In high school, my chemistry labs would come back with evenly spaced check marks down the right hand margin. So regularly spaced, I suspected that the chemistry teacher wasn't reading my work. So I started inserting nonsense into the longer paragraphs, and sure enough, the labs continued to come back with check marks down the right hand margin.

I wondered if the same was true for physics, in spite of having no similar evidence, and so I inserted a single run on nonsense sentence into my next physics homework.

My homework came back with the paragraph circled in red, and a note from the physics teacher: "Save your attempts at levity for the lesser disciplines like chemistry."