{"id":413,"date":"2023-03-02T20:16:39","date_gmt":"2023-03-02T20:16:39","guid":{"rendered":"https:\/\/content.one.lumenlearning.com\/introductiontopsychology\/chapter\/learn-it-vision-and-light-waves\/"},"modified":"2025-11-12T16:30:56","modified_gmt":"2025-11-12T16:30:56","slug":"learn-it-vision-and-light-waves","status":"publish","type":"chapter","link":"https:\/\/content.one.lumenlearning.com\/introductiontopsychology\/chapter\/learn-it-vision-and-light-waves\/","title":{"raw":"The Visual System: Learn It 2\u2014Light Waves","rendered":"The Visual System: Learn It 2\u2014Light Waves"},"content":{"raw":"

Amplitude and Wavelength<\/h2>\r\n

Light travels in waves, and understanding a few basic properties of those waves helps explain how we perceive color and brightness. Two of the most important characteristics of any wave are its amplitude<\/strong> and wavelength<\/strong>.<\/p>\r\n

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amplitude and wavelength<\/h3>\r\n

The amplitude<\/span><\/strong> of a wave is the distance from the center line to the top point of the crest or the bottom point of the trough. Wavelength<\/strong> refers to the length of a wave from one peak to the next.<\/p>\r\n

\r\n[caption id=\"attachment_8002\" align=\"aligncenter\" width=\"651\"]\"A<\/a> Figure 1<\/strong>. The amplitude or height of a wave is measured from the peak to the trough. The wavelength is measured from peak to peak.[\/caption]\r\n<\/figure>\r\n<\/section>\r\n

Wavelength is directly related to the frequency of a given waveform.<\/p>\r\n

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frequency<\/h3>\r\n

Frequency<\/strong> refers to the number of waves that pass a given point in a given time period and is often expressed in terms of hertz (Hz<\/strong>), or cycles per second. Longer wavelengths will have lower frequencies, and shorter wavelengths will have higher frequencies.<\/p>\r\n

\r\n[caption id=\"\" align=\"aligncenter\" width=\"510\"]\"Stacked Figure 2<\/strong>. This figure illustrates waves of differing wavelengths\/frequencies. At the top of the figure, the red wave has a long wavelength\/short frequency. Moving from top to bottom, the wavelengths decrease and frequencies increase.[\/caption]\r\n<\/figure>\r\n<\/section>\r\n
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Light Waves<\/h2>\r\n

The visible spectrum<\/strong> is the portion of the larger electromagnetic spectrum that we can see. As Figure 3 shows, the electromagnetic spectrum<\/strong> encompasses all of the electromagnetic radiation that occurs in our environment and includes gamma rays, x-rays, ultraviolet light, visible light, infrared light, microwaves, and radio waves.<\/p>\r\n

The visible spectrum in humans is associated with wavelengths that range from 380 to 740 nm\u2014a very small distance since a nanometer (nm) is one-billionth of a meter. Other species can detect other portions of the electromagnetic spectrum. For instance, honeybees can see light in the ultraviolet range (Wakakuwa et al., 2007), and some snakes can detect infrared radiation in addition to more traditional visual light cues (Chen et al., 2012; Hartline et al., 1978).<\/p>\r\n

\r\n[caption id=\"\" align=\"aligncenter\" width=\"975\"]\"This Figure 3<\/strong>. Light that is visible to humans makes up only a small portion of the electromagnetic spectrum.[\/caption]\r\n<\/figure>\r\n

Within the visible spectrum:<\/p>\r\n