mark cuban sheds light on the new ball

[playstation]

from his blog, you've got to give it to him, he always tries to bring science to the table:

NBA Balls....

Oct 27th 2006 8:57AM
I asked the University of Texas at Arlington Physics department to take a look at both the new and old NBA basketballs. I asked them to compare the 2 and let me know what they thought. No preconceived notions. No prejudice. Just science.

Below is their data and response. Before you get to it, i wanted to give my conclusions.

1. Keep the ball. Its not perfect, but it would create more hassles than it solves to change.
2. Check every floor in the NBA for "dead spots" and make sure the floors are consistent. This ball will be more impacted by soft spots on the floor.
3. Rather than waiting to see how moisture impacts play and if it creates turnovers, recognize the properties and advantages of the ball, that it is the same regardless of how old or new, and change out the balls at halftime, at the end of quarters, or when it gets wet. Just like they do in baseball and football.
4. The balls retain dirt. Lots of it. By the end of a game or two, the nets look like there have geen kids throwing dirt at them. We need to find a way to keep the balls clean and let every team know so if a fan touches one after a game they dont get grossed out. Changing the balls can help alleviate this problem.
5. AFter this season, look at the embossing and layout on the ball and see if there is a better option. This will make the new ball bounce "true" when compared to the old ball.

Here is the report and a big THANK YOU to UTA and all the hard work they did. They are a first class program and did a wonderfully thorough job

October 26, 2006: MavBalls Investigation

Executive Summary:

Thus far, over the period October 14-present, through various tests, we have determined four major performance differences between the old leather balls and the new synthetic balls provided to us by the Dallas Mavericks organization. It should be noted that the leather balls provided were not new, but rather had been used for extended periods, whereas the synthetic balls provided were brand new.

(1) The two types of balls have different heights of return bounce when inflated to the same pressures and dropped from identical heights. The new synthetic balls display measurably reduced return height than the leather balls - about 5% less on average, when dropped from about four feet. Our compression measurements also indicate differences in elasticity. The difference in bounce heights may translate to effects on players' reactions and handling in terms of dribbling, passing, rebounding off the backboard, bouncing off the rim, etc.

(2) The surface of the synthetic balls display a factor of two higher coefficient of static friction when both leather and synthetic balls are dry. This characteristic would make the synthetic balls easier to grip (stickier) than the leather balls, when dry.

(3) However, with a few drops of added moisture on the surface of each type of ball, the new synthetic balls have a coefficient of friction which is at least 30% smaller than similarly moistened leather balls. We have also measured the moisture absorption rate, which confirms that the synthetic ball absorbs moisture at a much slower rate, leaving more of the moisture on the surface. Therefore, when wet, the synthethic balls are much harder to grip and handle (slippery). By contrast, our measurements indicate that the grip of the leather ball improves after similar moistening.

(4) The synthetic balls bounce more erratically (i.e., at a wider range of angles) off floors. Preliminary measurements suggest about 30% greater deviation in the position of the synthetic ball after a bounce. More tests are scheduled to quantify this precisely.

All the above conclusions should be considered preliminary and subject to revision since we are still actively testing.

Details of Measurements:

(1) We have measured the size and weight of the two types of balls - they are essentially identical in these base characteristics (less than 1% difference). The conditioned leather balls and synthetic balls have similar patterns on the surface. However, prior to use/conditioning, the leather balls display a spherical appearance to the "pebbling" -- instead of the flatter apperance seen in conditioned leather balls and synthetic balls.

(2) Tests have shown that the synthetic ball bounces back

lower by 5-8% when dropped from a height of little over four feet, depending on the hardness of the floor. Specifically, for a hard linoleum floor with concrete underneath, the leather ball bounced back an average distance of 2.2 inches higher compared to the synthetic ball, when dropped from a height of 4 feet 3.7 inches. The coefficient of restitution is 0.81 for the leather ball at this height, increasing monotonically to 0.85 for successive bounces till they reach approximately one third of the drop height. The coefficient of restitution for the synthetic ball was 0.79-0.84 over the same range of heights. The difference in bounce was more pronounced (increasing to 4 inches) on softer, more pliant floors.

(3) In order to compensate for the difference in bounce, we re-tested the basketballs by overinflating the synthetic balls. The synthetic ball had the same bounce characteristic as a conditioned leather ball when overinflated to 14 psi (the required overinflation depends on the hardness of the floor). The leather ball was inflated to the recommended pressure of 8.5 psi for comparison.

