The Historical Changes in the Baseball A presentation to ABC News by A. S. Grader and P. M. Halleck Penn State D. Zavagno Universal Systems Inc. 29 June 2000 Motivation Historically, MLB denied that the baseball has changed. Years of unexplainable events resulted in a rigorous study of the structure of the baseball. We decided to look seriously at baseballs with one of our Petroleum Engineering CT scanners specifically designed to characterize core samples, and use proprietary software for data analysis. CT Imaging of baseballs A typical CT image of a baseball Leather skin String windings Outer shell Inner layer Central core Resistance Ring Surface strings 2000The "ring" is substantially thinner in the 2000 baseball. The two images on the left are perpendicular to the resistance band. The two images on the right are parallel to the resistance band. The 1999 band is thicker and hence, appears as a strong red color. The 2000 band is thin and shows as a faint orange color. 1999 Interior of a 2000 MLB Ball (2-mm thick slices) Baseballs through the decades: Total ball 1910s1920s1930s1940s1950s 1960s Early 1970s Late 1970s1980s1990s Baseballs through the decades: Center Pill 1910s1920s1930s1940s1950s 1960s1970s 1980s1990s Baseballs through the decades: Windings water air Approximate density Time Baseballs through the decades: Cork 1910s1920s1930s1940s1950s 1960s1970s 1980s1990s Baseballs through the decades: Cork water air Approximate density Time The center of a crushed ball: home run ball air Outer rubber shell cork Inner rubber shell