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September 14, 2005:

Porter Johnson *67

Porter Johnson *67 shows secondary school teachers how to incorporate interactive, real-world examples in their lesson plans. (Courtesy Illinois Institute of Technology)

A whole new ballgame
Porter Johnson *67 teaches the physics of baseball

Porter Johnson *67, a baseball fanatic, knows the conditions that make the air ideal for hitting home runs: high altitude, which reduces air resistance; warm temperatures, which decrease the air’s density; and high humidity, which allows the ball to travel through lighter-than-air water vapor. It’s information that would be especially useful to power-hitting first basemen, but Johnson, who earned a Ph.D. in physics and specializes in particle theory, prefers to relay the knowledge to high school science teachers and their students.

Johnson teaches the science of baseball in his work as a co-director of SMILE (Science and Mathematics Initiative for Learning Enhancement), a Chicago-area program that encourages secondary school teachers to use interactive examples in their lesson plans. He works primarily with teachers, some of whom have invited him to visit their classes as a guest lecturer. “The idea is to enrich the experience by having students see what science is, not just hear about it,” says Johnson, who has been a professor of physics at the Illinois Institute of Technology for 36 years.

The laws of physics are everywhere, according to Johnson, from the expansion of strings that flattens the tune of violins in warm weather to the V-shaped position that ski jumpers take in flight to reduce air resistance. But baseball is always the favorite for Johnson’s audiences, perhaps because of the professor’s encyclopedic knowledge of the topic.

Growing up in Chattanooga, Tenn., Johnson came of age in Mickey Mantle’s prime and faithfully followed the New York Yankees. He recalls listening to the final innings of Don Larsen’s perfect game in the 1956 World Series. “The principal played the game on the public address system to the whole school — this was considered a historic event,” he says. “Sputnik, interestingly enough, was not, except by me.”

In the classroom, Johnson’s most popular lesson involves showing how and why a curveball works — because of the Bernoulli effect. As a right-handed pitcher spins the ball counterclockwise, he says, the speed of the air over the surface of the ball on the left side is greater than the speed on the right side, forcing the ball to curve left. Johnson also enjoys illustrating the mechanics of baseball through numbers. For example, a pitcher releases the ball about 66 feet from home plate, and a 90-mile-per-hour fastball travels more than 132 feet per second. So batters have less than half a second to react and make contact with the ball.

Seeing baseball as a set of formulas has not made Johnson a dispassionate observer. If anything, he says, it gives him a greater appreciation of the players’ talents. And like most fans, he cannot resist the chance to critique the umpires — scientifically, of course. “The umpire misses the call [ball or strike] on 5 to 10 percent of the pitches,” he says. “He just can’t see well enough because the catcher is always blocking his view. ... Perhaps baseball would be well served if they had a telemetry system” to measure the ball’s position as it crosses the plate.

By B.T.