Anyone aware of any testing of balls and the results of that testing performed on balls before the cork center ball came in 1910-1911.
Anyone aware of any testing of balls and the results of that testing performed on balls before the cork center ball came in 1910-1911.
First I want to thank you for contacting me about this discussion and giving me the link to register and welcoming me to the discussion along with the others.
The Sherwood comment about additional research was in the Discover Magazine article by Curtis Rist, who did a lot of research of his own to put together a balanced article. The quote is at the end of the second to last paragraph of the article, May 2001, Vol. 22, No. 5, "The Physics of Baseballs", p. 26-27.
"For his part, Sherwood has run a battery of tests on balls dating back to the 60s, but he won't say when he will release the results. "That's privileged information," he says."
Shoelessjoe3, maybe you should track down Dr. Sherwood and see if he will join the discussion.
Last edited by Bill Burgess; 08-01-2007 at 07:32 AM.
This is very interesting stuff!! One thing I wanted to add about the liveliness of the balls is that in softball there are two components that are used to test the liveliness of the ball: COR and Compression. Balls with a higher compression are livelier than low compression balls. ASA tests indicate that compression appears to impact the liveliness of the ball more than COR.
I don't know if the ball compression varies much in regards to baseballs but if they do, that's something else to consider.
"Batting slumps? I never had one. When a guy hits .358, he doesn't have slumps."
Rogers Hornsby, 1961
Here is an artcile about the Copper Union tests done in 1953.
Near the end of the 1961 season there was again talk of a lively ball since Maris and Mantle were assaulting the record books. So once again another scientist took a look at the balls. The NYT wrote 3 page article about it. Here is the third page with the data. The COR was .5534 for a 34 year old ball, .5672 for a 25 year old ball, .5517 for a one year old ball, and .5638 for the 1961 ball
That equates to a COR of .567 for the 1953 balls and a COR of .548 for the 1952 balls. This article mentions the difference in compression as a factor too.
"Batting slumps? I never had one. When a guy hits .358, he doesn't have slumps."
Rogers Hornsby, 1961
Here is a little blurb about the 1987 ball which again says the change could very well be the stitching. The leagues did a test midway through the season for COR and found no change. I haven't found that study yet.:
Another thing I have seen so far is that the seams also play a role in this, in terms of distance traveled and not just on the pitchers ability to control the ball.
Great articles, Ubi. Things just keep getting more curiouser and curiouser ... and livelier and livelier.
With respect to the compression issue, I do believe it can play as significant role, for both balls and bats. Somewhat related may be the "trampoline effect," prominently demonstrated [more extremely] by longer hits off aluminum bats.
What appears to have happened over the years is an ever-changing admixture of both deliberate and inadvertant changes in ball manufacture. One thing's for sure, the Leagues have long known how to tweak the ball, if they were so inclined.
Some numbers from all of MLB, AL and NL, a couple of years before and after that 1987 explosion.
1987 we see 645 more home runs than in 1986.
1988 we see 1278 less home runs than 1987.
I can't say it was the ball, all kinds of theories over the years even the weather and the atmosphere.
The drop, the coming back to the real world 1278 less home runs hit in 1988 compared to 1987, a correction or change in the strike zone. OK I'll give MLB that one. But how do they explain the leap from 1986 with 3813 to 4458 home run in 1987.
To my knowledge the rule book strike zone was the same in 1986 and 1987.
Add to that all of MLB in one season 1987 (.263) hits for five points higher than just the previous season 1986 with .258.
Sorry it has been awhile, but the posts tended to die down and I got a bit sidetracked IRL
Ubi had asked about the weight of the pills and I had tried to get additional information. It was brought back to the forefront when i received an email from Eric Walker, who is the webmaster for the following sites:
Steroids and Baseball: http://steroids-and-baseball.com/
The High Boskage Baseball Web Site: http://highboskage.com/
His correspondence reminded me about the converssation started here.
I suspect that James Sherwood did not come along for a visit.
