Do you see things differently than your audience? Explain how to them.

Whenever I look at a flat surface of a pipe or plate that broke in a brittle manner, I shine a penlight at a low angle to that plane. As schematically shown above, V-shaped chevron markings will point back to where the crack originated. Then I look more closely at the origin to see what happened there.  

On  May 20th the TV program Nature premiered a documentary about the high desert called The Sagebrush Sea. Most of it was about the sage grouse, but it also mentioned other animals. Out in the desert rocks substitute for trees, and birds use their cavities for nests. At 16:45 they said that:

“The tiny American Kestrel is the only falcon in North America that uses cavities. With their ultraviolet vision they track rodents by following their urine trails.”

For those feisty little birds the sagebrush looks like a road map to dinner. Scientists have known for a couple of decades that kestrels see differently than humans.

Insects also can see ultraviolet markings, as shown in this brief BBC News video: An insect’s-eye view of flowers.

The image by LInda Tanner of an American kestrel came from Wikimedia Commons.