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Path: utzoo!watmath!clyde!akgua!mcnc!duke!ucf-cs!giles
From: giles@ucf-cs.UUCP (Bruce Giles)
Newsgroups: net.physics
Subject: Haloes on fogged-up glass...
Message-ID: <1201@ucf-cs.UUCP>
Date: Tue, 28-Feb-84 19:08:13 EST
Article-I.D.: ucf-cs.1201
Posted: Tue Feb 28 19:08:13 1984
Date-Received: Fri, 2-Mar-84 05:42:49 EST
Organization: University of Central Florida
Lines: 31

Partly in consequence of seeing the haloes around the sun last week, I
noticed that street lights seen through a fogged-up car windshield have
a colored halo.  The strange thing was that there were areas of color, with
no apparent order to where a particular color occured.

My question, should anyone decide to accept it, is: 

	What causes the light to be broken up into colors?



Various possibilities I came up with were: 

   (1)  Rayleigh scattering off of dust particles suspended in the
	mist,

   (2)  Diffraction effects from very fine scratches in the windshield,

   (3)  Absorbtion from chemicals that may be dissolved in the mist.

I'm not very happy with any of these ideas, however.  Any other ideas out
there?
       


ave discordia				going bump in the night ...
bruce giles

decvax!ucf-cs!giles			university of central florida
giles.ucf-cs@Rand-Relay			orlando, florida 32816