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Physicist Chang Kee Jung Keeps His Eye on the Ball


Chang Kee Jung, a SUNY Distinguished Professor in Physics, represents a rare breed of scientists who not only understand the densest of subject matter but can break it down in a way that makes it come alive for the lay person.  He has been doing both for a long time.

Chang Kee Jung
Chang Kee Jung in his office

Since arriving at Stony Brook in 1990 from Stanford University, where he conducted various particle physics experiments based on high-energy particle accelerators, he was in the vanguard of recognizing the important role that neutrino physics would play in the subsequent decades. He started a research group called Nucleon Decay and Neutrino (NN) at Stony Brook to study neutrino properties and search for proton decays.

The NN group participated in the collaborations that made an historic discovery of the neutrino oscillation phenomenon, resulting in a Nobel Prize in Physics in 2014 and a 2016 Breakthrough Prize in Fundamental Physics for further experimentation. Since 2014 he shifted his research effort to the Deep Underground Neutrino Experiment (DUNE), which is expected to discover charge-parity symmetry violation in the lepton sector, an important clue for scientists to understand the matter-antimatter asymmetry in the universe along with proton decay and neutrinos from supernova explosions.

In an “alternate universe,” Professor Jung has collaborated extensively with Stony Brook alumnus Bedel Saget ’88 and his award-winning New York Times graphics/multimedia team for sports that captured and explained the innovative feats of athletes such as Olympic gymnast Simone Biles.

In addition to teaching a number of courses designed for physics majors, Professor Jung, while at Stony Brook, has also adapted and created courses to help non-science majors gain a better understanding of how physical properties help explain both natural and human phenomena.  

Q: What got you involved in teaching The Physics of Sports, a course first available at Stony Brook in 2003? Are you an ardent sports fan and just naturally think about these types of things?

A: I truly love sports and follow all major sports and sports events. Growing up, I played all kinds of sports including soccer at the varsity level in college in Korea, ping pong and tennis. I was an expert rock climber though I don’t consider that a sport. And I still play volleyball. The only major sport I didn’t play is American football. Interestingly, my brother was a quarterback at one of the Korean universities that feature American football. I do not exercise for exercise’s sake, such as running or cycling. It must be some kind of a game for me to be interested in it. I wanted to be a physicist starting at the age of 12. I asked how big the universe was, where it ends and what is infinity. I didn’t choose religion, I chose physics. What I figured out is that a lot of sports can be explained with very simple physics. After you take my course you will never watch sports the same way.

Science on Tap
Chang Kee Jung discusses the physics of sports at a Science on Tap event sponsored by the Alda Center for Communicating Science.

Q: Would you consider your course, The Physics of Sports, to be relevant learning, pop science or a combination of the two?

A: What I am doing is somewhat similar to what Alan Alda (of the Center for Communicating Science) is doing, although his thinking is more in terms of actual scientific research. His emphasis is that scientists need to learn how to speak plainly and capture peoples’ focus. America looks at many, many sports on television.  I am focusing on the physics of sports, not research, but hopefully exposing physics to a wider audience. That can be achieved if we can teach physics in a way that people will be interested to learn. I am trying to find ways of teaching physics to the public without using complicated mathematics. My course is much more conceptual.

Q: How do you decide which topics you wish to pursue?

A: Back in 2003 I visited a Yale professor, Bob Adair, who wrote a book called The Physics of Baseball. We hit it off. I wanted to introduce a course that touches upon the physics in all popular sports so there would be even wider interest. How many people, other than sailors, are interested in the physics of sailing for example? My experience is that those professors who are concentrating only on the physics of individual sports don’t usually reach as many students.

Q: Can you talk a little about the course that you introduced to Stony Brook not long after you first arrived here in 1990?

A: Yes, it was called Light, Color and Vision. It was a course taught at a few other universities and I adapted and changed it. Light is generated by many different sources, such as the sun and lasers, and will propagate through the atmosphere. You can explain a rainbow, a double rainbow, a sundog (mock sun), through physics. You can even explain how Moses split the sea. I tell kids that this is mom and dad’s course because after they take it they can answer all the questions their children ask. I taught it for seven years. Other professors are teaching it now.

Q: How did you become the go-to guy to the media, for any unexplained phenomena in American sports?

A: As far as I can tell I was the first person to teach the Physics in Sports course in the country, perhaps the world. I was at the peak of my career, leading five different research projects. After I introduced the course that fact became quickly known. I received offers from publishers to write a book but I just had no time. In the meantime, I got quite well-known by the media. Whenever they wanted to know the physics behind something they came to me with questions. The New York Times and Wall Street Journal came to me to analyze baseball, soccer and American football footage. The National Football League became interested and came to Stony Brook to take video of a special lecture I gave for “NFL Films Presents,” a ten-minute program they produced. By the time Deflategate became an issue in 2015 I was all over the place. I got calls from ABC News to analyze stick figure drawings. NBC’s Brian Williams wanted to interview me the night before he was fired but I was on an airplane. I was on MSNBC and in USA Today along with many other news outlets. When you deal with the media you need to know how to be brief but also easy to understand, which is not easy for a physicist but I am getting more relaxed about it. 