(4) The bounce test was repeated with a new (unconditioned) leather ball. We found that the unconditioned leather ball had similar coefficient of restitution to the synthetic ball at same inflation -- that is, both bounced back essentially to the same height. We conclude that the conditioning of leather balls increases their bounce. However, thus far, we have not attempted to condition our new leather ball and repeat the tests.

(5) The synthetic balls absorb water at a much slower rate, averaging 8.6 grams per minute. The conditioned leather balls will absorb water more rapidly, about 70 grams within a minute. After quasi-saturation at these water masses, the leather balls absorb water at a much slower rate than the synthetic balls, averaging 3.3 grams per minute.

(6) We have performed compression tests of all the balls. The data is being analyzed. Qualitatively, we find that the leather balls compress more easily under the same load, compared to the synthetic balls. The compression is linear over reasonable range of forces; we are in the process of quantitatively determining the elasticity.

(7) Initial friction tests show a much higher coefficient of friction for the synthetic ball when dry. The coefficient of friction between the surface of the synthetic ball and a silicon surface (medical literature shows silicon to have a friction coefficient similar to the human palm) is about 3.2, for our experimental setup. The friction coefficient is 1.69 for the leather ball, using the same procedure.

(8) Friction tests with liquids such as Visine (which has viscosity higher than water, similar to human tear drop, possibly closer to sweat) applied to the silicon (one drop per 2"x2" area) show that the coefficient of friction increases for the leather ball. After repeated application of moisture to the leather ball, the coefficient increased gradually by at least 30%, thereby making it more "gripable". After quasi-saturation. adding drops reduced the coefficient by 20%, relative to a dry ball. However, for the synthetic ball, the coefficient of friction reduces immediately by 55% with the first drop of liquid. A larger reduction is seen with repeated application of liquid. In conclusion, the wet synthetic ball is significantly more slippery compared to wet leather balls.

(9) During our bounce tests, we observed that the synthetic ball bounced more erratically compared to the leather ball. Preliminary data shows an average horizontal deviation (near the apex after the bounce) of 15 mm for the leather ball, and 22 mm for the synthetic ball, after bouncing off the floor. Examination of the surface characteristics of the synthetic ball showed that more than 20% of the surface is embossed with text and logos to a depth of a few millimeters. We speculate that the more uneven surface of the strongly embossed synthetic balls is the principal cause for the erratic bounces in our tests. The surface of the leather ball is far more consistently spherical and even. We are continuing to improve these measurements.

Future tests:

(a) Continuing studies of friction to quantify the loss of

grip when the synthetic ball is wet.

(b) Wind tunnel test of aerodynamic drag is scheduled for

later this week.

(c) Futher quantitative measurement of erratic bounce is scheduled for next week.

(d) Repeat the bounce test (coefficient of restitution) at the American Airlines Center, if possible.

(e) All other tests are being repeated or redone with

increased precision.

Preliminary recommendations:

Based on our measurements so far, we would recommend that the embossing of the synthetic ball should be discontinued, to reduce erratic bounces. The material of the synthetic ball should be made more moisture absorbent, to increase friction and associated "gripability" when the surface is wet. The thickness of the rubber backing could be reduced to increase bounce. These relatively minor changes in manufacturing, it seems to us, would meet the dual needs of a more uniform low maintenance ball desired by the league with the performance characteristics approximating those which the players are accustomed to and prefer.

General comments about our measurements:

All tests were done with the balls inflated at 8 or 8.5 lbs. For comparisons shown above, old and new balls had the same inflation. Every measurement has been or will be repeated multiple times. We will include an estimate of errors in the next report. We used the following sample of balls for our studies: three conditioned leather balls provided by the

Dallas Mavericks, three new synthetic balls provided by the Dallas Mavericks, two new (not conditioned) official NBA leather balls purchased by us, and one new official NBA synthetic ball purchased by us. At this stage, please note that all measurements should be considered preliminary.

Kaushik De and Jim Horwitz

and the UT Arlington MavBalls Team

Department of Physics

The University of Texas at Arlington

 

[arthurracoon]

that was pretty interesting

 

[Errntknght]

I guess its just 'science', as Cuban claims, but it isn't particularly good science if the testing isn't done on real NBA basketball floors or the balls aren't all 'conditioned' the amount NBA game balls are - its silly to leave such easily controllable factors in play. It sounds like they are guessing about the embossing causing the erratic bounces - the standard deviation of the measurements, which they didn't mention, should settle that question. (The trouble is they didn't get the math department involved!)

