How Does a Ball Curve in the Air?

The Grip

The first thing the pitcher must concern himself with when throwing a curve ball is the grip. Place your middle finger on the laces and keep it on the seam during the delivery. You second finger should be next to the middle finger and your thumb should be directly underneath. This will give you the opportunity to throw a pitch that breaks significantly as it travels the 60 feet, 6 inches to home plate.

Impart Spin

The curve ball will either mover down and away or down and into the batter, depending on whether the batter is right-handed or left-handed. A ball that breaks down and away from the hitter is usually the most difficult to hit, but that is not always the case. In order to get the ball to curve, the pitcher must twist his wrist demonstratively. By the time he gets rid of the ball, the back of his wrist should be facing the batter. After throwing the ball in this manner, the ball will meet with significant air resistance and the spinning action will make the ball curve.

Air Flow

After the pitcher has snapped his wrist to create spin on the ball, the air flow around the baseball changes dramatically. The top part of the ball spins directly into the air and meets resistance while the bottom part of the ball spins with the air. The air under the ball is moving faster than the air on top and this is why the ball breaks down from the point it is released. There is an imbalance of force around the baseball and that's why it curves. This principle is called the Magnus Effect, so named for the physicist Gustav Magnus who discovered in 1852 that an object spinning in liquid will always move sideways.