Here is the study as written for publication by Dr. Chris Brown of the URI chemistry Department. Eric is interested in extending the experiment and he will also publish the paper at his website. Unfortunately the images in the report cannot be inserted, so you may have to go the Eric's website to view it or I can send it as an attachment to an email. My email: firstname.lastname@example.org
The Changing Anatomy of
Major League Baseballs
Chris W. Brown, Scott W. Huffman, and Kara Lukasiewicz , Department of Chemistry
Dennis C. Hilliard, R.I. State Crime Laboratory
Linda M. Welters and Margaret Ordoñez, Department of Textiles, Fashion Merchandising and Design
Otto J. Gregory and Michael J.Platek, Department of Chemical Engineering
University of Rhode Island
Kingston, RI 02881
America’s pastime sport of baseball has always held a certain mystique. The infamous spitballs or grease balls often bring objections from the home plate umpire. The secret hand signals from the manager to the third base coach to the second base runner appear to be a bit of wizardry. These signals are not much different than the one-, two-, three- and four-finger signals from the catcher to the pitcher, who keeps shaking his head until he receives the desired number of fingers. The current craze is batters who tug at and re-adjust their batting gloves after every pitch or simply jump out of the batter’s box as soon as the pitcher is ready to deliver.
Although much of the mystique still exists in baseball, considerable change has taken place during the century or so since the sport's introduction. The most notable development in recent years has been the smashing of homerun records several times in as many years. The record-breaking number of homeruns accompanies an increase in extra base hits relative to the number of single base hits. In the early 1900s, the "power factor" --the average number of bases per hit over a season--was about 1.30.1 After World War I, the average moved up to about 1.4 during the Babe Ruth era and stayed there until it decreased during World War II. After this war, the power rating increased to about 1.45 and stayed close to this average until the 1990s. Since 1994, the power rating has been greater than 1.55. The average number of runs scored per major league baseball game during the eight-year span from 1994 to 2001 increased by 15% over the same average for the years 1985 to 1992.1 These types of statistics lead baseball enthusiasts and commentators to speculate on possible causes.
One of the possible causes is changes in the ball. As a consequence of the record pace at which home runs were being hit in the Major Leagues during the early part of the 2000 season, a local radio station (AM 790 The SCORE) in Providence, RI solicited its listening audience to donate baseballs recovered from major league games at any time since 1960. Baseballs--purportedly obtained from major league games in 1963, 1970, 1989, 1995 and 2000 -- were donated to the radio station for testing. Subsequently, the radio station transferred the balls to the University of Rhode Island Forensic Science Partnership for evaluation and analysis.
Major League Baseball Specifications2,3
The components of a major league baseball are shown schematically in Figure 1. The center of a ball is called a “pill” and consists of a cork core surrounded by a layer of black rubber and a layer of red rubber. The pill is wrapped in 4-ply gray wool yarn followed by layers of 3-ply white wool yarn, 3-ply gray wool yarn and finally a cotton yarn. This outer layer of cotton yarn is enclosed in a full-grain cowhide leather cover, which is hand stitched together with 108 stitches. Finally, the specifications state that the weight of each ball is to be within 5 and 5 ¼ ounces and have a circumference between 9 and 9 ¼ inches.
The specifications were established in 18724 and according to Major League Baseball (MLB) the ball has not changed significantly since that time. The original rubber center was replaced with cork in 1910, and the cork was cushioned with rubber as of 1926. Synthetic rubber was used during the 2nd World War, and since 1974 cowhide as well as horsehide was authorized for the covers. The A.G. Spalding Company made baseballs from 1877 to 1976, when the Rawlings Sporting Goods Company3 became the supplier of the 700,000 plus balls needed by the major leagues each year.
Fallon and Sherwood5 at the Baseball Research Center Performances evaluated baseballs from the years 1999 and 2000. Investigations into the physics and activities of baseballs can be found in other reports.6,7
Our investigations into the anatomy of the five baseballs obtained by the local radio station focused on the materials used in the windings and in the pills. In both cases, the use of synthetic materials is an obvious source for changing the performance of the baseball.
According to Major League Baseball specifications, the wool windings may contain 15% 3% non-wool fibers. Windings from the oldest and newest balls are shown in Figure 2. As the five balls were dissected, the windings were separated into the four categories consisting of 4-ply gray, 3-ply white, 3-ply gray wools and cotton yarns by color. In all cases, the windings and the pills were handled with surgical gloves to avoid any contamination.