I wonder what the players have to say after using the ball in the preseason games and practices. That is far and away the most meaningful test. I'd be interested in seeing a breakdown of the players' opinion by position - it could be that centers love it and PGs hate it.

 

[elindholm]

Don't worry, physicists know about standard deviations as well.

De does high-energy physics and Horwitz does astrophysics, both of which are more theoretical than classical mechanics. (Well, almost anything is more theoretical than classical mechanics, but you know what I mean.) If your motivation in collecting data is to make a general assessment as to whether it supports a theory, error bars aren't so important. And the "MavBalls Team" is probably students -- it's inconceivable to me that faculty at a research institution would take time off for a silly project like this, especially while the semester is in progress.

Nonetheless, assuming they did an adequate number of trials, the difference in the friction coefficient of slightly wet balls is striking. Nash used to lick his fingers hundreds of times a game to improve his grip on the ball, but if these data are meaningful, that's a habit he'll want to cut out fast.

I wonder if the shooters who pre-tested the ball (Reggie Miller, Steve Kerr, and someone else I can't remember) didn't work up enough of a sweat to notice the slipperiness. It seems that should be very striking after even a brief session of handling under game conditions.

 

[nowagimp]

Don't worry, physicists know about standard deviations as well.

De does high-energy physics and Horwitz does astrophysics, both of which are more theoretical than classical mechanics. (Well, almost anything is more theoretical than classical mechanics, but you know what I mean.) If your motivation is collecting data is to make a general assessment as to whether it supports a theory, error bars aren't so important. And the "MavBalls Team" is probably students -- it's inconceivable to me that faculty at a research institution would take time off for a silly project like this, especially while the semester is in progress.

Nonetheless, assuming they did an adequate number of trials, the difference in the friction coefficient of slightly wet balls is striking. Nash used to lick his fingers hundreds of times a game to improve his grip on the ball, but if these data are meaningful, that's a habit he'll want to cut out fast.

I wonder if the shooters who pre-tested the ball (Reggie Miller, Steve Kerr, and someone else I can't remember) didn't work up enough of a sweat to notice the slipperiness. It seems that should be very striking after even a brief session of handling under game conditions.

I can appreciate some of the tesing and findings, though these are not fully anayzed, or at least disclosed. Statisticians would probably do better in analyzing the data, while physicists would do better in designing the tests with the exception of perhaps a multiblock ANOVA, which is generally beyond their understanding. Who cares, what the tests show is what everyone already knew: The new balls are grippier when dry, much less so when wet(how wet really matters here, but no def was provided), and suprise: the leather balls are grippier when wet. Gee, duh, I guess thats why Nash licks his fingers before foul shots. Better not do that anymore stevie, the new ball gets more slippery when wet, the opposite of what you expect. And watch those one-handed wrap around passes, when the ball is just a little wet, its a TO.

But not to worry, I'm sure the NBA saves alot of money, maybe even gets a sweet kickback deal from spaulding when all the kids out there use them so they can have an "official" ball.. Other sporting goods companies will be trying for a few years to get the formulation for the new ball "right". In the meantime, only spaulding will have a "real" NBA basketball(monopoly). Thanks alot bean-couter lawyer-jerk David Stern, you have screwed up the dynamics of NBA basketball.

Oh yeah, and Reggie and Steve Kerr are a couple of David Stern model shop vacuums, just sucking up.

 

[Errntknght]

Eric, "If your motivation in collecting data is to make a general assessment as to whether it supports a theory, error bars aren't so important."

I think you just made my point - the use I was contemplating of the standard deviation had nothing to do with error bars! In terms of statistics their speculation that the embossing causes the problem means that when the embossed logo isn't part of the contact then ball is about as erratic as the old ball but when it is then the new ball is considerably more erratic - i.e. you are mixing two distributions. That would show up in comparing histograms but it should also be apparent from the std. deviations. If the new ball just generally magnified the amount of deflection from a true bounce the ratio of the std. devs would be the same as the ratio of mean deflection (22/15) but if you were mixing, say, 70% of one distribution with 30% of another then the ratio of the std. devs would be significantly higher than that. (Of course, if the ratio were higher that wouldn't prove the embossing caused it, but if the ratio were the same then it couldn't be the embossing contacting the floor. It might be the embossing contributing to uneven weight distribution, however, or altering the aerodynamics.)

