Pitcher, Physics Major Studies Curve Ball

Baseball one of several athletic activities covered in Physics of Sports

March 26, 2014

nate Grady - Physics of Sports

An all-conference pitcher for the Prairie Fire baseball team, Nate Grady already knew the "how" of the curve ball. Now he has an in-depth knowledge of the science and the numbers behind the breaking ball. The physics major just spent winter term in the course Physics of Sports, which concluded with his project on the physics of the curve ball.

Students in the course examined a variety of athletic activities during the ten-week curriculum. Grady completed his project on the curve ball just as pre-season practice was beginning earlier this month. As a teammate practiced pitching, Grady tracked the movement of the ball with a high-speed video camera. Mark Shroyer, associate professor of physics and the instructor in the course, worked the radar gun.

Mark Shroyer, Nate Grady"We were able to capture video and radar data pretty well," Shroyer says. "Nate calculated the position of the ball as a function of time, and he was able to plot the sideways break of the ball."

Grady, the student and starting pitcher, explains the physics: "The spin of the ball creates different air velocities on the sides of the ball. The different velocities cause different pressures -- the Magnus effect -- and the ball moves in the direction of the lower pressure."

Shroyer, the physicist (and multi-sport athlete when he was in school), is also a student of the game: "Physics explains the breaking ball. As a pitcher, you want to make that happen in a consistent way, and in a way that doesn't hurt you. The next level is to have multiple pitches that all look the same from the perspective of the hitter. The best hitters are picking up what's about to happen by watching the pitcher's motion. The pitcher doesn't want to give anything away until the very last moment."

Grady says the course brought together his interests -- in his sports and in his studies. "I'm a thinker, and I've always thought about (how the ball moves) -- whether it's throwing a basketball, football or baseball... It looked like a fun course. It's been an awesome review."