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The Science of Spin: A Baseball Pendulum

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Areas of Science
Time Required
Short (2-5 days)
*Note: For this science project you will need to develop your own experimental procedure. Use the information in the summary tab as a starting place. If you would like to discuss your ideas or need help troubleshooting, use the Ask An Expert forum. Our Experts won't do the work for you, but they will make suggestions and offer guidance if you come to them with specific questions.

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For this project, you'll use a baseball as a pendulum weight, studying the motion of the ball with and without spin. Wrap a rubber band around the ball, and tie a string to the rubber band. Fasten the string so that the ball hangs down and can swing freely. Mark a regular grid on cardboard, and place it directly beneath the ball to measure the motion. You can also time the oscillations with a stopwatch. Lift the ball along one of the grid axes, and let it go. Observe the motion and record your results. Next, twist the string 50–100 times, and again lift the ball along one of the grid lines and let it go. How does spinning change the motion of the pendulum? Try changing the orientation of the seams of the ball: is the pendulum motion affected? What happens if you wind the string in the opposite direction? Can your results help you explain how a pitcher throws a curve ball? (Idea from Goodstein, 1999, 50-53. Adair, 2002, has an extensive treatment of baseball aerodynamics.)


  • Adair, R. K., 2002. The Physics of Baseball: Third Edition, Revised, Updated and Expanded. New York, NY: HarperCollins Publishers.
  • Goodstein, M., 1999. Sports Science Projects: The Physics of Balls in Motion. Berkeley Heights, NJ: Enslow Publishers.
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MLA Style

Science Buddies Staff. "The Science of Spin: A Baseball Pendulum." Science Buddies, 28 July 2017, https://www.sciencebuddies.org/science-fair-projects/project-ideas/Sports_p022/sports-science/baseball-spin-pendulum. Accessed 22 Sep. 2023.

APA Style

Science Buddies Staff. (2017, July 28). The Science of Spin: A Baseball Pendulum. Retrieved from https://www.sciencebuddies.org/science-fair-projects/project-ideas/Sports_p022/sports-science/baseball-spin-pendulum

Last edit date: 2017-07-28
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