(Gee, I hope I'm not treading, unknowingly, onto multi-variate statistics' ground here or I'll surely get pounced on again.)

 

[JCSunsfan]

Sorry to interrupt the geeks argument here but. . .

So we should,

inflate that ball more so it has the same "bouncability" as the leather ball.

and,

change the ball out regularly. Maybe twice a quarter and whenever a team in possession requests it (on a dead ball).

Its not like the teams can't afford it.

The immediatesolution to this problem isn't rocket science (or should I say physics or statistics).

 

[Errntknght]

I think the players should have the primary say in the decision - whether its going back to the old ball or how to adjust the new ball. Its pathetic that the league didn't take that approach from the beginning - shows you what happens when a lawyer is in charge.

 

[nowagimp]

Eric, "If your motivation in collecting data is to make a general assessment as to whether it supports a theory, error bars aren't so important."

I think you just made my point - the use I was contemplating of the standard deviation had nothing to do with error bars! In terms of statistics their speculation that the embossing causes the problem means that when the embossed logo isn't part of the contact then ball is about as erratic as the old ball but when it is then the new ball is considerably more erratic - i.e. you are mixing two distributions. That would show up in comparing histograms but it should also be apparent from the std. deviations. If the new ball just generally magnified the amount of deflection from a true bounce the ratio of the std. devs would be the same as the ratio of mean deflection (22/15) but if you were mixing, say, 70% of one distribution with 30% of another then the ratio of the std. devs would be significantly higher than that. (Of course, if the ratio were higher that wouldn't prove the embossing caused it, but if the ratio were the same then it couldn't be the embossing contacting the floor. It might be the embossing contributing to uneven weight distribution, however, or altering the aerodynamics.)

(Gee, I hope I'm not treading, unknowingly, onto multi-variate statistics' ground here or I'll surely get pounced on again.)

I think you are thinking right about this Errntknight. Different responses indicate a heterogeneous distribution that is not amenable to an analysis of variance which requires a homogeneous distribution. I would also like to add that dropping the ball for "bounce testing" is probably not good enough. What happens when the player forcably dribbles as in a crossover move? Is the return velocity similarly linear with force in the two balls, or more likely is the return velocity decidedly more nonlinear in one of the balls(bad). Are the distributional statistics changed by incident velocity deviations? Dribbling the ball is not like dropping the ball, and "wet" is a very subjective term. How wet was the ball? Some floors are a little wet and some are wet enough to prevent friction between your feet and the floor(you will fall). The more I think about this little study, the more I dont like it, its a sham. Its obviously does not represent the use of the ball under conditions in the NBA. When I dribble a basketball, it hits the floor harder(not a drop) at the times I'm moving the fastest, which are the times that it is hardest to control. That aspect was not tested at all, shame on those scientists. Maybe they need to find some physicists who know how to play ball so they can design a relevant experiment. These guys apparently do not. Apparently some poor graduate student drew the short straw on a project that will not count towards his thesis.

They should: examine different ball/floor velocity responses around the approximate "NBA speed", and quantify slip behavior under different levels of wetness. Then, the appropriate statistical analysis should reveal the relative behavior of the new ball vs the old one under NBA conditions.

 

[Errntknght]

I don't think one should worry overly about a scientific analysis at this point. Sure, when you're first experimenting with designs you should use a variety of tests to get you into the ballpark but the final test is how it behaves is actual use. It doesn't appear that Spaulding and the league did their due diligence on this decision - looks marketing driven to me.

 

[elindholm]

Is the return velocity similarly linear with force in the two balls

The return velocity had better not be linear with force...

 

[nowagimp]

Is the return velocity similarly linear with force in the two balls

The return velocity had better not be linear with force...

Thats why the next comment was which one is "more nonlinear", get it? Similarly linear was meant to asses a "degree on linearlity", not claim true linearity. Many physicist "linearize" data with a math transform, but that does not necessarily make it truely linear. Still it seems obvious, as Errnknght stated, that a standard deviation comparison is not appropriate for a heterogeneous distribution of bounces, right?

 

[sly fly]

I suddenly feel very inadequate.

 

[Errntknght]

nowagimp, "Still it seems obvious, as Errnknght stated, that a standard deviation comparison is not appropriate for a heterogeneous distribution of bounces, right?"

I wish I knew what you mean... I'm not at all sure I said that.

