With Grade 11 physics students at Oak Bay High now studying waves and optics, this is a good time to mention the sub-discipline known as atmospheric physics. Optics at the high school level is normally taught with simple wave tanks and lenses. This makes sense because these items are inexpensive and provide excellent demonstrations of the key concepts, but there is room for making the subject more engaging. When I have tutored students in optics, I have found it effective to supplement the traditional material with discussions of natural phenomena they may have seen but not given much thought to. The above photo from Earth Science Picture of the Day (EPOD) of a sun pillar is a perfect example. For more, just go to the Atmospheric Optics web site.
Fascinating and spectacular photographs on the Atmospheric Optics site.
What is it? Nx
The photo is of a sun pillar. Like a rainbow, it is not a physical thing that can be touched but an optical effect that results from an alignment of the sun, the observer, and water in the air. Unlike a rainbow, a sun pillar is seen when facing toward the sun and requires the atmospheric water to be in the form of flat ice crystals rather than round water droplets. The orientation of the crystals matters. Their faces must be approximately parallel to each other and tilted just right to reflect sunlight down toward the observer. Requiring ice crystals to be in the air, sun pillars are much more common in the prairies than they are on the coast.
Just the perfect initial conditions for this wonder to manifest…so cool! Nx