Archived posting to the Leica Users Group, 2006/12/17
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Oh yeah, thanks Doug, that's much clearer. Careful or we may alter the term Dougness to mean "providing intricate but dense detail" "The ray theory of the rainbow can be neatly represented as polar plots of the scattered intensity in different directions after one, two, or more reflections. To calculate these, we combine Fresnel?s formulae for the intensity of reflected and transmitted light [5] with simple ray geometry for different angles of scattering. We obtain the results shown in figure 5 for the scattered intensity for the two polarizations of light. In these figures, we have light coming horizontally from the left-hand side, incident on a raindrop at the centre; the left-hand diagram corresponds to light polarized with its electric field perpendicular to the plane of the diagram (s-polarisation), and on the right the electric field is in the plane (p-polarisation).The large lobe to the right of the drop in both figures represents light passing through the drop, refracted but without any reflection. The primary bow corresponds to the singularity in the scattering after one reflection at ?42? with respect to the incident light, showing up very strongly in s-polarisation, but much weaker in p-polarisation: the rainbow is strongly polarised." -----Original Message----- From: lug-bounces+hoppyman=bigpond.net.au@leica-users.org [mailto:lug-bounces+hoppyman=bigpond.net.au@leica-users.org] On Behalf Of Douglas Sharp Sent: Monday, 18 December 2006 10:13 To: Leica Users Group Subject: Re: [Leica] Regarding rainbows... http://www.europhysicsnews.org/full/37/article3.pdf Is this scientific enough :-) Douglas G Hopkinson wrote: > Adam did you want to know or just tell us that you were in a catamaran off > Waikiki ;-) > When you tilted your head down, did you also see a frosty drink in your > hand? How about sideways, were there attractive ladies in > bikinis? > > I imagine that the same optical rules would apply to the rainbow as to > reflections from the ocean's surface. It is after all water > reflecting light. In this case refracting it as well. Still I bet someone > on the list will provide a more scientific explanation. > Cheers > Hoppy > > -----Original Message----- > From: lug-bounces+hoppyman=bigpond.net.au@leica-users.org > [mailto:lug-bounces+hoppyman=bigpond.net.au@leica-users.org] On Behalf Of > Adam Bridge > Sent: Monday, 18 December 2006 05:06 > To: Leica Users Group > Subject: [Leica] Regarding rainbows... > > So we were out on a catamaran off Waikiki yesterday and everyone > started commenting on the gorgeous rainbow over the city - except I > couldn't see it. Then it occurred to me that I was wearing polarizing > clip-on sunglasses and darn if, when I tilted them down, there was the > rainbow. Tilting my head 90 degrees also revealed the rainbow. > > So why are rainbows polarized? I didn't expect this and I don't think > I've ever read that they were. > > Maybe I'm the only guy on the planet not to know this but in the > meantime I thought I'd share. > > Can anyone explain WHY rainbows are polarized? > > AB > > _______________________________________________ > Leica Users Group. > See http://leica-users.org/mailman/listinfo/lug for more information > > > > _______________________________________________ > Leica Users Group. > See http://leica-users.org/mailman/listinfo/lug for more information > > _______________________________________________ Leica Users Group. See http://leica-users.org/mailman/listinfo/lug for more information