They shot baseballs at loaded bats.
Does a corked bat help you win baseball games?
Yes it does, but not in the way you might think.
A "corked" bat is a baseball bat that’s been filled with something lighter, like cork. The theory is that if a bat is lighter, the player can swing the bat faster, and hit a baseball farther. Another idea is that hollow bats might be unfair because of the "trampoline effect." A hollow wooden bat’s surface might slightly deform and reform when it contacts a baseball, the same way a trampoline becomes elastic when you jump on it, an effect that has been observed in hollow metal bats.
But a baseball cannon has smashed both myth.
In a study called Corked Bats, Juiced Balls, and Humidors: The Physics of Cheating in Baseball, researchers built a cannon that fired baseballs at modified baseball bats, and discovered three intriguing things:
One, the trampoline effect doesn’t help.
Two, a corked bat doesn’t hit the ball any farther.
But three is interesting. Even though a ball goes the same distance with a modified wooden bat, a lighter bat allows the player to delay his swing by a fraction of a second. That may allow the hitter to be more accurate when he hits the ball.
So if a player’s caught with a corked bat, he may legitimately say:
"But science has proven that I’m not hitting the ball any farther."
And science may counter:
"Yes, but you might be hitting more accurately."
– The Misleading Myth Of The Corked Bat. The belief that a baseball can be hit further with a corked bat is wrong. But these illegal bats may still give an unfair advantage. Technology Review, MIT>>
– Corked Bats, Juiced Balls, and Humidors: The Physics of Cheating in Baseball, Cornell University Library>>