Q: Can a baseball pitcher throw a...

Q: Can a baseball pitcher throw a breaking curveball, a ball that curves in flight and then suddenly drops before it gets to the plate?

A: No, according to mathematician Keith Devlin of Stanford University. He can throw either a curveball or a breaking ball, but not both at the same time.

A baseball has 216 stitches on its surface. As the ball spins in flight, the stitches pull a layer of air around it. If the ball is thrown with sidespin, the air will be moving faster on one side, causing the ball to curve by Bernoulli’s principle. If it were not for the force of gravity, the ball would fly in a perfect circle, eventually returning to the pitcher. If the ball is thrown with topspin (forward spin), it will curve downward faster than it would if left solely to the forces of gravity. A pitcher cannot, however, impart both topspin and sidespin simultaneously.

By the way, he says, there is also no such thing as a rising fastball. If a ball is thrown with backspin, it will not sink as fast as it would if left to the forces of gravity, but it will not rise.