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August 2, 2007
Interview With a Physicist
"I think physicists are the Peter Pans of the human race. They never grow up and they keep their curiosity." - Nobel Prize winner Isidor Isaac Rabi
I'm not a physicist, but I play one on the Internet. Seriously, I enjoy dabbling in the popular descriptions of physics and its history and, as you may have noticed, like to sprinkle a few tidbits into this column paying homage as it does to an interesting episode in the history of quantum mechanics.
One person on whom the meaning of the moniker "Schrodinger's Bat" was not lost is the subject of today's column. Dr. Alan Nathan is a Physics Professor working in the Nuclear Physics Lab at the University of Illinois at Urbana-Champaign. Dr. Nathan received his B.S. in Physics in 1968 at the University of Maryland and then went to his earn a Masters and Doctorate at Princeton University in 1972 and 1975 respectively.
Dr. Nathan also happens to be a baseball and Red Sox fan, not necessarily in that order, and has been researching and writing about the interplay of physics and baseball for several years. He is active in the Society for American Baseball Research and you can read his work on his Physics of Baseball site. What follows are his thoughts on a few of the more prevalent intersections of physics and baseball.
Baseball Prospectus: You've been perhaps the most prolific person in writing on the physics of baseball over the last decade. How and when did your interest take hold and why did you start publishing on the subject?
Dr. Alan Nathan: I initially got interested by reading the famous book The Physics of Baseball by fellow physicist Robert K. Adair. I gave a talk on the subject to some local high-school students and got written up in our local newspaper. After that, I had lots of people contact me about giving talks on the physics of baseball. About a year later, I had a sabbatical and decided to spend some time on baseball research. I read an article about the dynamics of the ball-bat collision and thought I could improve on the calculations that were done there. So, I developed my own model and eventually published it. This happened in about 2000. My research has grown ever since.
BP: You're the chairman of the Science and Baseball committee of SABR. Tell us a little about some of the research coming out of the committee and what your hopes are for it?
AN: Actually, the SABR Science and Baseball committee is really not very active. Very few members of the committee are actually actively pursuing research in this area. [Note: One who has been active is former major league pitcher Dr. Dave Baldwin, who recently authored the book Snake Jazz.--DF]
BP: You have written in the past on the differences between wood and aluminum bats and how aluminum bats are tested. Given the recent controversy over replacing aluminum bats in youth leagues, what does the science say on the safety of wood versus aluminum, and do you support moving away from aluminum?
AN: There is no question that a typical aluminum bat will outperform a typical wood bat. There is also no question that the efforts by organizations such as the NCAA to regulate the performance [PDF] of non-wood bats have put a cap on the performance of these bats. Absent these regulations, there would be a much wider gap between wood and aluminum. Since implementing these performance standards, the pitcher/batter duel has returned to a more level playing field.
I am not really qualified to offer any scientific opinion on the safety issue. Regarding the banning of aluminum bats, I really have no scientific opinion about that. However, I do encourage those in a position to make these decisions to get the best possible scientific input from people like myself and people I work with.
BP: Would composite bats be a kind of compromise between aluminum and wood?
AN: That depends on what you mean by "composite." Steve Baum has built a composite bat that is very wood-like in look, feel and performance. On the other hand, hollow composite bats (such as the Easton Stealth) have the ability to perform even better than aluminum.
BP: Speaking of bats, following the example of Joe Carter, Barry Bonds and others, more and more players are moving away from ash bats to maple where the mix is now roughly 50-50. How significant, if any, are the differences between the two in terms of the ball-bat collision? Can the perceived increase in broken bats be attributed to the greater use of maple?
AN: I am skeptical that there are any significant performance differences between ash and maple, despite the claims of Sam Holman [maker of the Sam Bat, used by Bonds]. Laboratory testing has shown similar performance characteristics. One of Sam's claims is that maple is more durable than ash, so his bats ought to break less often. On the other hand, tree experts tell me that the grain in ash tends to be straighter than the grain in maple, so when a maple bat does break, it does so more catastrophically (as opposed to cleanly into two pieces).