Q: Do the best athletes have an instinctual understanding of how physics influences their game? And if so, how so?

A: They may not understand it in terms of theory but their body instinctually understands it. For example, an athlete doesn’t know the formula of how gravitational force works but knows how to work with it. In baseball, coaches tell you not to develop a golf swing. If you look at the top home run hitters, their bats are flat but the ball hits the upper part of the bat. Some players can command their brains and hands better than others. Players are all different and they have different levels of eye and hand coordination. And when a pitch is thrown, a batter has to instantly solve a highly complicated problem in four dimensions. It can land anywhere in the strike box but it also comes in on an angle. Then there is the timing. When a pitcher throws a ball a batter has .4 seconds to make up his mind whether to swing. If he blinks that is another .2 seconds. The general reaction time is .3 seconds.

Q: So much has been made about the Major League baseball being “juiced” in 2017. Does there appear to be sufficient evidence with more balls leaving the park and the league-wide Earned Run Average of pitchers significantly increasing?  How would any changes to the baseball affect the flight of the ball?

A: Having never actually touched a Major League Baseball during this time frame I cannot say. I have read some of the articles and looked at the data. Some analyses scientists are making are not quite correct either in theory or assumption. Looking at the data it does appear that something happened since 2015 — whether it was done on purpose or was a manufacturer’s deviation (same as football’s Deflategate). NFL gives a pressure range for the football as does the MLB for the size of the baseball. Both these rules date to a long time ago. Both sports are 100 years old. I am not sure if this has been updated and much progress has been made. Nowadays with the rapid advance in the high technology, Major League Baseball can specify the weight, diameter of ball and height and width of the stitches far more precisely. And then there is how manufacturers treat the surface of the baseball. All of these things can be controlled. You can make the surface smoother. Leather can be chosen that is smoother. Many things can be done in modern technology to make it harder for pitchers to grip the baseball. For effectiveness, four-seam fastballs, curves and sliders all rely on the number of RPMs spinning. Seth Lugo of the Mets may throw a 3000 RPM curveball but if his grip is bad and it is only 2000 RPM it won’t dive as much and would be easier to hit.

Pitchers could be losing the advantage to the batters because of the smoother baseball surface and as a result the exit velocity of batted balls can increase, which appears to have been happening since 2015 summer. The second thing that can happen is that the construction of the baseball can be similar but when wrapping the ball inside it can be tighter. The weight will remain the same but the diameter can slightly decrease. A small decrease in diameter will reduce air resistance. As for pitchers complaining about the grip and assuming what they say is true they may have lowered the stitches, which would make it harder to grip. Although it is likely this didn’t happen, a Major League Baseball official could give the signals to the manufacturers to make the ball more bouncy. A baseball is made with a core of many layers. They could make it more lively without changing anything else. It is said that baseball is a game of inches but it is really a matter of a fraction of inches. Whether a batted ball is a home run or a pop up is determined by the angle it strikes the bat, a matter of fractions of inches. It appears that the diameter of the ball may have actually decreased, which could explain why balls are going farther. One of the statistics that is harder to explain is the big jump in home runs beginning in 2015 up until 2017.

There is also another phenomenon called positive feedback loop, when the product of a reaction leads to an increase in that reaction. Let’s say I want you to do something you are reluctant to do but if I give you some rewards you will do it. Home runs bring accolades and excite fans. I don’t know this for a fact, but perhaps managers and coaches are asking players to swing harder or to move the position of the hands to make the ball travel shorter or longer. If all players are trying to hit home runs the result can be more home runs but also more strikeouts. Data supports that this is happening. The philosophy of the game may be changing and the ball itself may be changing as well.

Q: Since it is football season, can you talk about the physics involved in throwing a football for distance and accuracy?

A: Some scientists say the scientific law of energy conservation comes into play, as the arm can only generate so much energy. You will lose arm strength and speed if you concentrate on spin, which is not necessarily correct. When a quarterback throws the ball the speed comes from cocking the arm back and the muscle that moves it forward. The spin of the ball comes from the wrist and the wrist goes down with the release. Thus, generating a tight spiral (high RPM) and generating a high release velocity are semi-independent. A quarterback can train to increase both aspects.  My guess is that Aaron Rogers may generate a very high spin rate close to 700 RPM along with very high release velocity  of roughly 60 mph. The good quarterbacks have good arm strength and good wrist motion and can throw a relatively long distance without pulling the arm back very far, which is important in protecting the ball from defenders.

— Glenn Jochum

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