Visible Light Beams
From the side, a beam of light is only visible if part of the light is scattered by objects: tiny particles like dust, water droplets (mist, fog, rain), hail, snow, or smoke, or larger objects such as birds. If there are many objects in the light path, then it appears as a continuous beam, but if there are only a few objects, then the light is visible as a few individual bright points. In any case, this scattering of light from a beam, and the resultant visibility of a light beam from the side, is known as the Tyndall effect.
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Famous quotes containing the words visible, light and/or beams:
“To him who, in the love of Nature, holds
Communion with her visible forms, she speaks
A various language: for his gayer hours”
—William Cullen Bryant (1794–1878)
“But seldom the laurel wreath is seen
Unmixed with pensive pansies dark;
There’s a light and a shadow on every man
Who at last attains his lifted mark—
Nursing through night the ethereal spark.
Elate he never can be;
He feels that spirits which glad had hailed his worth,
Sleep in oblivion.—The shark
Glides white through the phosphorus sea.”
—Herman Melville (1819–1891)
“The highway presents an interesting study of American roadside advertising. There are signs that turn like windmills; startling signs that resemble crashed airplanes; signs with glass lettering which blaze forth at night when automobile headlight beams strike them; flashing neon signs; signs painted with professional touch; signs crudely lettered and misspelled.... They extol the virtues of ice creams, shoe creams, cold creams;...”
—For the State of Florida, U.S. public relief program (1935-1943)