URI research team finds compelling evidence of
livelier balls in Major League Baseball
KINGSTON, R.I. -- Oct. 25, 2000 -- A team of University of Rhode Island scientists has found that the cores of Major League baseballs from 1995 and 2000 bounce higher than ones from 1960s and 1970s and that they contain materials that could make them livelier. Click on image for Quicktime movie about this research!
Six researchers from URI's Forensic Science Partnership have found that balls from 1989, 1995 and 2000 contain synthetic materials in windings that are supposed to be made of wool and a greater concentration of rubber in the core, commonly known as the pill. In addition, the researchers found that pills from the 1995 and 2000 balls bounced an average of 20 inches higher than their 1989, 1970 and 1963 counterparts.
One of their conclusions says that the Rawlings Sporting Goods Co., the maker of Major League baseballs, doesn't follow its own specifications for some of the windings used in the balls.
The findings of Linda Welters, URI professor and chair of the Department of Textiles, Fashion Merchandising and Design; Margaret Ordonez, URI textiles professor; Christopher Brown, URI chemistry professor; Otto Gregory, URI chemical engineering professor; Michael Platek, electrical materials engineer, URI Department of Electrical/Computer Engineering; and Dennis Hilliard, co-director of the Forensic Science Partnership and director of the Rhode Island State Crime Laboratory at URI, concluded five months of study.
The work began in mid-May, when AM 790 (WSKO) Sportsradio the Score wanted to determine if balls from 1989, 1995 and this season were actually livelier than balls from 1963 and 1970. Hilliard, Gregory and others from URI began the tests during a live broadcast outside Quaker Lane Tool, during which the team conducted bounce tests on the balls, and then pulled them apart and did bounce tests on the core.
Even those basic tests showed the balls from 1995 and 2000 jumped significantly higher than their counterparts from 1963, 1970 and 1989. The same was true for the pill.
Listeners donated the balls. The covers of the 1989, 1995 and 2000 balls clearly identify them as Major League balls. The 1970 cover has some smudged writing that looks like a Major League mark, and it also has handwriting saying that the ball is from the Aug. 16 game between the Twins and Red Sox at Fenway Park, and that the ball was recovered from a foul hit by Rico Petrocelli. Petrocelli played for the sox from 1963 through 1976. The cover of the 1963 ball has no clear identifying mark, but some handwriting says it came from the bat of Chuck Schilling on April 16, opening day. Schilling was the second baseman for the Sox from 1961 through 1965.
Once the live demonstration in May was over, the balls' remnants were taken to URI labs for further testing. URI chemists, engineers and textile scientists closely examined critical components of each ball to assess liveliness. A Rawlings fact sheet says the company tests for liveliness by measuring the ratio of rebound velocity to impact velocity when a ball is fired from an air cannon at 85 feet per second, or 58 miles per hour, against an immobile northern white ash surface. Using that method, Rawlings comes up with a coefficient of restitution (COR), or resiliency, of a finished baseball. The COR shall be between 51.4 percent and 57.8 percent.
Hilliard said that the 1963 and 1970 balls were most likely made by Spalding, which manufactured Major League baseballs for 100 years beginning in 1876, while the three others were made by Rawlings, which became the MLB vendor in 1977.
Welters and Ordonez concentrated their efforts on the woolen windings. According to the Rawlings Major League Baseball specifications listed on its web site, all three layers of windings should be woolen. There is no mention of synthetic materials in the description of these layers.
"Since the Rawlings specifications indicate woolen yarns should be used to construct the baseballs, the amount of non-wool fibers was surprising," Welters and Ordonez said in their observations on the inner core.
"The large amount of synthetic fiber in the balls from 1989, 1995 and 2000 is bound to affect the performance of the balls," Welters and Ordonez said. "If the synthetic fiber is polyester as we suspect, then it has good elasticity, resiliency and loft. Although no tests exist to measure the performance of fibers used in baseballs, the synthetic materials could be expected to provide a liveliness to the ball that is not present in the balls of natural materials.
"Based on our tests, the manufacturer is not meeting Major League Baseball specifications for the balls. The composition of the inner core yarns includes synthetic fibers, probably polyester. Rawlings specifies woolen yarn for the first, second and third winds. The 1963 and 1970 balls fit the specifications better than the newer balls."
Hilliard said the team then focused on the pill. "In forensic science we want to compare items that are as much alike as possible, and we know that 37 years of heat, light and moisture could affect the 1963 ball. We believe that the pill was well preserved because the windings and the cover protected it. We believe the pill is what gives the ball its resiliency."
Gregory and Platek took the next step by doing compression tests using appropriate instrumentation in their engineering lab. They calculated the stiffness of each pill by squeezing each one and measuring the response. Gregory said that the stiffer the pill the less resilience it had. He said that the older pills were stiffer.
"The least stiff and most resilient by a dramatic amount were the 1995 and 2000 pills," Gregory said.
Platek and Gregory also conducted another series of bounce tests on the pills. They found that the average height of the bounces from the 1995 and 2000 pills was 83 and 82 inches respectively, when dropped from a height of 182 inches. Each of the pills from 1963, 1970 and 1989 bounced no higher than an average of 62 inches. For each of the pills, the scientists conducted about 20 drops.
Using infrared spectroscopy and digital photography, two of Brown 's students, Kara Lukasiewicz of Cumberland, R.I., and Scott Huffman of Hickory, N.C., determined that the year 2000 pill is similar in color to the 1989 and 1995 images, but "the design is unique among all years with a larger space between the two black rubber hemispheres. The cork area of the pills appears darker in the years 1989, 1995 and 2000 than that of the earlier years."
The results are in sharp contrast to a statement from Rawlings, which said in a press release earlier this year when it introduced its 2000 balls, that the official ball of Major League Baseball has undergone very little change since the early days of the game. Another statement from the Rawlings Website states that there have been no further changes in specifications for the balls since 1931, except for humidity and temperature controls, improved quality control and testing.
In fact, Huffman's and Lukasiewicz's analyses of the cork pills show a huge amount of variation between the three newer balls and the two earlier ones. Their digital photos show that even the pink outer layer of the pill is markedly different in the 2000 ball than it is in all the others. Huffman said the duo spent up to 40 hours doing the analysis of each pill.
Both students, Huffman, a doctoral student in chemistry and Lukasiewicz, an undergraduate studying microbiology, emphasize that they didn't do this to hurt the game. Both are strong fans of the Boston Red Sox.
"It's probably the most fun I have ever had doing science," Lukasiewicz said. "We're both sports fans, so we didn't want to hurt the credibility of the game."
For Information: Dennis Hilliard 401-874-2893, Linda Welters 401-874-4525, Christopher Brown 401-874-2369, Otto Gregory 401-874-2085,
Dave Lavallee 401-874-2116.