Jennifer Ouellette's book covers topics ranging from Fabio's close encounter with a goose to the ethical fallout of developing nuclear devices.
From Chapter 14, "Thrill Seekers"
One bright spring morning in 1999, a crowd gathered at Busch Gardens in Williamsburg, Virgina, for the opening of the park's new roller coaster Apollo's Chariot. On hand as a special celebrity guest was the male model Fabio -- he of the flowing blond locks, chiseled jaw, and impeccably sculpted torso. Best known for posing in strategically ripped shirts on the covers of mass-market romance novels, and for hawking butter substitutes on television, Fabio's Apollonian good looks made him an obvious choice to usher in the new ride.
But halfway through the initial 210-foot drop, disaster struck: a wild goose flew into the coaster's path and smashed into Fabio's face. The impact gashed Fabio's nose and killed the goose, whose broken body was fished out of a nearby river. Fabio ended the ride with his face covered in blood (whether his own or that of the goose, no one could say) -- a gruesome testament to the impressive forces a simple thrill ride can generate.
Affectionately dubbed the "great American scream machines," roller coasters derive from the giant ice slides that first appeared in the 17th century in Russia, near St. Petersburg. The slides were a favorite diversion of the Russian upper class. Catherine the Great was such a fan that she had a few built on her estate.
Roller coasters have come a long way since those rudimentary ice slides, but both rely on the same underlying principles of physics: inertia, gravity, and acceleration. A roller coaster is always shifting between potential (stored) and kinetic (released) energy. Roller coasters build up a large reservoir of potential energy while being towed up the initial "lift hill." The key factor at play is gravity, which applies a constant downward force on the coaster's cars; the tracks channel this force by controlling the way the cars fall. The higher the coaster train rises, the greater the distance gravity must pull it back down, and the greater the resulting speeds.
Thanks to the continual variation in forces, roller coasters put the human body through a number of exhilarating physical sensations in a matter of seconds. These are the so-called "g forces," which indicate how much force the rider is actually feeling. The riders' inertia is separate from that of the car, so when the car speeds up, they feel pressed back against the seat because the car is pushing them forward, accelerating their motion. When the car slows down, a rider's body tends to continue forward at the same speed in the same direction, but the harness or restraining bar decelerates it -- that is, slows it down.
A "g" is a unit for measuring acceleration in terms of gravity. It also determines how much we weigh, as opposed to our mass (how many atoms make up our body). Weight is determined by multiplying an object's mass by the force of Earth's gravity. The g forces arise because a roller coaster is accelerating: forward and backward, up and down, and side to side. This produces corresponding variations in the strength of gravity's pull. For example, 1 g is the force of Earth's gravity: what the rider feels when the car is stationary or moving at a constant speed. Acceleration causes a corresponding increase in weight, so that at 4 g, for example, a rider will experience a force equal to four times his weight.
At high speeds the g forces can be considerable. Fabio endured a lot of ridicule in the media after his encounter with the kamikaze goose; people were amused that the 6-foot, 3-inch, 220-pound hunk fared so poorly against a 22-pound waterfowl. But assuming the collision lasted a hundredth of a second, and the coaster was traveling at a speed of about 70 MPH, Fabio would have absorbed an impact equivalent to a hard tackle by the football player Mean Joe Green, delivered with a force equivalent to a solid punch from the heavyweight champ Mike Tyson. Yet not one reporter said, "That Fabio, he can really take a punch!"
Reprinted with permission from Black Bodies and Quantum Cats: Tales from the Annals of Physics , Penguin Books.