Dimples give batters more power.

Jeffrey Di Tullio of the Massachusetts Institute of Technology came up with his latest batty idea while sitting in a traffic jam. "I was sitting there, stuck in traffic, thinking about the work I'd been doing lwith my students," he said, "when I realized that if you could reduce the drag on a bat you might be able to swing it faster."

Conventional, cylindrical bats are not aerodynamic. Much of the energy required to swing such a bat actually goes into pushing air out of the way. Improving air flow around a bat, reasoned Di Tullio, would enable a person to swing if faster. A faster bat would strike the ball harder and send it farther.

although air flows almost all the way around airplane wings, it gets trapped in energy-consuming tornadoes, vortices, and swirls around the sides and back of a bat. Professional baseball notes wryly, but adding bumps or dimples to a bat's surface would make it a little more aerodynamic.

The advantages of bumps and dimples have been known for a long time, says Di Tullio. Whenever an object is moved through the air, a very thin layer of air sticks to its surface. The layers just above this move very slowly and contain very little energy -- not enough to swish all the way around a bat.

Surface roughness mixes the slower bottom layers of air with thye faster upper layers. "The net result is that [the dimples] add energy to the air right on the surface and give it that little extra [push] it needs to follow the contours of the bat," says Di Tullio. Because less air now needs to be moved out of the way, the bat moves faster.

Di Tullio tested bats with dimples rather than bumps because bumps might affect the trajectory of balls hit. He pressed the dimples into the bat -- rather than cutting them out, which might lighten the bat -- from about 18 inches above the handle to the end.

Di Tullio timed semiprofessional baseball players as they swung various bats in air tunnels at MIT. He found that they swung dimpled bats 3 to 5 percent faster than normal bats of the same dimensions.,

This increased speed added 10 to 15 feet to a fly ball, says Di Tullio, which might translate into more home runs.

Molecular clusters imitate laser snow

"Laser snow" was so named in the 1970s, when researchers discovered that chemical collisions induced by lasers caused white precipitates, later found to be polymer chains, to drift out of some mixtures of gases (cesium and hydrogen, for example, or carbon disulfide).

Now, John C. Miller of Oak Ridge (Tenn.) National Laboratory and colleagues at the University of Tennessee have discvered a newer form of laser snow. They reported their results at the American Physical Society's annual meeting in late April.

Miller's group began with small clusters, or "snowballs," of carbon disulfide. A low-pressure, low-density gas containing these clusters was irradiated inside a mass spectrometer. After analyzing the products of the reaction, the presearcher found that similar polymerization had occurred. But his time, the craches of excited molecules were not responsible.

Because of the low density, the carbon disulfide clusters did not collide. Instead, says Miller, "an initially ionized molecule 'eats' its way through the cluster like a moleculr Pac Man, creating bigger and bigger polymersd with each bite."

These reactions are unique: Even though they are caused bny a laser, thery take place soley within the cluster, says Miller. Cluster chemistry is a burgeoning field--witness the rise of the buckyball -- and these "clustering within a cluster" chemical reactions may shed additional light on this area of investigation, he adds.