Bubbles: as beautiful as they are hard to understand

They reside in Swiss cheese, Styrofoam, and volcanic rocks. They burrow into bread, nest in bathtubs. They love slime and hate dust, look solid but act liquid. Elegant, ephemeral, temperamental, they delight children, perplex mathematicians.

Bubbles are one of nature's most delicate enigmas. To examine and extol their evanescent contribution to science and frivolity, the Exploratorium, San Francisco's unorthodox science museum, recently convened what is presumed to be the world's first bubble summit. For three days physicists bantered on about bubble chambers and subatomic particles; computer programmers pondered ''bubble memory''; mathematicians contemplated soap-flim theory; and a musician conducted a percussive bubble concerto he called the San Francisco ''pops.'' As a ''fizz ed.'' finale, a local lawyer in bathing trunks lathered up and tried to walk through a five-foot soap bubble he had blown with two friends.

The man who stole the show, however, was not an academic, but a droll 84 -year-old sorghum farmer from Huntington, Ind., with the honest-to-goodness name of Eiffel Plasterer. Mr. Plasterer has been collecting old steam engines and blowing bubbles for over half a century; he shows no signs of running out of steam or breath. The former high school physics teacher with a Colonel Sanders goatee has formed a soap bubble 20 feet across - and also preserved one in a jar for 340 days. It was a four-inch bubble, blown with his secret glycerin-spiked soap solution.

In San Francisco, to a scratchy 78 r.p.m. record of a calliope playing ''I'm Forever Blowing Bubbles,'' Plasterer pulled out all his vaudevillian stops. With the assistance of his poker-face daughter Alice Jacobs, he ''married'' soap bubbles, coaxed them to defy gravity by rolling up a bent coat hanger, and then offered his effervescent Hoosier philosophy. ''Life is not a bubble,'' said Plasterer, ''but like blowing a bubble. We are always expanding our hopes, dreams, and aspirations.''

Also entertaining the masses was bubble troubadour Tom Noddy with his repertoire: caterpillar bubbles, smoke bubbles, carousel bubbles, and bubble cubes. Mr. Noddy, whose bushy red hair is gathered in a ponytail, began in the ' 60s as a ''hippie puppeteer'' doing political satire on the street. One afternoon in New York's Central Park, he discovered he could draw a crowd for his puppet shows by blowing soap bubbles as an introduction. He took up blowing bubbles to earn spare change and hasn't stopped in 12 years. Not long ago Johnny Carson had him on the ''Tonight Show.''

Noddy remains convinced his work has cosmological significance: ''Bubbles are basic to everything, even the origins of the universe,'' he says. ''Now even the scientists are putting bubbles in their big-bang theories of creation. I'm not kidding. Bubbles are the matter of the universe.''

The scientific community couldn't agree more. ''Bubbles are a very important mathematical concept,'' says Frank Oppenheimer, director of the Exploratorium. ''They are also beautiful, fragile, and connected to childhood.'' Dr. Oppenheimer is brother to the late Robert Oppenheimer, the American nuclear physicist who directed the Manhattan Project during World War II.

At the Exploratorium, Oppenheimer stooped to blow a cluster of tiny bubbles through a capillary tube into a deep tray of what looked like printers' ink. ''Water sticks together hard, but just the right amount of soap reduces the surface tension,'' he said. He puffed out another sudsy continent. ''This festival is a revival of curiosity, an attempt to help people understand. . . .'' Oppeneimer halted in mid-sentence.

A herd of grade-schoolers had galloped up to the tray and had begun swirling their fingers in the soapsuds. Oppenheimer held them off with a forearm. They persisted, apparently less interested in hydrogen bonding than in finding out what a handful of taco chips would look like under sail in Oppenheimer's experiment. The scientist fought back the fleet and finished his sentence: ''Many people have given up the hope they can decipher the world. But whether it's inflation, war, computers, or bubbles, the world around us can be understood.''

What remained a mystery was how a sorghum farmer could blow bubbles that lasted an entire year. ''Bubble longevity,'' says Ron Hipschman, one of the Exploratorium's resident physicists, ''depends on three things: the quality of the soap solution, the air on the inside of the bubble (carbon dioxide in human breath eats away at bubbles) and the air on the outside. Pollutants in the atmosphere pop bubbles, and a speck of dust is like a bullet. But after a rain storm, when the air is clean, a bubble will sail forever.''

''Bubbles are not easy to understand,'' says Mr. Hipschman, who also teaches physics at San Francisco State University. ''I don't get into bubbles until two-thirds through the semester. They are a very simple way to talk about surface tension. In fact, they personify surface tension.''

''There's something transient and enchanting about bubbles. And for some reason they're big news these days,'' says Hipschman. ''The London Times, Wall Street Journal, and two of the networks are here covering bubbles. What do you make of that?''

Anthony Tromba, a mathematics professor at the University of California, Santa Cruz, suspects the media is at last onto something which has captivated mathematicians for centuries: soap-film theory. Dr. Tromba has written a book on the subject called ''The Best of all Possible Worlds.'' It will be published later this year by Scientific American. This summer Tromba will also travel to Paris to deliver a 10-part lecture series on soap films to a group of European mathematicians.

Tromba, an amiable fellow, showed up at the Exploratorium wearing something to please everyone: a tweed jacket, blue jeans, white athletic socks, and Birkenstock sandals. ''Dip a wire into a soap solution 100 million times,'' said Tromba, twirling a length of copper around his knuckles, ''and you always get a film. The question the mathematician asks is: 'Might there be some shape so bizarre, perhaps too bizarre even to imagine, with which you will not get a film?' With a pencil and paper we should be able to say yea or nay.'' To this and other stumpers Tromba has dedicated his life and pencil supply. ''If you turn on the tap, water flows out,'' he says. ''Now it may sound silly, but it took mathematicians centuries to actually prove that fluids flow.''

''And did you realize,'' he continued, ''that the soap bubble solves the old dilemma of Queen Dido in Virgil's 'Aeneid'? To establish her city of Carthage, she was offered all the land she could encircle with the skin of an ox. The clever woman sliced the ox skin into an infinitesimally thin strip. And what was the shape of the largest area she could encompass?'' Remembering soap bubbles figured in here somewhere, I guessed: ''A circle?''

''Of course,'' said Tromba. ''Nature economizes. That is why the soap bubble is one of the simple profundities of nature. That is also why soap films have been studied since the 18th century and, believe it or not, have become one of the important areas of research in modern mathematics. And yes, you could say I am one of the world's authorities.''

Sterling Johnson is a bubble authority of more modest proportions. He blows them and walks through them, or at least makes an honest stab at doing that. Johnson, a San Francisco lawyer who claims to practice ''holistic civil law,'' blows bubbles when he's not in court. ''I got hooked on bubbles when I started playing with Ivory Liquid for a soap-film project in high school,'' says Johnson.

''The nice thing about bubbles is their playfulness and lack of pretension,'' he says. ''Having this bubble festival is about as pretentious as you can get.'' To the disappointment of many San Franciscans, the legal community included, the bubbly lawyer failed to walk through a man-size soap bubble without breaking it.

Technically, Exploratorium spokeswoman Linda Dackman says, the feat is possible. ''Bubbles don't know pointedness; they only know wet and dry,'' she explained. ''So if you're covered with soap, you shouldn't pop the bubble.'' To demonstrate, she walked to an experiment in which a five-foot-wide soap film is raised and lowered like a Venetian blind. Dackman dipped her hands in the soap solution, then shoved each hand through the film without bursting it. ''The experiment has only one drawback,'' she said. ''Dishpan hands.''