SEATTLE -- Bill Nye has just auditioned to play a mosquito in a bug-spray commercial. It's your basic caricature of a pest. Terrorize some picnickers, tromp around on their food, get sprayed, die screaming. The audition went well for Nye, especially the death scene. Still, something is gnawing at the Science Guy. He can't remember his character's name. "Mosquito, order and family ..." says Nye. He draws an anguished blank, like the spelling-bee champ who can't recall whether it's I before E except after C, or the other way around. "Gad, I should know that, shouldn't I? Housefly: Diptera muscidae. Cockroach: Orthoptera blattidae. June bug: Coleoptera scarabaedae. Mosquito: ..." Nye vows to look it up when he gets home. Of course he has a book at home where he can look it up. A spiral-bound volume with thousands of drawings of six-legged, usually winged invertebrates and thousands of Latinate words. He's had the book since high school. What do you expect from someone known as the Science Guy, someone so sure of his role that he put the moniker on his business cards right below his name and trademarked it? "I was really into insects for a while," Nye explains while adjusting his socks, which are embroidered with a pattern of atoms and the equation E=mc . "Really heavy. You put all the insects in the world on one side, all the mammals on the other. ..." A visitor remembers hearing this one before, about how the insects outnumber the rest of us. "Outweigh," corrects Nye. "Outweigh." He lets it sink in. "That's not even counting arachnids," Nye adds, conjuring an imaginary balance with his hands. "Go ahead, throw them on our side! Insects still win. What I'm saying is, don't mess with them. Sure, live your life. Buy a CD player. Crank your tunes. But insects have something to say." So too does Bill Nye. Since the casual chain reaction about three years ago that transmuted Nye into the Science Guy, the 33-year-old mechanical engineer, writer and actor has become an Emmy-winning fixture on Seattle TV's weekly comedy show "Almost Live!," which began its sixth season last month. The Science Guy shines his penlight of knowledge into the darkness of our ignorance. He tells us why the sky is blue. He shows us what happens when he eats a marshmallow that's been dunked in liquid nitrogen. To wit, smoke comes out of his nostrils. We laugh. We learn. The Science Guy -- sporting his trademark safety glasses and lab coat -- also has appeared in award-winning public service spots and an educational video about wetlands for the Washington State Department of Ecology. He writes a column for a syndicated children's newspaper and makes frequent visits to local classrooms to convey the wonders of science and the beauty of skepticism. Earlier this summer he taped eight segments for the Disney Channel's revived "Mickey Mouse Club." And in July he flew to New York to perform in a pilot for an offbeat adult infotainment show being hatched by Barry Sand, the former producer of "Late Night With David Letterman." Now the Science Guy is talking about the quantum leap he dreams about. "Roughly," Nye says, mapping it out as roughly as is possible for someone who uses a mechanical pencil, "to become the next Mr. Wizard." You remember Mr. Wizard. His long-running Saturday TV show that began in 1951 on NBC made him America's favorite science teacher. He built working volcanoes for kicks. Now Mr. Wizard -- Don Herbert to his letter carrier -- has relit his Bunsen burner on cable's Nickelodeon channel. "Was he an early influence?" Nye says, repeating an almost insultingly obvious question, "Ohmigosh yeah. Are you kidding me? The guy still pushes my buttons. He's my hero. "I think teaching people science would be the greatest good. That's my goal. We've got to turn kids on to science or we've got no hope." Take Mr. Wizard, peel away about 30 years, splice in a few genes of a stand-up comic, pour in a hefty dose of caffeine and inject a childlike sense of wonder at chemicals that burst into flames. Roughly, you wind up with the Science Guy. Of course, there's more to Bill Nye. On "Almost Live!" he has also started to show up regularly as Speed Walker, a super-hero who uses his blazing speed to fight crime while adhering strictly to the rules of the International Racewalking Association. For this season's debut, Nye also taped a segment based on his fascination with "Star Trek," a fascination that would materialize regularly in Nye's stand-up days. The result: a parody of all one-man and one-woman shows, called "Bill Nye Is William Shatner." "In regards to 'Almost Live!' I feel it's another building block in the great ziggurat of Bill Nye's career," Nye will say later, after removing Capt. Kirk's vinyl booties and double-knit space breeches. "Any time I can spend on TV just makes me better on TV. I love TV. But I really believe in science. I am the Science Guy. That's totally me. What are you, kidding me? Is that a joke?" No joke about this: When the two are in conflict, Nye makes humor yield to science. "We never cook the books or dry-lab," says John Keister, the host of "Almost Live!" "Any science thing Bill does is completely accurate. In one scene we wanted him to be playing the lottery. He refused. He said the Science Guy would never play, that the lottery is just a tax on people who are bad at math." Nye believes in the inviolability of the scientific method. He also believes in minimalism, zero population growth, safety glasses, 100 percent cotton tapered boxer shorts, the comic genius of Steve Martin and the simple elegance of the universe. He does not believe in destiny. The portrait in his high school annual makes you wonder, though. It shows Nye, hair appropriately shaggy for the class of '73, cuddling an oscilloscope. The quote underneath the photo -- "With this I could, dare I say it, rule the