The world's oldest operating roller coaster, Leap the Dips, opened in 1902 and is still going strong at Pennsylvania's Lakemont Park. Its sluggish speed (10 miles/16 kilometers an hour) and 40-foot (12-meter) height may be tame by today's standards, but the ride remains a Holy Grail for coaster aficionados.
Hamilton College physicist Amy Lytle explained that most modern coasters still employ the simple, but addicting, physics principles that the early designers recognized.
"All you have to understand is gravity and the conversion between two different kinds of energy--potential and kinetic," she said. "All the energy that you get in the ride is really from that initial lift hill."
Photograph courtesy National Historic Landmarks & National Register of Historic Places in Pennsylvania