Heat, humidity and home runs Sluggers: Baseballs are flying out of big-league ballparks like never before. Why? Scientists have no simple explanation.

September 26, 1998|By Mike Klingaman | Mike Klingaman,SUN STAFF

Who put the oomph into baseball this season? Balls fly out of big-league parks at a near-record pace, and Mark McGwire and Sammy Sosa swing as if they are hitting Flubber.

Both McGwire, the Bunyanesque first baseman for St. Louis, and Sosa, the Chicago Cubs outfielder, smashed the single-season record of 61 home runs set by Roger Maris in 1961. With two days to go, both have 66.

Seattle's Ken Griffey has 55 home runs, and eight other players have clubbed 40 or more.

Fans and pundits offer the standard skinny for the power surge, from second-rate pitching to smaller stadiums. But query a group of scientists and the home run theories go upscale. One college professor blames the heat; another, the humidity. Today's bats are feats of engineering, says one physicist. The swing is the thing, says another.

That's baseball, 1998: Even the folks in lab coats have gotten into the argument.

There is no evidence that the ball itself has been tampered with, or juiced, scientists say. "Quality control is very good," says Peter Brancazio, professor of physics at New York's Brooklyn College. "I know laboratories that check entire boxes of balls, from year to year, and find little variation."

Through Thursday's games, 4,962 home runs had been hit in the majors -- an average of one every 33 trips to the plate. Only twice has baseball showed more clout, in 1996 and 1987. But those years will forever pale beside 1998, the first time in history that two men hit 60 or more home runs.

What's going on? It's as if hitters are just teeing off.


"Anytime you swing like a golfer, like McGwire and Sosa do, the ball goes farther," Brancazio says. "The plane of their swing is upward, which puts a backspin on the ball and gives it an aerodynamic lift.

"A spinning ball will travel 30 to 40 feet longer. And McGwire really uppercuts the ball, resulting in some tremendous moon shots."

It's no coincidence that home runs are rampant as pitchers complain of a diminished strike zone, says Morton Tavel, a physics professor at Vassar College in New York.

"Watch a game and you can see that the strike zone has been lowered significantly," says Tavel, a baseball fan for half a century. "In the 1950s, when strikes were letter-high, guys like Ted Williams and Willie Mays took horizontal cuts -- and hit lots of line drives. Now the strike zone is lower and batters are swinging from the heels, like (Jack) Nicklaus, using the force of gravity to put more energy into it."

Bats are responsible for the home-run barrage, others say. Bats today are whippet-like kin of the lumbering 40-ounce models of Babe Ruth's day, says Porter Johnson, a physics professor at Illinois Institute of Technology. Bats are lighter and thinner, averaging 31 ounces, with anorexic handles that can shatter on impact.

"Nowadays, there's almost no wood [on the bat] below the trademark," says Johnson. "But, boy, can they hit."

He explains this in terms of a formula dealing with mass and force. The bottom line: The momentum of a lighter bat transfers greater energy to the ball.

"McGwire's arms may look like those in a Popeye cartoon, but he swings a 33-ounce bat -- and lighter bats add punch to the ball," says Howard Brody, professor of physics at the University of Pennsylvania. "Usually, the faster you swing, the farther the ball will go."

Coincidentally, an article in September's American Journal of Physics probes the dynamics of the collision:

"Batters know from experience that there is a 'sweet spot' on the bat, about 17 centimeters from the end of the barrel, where the shock of the impact, felt by the hands, is reduced to such an extent that the batter is almost unaware of it," writes Rod Cross, a physics professor at the University of Sydney in Australia.

Making contact at that point, players say, enhances their chances of hitting home runs.

Cross dissected a new bat and discovered not one but three sweet spots, all close together -- a bonus, perhaps, for power hitters.

Hot, humid weather is a boon to sluggers, say scientists, who rarely broach that aspect of global warming.

"It's a fact -- balls carry farther in hot weather," says Brody, the University of Pennsylvania professor. "Why does a hot-air balloon go up? Because hot air is less dense than cold air. So, if this summer has been hotter than normal, as many people claim -- Aha!"

Muggy weather also favors long-ball hitters, says Dieter Forster, professor of physics at Temple University in Philadelphia. "The atmosphere is actually less dense on sticky days because water vapor is [lighter] than air," he says.

But it may be that neither meteorology nor physics is the underlying factor. Perhaps it's a matter of psychology, says Forster:

"If I had to guess why there are more home runs this year, I'd say it had more to do with two men racing against each other, than with bats and balls."

Pub Date: 9/26/98

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