Choose Your Own Chemical Adventure

"Mmm. That wasn't very nice of me, was it? I'm glad you didn't injure yourself though – letter openers have been known to be quite dangerous. Don't want to lose a good student now, do we? You are James Joule, I presume."

"Yes, James Prescott Joule, Sir. I'm very sorry. I'm not sure what came over me." "I don't normally do such things - it's just...", you hesitate. "Well, it's just that sometimes I can't help myself. I'm quite inquisitive by nature."