Surface Science: Where Does a Basketball Bounce Best?
Playing basketball can be hard work. Players not only constantly run around the court, but just dribbling the basketball takes effort too. Have you ever wondered why that is? It has to do with how the basketball bounces. When the ball hits the court, its bounce actually loses momentum by transferring some of its energy into a different form. This means that to keep the ball bouncing, players must continually put more energy into the ball. In this activity, you will explore how high a basketball bounces on different surfaces compared to the height from which it was dropped. Which surface lets the basketball bounce the highest? Grab a basketball and try this activity to find out!
This activity is not appropriate for use as a science fair project. Good science fair projects have a stronger focus on controlling variables, taking accurate measurements, and analyzing data. To find a science fair project that is just right for you, browse our library of over 1,200 Science Fair Project Ideas or use the Topic Selection Wizard to get a personalized project recommendation.
Playing a game of basketball is hard work, and one part of that workout comes from just dribbling the ball. Why is this? When a basketball hits the ground (and as it flies through the air), it actually transforms some of its energy to another form. If players do not put enough energy back into the ball, they will not be able to dribble it effectively.
When a basketball bounces, it has two different types of energy: kinetic energy and potential energy. Kinetic energy is the energy an object has due to motion. Potential energy is the energy stored in an object due to its height above the ground. For example, when you hold a basketball at waist level, it has some potential energy. If you drop the basketball, the force of gravity pulls it down, and as the ball falls, its potential energy is converted to kinetic energy. When a basketball hits a court’s floor, some kinetic energy gets converted into energy in the form of sound, heat and briefly changing the shape of the ball (flattening it slightly). Some of the energy is also absorbed by the court’s surface.
Extra: Try to quantify your results from this activity. To do this, you’ll want to videotape your bounce trials and closely watch the videos on a large screen to determine the exact height of the basketball before being dropped, and the highest point in its first bounce. You could even graph your results. Exactly how high does the basketball bounce on the different surfaces?
Extra: You could try this activity again, but instead of investigating different surfaces, try bouncing a basketball at different temperatures. You could try storing a basketball in a refrigerator or freezer, and then bouncing it. Compare its bounce height to a basketball that was stored at room temperature. How do the bounce heights compare when the basketball is at different temperatures?
Extra: A basketball loses kinetic energy by transferring it to other forms when the ball bounces. But just how many bounces can a basketball make before losing all of its kinetic energy and stopping bouncing? And how does this change if you alter some factors, such as the surface the basketball bounces on or the drop height? Design an experiment to investigate how many bounces a basketball can make and how various factors affect that number, then try it out!
Observations and Results
Did the basketball bounce much higher on the harder surface compared to the softer one?
One factor that can affect the basketball’s collision with the ground is the type of surface the ball collides with. When a basketball bounces on a surface, some of its energy is absorbed by the surface. How much energy gets absorbed determines how much energy a player has to put back into the ball to keep it bouncing. A hard surface, like concrete, absorbs less energy compared to a soft surface, like carpet. The more energy that gets absorbed by the surface, the less energy remains in the ball for it to bounce. This is why you should have seen that when the basketball was bounced on a relatively hard surface it bounced higher (it lost less energy) compared to when it was bounced on a softer surface (where it lost more energy). For example, depending on the exact basketball and surfaces, you may have seen the ball bounce about 15 inches high on carpet and about 25 inches high on concrete.
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Teisha Rowland, PhD, Science Buddies
Science Buddies |
Energy, gravity, collisions, sports
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