Because last night, my beautiful son, you corrected me when I called a dimetrodon a dimorphodon, pointing out that the fin-backed toy dinosaur in my hand didn’t fly. And, indeed, if I can’t keep these two separate:
then I’m clearly unqualified to tutor you in science of even the most basic, classificatory kind. If I can’t keep these straight, how will I remember more complicated things, like the difference between halogens and noble gases or whether radio spectrum is lower- or higher-frequency than microwave or how to apply the right-hand rule? God forbid I try to give you a clear, concise definition of fields.
We had a good run, but I think we’re done here. From now on you’d better ask your mother.