I’ve blogged before about my eight-year-old son’s interest in science. His knowledge at this point is mostly made up of isolated facts, which he strings together in a stream of consciousness that often does not require much input.

A few weeks ago, when he told his four-year-old sister that a feather and a rock would fall at the same speed on the moon, she peppered him with questions that showed he wasn’t quite sure why that was so significant.

My wife was sitting with the children on the couch, and she started explaining the concept of atmospheric resistance, but I could tell Peter wasn’t getting it.

So I came in from the kitchen with a piece of paper and a cardboard box, and we re-created Galileo’s falling body experiment. But when I asked Peter some questions about what he saw, I could tell that he thought the cardboard box fell faster because it weighed more than the piece of paper.

So I held up two pieces of paper. “Which weighs more?” I asked.

“Neither.”

“Which will hit the ground first?”

“They’ll both hit at the same time.”

Then I dropped the papers to confirm his hypothesis.

Then, I balled one of them up. “Which weighs more now?”

“Neither.”

“Which will ht the ground first?”

“They’ll both hit at the same time.”

Then I dropped both, and the balled-up one hit the ground first.

Peter’s eyes grew wide. “Why did that happen?”

“Good question,” I said. “Now lie down on the ground, face up.”

I held the uncrumpled piece of paper over his face, at my shoulder height, and told him he should try to blow it aside when I dropped it. He was able to do that easily. Then I scrunched the paper into an even tighter ball, and did the same thing. The ball hit him on his nose. (We had to pause here because my four-year-old wanted to have things dropped on her own head, but that was fine because Peter got to watch it all again from a different angle.)

While my wife explained the concept of surface area, I folded the piece of paper into a paper airplane, and pointed out the tiny amount of surface area that the plane presents to the air in its path.

All this took five times longer than it would have taken simply to tell him about atmospheric resistance. But working through it this way got everyone in the family involved, and it was a lot of fun.

Stack of library science books, including “Magnesium”

Back when I thought Peter’s interest in atoms might just have been the latest phase after bugs and dinosaurs, I got him some library books on the elements — Nitrogen, Oxygen and so forth. For some reason, I felt like I was being too pushy by expecting my boy to read through the whole series of eight books, so I left one on the shelf. Later that week, the boy read the list of other books in the series, double-checked the stacks of books on the floor of his room, and blurted, “Where’s Magnesium?” So I went back and got it.

Our latest bedtime book is The Mystery of the Periodic Table. He has a periodic table of the elements taped up over his bed, and he spends hours exploring it. One of the games he likes playing goes something like, “Which is heavier, californium or yttrium? What do carbon and silicon have in common?”

Recently I was with the family at a story time sponsored by our university library. I introduced him to our new science professor. He told one of his favorite jokes: Two atoms walk down the street. One of them stops and says, “I just lost an electron.” The other says, “Are you sure?” And the first says, “Yes, I’m positive!” And he described his theories for building a kind of magnet that would aid in nuclear fission. The professor looked at me with that “Is he for real?” expression. “You should send him to the Jay Leno show,” she said.

Here was my chance to ramp things up a bit. “Peter, what’s the atomic weight of boron?”

Peter turns to me with a finger in the air. “Actually, Daddy, that’s the atomic number”

I felt pretty much like I did the first time he trounced me in chess — which is not a bad thing, at all.

(See also “The Carnegie Museum of Art’s Volcanic Magma: Lava It or Leave It“.)