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Isaac Newton never had a chance to ride a roller coaster. The first one was built 75 years after his death. But the principles involved in roller coasters are right up Sir Isaac's alley. Newton's laws of motion describe how forces determine the motion of objects. Designers rely on the acceleration caused by those forces to make a roller coaster ride both thrilling and safe. The trick is knowing how to use the forces properly. If the forces are too great in one direction, for instance, they'll throw the car off the track. If an upward force is too large (giving you a feeling of heaviness), your heart cannot pump enough blood to your head and you faint. On the other hand, the lack of supporting forces can create feelings of incredible lightness. This can provide an electrifying ride that delivers you safely to the end. Hypercoasters are about twice as tall as regular roller coasters. This larger scale adds new design challenges. Going down a 200-foot hill, a car has more time to accelerate and gains more speed. If while going at this fast speed the car experiences a sudden change in direction or speed, the car's acceleration changes. A big or sudden change in speed or direction can make a bigger acceleration. Since the force acting on the car (and you) is equal to its mass times its acceleration, the bigger the change in direction or speed and the less time that change takes, the greater the acceleration and the bigger the force you'll feel. To keep these forces at safe levels, the designer has to stretch out the time and the distance it takes to navigate the curve at the bottom of the hill. This spreads the change out over time, decreasing the force you feel. The top of the next hill has to be high enough to slow the coaster down, or stretched out to a gentler or banked curve, so the car doesn't fly off the track. Space is a problem. Coasters go forward two feet for every foot they climb. If the highest hill is 100 feet, it takes about 200 horizontal feet to get the car that high. If the highest hill is 200 feet, it takes 400 feet. Since land is expensive, the designers have to be creative about the use of space. A track shaped into a curve takes up less space than one left in a straight line.


Roller coaster design is a balance between a wild ride and safety. You try it. Materials (for each group)
  • 2 or more lengths of pipe insulation
  • tape
  • marbles (Be sure each team has one the same size and weight.)
  • stopwatch
  • steel ball
  • scissors
1. Divide into groups. 2. Cut the pipe insulation in half lengthwise to make two long chutes. Using classroom furniture and materials as supports, each group should build a roller coaster. Use tape to hold the coaster in place. Start each ride at 1 meter (3.3') high. Build the wildest ride you can that still delivers the marble to the end. Make the turns and dips as tight as possible. Measure the radius of the turns at the points where they work without a crash. 3. When all coasters are finished, evaluate them. Time five runs on each coaster. Rate each coaster on the following:
  • Average speed (length of original "track" divided by time)
  • Safety (Did it stay on the track?)
  • Number of turns and hills (include loops)
  • Originality
4. Test all the coaster tracks using a steel ball instead of a marble. Compare the times of the runs of this ball to the times for the marbles. 5. Work together as a class to design the "ultimate coaster" on the blackboard. Use the best qualities of each group coaster. Build and test your ultimate coaster. Decide what the best qualities for a ride are. 6. Build a hypercoaster. Start the first hill at 2 meters (6.6'). Make each hill twice as high as on your "ultimate coaster." Make the turns as tight as possible. Compare your hypercoaster to your ultimate coaster. Measure the radius of the turns at the point when they work without a crash. How do they compare between the two coasters? Evaluate the hypercoaster using the list of criteria. Would you change the design in any way because of the size? Questions
  1. How does the height of the ramp affect the design of the coaster ride? Would you design a hypercoaster using a different set of criteria than a smaller coaster? What new problems do hypercoasters present to the designers?
  2. What constraints had to be set on the hill heights after the initial hill drop? Why?


    Colt, G. & Rentmeester, C. (1993, Aug) The physics of fear. Life, pp. 68-72.
    Farrell, K. (1993, Oct 22) Holy Batman, the ride. Science World, p. 19.
    Silverstein, H. (1996) Scream machines. Roller Coasters -- Past, present, and
    future. New York: Walker.
    Timney, M.C. (1996, June) Ups and downs of coaster physics. Boys' Life, p. 50.
    Zubrowski, B. (1985) Raceways -- Having fun with balls and tracks. New York:
    William Morrow and Company.

    World of coasters:
    3M Learning Software: What's the secret? (vol 1). CD-ROM for Macintosh or
    Windows. (800) 219-9022.
    American Coaster Enthusiasts
    PO Box 8226
    Chicago, IL 60680
    (410) 385-1222