"Nodal Lines"

(sung to "Jingle Bells")

A day or two ago, I thought I'd check out light,
To see if what I'd learned, was absolutely right.
I held 2 pencils up, and put them to my eye,
And when I looked into the light, I knew it was no lie.

Oooooh, nodal lines, nodal lines, shifting all in phase.
Oh what fun it is to watch the pattern formed by waves.

Nodal lines, nodal lines, caused by bending light.
Oh what fun diffraction is unless the light's too bright.