A wonderful book which I believe every physics teacher should own is Color
and Light in Nature, by David K. Lynch and William Livingston. In the
tradition of Minnaert's classic work Light and Color in the Outdoors
(http://www.company7.com/books/products/light&color.html). It includes the
supernumerary rainbow as well as a plethora of other optical phenomenon
experienced in various natural settings, discussed both phenomenologically
as well as with brief technical explanations, graphs, and many color photos.
It is an amazing resource, and best of all it really serves to reawaken a
sense of wonder for the world which we can experience directly through our
senses.
(Or if the link doesn't work, search http://books.google.com - it has photos
of many pages.)
Cheers!
-Seth Miller
East Bay Waldorf School
John wrote:
A colleague insisted this was impossible, and cited the classical analysis
of rainbows. After looking in some books, I never saw any references to
extra bows on the same side as the main bow. Well, the colleague was right
that classical geometric optics does not predict it, but perhaps this
insistence is why he was never a Nobel candidate. The extra bows are called
supernumerary and are interference effects. It is strange that none of the
texts mention it at least in passing. After seeing this and knowing that
classical analysis did not predict the extra bows I wonder "what would
Feynman do?"