I was out for a walk with my son Leo yesterday and he was in a bit of a foul mood. I had torn him away from his video games on the premise that he needed fresh air, sunshine and a bit of exercise. I gave him options: bike ride, walk or throw ball around?

“Nothing! I want to play the iPad.”

Hm. Walk it is, then. I compelled him to come outside with me and we started off in no particular direction.

He was really miserable. Usually he stops complaining after a few minutes and forgets why he was cranky, but 20 minutes into it, he was still practicing his sarcasm skills on me and loudly decrying his unhappiness and the grievous injustice to which I was subjecting him. In the hope that letting him have some control over the experience would help, I let him decide where we’d go, so he chose the library.

Yes! Something he wants to do. We changed course and headed over. The complaining subsided a bit.

Closed on Sunday.

All improvements to his mood were lost. For that matter, dark storm clouds were starting to close in over my own disposition. Giving up, I started for home. By this point, though, Leo had decided he’d had enough of walking or doing anything I asked, so he stopped and refused to go any further. I was at a loss for how to get him back home without hoisting him in a fireman’s carry over my shoulders.

Then I remembered, totally randomly, my new iPhone’s Slo-Mo feature.

“Hey Leo, want to see something cool?” I asked.

I had tried the 120FPS feature on the iPhone’s camera only a couple of times before but had never shown Leo how it could smoothly slow down fast-moving action. I got him to chase off some birds in a parking lot while I shot some video, then showed him.

“Cool!” he exclaimed. “Can I try?”

I let him try shooting some video of me, and we watched it together.

“Can you film me running?”

“Sure,” I replied.

“How about backwards?”

“OK,” I said.

And so we made our way over to the nearest playground and had a bunch of fun as I took video of him playing, then showed him the slo-mo footage. The clouds parted.

When we got home, we got the footage into iMovie and started playing some more. Leo picked some music (“Royals” by Lorde), a black-and-white video effect and provided various bits of creative input . He insisted that I refer to him as a “show off” in the credits.

Here’s what we made:

As I worked on it, I realized that I could match this footage to pretty much ANY music and it would still look good. I showed Leo some other possibilities I had identified but his reaction was just, “Why did you change my music?”

Okay, “Royals” it is.