The Entire Universe~

The sixth graders in the hall were noisy. They were changing classes, slamming lockers shut, chatting loudly. A former student waved to me, her hand winging back and forth like she was wiping fog from a window. I smiled and waved back, a baby bye-bye fingertip wave, and shut my classroom door.

I faced my fifth graders. Together we'd explore "matter and energy," something fifth graders have little prior knowledge of, and lots of misconceptions about.

Everything in the world-- not just the *world,* the entire *universe*-- can be divided into two categories, I told them. Imagine that. The whole universe can be categorized into two groups. I was vastly oversimplifying for ten year-old minds, but they were with me, eyes wide.

Classifying, and categorizing things based on their attributes appealed to their sense of order. They liked knowing there was a place for everything.

We talked about matter-- something that has mass and takes up space-- and compared it to energy: the ability to do work, or make things move. I asked questions, they answered. They asked questions, I answered.

Then my question: "So if we put all the *matter* over here . . . " I motioned to one side of the room with a theatrical gesture, " . . . what would we put over there?"

A pause.

"Not matter?" asked one.

"Well, yes, in a way," I said. Matter *here,* and "not matter" over there. But what is the "not matter" called?

"Empty?"

"Yes, but what is the "empty" *called*? What have we just been talking about? The two things the entire universe is made up of. Matter and . . .?" I rolled my hand at the wrist like I was playing charades. In a way, teaching is a lot like playing charades.

"Matter and . . .," I repeated.

"It *doesn't* matter?" Steven asked tentatively. Kneeling on the seat of his chair, he searched my face hopefully.

No one laughed. Steven hadn't been joking. To the class, the answer made perfect sense.

The world is made up of "matter" and "it doesn't matter."