Foul Play: Episode 4
Producer Jeffrey Marlowe
In this episode of Foul Play: Robert Adair, Sterling Professor Emeritus of physics at Yale University, delves into the physics of what separates wood and metal bats. Adair, former official physicist for Major League Baseball's National League and author of the book, "The Physics of Baseball", is an expert in the field and has been studying physics in baseball for decades. The trampoline effect, moment of inertia, and Ball Exit Speed Ratio are all discussed as we try to answer if metal bats ourperform wooden bats.
Coming up next time: Our final verdict on whether or not metal bats are more dangerous than wood bats and what you can do to protect your child
To find out more about "The Physics of Baseball" and other books Robert Adair has written, visit his publisher's page here
Even though as Attorney Kallas asserts, "There are a number of other cases (in baseball and softball) in the tri-state area that have been settled out of court." He believes these lawsuits stay relatively unknown because "...parties are usually barred from speaking about the outcome of the case (usually a pre-trial settlement which has no finding or admission of liability and includes an agreement that the attorneys and the parties will not talk about the case)."
Q: Have there been any studies like the Brown University study since 2003?
A: No, there have been no conclusive studies on batted ball speed of balls exiting non-wood and wood bats like the Brown study since the change in BESR in 2003
Q: What is BESR?
A: Ball Exit Speed Ratio is a way to calculate the exit speed of a ball from a bat; given bat head and ball speed. The lower the BESR, the better the performance of the bat. The high quality wooden bats used to standardize BESR in non-wood bats today have a BESR of .728. The equation for BESR is:
Vbat(BESR + Â½) + (BESR â€“ Â½)Vball = Batted Ball Speed
Q: Are the Crisco-Greenwald and Brown University studies irrelevant? A: Yes and no. Shortly after both studies were released, BESR regulations were changed to make the bats used in the studies illegal. However, they do show the advantage of metal bats to wood in real world testing despite manufacturers' claims that the bats perform equally.
Q: What types of studies were done before the Crisco-Greenwald study?
A: Most studies involved shooting balls from a pitching machine at a stationary bat, where the rebound speed was measured to form a conclusion. These studies stated that wooden and aluminum bats performed equally, but studies using actual players swinging, such as a 1977 study and the Crisco-Greenwald study, found metal bats significantly outperformed wooden bats.
Q: How can the trampoline effect be regulated?
A: The trampoline effect is very complicated, to say the least. It can be minimized by adding more compliant barrels to the core of the bat, which increases the hoop frequency (frequency of mode of vibration in barrel) and helps deaden the bat.
Q: How is BESR now measured?
A: As of 2006, BESR is measured using a high-speed cannon that shoots balls towards the test bats at 138 mph. After the impact, bat speed and ball speeds (both initial and exit) are measured to come up with the BESR.