05.02.2005 20:07
Ahead of the curve
Today in 1802, Heinrich Gustav Magnus was born,
a German chemist and physicist who discovered the 'Magnus
effect'.
Why do curve balls curve, and more generally, why do knuckle balls move in more than one direction in their trip to the plate?
Since the Bernoulli effect tells us that the air pressure on the side spinning into the wind will be greater than the air pressure on the side spinning away from the wind (the direction of travel), and this creates a force pushing the ball sideways. (It's more complicated than that, but it works as a first approximation, as in 'First we approximate the Cow as a sphere of radius r.) Depending on the axis of spin, the ball might drop, slide or hop (or in the case of a knuckler, all three). The Science of Pitching by Edward Willett. Unless you're on Mars, where Curveballs become Screwballs.
Why do curve balls curve, and more generally, why do knuckle balls move in more than one direction in their trip to the plate?
Source: Physics of a Home Run by Scott Teresi.
Simplified Diagram of the Magnus Effect
Since the Bernoulli effect tells us that the air pressure on the side spinning into the wind will be greater than the air pressure on the side spinning away from the wind (the direction of travel), and this creates a force pushing the ball sideways. (It's more complicated than that, but it works as a first approximation, as in 'First we approximate the Cow as a sphere of radius r.) Depending on the axis of spin, the ball might drop, slide or hop (or in the case of a knuckler, all three). The Science of Pitching by Edward Willett. Unless you're on Mars, where Curveballs become Screwballs.