How Do They Do That? Throwing a Curveball
Throwing a Curveball
It's the bottom of the ninth; two strikes, two outs and Casey's at the bat. The pitcher throws and Casey swings, but the ball takes a sudden break downward and the bat goes helplessly over the top. Game over. You (and Casey) may be wondering just how the pitcher made that ball curve.
Learn a little of the skill and science behind the art of the curveball.
Pitching mechanics is pretty involved; we'll focus on a couple of things that help make the ball curve. During the throwing motion, the palm of the hand faces inward toward the ear. As the ball is released, a snap of the wrist toward home plate creates a forward spinning motion.
Going against the flow
Once the ball leaves the pitcher's hand, physics takes over. As the ball travels toward home plate, it pushes against air flowing on the opposite direction.
Because of the rotation, the seams and the ball itself are dragging air along with it. The bottom of the ball moves with the air, but the top is moving in the opposite direction.
This slows down the air at the top of the ball, because it's moving into the wind and speeds it up at the bottom, creating a pressure difference.
This acts as a force, pushing the ball downward from higher to lower air pressure.
This force is known as the 'Magnus Effect'.
Different grips and releases make the ball move in different ways, bringing pitches such as sliders, sinkers and change-ups into play.