Were you always interested in physics when you were a kid?

Somehow I knew I wanted to be a physicist at a pretty early age. I was born in Maine and lived there for 16 years. I was always interested in science. I never took a course in physics until I was a senior in high school and immediately loved it. After finishing high school in the Washington, D.C., suburbs, I attended the University of Maryland, where I studied physics. I got drafted and served in the Army during the Vietnam War, and then I went to graduate school at Princeton, where my research was in experimental nuclear physics.

How did you end up at the University of Illinois?

I had a post-doctoral appointment at the Brookhaven National Laboratory in Long Island, and then I came here in August 1977. I’ve been here ever since. I started as an assistant professor and worked my way up the ranks. I served as an active faculty member at the UI until I retired in 2008. I don’t teach any more, but I still do work.

Did you play baseball when you were young?

Yes, I played baseball up until my freshman year in high school. I was an outfielder and a pretty good one, actually. Since I was speedy, I could cover a lot of territory. But I was a very good runner, so I switched to track. I was a sprinter, running the 100-yard dash. These days, I play in one of the Champaign Park District’s senior softball leagues. I can still play the outfield, but I prefer first base.

How did you become a Red Sox fan?

I grew up in Maine, so naturally the Red Sox were my team. I went to a handful of games.

How did you make the connection between physics and baseball?

There was a book called "The Physics of Baseball" by Robert Adair. I had this book on my shelf for a bunch of years and never really got around to reading it until 1997, when our physics department had a community outreach program. We gave public lectures aimed at high school students on Saturday mornings. When they asked me to do a lecture, I decided I wanted to talk about the physics of baseball. That forced me to read the book, and I got quite interested in it. After the talk, people started calling me up, including Itch Jones, who was then the coach for the UI baseball team. I was asked to give talks to various Rotary Clubs and alumni associations for about a year. Since I had a sabbatical coming up, I decided to do my own research on the physics of the baseball ball/bat collision. After I did a paper on it for an academic journal, I got hooked up with the NCAA, who was looking to regulate aluminum bats. There were too many home runs being hit, and they wanted to return the college game to the traditional balance between pitching and hitting. I started serving on the NCAA’s advisory panel, and I studied how an aluminum bat performs. The goal was to come up with a standard to allow aluminum bats to perform more like wooden bats by reducing the speed of the ball coming off the bat. As a direct result of my research, there was a major change beginning with the 2011 season. Colleges and high schools now use what they call BBCOR bats. They are constructed with the same aluminum exterior as standard aluminum baseball bats, but they have a thicker wall to reduce the so-called "trampoline" effect. If you look at NCAA home run production, the number of home runs have more than cut in half since the change took place.

How did you get involved with the Society for American Baseball Research?

Originally there wasn’t a lot of scientific work being done by SABR until the organization formed a baseball and science sub-unit. A graduate student was aware of my work, contacted me and asked me to co-chair that committee.

How did you begin doing work for the Red Sox and other major league teams?

I was involved in research in something called the "pitch effects system," which has been used in major league stadiums since the 2006 season. They have cameras that track the pitched baseball. The chief technology officer for the company who developed it, Sportvision, was named Marv White, who I later learned was a University of Illinois grad in physics. I decided this area was a good match for the kind of things I do well. The cameras are mounted permanently in every major league stadium now. I helped with the setup of the system at U.S. Cellular Field in Chicago in August 2006. Every single pitch in every single game is recorded, and its trajectory is tracked for every 60th of a second. Major League Baseball made the data public, including how fast the ball was when it was released, how fast the ball was when it crossed home plate, where the pitch crossed the front of home plate (so you could check on the umpires), and how much movement there is on a pitch. All this is interesting both from a physics point of view and a baseball point of view. Any game on TV shows you a little box off to the side, and that info comes from the "pitch effects system." By 2008, we had a whole season of data to look at. Sportvision sponsored a series of "pitch F/X summits" in San Francisco from 2008 to 2011. I lined up speakers, and I spoke myself. Teams sent representatives there to hear what we were doing. Then I began being contacted by the front offices of major league teams. I’ve done work for the Red Sox, the Cardinals and the Nationals, largely based on this.

You got contacted by "60 Minutes Sports."

Several years ago I did some analysis on the knuckleballs of Tim Wakefield and R.A. Dickey. There is a certain perception that people have about knuckleballs — that they are zigzagging. Now that we had the "pitch effects system," we had the data to determine if that is true or not. I discovered that, mostly, they are not zigzagging. Knuckleballs move just as smoothly as other pitches move, except they are unpredictable. Normal pitches swerve at a very predictable arc. A four-seamed fastball is going to slide in to a right-handed hitter; a cutter is going to break in the opposite direction. But a knuckleball breaks in different directions. I found very few instances in which the ball was actually zigzagging. "60 Minutes" was doing a story on R.A. Dickey, and an assistant producer heard abut my work and contacted me. Lesley Stahl flew out from New York and interviewed me in Milwaukee. She even autographed a baseball for me. After her name she wrote, "60 tick, tick, tick."

How did you get involved with studying the humidor at Coors Field?

When Coors Field was first used for Major League Baseball, the number of home runs hit there were enormous compared to other places. At the elevation 1 mile above sea level, the air is thinner, so there is less air drag on the baseball. It just carries further. In about 2002, the Colorado Rockies started storing baseballs in a humidor. A humidor is a controlled temperature and humidity environment. They store the balls at 70 degrees Fahrenheit and 50 percent relative humidity. The moisture content of the air under those conditions is greater than what is typical in Denver in the summertime. By storing the baseballs at a higher relative humidity, the ball can’t be hit quite as hard. If the ball isn’t hit quite as hard, you aren’t going to see as many home runs. There was a 25 percent reduction in home runs per game after the introduction. In 2009, we decided to measure this at various relative humidities. I used physics to calculate what the effect of the humidor was. I found it was a 28 percent decrease. I was able to calculate it pretty well, and I had no right to get it that close. When we published my findings in the American Journal of Physics, I got a call from a reporter from the Arizona Republic, and he told me the Diamondbacks were considering storing their baseballs in a humidor. Phoenix is hotter and drier than Denver, so the effect of storing the balls there would be something like a 35 to 40 percent reduction of home runs there. I found out two months later the Diamondbacks decided to put this on hold for a while.

Did your experience as a track runner help you in your quest to climb down and back up the Grand Canyon?

I don’t know about that. I didn’t exactly sprint the Grand Canyon. In April, I went down the Canyon and back with a friend. It was a great experience. It wasn’t overly difficult, but I was tired. The path is wide enough and well maintained. We went down one night, stayed the night at the Phantom Ranch and went back up the next day. It took me five hours to go down a 7-mile trail and six hours coming back up, but I took a longer, less steep 10-mile trail coming back up. After the halfway mark, I was in the sun and dragging, but I kept putting one foot in front of the other and kept on going. At one point I stopped and had lunch.

Who was your baseball hero and why?

Ted Williams. I was a Red Sox fan, and he was the biggest name around. When Tony Gwynn ... died, I remembered his friendship with Ted Williams, and it brought a tear to my eye. I went back and replayed the video from the 1999 All-Star Game at Fenway, when the greatest living players were on the field. Ted was the last to show up and was a little shaky at that point, and Tony helped stabilize him so he could make the first pitch.

What is your advice to a young person who wants to get involved with physics and sports?

Get grounded in the basics. Learn physics. Pick up and read books and think about them. Get involved with baseball analytics or analytics with other sports.


Tim Mitchell is a reporter at The News-Gazette. His email is tmitchel@news-gazette.com, and you can follow him on Twitter (@mitchell6).

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