Essay On The Magnus Effect

Movement of a baseball

When a ball spins, it creates an envelope of air around it called the boundary layer. This boundary layer moves with the ball whether it spins forward or backward or sideways. The interaction of this boundary layer with the surrounding air results in an outside force that changes the path of the baseball.

This is the Magnus effect named for German scientist Heinrich Magnus, this effect is a principle of fluid dynamics that describes the lift created by the spin of an object that is moving through a fluidly. The shape of airplane wings causes air to move faster over the top of the wings than it moves beneath the wings. The faster moving air results in lower air pressure above the wing and greater air pressure beneath

When the ball has back-spin, like a fastball, the boundary layer under the baseball shoots air forward into the air that is trying to move around the baseball. The opposing air flows result in slower air movement and higher air pressure underneath the baseball. On top of the ball, the boundary layer shoots air backward in the same direction as the air that is trying to move around the baseball. These air flows compliment each other and combine to create faster air movement and lower air pressure on top of the baseball. The combination of slower air movement under the ball and faster air movement over the ball creates lift that opposes gravity. The Magnus effect, in this case, acts just like an airplane wing. For a curveball, the top-spin is like turning that wing upside-down. The opposing air flows are now on top of the baseball, and the complimentary air flows are on bottom. Here, the Magnus effect creates lift that compliments gravity. With a tilted spin axis, the Magnus effect creates a tilted lift. A left tilt adds right to left movement when the pitch has backspin and left to right movement when the pitch has topspin. A right tilt has the opposite effects. When a pitch spins perfectly sideways, like a screwball or a sweeping curveball, the Magnus effect does not create a rise or drop. Instead, it creates sideways lift. Viewed from the top, clockwise spin results in left to right lift, and counter

The obvious part is that greater movement is due to a greater Magnus effect. The not so obvious part is how to increase the Magnus effect to create even more movement. The simple answer is to give the ball more spin. The faster a ball spins, the greater the resulting Magnus effect will be. Squeezing just one extra rotation out of a pitch can have dramatic results on the pitches movement. You may have noticed that I didn't talk about the knuckleball at all. Well, the knuckle ball doesn't spin, so it has no Magnus effect. A knuckle ball's movement is strictly an aerodynamics issue where the seams cause immediate disruption in the surrounding air flow rather than through a boundary layer. On the pitch's way to the plate, chaos theory takes over and the knuckle ball waivers as the seams catch air and unpredictably change the path of the ball. Finally, release angles play a sizable role in creating movement. For example, if a pitcher releases the ball two feet outside of the rubber, it has to move roughly 3 1/2 feet to reach the opposite corner of the plate. Sliders and curveballs with glove-side lift will look like they are moving nearly 4 feet as they cross that corner, even though they only break about 3 to 5