Tennis balls elasticity

[mathre1122]

My project is due December 15, 2009 and I need an interview, quick!! The question is, What effect will varying the different brands of tennis balls have on the amount of time it bounces and how many times it bounces.

[MelissaB]

Hi,

Please see Science Buddies' policy on interviews: https://www.sciencebuddies.org/mentorin ... =26&t=4488 . An expert mat help you, but if they choose to do so they will not be able to give you their contact information.

Good luck!

[deleted-71547]

Hello mathre1122,

The question is also vague. Did you really mean "brands" or materials and types used for the tennis ball? Did you really mean the amount of time a tennis ball bounces or the speed of the tennis ball? If you focus on the number of times a ball bounces, you can simply conduct your own experiment, although you will probably need several tennis balls of varying brands.

If you want to investigate the speed, I'm sure you know that the speed of a tennis ball is not just affected by the brand and material of the ball but also by the power that the tennis player puts into the ball. Yahoo Sports reported that Venus Williams managed to serve a ball at 128 mph.

Then, the speed of the ball also changes during it's flight from the racket to the other court. Instead of interviewing general physics teachers like us, it would be more helpful for you to interview tennis players and ask their preferences about brands. You can specifically ask the player if such a preferred brand can make their serves faster. Then, you can verify their perceptions by using sports radar sensors or radar meters that are utilized in tennis courts.

Once you get your data, you can make comparisons of different brands. Of course, you will need someone who can hit those tennis balls with a fairly consistent force. Again, use a radar sensor to ensure that the swings of the racket for each ball would be precisely similar.

Good luck

[sciencebuddy]

Hmm, I interpreted it as dropping the tennis ball from a certain height and counting the number of bounces/the height of each bounce.

From wikipedia: Tennis balls begin to lose their bounce as soon as the tennis ball can is opened and can be tested to determine their bounce. A ball is tested for bounce by dropping it from a height of 100 inches (2.5 m) onto concrete; a bounce between 53 and 58 inches (1.35 - 1.47 m) is acceptable (if taking place at sea-level and 20°C / 68°F; high-altitude balls have different characteristics when tested at sea-level). Modern regulation tennis balls are kept under pressure (approximately two atmospheres) until initially used.

So an interesting experiment would be to see how time after opening the can will affect the bounce. Is it a drastic effect? After 1 day, no probably not. After a month, it should be noticeable I would think.