BP: Are there other woods that would perform better than either ash or maple?
AN: I am not such an expert on wood. I know people have tried using bamboo. Also, the Hoosier Bat Company makes a wood composite bat, where the barrel, handle and taper sections are of different woods (ash, maple and hickory, but I don't remember which goes where).
BP: With the recent article by Jeff Passan of Yahoo, former pitcher and Cy Young winner Mike Marshall and his institute in Florida have been in the news. What are your thoughts on the pitching motion that he teaches and its relation to the flight of a thrown ball? Besides his contention that his motion prevents injury does the motion allow a pitcher to impart more movement on a curveball, for example?
AN: Once again, this is something beyond my expertise. Dr. Mike will make a presentation at the annual SABR convention at the end of July, and I hope to learn more when I hear his talk. Marshall tends to be unconventional in his views, and his theories do not seem to be generally accepted by professional baseball people. Of course, that certainly does not mean that he is wrong. I would very much like to see an open dialogue between Marshall and his detractors.
BP: In science it is sometimes the case that our best theories are highly counterintuitive. Special and general relativity, along with quantum mechanics, are just a couple of the most famous examples. In your experience what are a couple of baseball-related results related to physics that are the most counterintuitive to fans and players alike?
AN: One example is that the grip the batter has on the bat does not play a role in the ball-bat collision. That is, a batter could just as well let go of the bat an instant before contact, and it would not make a bit of difference to what happens to the ball. Most people tend to be very skeptical of this conclusion, since they believe a batter "muscles" the ball when it is in contact with the bat. But, that is not what happens, as shown not only "theoretically" but also experimentally.
Another example has to do with the ability of the batter to track the incoming pitch. In fact, it is really impossible to do so. So, just like my previous example, the batter could just as well close his eyes when the ball is halfway to home plate and it won't affect the outcome of the swing.
A final example: Can a batter get to first base quicker by running through the base or in a head-first slide? Most people believe the former. I believe the latter. The essential physics is that by sliding with outstretched arms, the batter reaches the bag before his center of gravity reaches it, whereas those two times more or less coincide when running through the bag.
BP: Of course we had to sneak in a question on the gyroball. You've written on the aerodynamics of several variants of the pitch and concluded that rather than sideways break, the pitch should simply drop much more than a typical fastball. Do you have evidence that Daisuke Matsuzaka throws the pitch and if so does your description of the pitch match with reality?
AN: Try though I might, I have found no hard evidence that Dice-K throws such a pitch. I have searched through the MLB PITCHf/x for evidence of a ball with neither a horizontal nor a vertical break, as would be expected for a perfect gyroball. I have found no convincing evidence for one. For sure, one can say that if he does throw it, he doesn't do it often.
BP: Looking forward, what topics or avenues for research are you, or would you like to see, actively explored in the intersection of baseball and physics?
AN: Most of my work has involved either the physics of the baseball-bat collision or on the aerodynamics of a baseball in flight. I still find both these problems interesting and I continue to pursue both.
Some of the problems are very practical, such as the best way to measure and regulate the performance of bats. Another problem is one of estimating how far a home run would have traveled had it not hit something (like a wall or a seat).
Some of the problems are things that would interest only a physicist. For example, when a fly ball is hit to the outfield with backspin, does the spin on the ball remain constant throughout the flight or does it slow down? Another thing that interests me is learning in more detail how a batter puts spin on the ball by undercutting (backspin) or overcutting (topspin) the ball. We understand these things qualitatively, but I am interested in a more quantitative description. I am constantly discovering new tools to do studies relevant for baseball, such as the Doppler radar that is currently used to track golf balls, measure the spin, measure the club speed, etc. If one can successfully adapt this technology to baseball, that will open up many new avenues of research.
BP: Thank you, Dr. Nathan, for you insights.