Bounce Angle for a Super-ball

By Niko Pearson and Kristin Kozlowski

Abstract: Through this exploration we will be looking at what makes the best super-ball. A good super-ball should be able to conserve energy after its bounce. The best super-ball is called the Wham-O invented by Norman Stingley in 1965 and was made of Zectron, and can conserve up to 93% of its kinetic energy. We will be focusing on sizes and densities and their relation to a super-ball's bounce. Hopefully we will end up one step closer to answering the age old question of "what makes the best super-ball?"

superballs_full.jpg
Subject Author Replies Views Last Message
Halfway Point pasquinit pasquinit 0 49 Nov 29, 2009 by pasquinit pasquinit

Guiding Question

How do angle dropped, size, and density affect the bounce of a super-ball?

Hypothesis/Prediction

Angle dropped- The more vertical the angle of the drop, the higher the ball will bounce, and the smaller the distance the ball will move horizontally
Size- Size will have no significant effect on the bounce of the ball.
Density- The denser the ball the higher/further horizontally the ball will bounce.

Experimental Procedure

1. Collect any number, in this case, four bouncy balls of various sizes. Find the mass and volume of each ball.
*Vsphere = 4/3pi *r²
2. Now collect the density of each ball.
* Density = mass/volume
3. After you've done this take a high speed camera and set it up so that you can record the ball drop. (You should set up a meter in the background so you can measure how high the ball bounces).
*We suggest that you do a close up shot (so you have a close-up view of the bounce) and once farther back so you can analyze the height of the ball.
4. After capturing a bounce upload the video into loggerpro and plot points as the ball is descending and bouncing up. (If using a high-speed camera you will need to make a new calculated column of real time: Real Time = Time*30/420(or number of frames per second)). Now your graph should have a V-like shape.
5. Now you will take the slope of each side of the graph (the part where the ball's descending and the bounce-back). To be more accurate you will take to slope in chunks of points rather than one piece. The chunks should be equally spaced.
6. Now find the amount of kinetic energy conserved KE=1/2mv². To do this you will find the kinetic energy of one point on the descending side and the opposite point on the rebounding side. To find energy conserved, or percent difference, you will do ((KEdrop - KErebound)/KEdrop *100). This will tell you how much energy is conserved and from here you will discover which superball will conserve the most energy.

Experiment

Big Blue
Big_Blue_Graph.JPG

Medium Green
Med_Green.JPG


Small Multi-color
small_multicolor.JPG
"Basketball" ball


bball.JPG

Data/Analysis

Big Blue
external image x-ms-wmv.png Bounce 1.wmv

Mass of ball: 89.60g
Diameter: 4.8cm
Density: 1.55 g/cm³
Volume: 57.91cm³
Height Dropped: 100cm
KE Lost: 44.67%

Medium Green
Mass of ball: 18.14g
Diameter: 2.5cm
Density: 2.2 g/cm³
Volume: 8.18cm³
Height Dropped: 100cm
KE Lost: 19.62%

Small Multi-color
Mass: 8.87g
Diameter: 1.8cm
Density: 2.91 g/cm³
Volume: 3.05cm³
Height Dropped: 100 cm
KE Lost: 41.77%

"Basket Ball" ball
Mass: 8.34g
Diameter: 1.9cm
Density: 2.32 g/cm³
Volume: 3.59cm³
Height Dropped: 100cm
KE Lost: 55.63%

Results: From our data we discovered that the medium green super-ball was able to conserve the most kinetic energy. We were unable to determine any specific reason for this occurrence other than the fact the ball seemed to be best at reforming its shape after a bounce.

Conclusion

From our experiments we realized that if the balls have similar size the denser ball will conserve the most energy. Once, you take varying size into account however density does not have an effect. We found that out of all four of our super-balls the green one conserved the most energy. This led us to question what makes this the best super-ball? The green ball was the second least dense, and there were no other patterns to indicate what made it perform significantly better. What we do know is that an effective super-ball will conserve a great deal of energy. When a good super-ball comes in contact with a hard surface it will momentarily bend (conforming to the shape of the ground), but will immediately regain its shape, causing it to bounce back up. This is why a bag of sand wont bounce, it just hits the ground and takes the shape of what it lands on, it has no ability to rebound. This is why the basketball lost the most kinetic energy, it was squishier; therefore less able to rebound from its impact with the ground.

This experiment would have been more effective if we could have more accurately measured the dimensions of the super-balls. Knowing the composition of the super-balls that we used would have also been very helpful (The fewer the variables there are, the better). Knowing the composition would've given us better insight into why our green super-ball only lost 19.62% of its KE.

We were unable to address angle dropped, or the effect of height dropped due to time constraints. We wanted to focus more on the analysis of the data we already had.

SourcesProvide
Super-ball History (Wham-O)

Acknowledgments

Thank the people who have helped you complete this exploration.

Additional information on these sections can be found on the inquiry model page.