In keeping with today's blog

In keeping with today’s blog theme:

The True Life Story of Baseballs answers a question I’ve long wondered: how many baseballs are used over the course of one major league game? I’d heard it was more than 100, and this article confirms it. Between games, batting practice, and spring training, MLB uses almost 1 million baseballs each season, with the average “life span” of a major league baseball being about eight days (used in one game, then a couple days of batting practice, then a few days in the batting cages, then shipped to the minors or elsewhere as practice balls).

Predicting a Baseball’s Path is a very scientific look at why pitches behave the way they do. Of course, it’s all based on the spin rate of the ball as it leaves the mound, the direction of the spin axis, and how fast the pitch was thrown. Different grips produce different spins. The article also has a cool graphic of how a fastball, curveball, slider, screwball, changeup, and knuckleball move on their way to the plate, which finally straightened it all out for me.

This article also discusses the skills hitters need to pick up on what pitch is headed their way. First they can watch the angle of the pitcher’s arm, and with good eyesight, can sometimes see the grip on the ball, or how the pitchers fingers roll on it. But the most important part is that good hitters have better-than-average dynamic visual acuity, or the ability to perceive moving objects, thus they can pick up the spin on the ball as it comes toward them. Hitters must figure out the speed and spin in 1/7 of a second. In the next 1/7, they decide whether to swing, and if so, when and where. Then they have another 1/7 of a second to actually swing. To hit a fastball, a batter begins to swing when the ball is still about 19 feet from the plate.

If you are at all interested in baseballl, they are both very good articles.

And finally, The Physics of Baseball, a website done by a UIUC Physics professor. I haven’t had the chance to look through it much yet, but sounds interesting as well.