How Do Roller Coasters Work?

Young friends on roller coaster ride
Jacob Lund/Shutterstock

Roller coasters are the closest we’ll probably ever get to the sensation of flying. But have you ever stopped to wonder exactly how these machines work? What holds everything together and makes the coaster go so fast? Let’s look into the science behind roller coasters.

The History

The first roller coasters date back to 16th-century Russia, where Russians built giant wooden slides and covered them with ice for people to use as sleds. In the 1800s, the French expanded upon this idea and built the first short train attached to a track. This design grew with the development of technology. Over time, longer tracks, sharper turns, and steeper hills were added.

The United States built its own version in the mid-1800s as a scenic ride up a mountain, which culminated in an exciting and bumpy ride down. Eventually, the idea made its way to amusement parks. By the 1920s, over 2,000 roller coasters were operating across the country.

The Components

Roller coasters are complex machines. They resemble a passenger train but operate without an engine, relying mostly on momentum and gravity for movement. (Some newer coasters are equipped with state-of-the-art technology, but we’ll be sticking to information about traditional coasters here.)

There are a few important components involved in getting a roller coaster from a healthy start to a safe finish. The first is the chain lift—a long chain under the track that runs up a steep hill—which allows the coaster to make it up that first slow, gut-wrenching hill. Its design is fairly simple: It’s connected to a motor-operated pulley system with gears at the top and bottom of the hill. The bottom of a roller coaster is usually equipped with hooks or grips that allow the ride to securely fasten onto the chain as it is carried up the hill. The chain is released at the summit and the ride is let loose.

Some newer coasters use a catapult-launch lift that uses electromagnets to build up a sufficient amount of kinetic energy faster than usual. These rides usually send passengers flying from the very start without the need for a large hill.

Once the coaster takes off, gravity takes the reigns and sends passengers shooting down the track—that is, until the ride hits another chain or catapult-launch lift, or until it’s all over. (We’ll talk about gravity more in the next section.) A brake system made of clamps is built into the track to bring the ride to a halt. A computer system recognizes when the train has reached this point, and the clamps subsequently close onto hooks or fins that stick out of the ride under the track, the purpose of which is to slow the coaster down to a complete stop.

The Physics

Roller coasters function largely due to the workings of potential and kinetic energy. As the coaster makes its slow ascent up the hill (or uses magnets to create a quick start), it builds up a large supply of potential energy. And the higher a coaster initially climbs, the farther down gravity can pull it later.

Once a roller coaster crests the first hill and begins its downward journey, gravity takes over and all the potential energy is converted into kinetic energy. The energy pulls the cars forward and down, with the slope of the tracks determining exactly how fast they move.

Because of Newton’s first law of motion (an object in motion tends to stay in motion), a roller coaster maintains a forward velocity even when it’s going up a hill because it doesn’t hit any barriers. As it moves up, it generates potential energy that will turn to kinetic energy as soon as it crests the hill. This is why many coasters have multiple hills to traverse—it’s just physics’ way of keeping the ride moving along.

Today’s roller coasters encompass anything from fast starts to track changes to seemingly gravity-defying stunts, but basic physics is at the core of all these rides. See if you can convince your physics teacher to take the class on a field trip to the amusement park. After all, the experience can serve as a highly educational one.

Anne Taylor Anne Taylor
Anne Taylor is a writer with a BA in Journalism and a passion for storytelling. Her work has been published on a variety of websites including Listverse and Introvert, Dear, and she is currently working on her first novel. When she's not breaking down complex topics into readable material, she loves to stay on the lighter side and blog about Disney and Universal parks on Taylored Trips Blog. Read Full Bio »