Charles Nailen/The Hoya  

Behind the emotion, sweat and muscle of baseball lies a game dictated by the immutable laws of physics. Baseball fans often miss this scientific layer, as everyday baseball jargon undervalues the scientific phenomena of the game. Fans hear and speak of “curveballs,”sliders” and “knuckleballs,” but what exactly occurs on the scientific level when a pitcher unleashes from his arsenal one of these seemingly physics-defying pitches? The combined effect of spin direction, speed, arm angle and even microscopic air molecules play a significant role in determining the unique movement of a pitched ball.

The “science” of pitching has evolved tremendously over the course of baseball history, a game that originated in Cooperstown, N.Y., around 1839. In its earliest form, baseball games featured pitchers that lobbed the ball to the expectant batter, actually assisting him in connecting for base hits. One of baseball’s first real stars, James Creighton of the Brooklyn Niagaras, changed that tradition and, ultimately, the way baseball is played. Instead of simply lobbing the ball to the expectant batter, Creighton threw what the opposition described as “speedballs,” which certainly proved difficult considering his proximity to home plate (only 45 feet at the time).

Creighton popularized the most important pitch in baseball, the fastball. Present-day fastball pitchers such as Randy Johnson and Bartolo Colon dominate the league with these lightning-quick pitches. With only a small fraction of a second to respond to such speed, hitting a fastball is clearly a difficult task. Regardless of how complete a pitcher’s arsenal may appear, continued success on the mound demands a decent fastball. In major league baseball, the speed of a respectable fastball generally hovers around 90 mph. Nolan Ryan set the major league record with a fastball clocked at an astounding 100.9 mph.

As the game progressed, pitchers began to mix speed with deception. In the 1860’s, a young Brooklyn teen, William Cummings, noticed his ability to make a clamshell curve as he threw it through the air. As a lover of baseball, he wondered if this trick could be applied to pitching. Only a few years later, in 1867, “Candy” Cummings, as a pitcher for the Brooklyn Excelsiors, tested his experimental throw against Harvard’s team. Convinced and overjoyed at his success after striking out several batters, Cummings later explained his secret, which was to give “the ball a sharp twist with the middle finger which causes it to revolve with a swift rotary motion.” The ball’s topspin, similar to that used on the ball in tennis, causes the crafty downward movement.

The true secret behind a good curveball lies in its physics. Professor Scott Heron teaches the Georgetown physics course, “The Way Things Work” and explains the theoretical base behind the magic pitch. “Baseball physics is based on fluid dynamics. A pitch produces a turbulent wake of air behind the ball. The wake gets deflected depending upon which way the ball rotates. For a fastball, this wake gets pushed down, which then pushes the ball up .. A curveball’s rotation makes this wake point up. The wake is pushed upwards, and, in turn, the ball is deflected downward by the wake.”

The inception of the curveball led to the development of other pitches that utilized an alternative spinning of the ball. The slider, or “nickel-curve,” became popular in the 1960s. This throw combines fastball with curveball as the ball is essentially launched the same way as a spiraling football. The slider’s sidespin rotation causes the ball to move across the plate according to the same physics principles. “The differing speeds of the air molecules compared with the surface of the ball is the reason why the force is created, whether it be up, down, or sideways,” explains Dr. Heron.

Thus far, the pitches discussed have centered on the direction of spin and speed of the ball as the determining factors for its movement. What would happen then, if the ball could theoretically be kept from spinning? Try it sometime. It’s almost impossible to do over the traditional pitching distance. Left-hander Toad Ramsey of the American Association began to tinker with such an idea in the 1880s. A severed tendon in his middle finger encouraged him to grip the ball wide with his neighboring fingers, producing a pitch with very little spin. Building on Ramsey’s idea, Eddie Cicotte, known as “Knuckles,” pioneered a grip that produced a no-spin effect. By utilizing the nails and fingertips and by pushing the ball out of the hand instead of throwing it, he developed the most mystifying pitch in baseball, the knuckleball. If there is no spin, what path could the ball take? Interestingly, there is no defined answer when there is no defined spin. The pitch can take on the movement of any other type of pitch.

Tim Wakefield of the Boston Red Sox has made quite a career for himself as the premier knuckleball pitcher in major league baseball. While successfully feasting off the steady diet of fastballs thrown their way by the rest of the league, the sport’s best hitters cringe at the sight of the wobbly and slow-moving pitch. Most knuckleball pitchers throw their trick pitch at a speed merely in the 60-70 mph range, yet batters lose their balance attempting to hit these unpredictable pitches.

The ideal knuckleball should complete one half of a rotation over the course of its path to the catcher. Dr. Heron explains, “The knuckleball’s effect is entirely dependent on its seams. The air has to travel at different speeds on different places of the ball. Some air molecules have to travel over the ridges created by the seams, while other molecules travel over the smooth surface of the baseball. This relative difference in speed creates a force that pushes the ball in one direction as the ball slowly spins, causing a change in the ball’s orientation , allowing for a similar process to occur but with a different outcome.” Acting like a pitch from a “Goofy” cartoon, the ball essentially gains the ability to move up, down and sideways over the course of its travel to the plate.

Pitchers have difficulty throwing the pitch faster than 70 mph. However, this speed ideally serves to maximize the effects of the pitch. At a lower speed, the turbulent wake would not develop, and at higher speeds, the wake actually reduces in size and decreases the strength of its overall effect. A perfect blend is found at speeds in the 60-70 mph range.

The principle behind the knuckleball explains the forkball, or split-finger fastball, which mixes the speed of a fastball with a knuckleball’s wobbling effect. By stretching the index and middle fingers over the horseshoe part of a ball’s seams, pitchers can minimize the spin and still throw at high speeds. Looking like a fastball at first, a tumbling effect occurs as the ball drops, knuckling slightly all the way, just before it reaches the batter.

By utilizing simple principles of physics, pitching has undergone a dramatic evolution, transforming the position into a science. Greg Maddux has compiled a Hall of Fame career not with overpowering speed, but rather with a full arsenal of pitches marked by tremendous movement, deception and accuracy. Creating the timeless physical chess match between the pitcher and the batter, the craft of pitching employs these laws of physics to always keep the batter guessing.

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