For those of us in Texas, October is the beginning of Fall. It may not be any cooler but we just cannot wait any longer. October is also time for the World Series of Baseball. I remember being in a subterranean Back Bay bar in 2004, with a hundred college students, as the Red Sox finally won the series after a hiatus of 86 years. OK, so what has baseball to do with science? This month we consider the aerodynamics of the baseball.
Specifically, we will look at the phenomenon of the Rising Fastball. Or as it is known more technically the Induced Vertical Break.
Let’s begin with the theory behind how moving objects create lift. We know the airfoil shape of an airplane wing creates lift as the air passing over the top of the wing moves faster than the air on the bottom. Likewise a spinning cylinder creates lift in a similar way. A baseball is basically a rotated cylinder and the mathematical equation for the ideal theoretical lift of a spinning, smooth ball is:
Where L is lift, b is the radius of the ball, s is the spin of the ball, ρ is the density of the air, V is the velocity of the ball, and pi is the standard 3.1415…
“All that is necessary to create lift is to turn a flow of air. The airfoil of a wing turns a flow, and so does a rotating cylinder. A spinning ball also turns a flow and generates an aerodynamic lift force… The equation given above describes the ideal lift force generated on a smooth, rotating ball.” It has ignored the viscosity of the air. “Viscosity generates a boundary layer on the ball and the stitches used to hold the covering of the ball together stick up out of the boundary layer and disturb both the boundary layer and free stream flow.” (NASA).
It is the stitches and the manner in which the pitcher spins the ball that creates a rising pitch. Now, a rising pitch does not actually rise. Because the spinning stitches increase lift, the increased lift has countered gravity to make the flight path longer. When the ball passes the plate it is higher than the batter expects, but it has not risen.
The rising pitch is very hard to hit. It takes about half a second for the ball to get to home plate. The batter’s reaction time is about a quarter of a second. That leaves just a quarter of a second for the batter to decide where the ball will end up. With the rising pitch, that ball is not where he/she expects it to be.
It struck me that baseball catches the attention of children while mathematics often does not. I suggest the dynamics of baseball (interesting) might be used to make mathematics (uninteresting) attractive.
Anyhow, my two cents in favor of STEM.
Resources
- The ‘rising fastball’ was a tantalizing myth, Chad Jennings, Dennis Lin and Eno Sarris, New York Times, September 2025.
- Aerodynamics of Baseball, Glenn Research Center, NASA.
- Ideal Lift of a Spinning Ball, Glenn Research Center, NASA.
- HOW LONG DOES A BASEBALL TAKE TO REACH HOME PLATE?, Plate Crate, 2025.
- The Science Behind Hitting a 95-MPH Fastball: How Pro Athletes Defy the Impossible, Lionel University.
- Illustration – If You Print It, They Will Come: Baseball’s Early Years, Patrick Hastings, Library of Congress, 2025.
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