Photographer: Merida McDonald
Summary Author: Merida MCDonald; Jim Foster
I li
ke to hang prisms in my living room windows to see how light interacts with the glass during the course of the day. On this winter's afternoon, the low-lying Sun struck the largest of my prisms at the perfect angle to throw distinct rainbow colors 25 ft (8 m) onto my kitchen ceiling. The prism responsible for the colorful array is approximately 3 in (8 cm) across and has a diamond shape -- 10 facets (see inset). Regardless of their size, prisms bend light by refraction. As a beam of white light passes through the prism, each wavelength of light is dispersed to produce the rainbow colors we're all familiar with. For a given material, each wavelength of light has a different refractive index -- the optical density of a medium or material. In essence, blue light travels slightly more slowly though the glass than does red light since its refractive index is a bit greater and so it's bent more. The bending is most noticeable where the rays emerge from the prism. However, note that the color separation above is greatest at right, furthest from the prism. I'm prone to spinning my prisms to get dozens of colorful strips of light dancing all over the living room and kitchen -- sure brightens up a cold winter's day. Photo taken at 4:06 p.m. on February 13, 2012.
Photo details: Camera Maker: Research In Motion; Camera Model: BlackBerry 9700; Focus Distance: 0m; Exposure Time: 0.0000 s (1/Infinity); Flash Fired: No (No Flash available); Orientation: Normal; Color Space: sRGB; Software: Rim Exif Version1.00a.
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