Initial investigation involved taking 5 cm cuttings of each of the three wool windings. Each of the cuttings was dried, weighed, treated chemically to remove the wool and weighed again. Results showed that the three recent balls contained significant proportions of non-wool fibers in all three of the wool windings. The percentages of non-wool fiber for each of the three windings for the five balls are shown in Figure 3. Not only did the synthetic fibers in the windings increase between the 2 early balls and the 3 more recent balls, the percentages in the three windings of the newer balls in some cases exceeded the tolerance levels for non-wool fibers
How would synthetic fibers in percentages of nearly 20% change the performance of the ball? Before we try to answer that question, we must consider the types of synthetic fibers used in the balls. Several types of synthetic materials could be added to the windings and each has different properties. Textiles are often blends of natural and synthetic fibers. Each type of fiber, whether it is natural or synthetic, has specific physical properties. By blending synthetic fibers with natural fibers, it is possible to obtain materials with a desired set of properties for specific end uses: for example, carpets.
We decided to conduct additional tests to determine the fiber content of the non-wool fibers from the 1989, 1995 and 2000 balls. Because the windings are made from recycled carpet fibers, we focused on tests for acrylic, nylon and polyester since these are the major synthetic carpet fibers. Using a modification of AATCC test method 20A-1955, we homogenized 3 mm cuttings from each of the wool windings. Figure 4 shows the percentages of acrylic, nylon and polyester in the non-wool fibers in the three newer balls. The percentage of acrylic fibers was fairly constant, ranging from 40 to 55%. The percentage of nylon and polyester varied considerably between the three balls.
Two fiber properties that are important in baseballs are resiliency and moisture regain. Resiliency is the ability of a fiber to spring back to a natural position after folding, creasing or other deformation, whereas moisture regain is the ability of a bone-dry fiber to absorb moisture at 70 F and 65% relative humidity. Wool, nylon and polyester have excellent resiliency, while acrylic has good resiliency. The property that varies the most between wool and the synthetic fibers is moisture regain, as seen in Figure 5. Wool regains 15% of its weight in moisture under standard conditions, while nylon, acrylic and polyester regain significantly less moisture. In humid conditions (> 65% relative humidity) wool can absorb up to a third of its weight in moisture. Thus, an all-wool ball will be heavier and slower than a ball with 16-20% synthetic fibers in the windings. In other words, the balls from 1989, 1995 and 2000 would be lighter than the 1963 and 1970 balls under any conditions except bone dry air.
The pills were removed from each of the baseballs and were tested individually for resilience and bounce. To insure that the pills were not damaged during removal, the individual windings were simply unraveled. The mechanical properties of the pills would prove to be very insightful since the pills were protected by layers of windings and the rawhide cover, making this part of the baseball the least exposed to the elements that could possibly degrade the materials; i.e. UV light, heat and humidity.
Mechanical Testing of Pills. Given that the mechanical properties of the central pill differ from the mechanical properties of the entire baseball, a relative study of the mechanical properties of the pills was undertaken. These tests included a bounce test for rebound and a uniaxial compression test to evaluate elastic modulus and stiffness. Since the windings and leather covers have different mechanical properties than the pill itself, the overall performance of the baseball including resilience and elastic/plastic deformation will be different. However, we believe that the pills offered the best opportunity to evaluate the mechanical properties of aged baseballs and the nature of the materials used to assemble the balls over the past 40 years, since the premise that balls are indeed livelier is based on changes in the materials of construction.
The rebound test consisted of dropping the pills from the different major league baseballs from a height of 182 in onto a concrete floor and measuring the rebound distance with a tape measure. A total of 10 measurements were made on each pill and the rebound distances were averaged. The results of the drop test are presented in Figure 6. It should be noted that wind resistance was minimal due to the relatively low terminal velocity of the pills falling from that height and that there was little plastic (permanent) deformation as a result of the pill impacting the concrete surface. The pills were checked for any plastic deformation after the bounce test and there appeared to be little if any permanent distortion.
