Jeremy Benson, the director of summer camps at Northern Illinois University’s STEM Outreach Team, recently visited the Vernon Area Public Library, where he gave a presentation about the science that goes into roller coasters. Many understand the main agent, gravity, but Benson had to explain to young minds how the smoothness of the track, the lubrication on the wheels and the resistance of air make the experience rock hard —and how restrictions on curvature and speed keep riders’ brains from turning into rocks.
“You can actually get enough acceleration that you’ll black out,” he explained. “Which makes the ride not as fun.”
Q: [With roller coasters] why don’t variables like the weight of passenger loads or the humidity of a summer day ever cause problems?
A: That’s actually a very interesting question. The biggest concept is that trade-off between potential energy and kinetic energy. The first hill has to be the biggest hill, because that’s all the potential energy we’re going to have. Each hill has to be a little smaller than the one behind it, but the rest of the factors you’re talking about —friction and that —do not play as big a role as you think. Friction is actually one of the smaller forces at play in a roller coaster. The difference in weight of the different riders is negligible, once a roller coaster that is heavy enough and streamlined properly gets going.
Q: If we could build a roller coaster that started at the edge of the atmosphere, and drop people straight down, would it just keep speeding up, or does gravity have a speed where it cannot pull you any faster?
A: You’re talking about terminal velocity.
Q: You mean that’s not just a cool name for a rock-climbing movie?
A: It is an actual thing. With terminal velocity, you have gravity accelerating you, but then you have wind resistance. The faster something is moving, the greater the wind resistance is going to be. Eventually you reach a point, and you can calculate the speed mathematically, where the air resistance will cancel out any future acceleration.
Q: You were talking earlier about what physics has yet to discover. What is that? Where is physics going now?
A: The most exciting things that are happening are the particle colliders, like Fermilab. The cutting edge of physics is on the microscopic level, the nano level. We understand how galaxies move, how comets move. But when we look at how the building blocks of atoms are moving, there’s still a lot more to discover. We’re going down to the quarks, which right now we think are the smallest pieces.
— Ronnie Wachter, Pioneer Press