"Dad", said the boy, "Why is the sky blue?"
"Well", I said, "It has something to do with diffraction of light, or was it refraction of light? And the blue light isn't scattered as much as the rest of the spectrum, or is it scattered more? Don't ask me", I said, "I don't have a degree in physics!"
"Yes you do", said the boy.
"Oh yeah, I do", I said, "I do..."