JHolsted20
Registered: November 2012
Posts: 1
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Imagine the tennis grand slams without the pros. What if Roger Federer, Rafael Nadal, the Williams Sisters, and other big names in the world of tennis just decided they did not want to show? What would Wimbledon do with the 54,500 brand-new balls they order every year (Rainey)? The Australian Open’s 48,000 they ordered ("Event Guide - Australian Open Tennis Championships 2012 - Official Site by IBM")? The millions of dollars spent every year for balls would just be a waste. Is it really necessary that these major grand slams and the average player to buy new balls every time they have a new game? The International Tennis Federation (ITF) requires that if a ball is dropped from 100 inches (254 cm) in a sixty-eight degree Fahrenheit (20°C) room onto a concrete floor, it must bounce back between fifty-four (135) and fifty-eight (147.5) inches to be considered “good” enough for competition ("ITF Tennis - Technical - Rebound"). Companies that specialize in recharging of tennis balls that do not bounce that high help in repressurizing the balls so they can be “good” enough for competition. My hypothesis is that the more fuzz that is on the balls, the more accurate the ball will be. The balls that are older that pass the ITF test but still have a substantial amount of fuzz on them will perform just as well has the balls that fresh out of the can. When the ball starts to lose its fuzz and do not pass the ITF test is when the ball starts to lose its accuracy. If the old balls with a substantial amount of fuzzed that have been “recharged” at businesses like Rebounces and are approved by the ITF test work just well as the new balls out of the can, this would be more eco-friendly and cost efficient option for the player. What prompted my research was that I only play tennis one season out of the year so I have a hopper full of balls that are still in good shape but are a year old or so. So I wanted to test to see if every summer that I play if it was really necessary to go out and by a few cans of balls to play a few games. I hope to achieve that I accomplish my goal of not being necessary to buy new balls every year. This goal would be more cost efficient and more eco-friendly for the environment and our landfills.
My materials in this project all have to do with the game of tennis. My dad went to Wal-Mart and bought two brand new cans of Penn Coach Tennis balls with three balls in each can. Then I went out into my hopper of balls in the garage and grabbed three Penn balls that were still in good shape. My dad and I got a two-by-four that was at least 100 (254 cm) inches high and made a giant ruler marking up every ten centimeters up to at least 160 centimeters. First, we started with the old balls and dropped them five times for each ball calculated an average and the coefficient of restitution. Then we popped the seal on the can of new balls and did the same procedure for them. If the average was between 135 and 147.5 centimeters, I considered them “good,” according to ITF standards. After we dropped the balls, my dad and I went to our local country club and used their Playmate throwing machine and tested to see the scatter pattern of the balls from the service line to the right alley line (see A4-A8). Then we shot the balls from 12 meters (distance from base line to net) to a wall to see how far they bounced back and where they hit on the wall. In Harrison, we have the headquarters of the business Rebounces. Rebounces “recharges” tennis balls back to their original state. We contacted the owner, and he was willing to recharge my old and slick balls to have those as variables. After we got the recharged balls back, we went back to the country club, shot the balls for scatter pattern, and against the wall, just like the new and old balls. After all scatter patterns where completed, I found the vector resolution of all balls to determine the accuracy of the types of balls.
My results varied all across the board. The ball drop test showed that out of the eight of the fifteen balls tested were approved by the ITF. Out of the old fuzzed balls, balls B and C were approved, and ball A got cut. Ball B averaged 141.8 centimeters, ball C averaged 135.8 centimeters, and ball A averaged 143 centimeters, missing the acceptable margin by one centimeters. All three of the new fuzzed balls passed the bounce test. Ball 1 averaged 137.2 centimeters, ball 2 141.2 centimeters, and ball 3 137.6 centimeters. None of the slick balls passed, missing the margin by a margin of 5.4 and 13.6 centimeters. Ball S1 rebounced 121.4 centimeters, ball S2 126.4 centimeters, and ball S3 129.6 centimeters. After the old and slick balls were recharged, only three of the six balls passed the test. It was not that the balls did not bounce high enough, they bounced too high. Only one of the recharged old balls passed the test. Ball RA rebounced 145.8 centimeters. Balls RB and RC rebounced 161.2 and 151.2 centimeters. They missed the margin by 14.7 and 3.7 centimeters. Two of the three recharged slick balls passed the test. Ball RS1 and RS2 rebounced 137.6 and 143.6 centimeters. Ball RS3 rebounced 151 centimeters, missing the requirement by 3.5 centimeters.
The coefficient of restitution (COR) showed that the balls had an inelastic collision with the floor. All of the ball’s COR were less than one but higher than zero. This showed that the balls had enough kinetic energy from being dropped from 254 centimeters to bounce back at least half its original distance.
The vector resolution of the balls varied all over. The center of the scatter plot was one meter from the service line and 4 meters from either alley line. The new fuzzed balls were off
center at a vector of 0.527 m at an angle of 145.978 degrees. The old fuzzed balls were at a vector of 1.105 meters at an angle of 103.102 degrees. The slick balls were at a vector of 1.36 meters at an angle of 109.583 degrees. The recharged old fuzzed balls were at a vector of 0.88 meters at an angle of 206.033 degrees. The recharged slick balls were off center at a vector of 0.773 meters at an angle of 177.567 degrees. The vector resolution showed that the new balls were the most accurate, data wise. The recharged slick and old balls were in range of being just as accurate as the brand new balls.
The balls shot at the wall all bounced back a reasonable distance from the wall. The balls bounced back a range of 3.9878 meters to 7.7244 meters. This would be like someone hitting a drop shot from the net, and the ball bouncing back in “no man’s land,” the area between the service and base line. All the balls hit in 0.6096 circle on the wall, showing that they all hit in relatively the same spot.
My data widely varied between observations. On the scatter plots, the balls, new or old, were either super, super tight or far out in some trials. The ball drop test varied the most. The ball was dropped from the same distance each time, but the same ball dropped rebounced different distances each time.
I had to do my experiment outside. I started in November just as the temperature was getting colder and windy. The temperature affects the performance of a tennis ball. If the ball gets too cold, the ball will get tight and not fly as far. The wind was a big issue. The flight patterns of the balls were affected by the wind and could have messed with my results.
What I would do differently next time would try to start my project earlier in the year when the weather is still nice and the wind is not an issue. I also could try to find an indoor tennis facility so the temperature and wind would not be factors of the experiment.
Continuations for this project could be something along the lines of temperature variance. My question would be would heating or cooling the ball to certain temperatures affect the flight pattern of the balls. I would use the average temperatures of the major grand slams around the world and see if temperature does have an effect on the balls.
The data shows that age of the ball does affect the performance of the ball. The brand-new balls performed the best at a vector of 0.527 meters at an angle of 145.978 degrees. The balls that were older but revived back to their original state performed, in my opinion, just as well as the brand new balls. The recharged old balls performed at a vector of 0.88 meters at an angle of 206.033 degrees, and the recharged slick balls were at 0.773 meters at an angle of 177.567 degrees. My hypothesis is supported by this data. It is not necessary to buy new balls every time you play a game of tennis.
I would like to say a big thank you to Bill Durst and the team at Rebounces. He is the founder and owner of Rebounces in Harrison. His mission is to keep as many tennis balls out of landfills and back on the playing field as possible. He was generous enough to let me use his facilities and services, free of charge. My project could not have been what it was without his contributions. I truly thank you.
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