April 14, 2005


Sosa's Corked Bat (Ivars Peterson, Science News)

On June 3, 2003, in the first inning of a baseball game between the Chicago Cubs and the Tampa Bay Devil Rays, slugger Sammy Sosa hit a ground ball toward second base. The impact split Sosa's bat. The Devil Rays catcher picked up one of the fragments and tossed it over to the home plate umpire, who found a cylindrical piece of cork embedded in the wood.

Sosa was thrown out of the game for using a corked bat and was subsequently suspended for seven games as a punishment.

The rules of Major League Baseball specify that any player who "uses or attempts to use a bat that, in the umpire's judgment, has been altered or tampered with in such a way to improve the distance factor or cause an unusual reaction on the baseball" be called out and ejected from the game. This includes bats that are "filled, flat-surfaced, nailed, hollowed, grooved."

How does a corked bat help a hitter? Drilling out the center of a wooden bat and replacing the wood with cork reduces the bat's weight and changes its center of mass, shifting it toward the bat's handle. Such changes suggest that the bat could become easier to swing and that it could be swung faster. Presumably, hitters could send a ball farther by using a corked bat.

Sosa himself, now with the Baltimore Orioles, admitted that he sometimes used a corked bat in practice just to put on a show for any admiring fans who might be present. He denied ever using such a bat in a game—except by accident on this one occasion.

In fact, tests on 76 bats that belonged to Sosa and were seized by officials after the incident, revealed no evidence of tampering.

Is there any evidence in Sosa's hitting statistics that might reveal that he had been using a corked bat?

The book mentioned, The Physics of Baseball by Robert K. Adair, is fabulous.

Posted by Orrin Judd at April 14, 2005 12:00 AM

I've always thought you could make a tough subject like physics go down a little easier via the creative application of sports examples. There's a physics professor at Nebraska named Tim Gay who does a popular segment called "Football Physics" once a game on the replay boards.

He once showed, for example, a Husker kick returner as he outran some straggling defender for a score, briefly paused the play, drew two vectors from each player that converged, and asked: "Why does Bobby Newcombe not get tackled? The answer is a factor physicists call speed." Then the picture unpaused and we got to watch a great play.

The home crowd invariably loves this stuff.

Posted by: Matt Murphy at April 14, 2005 8:00 AM

I should've figured that if he'd written a book, you'd have read it! Thanks for the heads up...

Posted by: Matt Murphy at April 14, 2005 4:53 PM

The best corked bat story was Albert (Don't Call Me Joey) Belle. The ump confiscated his corked bat during a game in Chicago. One of his teammates got into the plenum above the umpires locker room broke in through the ceiling and switched bats.

Posted by: Robert Schwartz at April 14, 2005 10:28 PM