We got snow yesterday. Lots and lots of snow. It snowed for 10 hours. Rilla came trudging up the hill from the bus stop after school with her coat hanging open and complaining of cold feet. She had left her 6 year old brother behind, so I had to send her back for him. (I don't know how many times I've asked her to wait for him. sigh.) Before she headed back, I got after her for leaving her coat unzipped. In times past, I had no reply for the "but I'm not cold there!" argument my kids gave me when I asked them to zip their coats. I watched mountain climbers on Nova recently, though, so I have a rational reason for making them keep their coats zipped.
"Rilla," I said, "You have to keep your core warm or your body steals heat from your extremities to maintain the core temperature."
She just nodded her head because she's used to her mom spouting off completely foreign words at her.
I tried again. "Your body has to keep your heart warm so if you leave your coat unzipped it will steal heat from your fingers and toes to warm it up."
"oh." and a lightbulb went off above her head.
See it all makes sense. Now go zip up your coat.