The Physics of Baseball
Argonne National Laboratory
19 July 2006
Porter W Johnson
Illinois Institute of Technology


Baseball is our national sport, and it also has broad international appeal. It is by far the oldest organized professional sport. Its development reflects the history of our nation, as well our increasing technological sophistication. The application of physical principles to baseball is considered. Dynamical issues in pitching, hitting, fielding, and running will be examined.

A Few Important Parameters
Highlights in the History of Baseball
1839  Alexander Doubleday allegedly invented baseball in Cooperstown New York
1865Overhand pitching legalized
1876National League organized
1900American League organized World Series begun
1919Chicago White Sox scandal
1920“Live ball” era “Spitball” banned
1927Babe Ruth hits 60 home runs in a season
1932Leagues adopt common baseballs
1935Night baseball begun
1941Joe DiMaggio hits safely in 56 consecutive games
1947Jackie Robinson plays for Brooklyn Dodgers
1961Roger Maris hits 61 home runs in extended season
1962Maury Wills steals 104 bases in a season, breaking Ty Cobb’s record of 97
1971Cowhide substituted for horsehide on baseballs
1972American Leagues adopts “designated hitter” rule
1984Pete Rose breaks Ty Cobb’s lifetime record of 4189 hits. (4256 total)
1998Sammy Sosa and Marc McGwire break Ruth’s Home Run record
2000Leagues adopt common standards and training programs for umpires
2001Barry Bonds hits home run #73, averaging one per 6.5 at-bats
2004Ichiro Suzuki gets 258 hits in a season, breaking George Sisler's 1920 record of 257 hits
For information on the cultural roots of baseball, see the website

Other Sports

Results of World Baseball Tournament: held  03 - 20 March 2006


The pitcher stands less than 20 meters from the batter, and throws the ball at speeds of around 40 meters/sec. In that time the ball drops from its "straight line" path by about 1.2 meters.

Because of the stitches on the baseball there is considerable turbulence affecting its motion, and it may behave somewhat erratically. The complications in the motion of the ball arise from the Prandtl Layer of air that moves with the baseball, and which has a dominating effect on the motion of the ball.

The pitcher may put considerable spin on the baseball, corresponding to about 20 revolutions over its path.

A few pitchers have been able to perfect the knuckleball, which hardly spins at all, and which drifts somewhat arbitrarily in its motion.

Ty Cobb's remembrance of his introduction to Walter Johnson:

"On August 2, 1907, I encountered the most threatening sight I ever saw in the ball field. He was only a rookie, and we licked our lips as we warmed up for the first game of a doubleheader in Washington. Evidently, manager Pongo Joe Cantillon of the Nats had picked a rube out of the cornfields of the deepest bushes to pitch against us. ...

The first time I faced him I watched him take that easy windup-and then something went past me that made me flinch. The thing just hissed with danger. We couldn't touch him...every one of us knew we'd met the most powerful arm ever turned loose in a ball park."


The batter has about 0.5 seconds to gauge the path of a pitch, and the bat must be at the right place [within about 1 cm] at the right time [within 0.01 seconds] to make solid contact.

The bat-ball collision lasts typically for 0.001 seconds, and the average force on this ball is of order 10,000 Newtons, corresponding to a mass of about 1000 kg [or a ton].

The process of hitting is mysterious, but with God-given quick reflexes and many years of practice, a few players can learn to hit the ball regularly.

Ted Williams said "Hitting is fifty percent above the shoulders" and wrote a book entitled The Science of Hitting, in which he analyzed hitting with detail normally reserved for scientists and scholars.

"Did they tell me how to pitch to Williams? Sure they did. It was great advice, very encouraging. They said he had no weakness, won't swing at a bad ball, has the best eyes in the business, and can kill you with one swing. He won't hit anything bad, but don't give him anything good." - Bobby Shantz

"Willie Mays was never sick, he was never hurt, he never had a bellyache, he never had a toothache; never had a headache. He came to the park every day to put on the uniform and play." - Leo Durocher, manager.

Batting Fundamentals by Ty Cobb


Like the conductor of a symphony, the catcher directs defensive play, calls the pitches, and keeps the team focused on getting the batter out.

Also, a good catcher can manage to block the umpire's view of a pitch on the outside corner, to keep the hitter psychologically on guard, and guide the pitcher to success.

The catcher is the ultimate line of defense against a stolen base.  A quick runner can steal a base in just over 3 seconds.  The catcher has a little over a second to catch the pitch and throw it accurately to stop the runner.  

The catcher gets more than his share of bumps, bruises, and sprained fingers from foul tips, bad pitches, bats, and aggressive base runners.

Catchers are frequently required to chase after pop-ups behind the plate. These poorly hit pitches usually have a lot of spin, and move erratically, so that pop-ups may be very difficult to catch. A great catcher makes catching them look easy, in spite of the perils of bats, other equipment, dugout steps, fences, screens, and railing.

"Why has our pitching been so great? Our catcher (Yogi Berra) that's why. He looks cumbersome but he's quick as a cat." - Casey Stengel

The ball bounces differently in every ball park, and the differences are especially pronounced on artificial turf, on which the ball has a lively bounce.

A third baseman has to knock a ground ball down or block it, grab it, and then throw it to the first baseman --- all before two seconds have passed.

It is somewhat of a mystery as to how outfielders are able to gauge the flight of the ball, since it can vary greatly because of spin, wind conditions, and atmospheric drag.

Baseball Quotations

"Throwing a fastball to Henry Aaron is like trying to sneak the sun past a rooster." --- Curt Simmons, pitcher

"Hitting against Sandy Koufax is like drinking coffee with a fork." --- Willie Stargell

"Hitting is timing. Pitching is upsetting timing." --- Warren Spahn

"I never saw anyone like Ty Cobb. No one even close to him as the greatest all-time ballplayer. That guy was superhuman, amazing." --- Casey Stengel.

"I never threw an illegal pitch. The trouble is once in a while I toss one that ain't never been seen by this generation." --- Satchel Paige

"I'd go through hell in a gasoline suit to keep playing baseball." --- Pete Rose

"When I came to Detroit I was just a mild-mannered Sunday-school boy." --- Ty Cobb

"He should play in handcuffs." --- A Sports Writer on Willie Mays

"He's got a gun concealed about his person. They can't tell me he throws them balls with his arm." --- Ring Lardner about Walter Johnson

"Ninety percent of baseball is mental, and the other half is physical." --- Yogi Berra

"I'm not sure what the hell charisma is, but I get the feeling it's Willie Mays." --- Ted Kluszewski

"I swing big, with everything I've got. I hit big or I miss big. I like to live as big as I can." --- Babe Ruth

Types of Pitches
  1. High Speed
  2. Moderate Speed; high spin
  3. Seam Orientation Dependent
  4. Off-speed

Baseball Films (my order of preference)