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:
“With each divine impulse the mind rends the thin rinds of the visible and finite, and comes out into eternity, and inspires and expires its air. It converses with truths that have always been spoken in the world, and becomes conscious of a closer sympathy with Zeno and Arrian, than with persons in the house.”
—Ralph Waldo Emerson (18031882)
“However, the danger in [socially unbalanced relationships] is that the subjection of the woman temporarily calms the mans jealousy but also renders it more demanding. He ends up making his mistress live like those prisoners on whom light is shone day and night in order for them to be better watched. And things always end in tragedy.”
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“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)