As in all competitions, there are rules: No tampering with the projectiles. No instant replay. Judges accept the risk of sun- and/or windburn. Competitors must “skip expeditiously, with no shilly-shallying or dilly-dallying.” These are very different forms of lollygagging that should not be confused. The former shows hesitation in thought, the latter in action. Neither is permitted.

Such is the serious business of competitive rock skipping. There are a few annual competitions. One of the most popular takes place on Mackinac Island , in Michigan. The world championships will be held at the end of September, on Easdale Island in Scotland.

Nobody would blame you if you didn’t know this was a thing. I didn’t — until a few weeks ago, when my husband, Matt, came home from grocery shopping near our cabin in rural Pennsylvania with an oddly playful smile and a flier. I read the proffered page as the 45-year-old man before me reverted to a version of what I imagined to be his 10-year-old self. The competition, it turned out, was scheduled for the next day, and entries would be accepted until the starting time. Matt suddenly abandoned his work and giddily enlisted our kids in helping him collect river rocks. 

A day of hasty practice later, we traipsed 30 minutes to the confluence of French Creek and the Allegheny River in Franklin, Pa., site of the annual state championships since 1998. Participants of all ages are typically welcomed, though it seems only fair to have a special division that pays tribute to the originators, i.e. children, who invented the pastime: They know, after all, that when one comes across an object of any size on the ground, it is almost impossible not to want to lob it across the nearest body of water. 

The physics of rock-skipping have been studied for centuries. A couple hundred years ago, an Italian scientist named Lazzaro Spallanzani examined how it worked: The stone pushes water down as it moves, generating lift. Flat and round work the best, although the verdict is out on size. Heavier rocks can serve well in wind; pebbles without. In 2004, a research team led by French physicist Lydéric Bocquet discovered that maximum bounce can be achieved when the rock is released at an angle of 20 degrees.

But you can intuit most of that yourself if you throw a few stones across a creek — and certainly if you attend a competition. We settled down on the grass to watch, along with about 100 others. The Pennsylvania High Commissioner of Stone Skipping ceremoniously began the proceedings. First came the youth competition, with girls and boys ranging in age from 5 to 18. Next came the adult amateur division. Any amateur who scored at least 25 skips was invited to then participate in the final stage, the professional division. Each participant could play six stones, two at each turn. Some waded into the water. Outfits varied. So did style, each as different as any Major League Baseball pitcher’s. 

When it was my husband’s turn, he stepped up to the “plate” wearing a T-shirt and shorts. He focused, then whipped his arm sideways, sending his rock low. The judges stood in a group, scanning the horizon and counting to themselves. They quietly convened and, by some unseen process, settled on a score. The announcer spoke into the microphone. “Two!” she called out. I cringed. Suddenly, it seemed strangely important to me that Matt do well. Though the action was minimal, the air felt heavy with intense gazes and the auditory sympathy of sighs, aahs and the descending timbre of “ohhh” when a rock sank with a peremptory plonk.

In the end, my husband placed second in the amateur division of the Pennsylvania Stone Skipping Championship . His best rock had tripped across the water 32 times, earning him a nod from Kurt “Mountain-Man” Steiner — who once set the record at an implausible 88 — as well as an invitation to compete in the professional round that capped the tournament. Matt was awarded a plaque and a half-pound of fudge. He ran over to me, exuberantly. “I’m going to do it,” he yelled. “I’m going to turn pro!” 

I never meant to be a birder. But the birds didn’t give me any choice.

Unfortunately, a combination of arm fatigue and anxiety led to a dismal performance on Matt’s part in the finals, with a high score of 22. The winner was Gabriel Garfinkle, a professor who’d driven in from Philadelphia and who was also competing for the first timeHe won with a 44-count skip. 

By the end of the day, I boasted a new vocabulary. A stone that surrenders immediately to gravity upon entry is a kerplunk or gerplunk, an onomatopoeia of a sinking rock. The tight sequence of touches at the end of a throw is the pitty-pat. A skronker is kind of like a home run, but without any of the rewards: It’s a rock that somehow, inexplicably, manages never to hit the water.

I’d never planned to pass a summer day this way, doing more nothing than I’d ever done before. But, in the end, it was magical. I spent the time contemplating what could be so appealing about tossing a rock into water. Is it sport? Meditation? Boredom? A natural study of physics? Whatever it may be, we usually grow up and stop doing such things. Is it because there isn’t even enough time for the necessary activities? Or because we no longer see the point? Perhaps what makes these competitions so popular and appealing is how they can trigger a brief sojourn to our younger selves and the vivid luxury of a time when play was all that was required of us. There’s no denying the beauty of a rock as it dances across a surface, sketching a path to the horizon, obliterating responsibility and complexity for five 5 or 15 seconds; in every widening ripple, a silence.

My kids want to enter next year. I think I’m game, too. I’ll have to schedule some time to practice. Child’s play is serious work. 

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