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Backyard Ballistics

A treasure trove of science projects for grown-up boys



The Diamond and I mostly pretended to be helpful while a friend of ours built “Donny America” for us on a back porch in Stevensville with 2-inch schedule 40 PVC pipe, cement, primer and the sparker for a propane grill. No one asked us if we were building a potato cannon when we picked up our supplies at the hardware store, but we practiced an entertaining lie just in case: we needed pipes cut to build a bidet in a friend’s hard-to-fit attic apartment. The lumpy teenager who cut the pipe and helped us fit it with the right bushings had never heard of a bidet. “What are them?” he asked us blankly.

By the time the PVC cement was dry in the joints, the kegger was in full swing and it was already too dark to see how just far Donny A. could toss a russet plug. Far, we knew—real far, but how far? We cored out a little divot in the next spud and filled it with a fluorescent glow-stick like the ones you see at clubs and outdoor rock concerts. Then we tamped the potato the rest of the way down the barrel, fueled the chamber and fired Donny America straight up in the air.

The spud took off with a trail like a green tracer bullet. We lost it against the speckled baldachin of late summer stars for five or ten seconds before one of those stars suddenly appeared to be spinning wildly off its axis and the potato came streaking out of the sky like a vengeful comet. As partygoers scattered in panic, the two-inch plug smacked into the roof of the house not 15 feet from where we launched it toward the firmament, shattering into pea-sized lumps and a beautiful spray of glowing green juice.

I couldn’t duplicate this feat today if I spent all night trying. It’s easily the most impressive parlor trick I’ve ever managed to pull out at a party, all the more so because it stupidly put everyone present in harm’s way and we all lived to recount the danger with no broken skylights (missed it by about five feet), no missing eyes and no potato-shaped dents in anyone’s noggin to sober up an otherwise impressively reckless tale of misadventure. Since that evening, you’ll be pleased to know, safety has had priority over kicks at any cost. When we take Donny out to blow the stink off him we always go somewhere with an 180-degree field of unobstructed vision where we can follow the trajectory to terminus—and miles away from anybody.

Boys will be boys, eh? You know how it is with us. We delight in anything that blows up, burns well, shoots something out of it or makes a loud noise. You gals say Sleepless in Seattle, we say Force Ten from Navarone. Get a bunch of teenage boys around a campfire sometime and catalogue the varying capacities of every substance in a 100-yard radius to combine with oxygen. Or, for that matter, a bunch of balding accountants around a barbecue, each of them staring into the glowing coals with a beer in each hand and a distant expression that bespeaks manly rumination and long-slumbering Jungian archetypes.

Backyard Ballistics is a book for grown-up boys. Author William Gurstelle, a professional engineer, has assembled the most exciting collection of loud, bright and spark-shooting home science projects since the Chinese invented gunpowder. They range in size and complexity from paper match rockets (a diabolically tricky endeavor, as it turns out) to carbide cannons, with an arsenal of hot air balloons, scale-model catapults and lighter fluid and hairspray-powered potato cannons and tennis ball mortars in between. In a chapter devoted to something called a “Cincinnati Fire Kite,” we learn to make a cushion of perfectly-folded newspaper that can float to tree-top level under the right conditions after its four corners are simultaneously ignited. Another section devoted to “Pnewton’s petard” ups the ante on potato-huckin’ technology by showing the reader how to build a pump-powered PVC contraption that can propel an Idaho russet—soundlessly—across the Panhandle.

Nervous yet, parents? On the face of it, Backyard Ballistics might sound like a slightly toned-down version of an online Anarchist’s Cookbook, with detailed plans for nail bombs and fuel oil explosives and so forth. But really it isn’t. It’s a fascinating book of science projects for older kids and grown-up dads to try a hand at together. In eleven gleefully instructive chapters, author Gurstelle takes the reader back to a time when implied but usually avoidable risks to life and limb were the norm for boys’ science projects. On the first page of his introduction, he mentions a picture of a lad stepping off a cliff in a homemade glider from a favorite book of his own, the 1913 edition of The Boy Mechanic: 700 Things for Boys to Do. “Back then,” Gurstelle writes, “It was your own carelessness, not Popular Mechanics’, if you didn’t make your glider’s joints fast and strong.”

But Gurstelle obviously does care—not just about the kicks potential of the finished projects, but also about imparting a joyful sense of discovery and handicraft to the procedures, processes and properties behind each one. Historical background and clear explanations of the physics involved accompany instructions for making every grown-up toy in Backyard Ballistics, and sections devoted to the life and work of Archimedes, the ballooning Montgolfier brothers, Alfred Nobel and Robert H. Goddard fill it out nicely. Ever wondered what’s in Greek fire? Where the expression “hoist with his own petard” comes from? How about the origin of the backwards V sign that’s England’s equivalent to the American bird? All this and more, friends—all this and so much more.

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