Balls Bouncing Off of Surfaces *
AbstractFor example, think of hitting a baseball, heading a soccer ball into the net, or hitting a tennis ball with a racquet. Where the ball goes depends on...what? You can set up a simple model to start your investigation. You'll need a marble, a flat piece of wood, a flat piece of cardboard, a pencil, a ruler, a protractor, and a level surface. Lay down the cardboard down on a level surface and set up the flat piece of wood at one edge. The wood will act like a wall, and you're going to roll the marble at it from different angles to see how the marble bounces off. On the cardboard, mark the starting point, the point where the marble strikes the wood, and a point along the marble's path as it rolls away from the wood. Use the pencil and ruler to connect the incoming and outgoing trajectories of the marble to the point where the marble bounced off the wood. Draw a line perpendicular to this point, and measure the angle between the perpendicular line and the incoming and outgoing trajectories. Do this for at least 10 trials at each of several different angles. What is the relationship between the two angles? Now apply what you learned to a real-life sports situation (like heading a soccer ball or hitting a baseball). In the real-life situation, the ball is no longer hitting a stationary target and bouncing off, it's hitting something that is moving. That makes it harder to measure the angles; just remember that what is important is measuring the angles at the point of impact. For a more advanced project, you may also want to consider how the spin of the ball can change its trajectory. You could choose to concentrate only on the spin imparted by the kick, the bat or the racquet, or you may want to get really complicated and consider the spin of the incoming ball as well. (Idea from Wiese, 2002, pp. 31-34. For more advanced explanations, including the effects of spin, see the Bibliography for a book on the particular sport which interests you.)
Cite This PageGeneral citation information is provided here. Be sure to check the formatting, including capitalization, for the method you are using and update your citation, as needed.
Last edit date: 2017-07-28
BibliographyWiese, Jim. Sports Science: 40 Goal-Scoring, High-Flying, Medal-Winning Experiments for Kids. New York: John Wiley and Sons, 2002.
News Feed on This Topic
Ask an ExpertThe Ask an Expert Forum is intended to be a place where students can go to find answers to science questions that they have been unable to find using other resources. If you have specific questions about your science fair project or science fair, our team of volunteer scientists can help. Our Experts won't do the work for you, but they will make suggestions, offer guidance, and help you troubleshoot.
Ask an Expert
If you like this project, you might enjoy exploring these related careers:
MathematicianMathematicians are part of an ancient tradition of searching for patterns, conjecturing, and figuring out truths based on rigorous deduction. Some mathematicians focus on purely theoretical problems, with no obvious or immediate applications, except to advance our understanding of mathematics, while others focus on applied mathematics, where they try to solve problems in economics, business, science, physics, or engineering. Read more
PhysicistPhysicists have a big goal in mind—to understand the nature of the entire universe and everything in it! To reach that goal, they observe and measure natural events seen on Earth and in the universe, and then develop theories, using mathematics, to explain why those phenomena occur. Physicists take on the challenge of explaining events that happen on the grandest scale imaginable to those that happen at the level of the smallest atomic particles. Their theories are then applied to human-scale projects to bring people new technologies, like computers, lasers, and fusion energy. Read more
News Feed on This Topic
Looking for more science fun?
Try one of our science activities for quick, anytime science explorations. The perfect thing to liven up a rainy day, school vacation, or moment of boredom.Find an Activity