Thursday, March 26, 2009

Rainbows

This time of the year is a fabulous time to switch on the "science" light in young minds. March and April are littered with rainbows. Next time you are out and about in the showers, have a really good look at a rainbow.
Things to look for...
The colours are staggeringly pretty. We don't see Red-Orange-Yellow-Green-Blue-Indigo-Violet. Victorian poppycock. We see deep red, orange-red, yellow (a lot), a thin green zone, cyan, blue and violet. The colours aren't distinct. They melt into one another. Inside the bow it is much brighter than outside. Outside the main bow there is often a secondary bow, much fainter, where the colour order is reversed. There may be some other bands of colour too. If the sun is low in the sky the bow will be very high, and vice versa. You never need sunglasses when you are looking at a rainbow. The sun is shining on the back of your head. Evening rainbows are much redder than midday rainbows. The pot of gold is the illumination of the ground where the bow meets the earth. You can also get rainbows at night. Ghostly moonbows; best around full moon.
Show your children. "See" rather than "glance". After a lifetime of being immersed in science I still love seeing rainbows. They replenish my love of physics.

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