So I'm driving in the car with Macey (she is four), and we have this conversation -
Macey: Mama, what is that thing that keeps stuff from floating?
Me: That thing.. hmm. It keeps stuff from floating?
Macey: Yeah! It keeps stuff from floating!
Me: Um, do you mean rocks?
Macey: No, no! It keeps STUFF from FLOATING. You know what I mean!
Me: Hmm. I really don't know, I... uh.. hmmm....
Macey: It's GRAVITY! And it works just the same in the spring as it does in the winter! Just so you know!
Me: Oh, THAT! Thanks for letting me know!