A soccer ball bounces so many times during a game that the characteristics of its bounce can have a huge effect on the game and its outcome. Since a ball's bounce is directly related to its air pressure, and since temperature affects air pressure, different temperatures influence a soccer ball's bounce differently.
Air Pressure and Kinetic Energy
Air pressure and kinetic energy are responsible for the way a soccer ball bounces. When a ball bounces, it compresses against the ground or whatever surface it is bouncing against. As it compresses, the amount of space in the ball for the air molecules decreases. This decrease of space forces air molecules into each other and increases air pressure inside the ball. The air pressure is exerted against the ball's exterior, which is pushed against the surface the ball is bouncing off of, creating the bounce you see as the ball decompresses back to its regular shape and flies into the air. Another way to understand the way a ball bounces is through kinetic energy. According to the Law of Conservation of Energy, energy is not created or destroyed, but only transferred. When a ball bounces, kinetic or moving energy from the ball is transferred into the ground and then back into the ball, causing it to bounce.
How Temperature Affects Air Pressure
Temperature's major effect on the way a soccer ball bounces is through its effect on air pressure. Air pressure increases in warmer temperatures and decreases in cooler temperatures because air molecules are more active in warmer settings. In other words, when the ball compresses against the ground as described in the section above, the pressure the air molecules exert on the ball's exterior is greater in warm settings than cooler temperatures. In this way, a heated soccer ball or a ball that is bouncing in warm weather will be bouncier than one in cold weather.
Ground Temperature
Ground temperature also has an effect on the way a soccer ball bounces. Consistent freezing temperatures, for example, can freeze the ground on which a soccer game is played, making the ground firmer. The firmer ground provides a harder base for the ball to bounce against and increases bounciness, but it is unlikely that a ball could stay warm in such a setting, in which case the cold ball and frozen ground would most likely cancel each other out.
Effect in a Game Situation
The bounciness of a ball can affect the way teams play. If the ball is so bouncy that it is impossible to predict, defenders are less likely to stand farther up the field (in case the ball bounces past them). Attacking players, meanwhile, are more likely to simply kick the ball forward, knowing that defenders have trouble with the ball's bounces. Goalies, meanwhile, are most at risk because they are less likely to save a ball that is bouncing enormously.
References
- University of Illinois at Urbana-Champaign Department of Physics: Q & A: Temperature affecting bouncy balls
- "Skills and strategies for coaching soccer"; Alan Hargreaves and Richard Bate; 2010
- Exploratorium: Bouncing Balls
- University of Virginia Department of Physics: The Effect of Temperature on a Bouncing Ball
- Exploratorium: Bouncing Balls
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