world!" -- comes from Boris Karloff. Another block of free-associative text records some of the people and activities that meant the most to him, including: yo-yo team; Frisbee; Mad Scientists' Club; J. Milton (not the epic poet but a local semi-pro hockey player of the time); Capt. Kirk. "See, I was a nerd from the word go," Nye says. "Am I making this clear to you? I always had pounds of pens in my pocket." He usually wore a tie too, even after his Washington, D.C., private high school had abandoned its dress code. "We had enough oddballs in that school so that there weren't oddballs," remembers Nye's classmate Stephen Bernheim, now a legal writing instructor at the University of Puget Sound Law School. "Lots of people were physics majors and chess players, carried briefcases and wore short pants, so they didn't stand out. Bill was really gregarious, outspoken, and always making fun of something." Bernheim also remembers a device that Nye rigged up in the family car. It allowed the driver to hoist a sign in the rear window saying "Thanks" to the driver following behind. Long before Nye could drive, his father and mother bought a thick dictionary and set it on a stand in the dining room for easy reference by Nye and his older brother and sister. "We'd have these big conversations," remembers his father, Ned Nye, a retired advertising salesman, "and when there was an answer to be had, bingo. All questions were always answered." Another popular family activity involved solving the word puzzles in the back of Atlantic magazine. "That's how he got into this knowledge thing, I guess," says brother Darby Nye, director of purchasing for a Washington, D.C., hotel. At Cornell University, Nye majored in mechanical engineering. By his senior year, a young comedian named Steve Martin had become popular enough to begin appearing on TV, where one of Nye's friends saw Martin and noticed a similarity in Nye's sense of humor, his appearance and his demeanor. After graduation, Boeing hired Nye to work on an electromechanical system in the rudder of the 747. Meanwhile, friends from his Ultimate Frisbee team here persuaded him to enter a Steve Martin look-alike contest sponsored by a Seattle radio station. He won. Nye didn't fare as well against all the other local winners at the national Steve Martin-off in San Francisco. But back in Seattle he began getting offers to do his "Wild and Crazy Guy" routine at office parties and birthdays. Before long, Nye was developing original material heavy on engineering jokes and honing his stand-up act at local comedy clubs. His family had always stressed the value of education and of a sense of humor. Engineer by day, comic by night, Nye seemed to be fulfilling exactly what nature and nurture had prepared him for. On Seattle's then-fledgling club circuit Nye met other young comics such as Ross Shafer, later to become the first host of "Almost Live!," and John Keister, who became one of the show's first writers. Nye also remembers opening once for Harry Anderson, a comedian who mixed magic with his jokes, now a star of the sitcom "Night Court." Anderson told Nye that to win an audience a comedian needs something even more important than strong material: a strong character. Nye soon found his. He joined the writing staff of "Almost Live!" in the fall of 1986. After a few months the Science Guy persona emerged from the show's creative Crock-Pot. The Science Guy, in full regalia, walked onto the show's set in front of a live audience. He removed the lid from a plastic foam cooler filled with liquid nitrogen. He explained the wonders of the super-cooled gas in the voice of a man who could get hot and bothered over a freshly lubricated slide rule. Then he plunged a sweet yellow onion into the cooler, pulled it out and shattered it as if it were a light bulb. The crowd went wild. The local chapter of the National Academy of Television Arts and Sciences added its praise by awarding Nye a talent Emmy for the segment. So maybe it wasn't on a par with the discovery of radium. Still, Nye had found his character, and his character had found a name. Nye soon was hosting a weekly hour-long question and answer show on radio and branching out into other areas. A children's book publisher, for example, recently approached Nye about hosting a video on bacteria. Back in his small condominium after the show, Nye locates his insect book. It's on the shelf that also holds three of his four local Emmy trophies (the fourth broke in shipping and is in the shop), a radiometer, a small safe with his ticket stub from a 1965 Beatles concert, and three books by another Bill Nye, a distant relative who worked as a humorist writing for a Wyoming newspaper in the late 19th century and who is remembered today, if at all, as a sort of second-string Mark Twain. On the coffee table sits the latest issue of his favorite periodical, Skeptical Inquirer, and a dense and dangerous-looking hunk of metal. Nye refers to it as "the worthless piece." A project required of every mechanical engineer at Cornell, the once-solid piece has been threaded, chamfered, tapered, milled, reamed, broached, counter-bored, beveled and tapped. But it serves no function beyond proving that Nye mastered all those skills. Nye finds the mosquito. Same order as the fly, different family. Diptera culicidae. Nye squints his eyes shut and repeats the words. Across from the table near the fireplace hangs a sepia-toned photo of Nye's maternal grandfather, Sanford Jenkins, a man Nye never met. In fact, he never even saw the photo until after Jenkins died last summer. It shows a snowy-haired man, a chemist who helped develop the adhesive to hold cork on bottle caps, wearing a lab coat and sitting before a bench covered with glass beakers and tubes. "I got the shakes when I saw that," Nye says. "It's not destiny. It's genes, maybe."