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||Apart from the fact that you
appear to be confusing
fluorescence (shining under
ultraviolet light) with
||Phosphorus was discovered accidentally by someone (I forget who, as usual) heating a mixture of sand and urine (his own). He was hoping to produce gold. Oh well.
||DrCurry, fixed -- but I must say I thought I heard the term fluorescent used to describe same effect
||I'd be damned -- glow in the dark roads
||Fluorescence is often misused in every day
speech, but it refers specifically to something that
immediately emits a different color of light than it
receives. Part of the reason it is misused is that
the application most in the public awareness is
the use of invisible black light to excite a response
in the visible spectrum, resulting in an apparent
"glow in the dark". (Fluorescent lighting works the
same way, as do most "white" LEDs, but people
never see the excitation spectrum in either of
those cases, only the emission)
||Phosphorescence is closely related, but it is a
process that is slow to emit the absorbed light.
This results in a true "glow in the dark"
phenomenon, as the emission continues long after
the light source is removed.