Knuckleball

A knuckleball is not the same as a curve ball. The curve ball moves downward. The knuckleball actually "dances" through the air on its way to the batter. No one knows why this happens, for sure.

The curve ball spins fast as it moves toward the batter. The knuckleball is thrown slowly with no spin. However, it is believed that the stitches on the ball cause it to turn slowly. The stitches on the ball may affect the changes in the forces on the ball.

The air flow over the surface changes from smooth to rough (laminar to turbulent). The stitches may also cause the ball to change direction (rotation). This change causes air flow to become smooth, then turbulent (rough). Even if the ball is thrown without any spin, these force changes will still cause it to spin. The "dance" begins!

The Spitball and Vaseline Ball

The knuckleball is very difficult to throw. Another way to get the same effect is to use saliva (spit) or vaseline on the ball. The ball slides through the pitchers fingers and the pitcher can throw it with no spin as a "fast ball". This makes it almost impossible to hit. This is why it is illegal, in professional baseball, to put spit or vaseline on a ball.

Another "dirty trick" is to rough up one side of a ball and polish another side. Various pitches used by pitchers will be exaggerated (made greater) helping to confuse the batter. A pitcher must know aerodynamics, too !