The Burning Questions of Sixth Graders

Student: Ms. Frizzle, where does the word 'period' come from?

Me: quizzical look

Student: "Not that kind of period, that kind of period."

Me: Oh. The kind at the end of a sentence, or the thing that happens to girls?

Student: The second one. *blush*

Me: Well, do you remember the Periodic Table? It got its name because certain things kept repeating every so often for the elements?

Student: I guess...

Me: Okay, well, a girl's period is something that comes back every month, after a period of time, and it lasts a short period of time each month.

Student: Ohhhhh. Walks away, curiosity apparently satisfied.

Believe it or not, I answered that exact same question last year.