Carlson says that there's nothing contradictory about the head of an association for amateurs holding an advanced degree. The Ph.D., he says, is a "union card" that gets professional scientists to take him seriously.

Plus, with the specialization required of academics, he says his advanced training is, in fact, quite limited.

"I'm a professional nuclear physicist," Carlson says. "I'm an amateur everything else."

Carlson traces his real science education to his grandfather, a serious amateur investigator who accumulated mountains of rejection slips from scientific journals.

"My science education came on my grandfather's knee," he says. He's "been privileged to know Nobel Prize winners and members of the National Academy of Sciences. But in terms of sheer, raw creativity, my grandfather is the best scientist I've known."

In 1970, Carlson's grandfather made his first and only appearance in the scientific literature when C. L. Strong, then the author of the Amateur Scientist column, based a column on his experiments with plant growth under conditions of abnormal gravity.

Carlson, who was 10 years old at the time, says that within two years, he had figured out a solution to a question that that had eluded his grandfather in his experiments: how to grow plants under a gravitational force greater than zero but less than the earth's gravity.

The device he developed--using bicycle wheels and pantyhose--formed the basis for his fourth Scientific American column--and prompted a call from NASA scientists who hoped to use the technique in their research.