Let Physics Make You Feel Small

There’s a playground next to our house. It has two swings. Yesterday, it was a nice, warm evening, so after walking home, I swung by the swings. It had been years since I sat on one, but I guess swinging is like cycling: Once you know, you’ll know forever.

As I was slowly gaining momentum, I remembered the swing across the house where we lived when I was nine. I used to go so high on it! I would push it as much as I could — and then I’d jump off! For a while, I turned it into a sport. How far would I make it this time? How high could I go on the swing?

In the present, meanwhile, I got a funny feeling in my stomach when the swing went to about half its possible height. “Wow! This is, like, some serious momentum,” I thought. Having learned a thing or two about physics between now and then, I was wondering about speeds, acceleration, and gravity. “You could seriously hurt yourself on this thing. Crazy!”

It’s such a simple device, isn’t it? A swing. It’s on every playground. Millions of children use it every day. And yet, even this most basic of human constructions has the power to show us how small physics makes us all look. Puny humans playing with the forces of nature — how easy it is to get burned!

As a child, I didn’t know anything about the scientific rules of swinging, and perhaps that was the best thing about it. I saw a toy, and I played with it. I made the most of it. Until, one day, as I also remembered, my arm got twisted in the rope of the swing. Ouch! I still managed to jump off, but I scraped my entire forearm in the process. That was the day I discovered the power of physics. Needless to say, my highest jumps were behind me.

There are two ways to look at this. One is to say, “Oh, how sad, he lost his relentless drive and curiosity. He grew up.” While that’s true, there are more things in life than swinging one can be curious about and driven towards. The other perspective is that, actually, this was a timely and useful reminder: “You can swing as high as you like, but you’re still just a small human. Don’t get too cocky!” Thankfully, I didn’t need a more serious injury to teach me that I am not Superman.

Another benefit of receiving such a reminder early on is that now, 20 years later, I can deliberately reapply it in small doses to achieve the same effect — by sitting on the swing behind my house for 15 minutes, going as high as I dare go, and musing about the unbendable laws of physics.

Every now and then, let the world make you feel small. Find your swing, and revisit. It’s not a bad thing to keep your head on straight.