A good rule of thumb is that one should be on one’s guard whenever a copywriter uses the word, amazing<\/em>. This was no exception. The picture was not of a rainbow but was the result of stress polarization in a birefringent aircraft widow—a phenomenon\u00a0previously\u00a0treated<\/a> in this blog.\u00a0<\/p>\n The explanation and picture from that earlier posting is:<\/p>\n The aircraft window, itself, can show some interesting features. The stressed plastic of the window is birefringent and so produces colours when seen with polarized light. The light from most scenes is not strongly polarized, but a reflection from a body of water is, so the colours seen here are a consequence of both the reflection (from, in this case, Georgia Strait) and the aircraft window. To me, what was particularly interesting is that the person who took the picture in the article, Melissa Rensen from London, Ontario, had come close to guessing\u00a0what caused\u00a0the colour in her picture: She speculated that it was the result of “the polarized window on the plane.” (The window isn’t polarized, light is polarized, but the window is birefringent). However, another photographer then misled her by suggesting that it couldn’t be in the window by pointing\u00a0“out that the rainbow was beneath the clouds.” That other photographer was wrong.\u00a0<\/p>\n The colours seen require three things: polarized light (this comes from sunlight reflected off the water); a birefringent medium (the stressed plastic of the aircraft window); an analyzer (probably the second aircraft window—they are double). The colours do not appear against the clouds in her picture because the light from the clouds is not polarized.<\/p>\n It all goes to show that copywriters should do better research, and should bite their tongues when tempted to use\u00a0the word, amazing<\/em>.<\/p>\n \u00a0<\/p>\n","protected":false},"excerpt":{"rendered":" Today on ten-minutes’ notice, I was interviewed for a BBC science programme. Unexpectedly, I was asked to comment on an article in a British newspaper with the intriguing title: Passenger’s amazing photo captures moment her plane flew directly over … Continue reading ![\"\"](\"https:\/\/blog.kootenay-lake.ca\/wp-content\/uploads\/2012\/03\/stresspolarization20120306s.jpg\")
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