 

[elindholm]

I think what nowagimp meant was that, allegedly with the synthetic ball, you have really two superimposed distributions: one for when it lands on a design and one for when it doesn't. So it probably isn't possible to represent the variance in that distribution adequately with a single number for sigma.

 

[nowagimp]

nowagimp, "Still it seems obvious, as Errnknght stated, that a standard deviation comparison is not appropriate for a heterogeneous distribution of bounces, right?"

I wish I knew what you mean... I'm not at all sure I said that.

Sorry, assumed that you meant that because the synthetic ball bounces differently on the emblem, that the use of standard deviation comparisons to assess equivalence in the behavior of the synthetic and leather balls is irrelevant. It does seem obvious however that a ball that bounces less consistently is harder to control, especially when its handling characteristics degrade when wet. My suspicion is that its even worse when you bounce it with energy, that the differences in ball velocity off a bounce become more exagerrated, which was the point I was trying to make in the previous post about nonlinearity. I was just using the correct statistical terminology in case a statistician was out there. That said this little research project of cubans seemed to be designed to answer questions for people, but not about the real performance of the ball. The best ballhandler in the game is telling everyone about the ball, and no-one is listening. I guess its either that or he's a headcase. I know what I believe.

 

[nowagimp]

I think what nowagimp meant was that, allegedly with the synthetic ball, you have really two superimposed distributions: one for when it lands on a design and one for when it doesn't. So it probably isn't possible to represent the variance in that distribution adequately with a single number for sigma.

Exactly, Eric! But seriously, I support further testing of the ball under greater kinetic variation to characterize the changes. I think it may take awhile.

 

[tobiazz]

inflate that ball more so it has the same "bouncability" as the leather ball.

and,

change the ball out regularly. Maybe twice a quarter and whenever a team in possession requests it (on a dead ball).

A) I don't know how much bouncability corresponds with hardness, but overinflation may have any number of unwanted side effects.

B) They should swap the ball out often, but it may not alleviate the problem since the players hands will remain sweaty and the new ball does not readily absorb moisture.

 

[Mainstreet]

I think the players should be allowed to select the balls they are going to use before the game and a ball cleaner (such as in a bowling alley) be used to clean the balls during the game.

Really, are two manufactured products ever really alike although they are supposed to be made to the same specs? Even so, aren't balls frequently changed in many sports because of wear factors?

I really think this is a money making venture like changing team jerseys every so often. IMO, a new an improved version will be on the scene in another year or so necessitating wannabes to buy the newer 2.0 version. I'm still waiting for the ABA basketball to make a comeback.

 

[Errntknght]

nowagimp, "Sorry, assumed that you meant that because the synthetic ball bounces differently on the emblem, that the use of standard deviation comparisons to assess equivalence in the behavior of the synthetic and leather balls is irrelevant."

You are assuming the embossed emblems cause more erratic bouncing while the question I was addressing is whether or not the embossed emblem hitting the floor does in fact, cause it, so I was right about you attributing to me something I was a long way from saying - intending to say, at any rate. The testers attributed the greater deflections than the old ball had to that, without offering anything to substantiate it. I argued that using the std. deviations and means instead of just the means offered a way of testing that assumption - so I was hardly saying that the std. deviations were irrelevant. What I'm calling an assumption they called a speculation, which comes out to about the same thing. Of course, they could run more controlled tests and test it directly but why not use all the information you can wring out of the existing data.

Personally, I think if the logo embossing plays a role its because it changes the weight distribution, making it less uniform. I know from playing with those cheap plastic balls you buy at the grocery store that uneven weighting can have very pronounced effects. Ever try to dribble one of those things? Heck, the way they did the tests the main contribution could be from aerodynamic effects - that would much diminished when a player was dribbling the ball so the players might well detect little change from the old ball in that regard. Of course, it ought to wreak havoc with shots and that hasn't been reported yet.

 

[Errntknght]

Eric, "I think what nowagimp meant was that, allegedly with the synthetic ball, you have really two superimposed distributions: one for when it lands on a design and one for when it doesn't."

I'm not sure what he is saying but 'superimposing' two distributions is what I called 'mixing' two distributions so I understand that just fine. The sigma of the resulting distribution is perfectly adequate for the purpose I advocated - namely trying to determine whether or not you were looking at mixed distribution of a particular kind. I wouldn't disagree that once you've established a mixed distribution and measured its parameters then that gives you a better representation of the distribution than a single mean and sigma - how could it not. Still the resulting distibution mean and sigma are still valid and adequate for most statistical purposes.

