True story: my brother and I were rural latchkey kids, left alone for hours in an (for then) advanced house. I got bored one day, I think I was twelve, my brother was ten. We had this kind of switch for our thermostat, but it was in the cover. I'd pried that thing free months before my bright idea.

I thought the giant jiggling lump of mercury was fun to watch as it went back and forth. I didn't know what a bimetallic spring was, but I did know if I touched one side of the spring it made the whole thing twist in an interesting way and the mercury ball slid back and forth.

Here's where it gets fun: we were one of the first families on the block with a microwave oven. We were alone. My brother was bored and driving me bonkers.

"I know!" I said. "Let's put this spring thing with the mercury switch in the microwave!"

Oh yes I did. I didn't count on all the sparks. A half second after I turned it off I yanked it out and that spring was wound TIGHT. Physics probably saved me from mercury poisoning that day.

There's a reason why women live longer.