A student wanted to ask me a hypothetical question. Well, I'm game.
"Assume that someone invented a time machine. Then I go back in time and kill him before he has a chance to invent the time machine. Did I go back in time?"
I'm well-versed in science fiction tropes. So, I went with the parallel universes response--the universe created by killing the time machine inventor would be different than the one the student originated from.
This was not the response the student wanted. Apparently, she'd been asking various friends this, convinced that the only solution was that then she never would have gone back in time. The friends found my answer amusing, saying that I'd "schooled" her.
I hadn't intended to shame her or "school" her. She asked a question that I had an answer to.
So, I introduced her to the grandfather paradox. It was pretty much what she had come up with, just in a slightly different form. And that one blew her mind as well.
Deep thoughts are good things. (Even if it was a history class, and this was not history.) I posed some other questions that were just as mind twisting, and we got into an interesting discussion about physics and science and science fiction and...
We both jumped when the student's shoe hit the ceiling. What he was doing that made it fly off his foot...
So, back to work. I glared at that boy. Asked him what the blank? (I was good. I didn't swear.) He was more chagrined than anything. He didn't expect the shoe to do that. (Although what he was doing that made this possible didn't seem to be an issue to him.)
The class got back to the study guide that they were working on. And another student asked me if I watch Doctor Who. Well, as a matter of fact...