August 16th is National Roller Coaster Day, and so it’s a good time to take a look at the science of the rides that paradoxically have us queuing for hours in order to scream in terror.
Roller coasters get more exciting year after year, but ever since 16th-century Russians first came up with primitive ice-coasting versions, the basic principle has been the same: Potential energy is stored up, often simply by using a big hill, and then gravity and kinetic energy do the rest.
Even in most modern roller coasters, the only energy assists come at the beginning and the end. The work is done by energy manipulation and the weight of the coaster itself.
Always advancing
So if the basics are the same, how did we progress primitive ice coasters to today’s scream-inducers?
Firstly, the wheels are very important. Running wheels guide the coaster on the track, friction wheels control lateral motion (movement to either side of the track), and a final set of wheels keeps the ride on the track even if it’s inverted.
The type of track used is also important, and a major breakthrough came when wooden tracks were replaced with steel ones. Roller coasters had a golden age just before the Great Depression, with classics such as “The Cyclone at Coney Island” using wooden tracks. There followed several decades of declined interest, before a new era began with steel-tracked designs.
In 1959, Disneyland introduced Matterhorn Bobsleds, the first roller coaster to use a tubular steel track. Unlike wooden coaster rails, tubular steel can be bent in any direction, which allows designers to incorporate loops, corkscrews, and other maneuvers into their designs.
Since then, what has changed more than the technology is the extent of the thrill that riders are seeking. By having people stand up, hang beneath the track, or by using “fourth dimension” coasters to spin or rotate seats as the ride moves, the experience is enhanced, even with the same basic principles.
Higher and higher
Then, of course, there is the sheer height of the drop. Coasters are categorized by this, with a “hyper coaster” having a height or drop that ranges from 61 to 91 meters, a “giga coaster” having a height or drop that ranges from 91 to 122, and a “strata coaster” being anything above that height. Only two strata coasters have been built to date– Top Thrill Dragster at Cedar Point, OH, which opened in 2003, and Kingda Ka at Six Flags Great Adventure, NJ, which opened in 2005. At a height of139 meters, Kingda Ka was and still is the tallest roller coaster in the world.
Inevitably, there have been technological attempts to make coasters go harder and faster, such as the use of hydraulic or pneumatic power, and even catapults using diesel engines or huge dropped weights. But from 16th-century Russia, through Coney Island and beyond, most roller coasters remain an exciting yet simple lesson in physics.
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Image credit: Thinkstock
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