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Roller Coaster Science: Marbles, Tubes, and Loops

Building paths for marbles to race, climb, and loop brings physics to heart-pounding life—minus the admission fee, height requirement, and endless wait in line. A willingness to uncover principles of energy and laws of motion is required; cotton candy is optional.

Image: Bigstock

Roller coasters and marble runs offer an engaging platform for invention, engineering, and physics-based investigation. Get hands on exploring what kinds of loops are possible, how energy changes during a ride, and how the laws of motion come into play. Building a simple marble-run or tube-based coaster is only the beginning. Can you wire your track to add lights or sounds? Can you make your run motion sensitive or trigger an effect as the marble passes a certain point?

Try this at home!

Roller coaster science can be fun for the whole family and all ages! Younger students can learn about the laws of motion and centripetal force by using Jell-o, marbles, and paper cups to investigate how we stay in our seats when riding a roller coaster and going around loops. There is more at work than just the seat belt! This is a great—and jiggly—family science opportunity. If you give it a try, we would love to see a photo and hear how it went!

One of my family's favorite stopping spots at the Exploratorium, our local science museum, is the "Tinkering Studio" where a pegboard wall, bins of low-tech building materials, and rolls of masking tape are available for impromptu marble-run construction. The build-at-will lab is nestled in the far back corner of the museum, but it's a beeline destination for many. The perpetual hands-on exhibit invites kids of all ages to position ramps and tubes so that a marble will roll down one length, drop to another, and continue, hopefully, until it lands in some form of cup at the bottom. Some kids build small-scale runs, content to see the marble make it through one or two connections and into the cup. Others create more sophisticated runs, testing and re-testing to correct angles and positioning as they work on perfecting their layouts. Always, the energy in the air is exciting, and when a kid stands up, holds a marble over the starting point for a final run, and sees the construction succeed, the marble rattling to its final stop in a plastic bin at the bottom, the reward is clear: I made it work.

Having seeing how immersive this kind of building can be, I have often thought it would be amazing to line a hallway or bedroom wall with pegboard for this purpose at home. There are many ways to transform a household wall into a space for creativity, invention, and hands-on, perpetual discovery. At various points, I considered both magnetic and chalkboard walls, but marble runs may have more longevity in terms of kid interest. With their quirky and wide-ranging assortment of parts and components and anything-goes aplomb, run building , captivates and challenges both tape-happy younger students and older students with a developing thirst for structural finesse. Whether you take a DIY approach and put together your own wall-based, standalone, or travel-ready kit, or whether you invest in a ready-made marble run or rollercoaster building kit, these kinds of activities, an extension, maybe, of early fascination with brick and block building, are great for letting kids explore principles of physics and engineering.

The Roller Coaster Connection

While angles and trajectories are critical to a marble run's success, the path usually moves in one direction, top to bottom, and any quasi-lateral rolls probably still involve a bit of a decline. Roller coasters, on the other hand, often climb, drop, and climb again, which requires different energy and momentum. What makes a ride thrilling in person is often a combination of speed and stomach-lurching looping, a combination that relies upon and illustrates Newton's laws of motion and conservation of energy. Students who love to ride roller coasters can turn summer amusement park thrills into an informal physics exploration with a homemade vertical accelerometer using "The Chills and Thrills of Roller-Coaster Hills" project. Take the tool along for the ride and measure the g-force at different locations during the ride. Be prepared to ride several times in a row to gather data!

Using the DIY accelerometer to collect g-force measurements gives validity to riding "just one more time" at the amusement park, but once home again, there's plenty of thrilling science to recreate with a DIY roller coaster made from foam tubing. The "Roller Coaster Marbles: Converting Potential Energy to Kinetic Energy" physics project guides students through construction and the tracking of potential energy as it is converted to kinetic energy during a marble's path from start to finish. The same tubing can be used to investigate the math upon which coaster loops depend. The "Roller Coaster Marbles: How Much Height to Loop the Loop?" project explores the ratio between height and loop size. It wouldn't be much fun if you got halfway up the loop only to slip back to the base and stall, right?

Making Connections

Perfect for at-home exploration, marble runs and roller coaster experiments fall in line with bridge building, tower construction, and even exploration of simple machines. What will your students construct this summer?

In a recent essay, Dale Dougherty writes: "'Making creates evidence of learning.' The thing you make—whether it be a robot, rocket, or blinking LED—is evidence that you did something, and there is also an entire process behind making that can be talked about and shared with others. How did you make it? Why? Where did you get the parts? Making is not just about explaining the technical process; it's also about the communication about what you've done."

If you have a student that loves to build, invent, design, and problem-solve in hands-on ways, see the Engineering Design Process guide.

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