 物质

Spectroscopy 光谱学

Zinc 锌

Pigment 颜料

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.最简单的对光谱学的理解是,光谱学是研究物体和光的相互作用的学科。可见光是由不同颜色的波长组成的,这些合起来叫做光谱,像我们看到的彩虹一样,有不同的颜色。

2.所有形式的物质可以根据它们对不同波长的光的吸收和反射来被区分。每一个元素都有它特有的光谱特征。我们可以通过不同的光谱特征来辨别不同的物质。

以上就是关于托福听力讲座光谱学相关考点和知识的梳理分享，托福听力能力提升的关键在于加强练习与反思，各位TOEFLer一定要注意在备考托福听力的过程中保证高效且持续的精听泛听训练，听力水平提升之后托福听力分数自然也会获得上涨。