The pills were also tested in compression using an MTS tensile testing machine8. The crossheads of the tensile testing instrument were adjusted such that the pills were placed in between the crossheads and an extensometer (strain gage) was placed between the crossheads to determine displacement as the crossheads traveled towards one another as the pill was placed into compression. The load and corresponding displacements were recorded. The slope of the linear portion of the resulting stress-strain curve is related to the elastic modulus or stiffness of the material comprising the pill. The elastic modulus was established for each pill. Since there was considerable plastic deformation of the pills at higher loads, each pill was tested only once in compression. The pills experienced considerable permanent deformation as a result of the testing and took the form of plats on either end of the pill i.e. the pills were no longer round. Since the modulus of resilience is inversely proportional to the elastic modulus or stiffness of the material, only the elastic modulus was presented in Figure 7. The modulus of resilience can be inferred from the elastic modulus in each case. The experimental results showed that the pills taken from the earlier three baseballs had the least rebound distance averaging only 60 inches, whereas those pills taken from baseballs in 1995 and 2000 had substantially larger rebound distances, averaging more than 80 inches. This represents a 33% increase in rebound distance and, if the rest of the materials comprising the baseball were considered perfectly elastic for purposes of discussion (which of course they are not), this would translate into a baseball that would be 33% livelier than the baseballs used decades earlier.
The experimental results from the compression tests were consistent with those established from the drop tests, i.e. the pills that exhibited the largest rebound distances had the lowest elastic modulus (highest modulus of resilience) and those that exhibited the least rebound distance had the largest elastic modulus (lowest modulus of resilience). The experimental results also showed that the pills taken from the earlier three baseballs had the largest moduli of elasticity ranging from 700 to 1000 psi, whereas those pills taken from newer baseballs had substantially smaller moduli of elasticity, ranging from 500 to 575 psi. From Figure 6, it was shown that the rebound distance for the pills taken from the earlier baseballs were very consistent with one another suggesting that the materials of construction did not change much over that time period. The rebound distances for the pills taken from the newer baseballs were also consistent with one another, suggesting that the materials of construction did not change after that time. A similar result was obtained from the compression tests, which provides further support for the case that the balls were juiced between 1989 and 1995.
FTIR Spectra and Images of Pills. Once the physical testing of the pills was completed, the pills were bisected. The two halves of the five pills are shown in Figure 8. There are obvious visual differences between the 2 early balls and the 3 more recent balls; the center core of the older balls looks like cork, whereas the same sections of the newer balls are much darker. In addition, the outer red (pink) layer of rubber is darker in the three newer balls; this difference can be seen on the outer surface of this layer and in the cross-sectional view.
The visual differences suggest that there might be chemical differences between the materials used to make the pills. Thus, we subjected the pills to infrared spectroscopic analysis. FTIR spectra can be used to identify chemicals present in a sample, whether the sample be pure or a mixture. Each pure chemical absorbs different
amounts of infrared radiation at different wavelengths. The intensities of light absorbed at different wavelengths is plotted as a function of the wavelength and this gives the infrared spectral fingerprint of the material. Thus, each pure chemical has an individual infrared fingerprint consisting of a graph showing a number of peaks and valleys. This fingerprint can be matched with known fingerprints stored in a library. In the case of chemical mixtures, the infrared pattern is a composite of the patterns for the pure components. There are mathematical methods for extracting patterns of the pure components from the composite pattern.
Infrared spectral fingerprints of each layer in the pills were measured and are shown in Figure 9. For the two early balls (1963 and 1970), spectra and therefore the chemical components are very similar within each of the three layers. As can be seen on the right side of the figure, the spectra of the cork cores for the early two balls are very similar to the spectrum of a laboratory cork. The spectra of the black layers are nearly identical for the early two balls, although the relative intensities of the bands vary slightly. This is probably due to variations in the ratios of the chemical components in this layer. The same is true for the red rubber of the early two balls, and again, there are some variations in the ratios of bands.
Major spectroscopic differences are observed for the cork core and the red rubber, when comparing spectra for the 3 newer balls with the 2 older balls. The spectra of the cork core no longer resembles the spectrum of the laboratory cork Spectra of the red layers are similar in the new 3 balls, but they differ considerably from spectra of the early 2 balls. Spectra of the black layer are similar for the 2 early balls, but there is a noticeably change with the 1989 ball and another change with the 1995 ball; the two recent balls are very similar.
