Playground

I don't think of it as a playground. I think of it as a physics lab, by which I mean a festival of applied math.

The swing, one might assume, hangs in a parabolic shape. One would be wrong. It's a catenary. That's the shape formed by a hanging chain. Oddly, if you hang a cable and then use it to build a suspension bridge, the weight of the bridge causes the cable to become a parabola. There is order to the world.

None of this really matters to Nate, my 3-year-old nephew and playground companion. He loves to swing. I thought that I'd be stuck pushing him -- not my favorite thing to do, but an expectation of the uncle at the playground nevertheless. I did have to lift him up on the swing, and then I was pleased to find that he preferred that I swing next to him. We rocked gently for a while, just a few feet off the ground, sometimes in sync, sometimes not. After a while, I stood up and then realized that Nate was holding back out of courtesy to me. He swung higher and higher, until I started to get that feeling you get when you watch a 3-year-old who can swim go underwater. Logic says he knows what he's doing; emotion says "aaaaaaaaaah!" I withheld my panic, and Nate did just fine.

On the slide, he was on his own. I couldn't fit through the tube.