According to Carnegie Magazine, roughly 290 million people ride roller coasters each year. On a roller coaster, you experience the thrill of cognitive dissonance, in which one part of consciousness understands that you're in no real danger and the other part is experiencing genuine fear. This leads to a powerful adrenaline rush that keeps riders coming back for more. A roller coaster designer combines the principles of human psychology and simple physics to create a hair-raising experience.
G-Forces (See Reference 2)
G-forces are the forces that your body feels as the roller coaster accelerates and decelerates around the track. The loops in a roller coaster, known as clothoid loops, are responsible for most of the g-forces. As the coaster accelerates around a loop, your direction of motion is constantly changing. The force of gravity always pushes down toward the ground, while the force of the seat against you always pushes toward the track. At the bottom of the loop, both forces push you down, making you feel heavier. At the top of the loop, the forces compete with each other, making you feel lighter.
Potential and Kinetic Energy (See Reference 3)
Roller coasters are driven by gravity. As the coaster climbs the first rise, it stores potential energy. The amount of potential energy is affected by the height of that incline. As the coaster crests the rise, gravity takes over, converting the potential energy to kinetic energy, or the energy of motion. The kinetic energy drives the ride, but there must be sufficient potential energy for it to complete its run.
Psychology (See Reference 4)
While physics are responsible for the actual movement of a roller coaster, psychology is what makes it worth riding again and again. Yet emotions are highly personalized and no two people experience feelings in exactly the same way. Roller coaster designers have gone high-tech in their quest to find the right balance between excitement and terror. Measuring skin conductivity, heart rate and even tiny changes in the facial muscles helps them understand what riders are thinking and feeling.
Wooden vs. Steel Coasters (See Reference 5)
Wooden roller coasters rarely go upside down, while almost every steel coaster does. This difference has to do with the tracks. Wooden roller coaster tracks are not as flexible as steel tracks. Wooden coasters depend on the centripetal force generated when the coaster goes around curves and the acceleration generated when the coaster goes down a hill. Tubular steel coaster tracks are flexible and able to withstand the forces generated when the coaster goes upside down. Steel coasters also provide a smoother, less bumpy ride.