Bahill's Science of Baseball Research

Bahill has done research on the Science of Baseball, because he thinks it helps lay people to understand basic research. Here is a list of his baseball publications.

Our most recent work is laboratory simulations of the pitch. Here are pictures of simulated four-seam and two-seam fastballs. And here is a ten-second video of the four-seam (left) and two-seam (right) fastballs. Warning this file contains 8 Mbytes. The two-seam fastball is easily distinguished by the two big pink vertical stripes. These simulations are for an overhand pitch. A three-quarter arm delivery would have the stripes leaning over at perhaps a 45 degree angle. For these videos the ball rotation rate was about 20 revolutions per second (rps) and the camera video rate was 60 frames per second. Photo credit Zach Bahill.

Here are pictures of simulated four-seam and two-seam sliders. And here is a five-second video of our simulated four-seam (left) and two-seam (right) sliders. Warning this file contains 5 Mbytes. For both of these videos the ball rotation rate was 8 revolutions per second (a major league slider probably rotates at more then 20 rps) and the camera video rate was 60 frames per second. The four-seam slider is easily distinguished by the red dot in the upper right quadrant. It is sometimes called a dime slider, because this red dot is about the size of a dime. Photo credit Zach Bahill.

These differences between balls thrown with the four-seam or two-seam grip were explained in our American Scientist paper Predicting a Baseball's Path with subsequent letters to the editor letter one and letter two.

We took these pictures of baseballs that were mounted on drills and rotated at up to 25 revolutions per second. It was difficult to drills holes right through the center of the baseballs. Here are pictures of the jig1 jig2 that I used to stabilize the balls during drilling.

Most of Bahill's recent science of baseball papers are co-authored with Dave Baldwin. Dave Baldwin, as a relief pitcher for the Washington Senators, Milwaukee Brewers and Chicago White Sox during the 1960s and 1970s, compiled a lifetime ERA of 3.08 with 6 wins, 11 losses and 22 saves in 176 games. While with the Washington Senators, his manager was Ted Williams and his pitching coach was Johnny Sain. Following a 16-year baseball career, he earned a Ph.D. in genetics and an M.S. in systems engineering from the University of Arizona. His memoir is excellent.

The keynote address that I gave at the Asia-Pacific Congress on Sports Technology, September 11-14, 2005, was based on this paper A Zachman Framework Populated with Baseball Models. And here are the PowerPoint slides for that presentation.

Here are some simulations for pitches thrown by a right-handed pitcher with a three-quarter arm delivery: four-seam fastball, two-seam fastball, four-seam curveball, two-seam curveball, These videos are five seconds in duration. Warning these files contain 5 Mbytes. For all of these videos the ball rotation rate was about 20 revolutions per second (a major league curveball rotates at up to 33 rps) and the camera video rate was 60 frames per second. Photo credit Zach Bahill.

Here are some simulations for pitches thrown by a left-handed pitcher with a three-quarter arm delivery: four-seam fastball, two-seam fastball, four-seam curveball, two-seam curveball, These videos are six seconds in duration. Warning these files contain 5 Mbytes. For all of these videos the ball rotation rate was about 20 revolutions per second, and the camera video rate was 60 frames per second. Photo credit Alex Bahill.

Al Nathan has an excellent web site on the Physics of Baseball, and Dan Russell has some really cool animations of the trampoline effect.

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This site is owned by Terry Bahill (520) 621-6561 It was last changed on August 11, 2011.