Team shooting stats are mixtures of the individual players stats but that doesn't mean you always have to break it down to that level. Sometimes you want to break it down to those components and other times that would just muddy the water.

 

[JCSunsfan]

Eric, "I think what nowagimp meant was that, allegedly with the synthetic ball, you have really two superimposed distributions: one for when it lands on a design and one for when it doesn't."

I'm not sure what he is saying but 'superimposing' two distributions is what I called 'mixing' two distributions so I understand that just fine. The sigma of the resulting distribution is perfectly adequate for the purpose I advocated - namely trying to determine whether or not you were looking at mixed distribution of a particular kind. I wouldn't disagree that once you've established a mixed distribution and measured its parameters then that gives you a better representation of the distribution than a single mean and sigma - how could it not. Still the resulting distibution mean and sigma are still valid and adequate for most statistical purposes.

Team shooting stats are mixtures of the individual players stats but that doesn't mean you always have to break it down to that level. Sometimes you want to break it down to those components and other times that would just muddy the water.

"All morons" --- Vizzini

 

[nowagimp]

nowagimp, "Sorry, assumed that you meant that because the synthetic ball bounces differently on the emblem, that the use of standard deviation comparisons to assess equivalence in the behavior of the synthetic and leather balls is irrelevant."

You are assuming the embossed emblems cause more erratic bouncing while the question I was addressing is whether or not the embossed emblem hitting the floor does in fact, cause it, so I was right about you attributing to me something I was a long way from saying - intending to say, at any rate. The testers attributed the greater deflections than the old ball had to that, without offering anything to substantiate it. I argued that using the std. deviations and means instead of just the means offered a way of testing that assumption - so I was hardly saying that the std. deviations were irrelevant. What I'm calling an assumption they called a speculation, which comes out to about the same thing. Of course, they could run more controlled tests and test it directly but why not use all the information you can wring out of the existing data.

Personally, I think if the logo embossing plays a role its because it changes the weight distribution, making it less uniform. I know from playing with those cheap plastic balls you buy at the grocery store that uneven weighting can have very pronounced effects. Ever try to dribble one of those things? Heck, the way they did the tests the main contribution could be from aerodynamic effects - that would much diminished when a player was dribbling the ball so the players might well detect little change from the old ball in that regard. Of course, it ought to wreak havoc with shots and that hasn't been reported yet.

You raise some interesting points that I hadnt considered. One that I think is important, having played some ball, is that the deformation of the new ball is 30%(?) lower. This means that it behaves more elastically under collision, like a superball(in the limit). This is very undesirable as the velocity differential between a soft and a hard dribble will be greater, where as in the case with greater inelastic behavior the return velocities will not increase as sharply with increased dribble energy. You can deflate the ball some but it will become more of a light touch ball on the dribble. Problem there is the NBA is not very light touch, just watch DWade fall a few more times.

One final note is that if they tell you the new ball is 15% different at some parameter, no-one has a reference for how that impacts the behavior of the ball under NBA conditions. This whole thing is an experiment, and I resent that they would do this at a time that the suns seem to have everything going for them, and a short Nash window of opportunity. A young kid coming into the league has everything to learn, while an old vet who handles the ball needs to re-learn his craft, to some extent. Generating stats about the ball in this case just leads to a subjective answer without real meaning. If Cuban is doing this for the good of the NBA and not to mollify fans, I will gain newfound respect for him. The problem is that the NBA will use this ball for this whole year and I think that the re-design of the NBA ball is going to be an evolving process that, at least temporarily, degrades the quality of play.

 

[Errntknght]

I hope this doesn't set JCSunsfan off again. At least he has the self-knowledge to include himself...

nowagimp, "One that I think is important, having played some ball, is that the deformation of the new ball is 30%(?) lower. This means that it behaves more elastically under collision, like a superball(in the limit)."

Where did you get the information that the new ball deforms less than the old one? In any case, the fact that it does not bounce back as much as the old one indicates that it is less like a super ball than the old one. As far as elasticity goes, they are both close to perfectly elastic as they do keep returning to their original shape - they'd be the devil to play with if they didn't. I don't think elasticity per se has anything to do with how well a ball bounces - a ball made out of 'memory foam' wouldn't bounce to speak of but it would eventually return to its original shape so it is quite elastic. IIRC, nerf balls behave much like that.

 

[Louis]

In light of all these comments...

How many here have actually own the new ball or have had the oppurtunity to play with it?