Sometimes you get lucky and see a double rainbow. But how does the second rainbow form?

On my first 17th of May in Bergen, Ellen invited me to her home for a traditional dinner, which was exceptional. And as a bonus we got to see a double rainbow over Store Lungårdsvann!

Double rainbow in Bergen on May 17th 2011

The outer rainbow is the so-called secondary rainbow, and as you can see the colors in the secondary rainbow are reversed, with red being on the inside and blue being on the outside.

Having watched my explanations in the textbook-style movie or in the short movie collection, is the sketch below enough information for you to make sense of how a secondary rainbow forms?

If the sketch isn’t clear – what additional information would you need to make sense of the sketch?

Here comes the movie in case you’d like to watch it:

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I have yet a newer version of the rainbow movies as well as the one pictured above ready for you, but I thought I’d give you a bit of a break from rainbows and talk about something else for a while. But we’ll be back to rainbows soon, promise!