Eight Centimeters Of Cheating

(In my biology class, we have a lab exam with a section that requires us to get up and walk around to different stations in the lab. Our professor warns us against taking the opportunity to cheat, saying he’ll know and grade us a zero. On the following lecture, after he has handed back the exams:)

Professor: *while giving the correct answer to a question about the depth of field shown on a microscope* “On this question, two different people said it was eight centimeters.”

(He holds up his hands eight centimeters apart showing the distance is at least twice the width of the entire microscope.)

Professor: “There is no way more than one person could get it this wrong on their own.”