Colour and the Spectrum | 颜色与光谱

📚 Colour and the Spectrum | 颜色与光谱

White light seems plain, but it hides a whole family of colours. When sunlight or lamp light is spread out, it forms the visible spectrum from red to violet. This article explains how white light is split, how colours mix, and why objects appear coloured. Understanding these ideas is central to the CIE KS3 Physics topic on light.

白光看起来平淡，但它隐藏着一整套颜色。当阳光或灯光被展开时，会形成从红到紫的可见光谱。本文将解释白光如何被分解、颜色如何混合，以及为什么物体会呈现不同颜色。这些概念是 CIE KS3 物理中关于光的主题的核心。

1. What is White Light? | 什么是白光？

White light is not a single colour. It is a mixture of all the colours of the visible spectrum. When these colours travel together, the human eye perceives the mixture as white. Isaac Newton showed this in the 1660s by letting a narrow beam of sunlight pass through a glass prism.

白光并不是一种单一颜色。它是可见光谱中所有颜色的混合体。当这些颜色一起传播时，人眼会将这种混合感知为白色。艾萨克·牛顿在 17 世纪 60 年代让一束狭窄的阳光穿过玻璃棱镜，证明了这一点。

This discovery changed the way scientists thought about light and colour. It showed that white light can be separated and then recombined to form white again.

这一发现改变了科学家对光和颜色的看法。它表明白光可以被分解，也可以重新组合成白光。

2. The Visible Spectrum | 可见光谱

The visible spectrum is the range of colours that the human eye can detect. The traditional colour order is red, orange, yellow, green, blue, indigo and violet. Many students use the memory aid ROYGBIV to recall the order.

可见光谱是人眼能够检测到的颜色范围。传统的颜色顺序是红、橙、黄、绿、蓝、靛、紫。许多学生使用记忆口诀 ROYGBIV 来记住这个顺序。

Red light has the longest wavelength in the visible spectrum and violet light has the shortest. The wavelength is the distance between one wave crest and the next. Longer wavelengths are bent less by glass or water than shorter wavelengths.

在可见光谱中，红光的波长最长，紫光的波长最短。波长是一个波峰到下一个波峰之间的距离。与短波长相比，长波长在玻璃或水中弯折较少。

3. Dispersion by a Prism | 棱镜色散

Dispersion is the splitting of white light into its separate colours. When white light enters a glass prism at an angle, each colour is refracted by a different amount. Violet light bends the most and red light bends the least.

色散是白光被分解成各种单色光的现象。当白光以一定角度进入玻璃棱镜时，每种颜色被折射的程度不同。紫光弯折最多，红光弯折最少。

In a prism: violet bends most; red bends least.

Because the colours leave the prism at slightly different angles, they spread out into a continuous band called a spectrum.

由于各种颜色以略微不同的角度离开棱镜，它们就展开成一条连续的色带，称为光谱。

4. Why Colours Refract Differently | 为什么不同颜色折射不同

Each colour of light has a different wavelength and frequency. When light enters glass, it slows down. Shorter wavelengths, such as violet and blue, slow down more than longer wavelengths such as red and orange.

每种颜色的光都有不同的波长和频率。当光进入玻璃时，速度会减慢。紫光和蓝光等较短的波长比红光和橙光等较长的波长

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