WHY?

I was totally unprepared for Jack's first "why" question today - "Mommy, why is it cold outside?" Quickly followed by "Why does the sun go down?" So I launched into this whole explanation, with props, about the Earth's orbit, it's axis, seasons, etc. When Chris, the astronomer, gets home and Jack asks the same questions - Chris says, "because it's nighttime." OOooohhhh. I am so much like my Dad :)