The most significant changes between the 2 early balls and the 3 newer balls are in the cork cores and the red rubber layers. The spectra of the red rubber in the 3 newer balls are very similar to the spectra of the “cork” cores in the same 3 balls. Thus, it appears that the cork cores may not be cork. To understand this better, we measure infrared hyperspectral images of the cork areas. These measurements were performed with a 64x64 pixel infrared sensitive camera attached to an Fourier Transform infrared spectrometer9. Microscopic images of areas ~0.5 x 0.5 mm were obtained. Two spectral images of a cork area from the 1963 ball and one spectral image of the cork area of the 2000 ball are shown in Figure 10. The small 0.5x0.5 mm spot on the 1963 ball consists of two different materials; the spectra and the images are for these two materials. The top spectrum is that of cork and the image shows the location of the cork in the false color image (red color indicates high and blue low concentrations). The second spectrum for the 1963 ball is that of a mixture of butadiene-styrene copolymer and calcium carbonate. The image corresponding to this spectrum is for the same location as the first image, but it shows the location of the butadiene-styrene copolymer / calcium carbonate. The images of the 1963 ball indicate that the cork core was mainly cork surrounded by the butadiene-styrene / calcium carbonate mixture.
The lowest spectrum and image in Figure 10 were obtained for the 2000 ball. The infrared spectrum corresponds to a mixture of latex rubber and clay. The entire 64x64 image corresponded to this mixture. We could not find any evidence of cork on the cross-sectional surface of the 2000 ball. The “cork” cores of the 1989 and 1995 balls also consist of a latex rubber / clay mixture and cork could not be found. The core of the 1970 ball had a similar distribution of cork and butadiene-styrene copolymer / calcium carbonate as the 1963 ball. The infrared spectral analysis shows that there are major differences between the features and compositions of the early 2 balls and the 3 recent balls
The analyses of components from the five baseballs in this study clearly show that there were material differences between the 2 early balls and the 3 newer balls. From the analysis of the windings, we conclude that the increase in amount of synthetic fibers used in the baseballs from 1989, 1995 and 2000 could make the balls go further than balls with higher wool content. Furthermore, infrared analysis of the pills from the five balls showed that the materials used in making the pills also changed from the 2 early balls to the 3 newer balls. The minor changes in the compositions of the pills during the 1990s most probably accounts for increase in rebounds (bounce) of pills for the 2 newer balls.
To confirm the observations reported herein more documented baseballs are needed. Questions do arise as to the age of the balls and the effects of degradation with time. The aging effects could account for the reduced bounce in the older balls, but they cannot account for the compositional changes in the windings and pills. It would be very useful to examine documented balls from the last four decades at 5-year increments. In this way the mechanical and chemical properties could be correlated with each other and possibly with baseball “power factor.”
1) High Boskage House Baseball-Analysis Web Site http://www.highboskage.com/THEBALL.htm
2) Rawlings Sporting Goods Company, St. Louis, Mo (2000).
3) Muscel Shoals Rubber Company, Batesville, Mississippi, June 1, 2000, MajorLeagueBaseball.com.
4) Spitters, Beanballs and the Incredible Shrinking Strike Zone, G. Waggoner, K. Moloney and H. Howard, Triumph Books, Chicago (2000).
5) L. P. Fallon and J. A. Sherwood, Baseball Research Center, University of Mass-Lowell, “Performance Comparison of the 1999 and 2000 Major League Baseballs” submitted to MBL on June 27, 2000.
6) “The Physics of Baseball” Alan M. Nathan, University of Illinois (http://www.npl.uiuc.edu/~a-nathan/pob/) (2003).
7) “Bouncing Balls”http://www.exploratorium.edu/basebal...ing_balls.html (2003).
8) Materials Science and Engineering:An Introduction, 5th Edition by William D. Callister,Jr., Wiley,1999, p. 130
9) Stingray 7000 FTIR Imaging Spectrometer, Digilab, Randolph, MA.
Thanks for posting that.
Ubi had asked about the weight of each pill from the URI project. I asked Dr. Brown to weigh the pills and he provided the following data, which is a little suprising in the difference. Just in case you are metrically challenged 1 ounce equals 28 grams.
The weights of the pills are as follows:
1963 24.89 grams
1970 22.44 grams
1989 26.53 grams
1995 27.57 grams
2000 26.32 grams
That is a pretty big difference.
I would think a weight difference would alter the tests would it not?
I don't do physics real well but I do believe that would impact the bounce test.
My mistake this is what I meant to illustrate in post #179.