电磁频谱

What are waves?
::什么是波浪?

Waves can come in many sizes. Here we see a large wave crashing on the beach. Other waves can be very small and regular. We normally think of waves as being made of water, but there are forms of energy that take on the characteristics of waves. The idea of a wave has played a major role in our understanding of how the is put together and why it behaves the way it does.
::海浪的大小可能很多。 我们在这里看到海滩上大波崩塌。 其他海浪可能非常小而且经常发生。 我们通常认为海浪是由水组成的, 但我们通常认为海浪是由水组成的, 但海浪的特质有多种能量形式。 海浪的理念在我们理解如何组合在一起以及为什么它会以这种方式行事方面发挥了重大作用。

Properties of Light
::灯光的属性

The nuclear atomic model proposed by Rutherford was a great improvement over previous models, but was still not complete. It did not fully explain the location and behavior of the electrons in the vast space outside of the nucleus . In fact, it was well known that oppositely charged particles attract one another. Rutherford’s model did not explain why the electrons don’t simply move toward and eventually collide with the nucleus. Experiments in the early twentieth century began to focus on the absorption and emission of light by matter. These studies showed how certain phenomena associated with light reveal insight into the nature of matter, energy, and atomic structure.
::鲁瑟福德提出的核原子模型比先前的模型大有改进,但仍未完成。 它并未充分解释核心外广阔空间中电子的位置和行为。 事实上,众所周知,反向充电粒子会相互吸引。 卢瑟福德的模型没有解释为什么电子不能简单地向核的方向移动并最终与核相撞。 二十世纪初的实验开始侧重于光的吸收和排放。 这些研究揭示了与光有关的某些现象如何揭示物质、能源和原子结构的性质。

Wave Nature of Light
::光波的自然性质

In order to begin to understand the nature of the , we first need to look at the properties of light. Prior to 1900, scientists thought light behaved solely as a wave. As we will see later, this began to change as new experiments demonstrated that light also has some of the characteristics of a particle. First, we will examine the wavelike properties of light.
::为了开始理解光的性质, 我们首先需要看一看光的特性。 在1900年之前, 科学家认为光只是作为波。 正如我们稍后会看到的那样, 新的实验显示光也具有粒子的某些特性, 这开始改变。 首先, 我们将检查光的波状特性 。

Visible light is one type of electromagnetic radiation , which is a form of energy that exhibits wavelike behavior as it moves through space. Other types of electromagnetic radiation include gamma rays , x-rays, ultraviolet light, infrared light, microwaves, and radio waves. The figure below shows the electromagnetic spectrum , which is all forms of electromagnetic radiation. Notice that visible light makes up only a very, very small portion of the entire electromagnetic spectrum. All electromagnetic radiation moves through a vacuum at a constant speed of 2.998 × 10 ⁸  m/s. While the presence of air molecules slows the speed of light by a very small amount, we will use the value of 3.00 × 10 ⁸  m/s as the speed of light in air.
::可见光是电磁辐射的一种类型,这是一种能量形式,显示在穿越空间时有波状行为。其他类型的电磁辐射包括伽马射线、X射线、紫外光、红外光、红外光、微波和无线电波。下图显示了电磁频谱,这是电磁辐射的各种形式。请注意,可见光仅构成整个电磁频谱中非常小的一部分。所有电磁辐射都以2.998×108米/秒的恒定速度在真空中移动。空气分子的存在使光速减慢了很小的数量,但我们将使用3.00×108米/秒的值作为空气中的光速。

Figure shows how the electromagnetic spectrum displays a wide variation in wavelength and frequency. Radio waves have wavelengths of as long as hundreds of meters, while the wavelength of gamma rays are on the order of 10 ^-12  m. The corresponding frequencies range from 10 ⁶ to 10 ²¹ Hz. Visible light can be split into colors with the use of a prism ( Figure ), yielding the visible spectrum of light. Red light has the longest wavelength and lowest frequency, while violet light has the shortest wavelength and highest frequency. Visible light wavelength ranges from about 400 – 700 nm with frequencies in the range of 10 ¹⁴  Hz.
::图中显示了电磁频谱如何在波长和频率上显示巨大差异。无线电波波波长长达数百米,而伽马射线波长为10-12米。相应的频率在106至1021赫兹之间。可见光可以通过使用棱镜(图示 ) 将可见光分成颜色,产生可见光谱。红光有最长的波长和最低频率,紫外光有最短的波长和最高频率。可见光波长在400至700纳米之间,频率在1014赫兹之间。

If we could see other wavelengths of energy, would they appear as colors? Use this simulation to explore the electromagnetic spectrum: 
::如果我们能看到其他波长的能量, 它们会作为颜色出现吗?使用这个模拟来探索电磁频谱:

Summary
::摘要

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• Electromagnetic radiation is a form of energy.
  ::电磁辐射是一种能量形式。
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• Visible light has wavelengths from 400-700 nm.
  ::可见光有波长400-700纳米的波长。
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• The speed of light in air is 3.00 × 10 ⁸  m/s.
  ::空气中的光速为3.00×108米/秒。

Review
::回顾

播放段落
1. What did Rutherford’s nuclear atomic model not explain?
   ::卢瑟福的核原子模型没有解释什么?
播放段落
2. Prior to 1900, what did scientists believe about the nature of light?
   ::1900年以前,科学家们对光的性质 有何看法?
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3. What is visible light?
   ::什么是可见光?
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4. What is the range of wavelengths for visible light?
   ::可见光的波长范围是多少?