From far away, some time later, I surmise that the metal stirrup—remnant of a broken swing—that hit my daughter Sara in the left temple carried with it a momentum of roughly eight kilogram-meters per second as it traced its arc from my daughter Adriana’s hand as she followed it with her widening eyes as she realized its trajectory would intersect her younger sister’s. Given that Sara’s mass, even at age three, was substantially more than the swing’s, the momentum would have been easily conserved in simply knocking her a half meter or so in about a second; but given that she may have sensed the impending collision and thrown herself backward, the calculations would be nearly impossible. In any case, I wasn’t there to witness the event or to take measurements. And ultimately, this is not so much a question of momentum as of force concentrated in a narrow shim of iron cutting bluntly into millimeters of flesh over bone.
This essay came from my desire to write short, complete pieces, to oppose my tendency to write long, circuitous, rambling essays. The central moment, my daughter’s injury and frantic hospital trips on our family’s last day in Uruguay, seemed narratively self-contained, but thematically insufficient for the kind of thoughtful engagement I prefer to write (and to read). I found a satisfying overlay in the physics of momentum transferred from broken swing to toddler’s head, and a more harrowing parallel story in my brother-in-law’s tragic burning when he was a toddler, which gave me access to the helplessness a parent sometimes feels in the face of all that can go wrong in a child’s life. I figured that most characters were, for the purposes of this essay, inconsequential and didn’t need fleshing out beyond a few names and/or relationships, though I can reveal here that Karina is my wife and David is my brother-in-law by marriage to Karina’s sister Graciela. Hoping to make a statement a bit more resounding and open than “parenting is scary,” I returned to a metaphor from physics at the end, recalling a study that found that outgoing college seniors who’d taken a physics course by and large retained incorrect notions about certain ways the world works (for instance, that a heavy object falls at the same rate as a light object). It occurred to me, too, that most of us think that weight equals mass, and that the word gravity has a double meaning that ties together both physics and the perils of parenting.
This was our last day in Uruguay visiting Karina’s family. We were to have a feast attended by the whole clan. My father-in-law and Fernando tended the grill, shoveling coals, adding wood to the fire, turning the ribs, while David and I stood around chatting. Inside, Karina and her mother and sisters readied the table with plates and empanadas. Most of the children were at the nearby playground, squeezing out every last moment. Then my two oldest, Pato and Adi, ran breathless and crying around the gray corner under the broken ombú tree:
Amid a string of unintelligible overtalking.
I bounded past the ditches, over the low brick wall, to the sight of my baby stunned, standing silent in the middle of the concrete playground, holding her scarlet head above a growing pool.
I swept her up, cradled her in the crook of my arm, and bounded back, past the chimney, into the house, to grab a towel, to wash the wound, to call a taxi, to rush us to Saint Bois. Karina and David came along. Fernando and his parents stayed at home with the other children, to calm and console them. By the time the taxi arrived, minutes later, we still had no real idea what had happened.
Sara was calm, mute, wide-eyed, the whole ride. Our driver was safe and fast, taking corners without a downshift, taking traffic signs as suggestions. The hospital staff, seeing the blood and stillness and thinking Sara more gravely injured than she was, took us right in and assessed her injury, eventually, as superficial, deep and wide enough to require stitches but nothing eternal, nothing visible to the future. It was behind her hairline, just barely.
Our own assessment required a quick phone call home to ask once more, calmly, what had happened. Fernando, acting as intermediary, pieced together from Adriana’s sobs what I’ve told you above: that she’d thrown the broken swing just as Sara happened by. It was thus Fernando’s job to comfort Adi, to let her know that Sara would be fine and that we’d all be home and happy soon.
Not so soon, it turned out, as we were sent downtown to Pereira Rossell after the stitches, for a CAT scan. So David went home to eat with the rest of the family, while Karina and I traveled in the ambulance beside our daughter, Karina whispering lullabies and I staring ahead, imagining the day 30 years ago when my mother-in-law left the water boiling on the stove awaiting the evening’s pasta. In only a moment of turned-back, mind-on-something-else, her son Fernando toddled into the kitchen and tipped the pot onto his right side, scalding the skin off his face, arm, and leg. Of course, the scene I construct takes place in their current home, because I’ve never seen the house they lived in then, so I already know somewhat of the limits of imagination when it buts up against the horror of a mother’s momentous guilt at knowing she’s caused her son everlasting pain: in the series of grafts, in the incessant taunts and too-long stares of passersby. When Fernando was in his late teens, doctors began a process that would implant healthy skin in place of his undulated scars, but he gave up before the shunts could do their work. He’d lived his whole life looking like that, he reasoned. Why bother trying to change it all now?
All of this is a memento mori: what you can lose in a moment of distraction or inattention, in a split second of misdirected curiosity, in a clepsydra’s drop of bad luck, in all the times you’ve used the front burner without incident, in a little girl turning her head just an inch toward instead of away or rocking left instead of right. Fractions from fractures: all things considered, this was a blessing, because it was so close to so worse, because her eyes were averted when the pendulum struck.
Physics isn’t really that hard to understand, given the right brand of curiosity and a nudge in the right direction; yet for people whose daily life is dominated by the mysterious observable, even small miracles can fade to mundanity. Of all the elementary concepts requisite for a beginning conception of the mechanical world, mass is fundamental, a block to build on and calculate from; yet people everywhere, old and young, struggle to distinguish mass from weight. For them, as for all of us, really, everyday experience is inextricable from gravity.
Header photo of old swing set on playground courtesy Shutterstock.