LEGENDS:The prize is the pleasure of finding the thing out, the kick in the discovery, the observation that other people use it . . . those are the real things

WE TEND to caricature physicists as eccentric, wild-eyed and definitely wild-haired - essentially, a bunch of little Einsteins. In practice, of course, most are pretty normal, albeit more obviously cerebral than the average Joe. Sometimes they are a little slow with crowd-pleasing badinage, but they're not obviously different.

Even the most self-assured physicist, however, is unlikely to claim they are entertaining - it's not a profession that attracts attention-seekers. The one exception, the most defiantly entertaining physicist of all time, was Richard Feynman. The Nobel laureate was unquestionably one of the finest theoretical physicists of the 20th century, working on the atom bomb at Los Alamos and redefining the theory of quantum electrodynamics. To a large degree, however, it was his deserved reputation as a scientific showman that earned him his popularity.

Like so many American geniuses, Feynman was the son of immigrant eastern European Jewish parents. Born in Queens in 1918, he never lost his trademark Noo Yawk accent - even when waxing lyrical on the beauty of physics, he could sound like a carny on Coney Island. That sense of accessibility was a major part of Feynman's appeal, and what set him apart from so many of his peers.

His mathematical brilliance was apparent from an early age, and his undergraduate studies at MIT, from which he graduated in 1939, saw him focus on physics. From Massachusetts, he headed to Princeton for his PhD studies - the university and its Institute for Advanced Study, founded in 1930, were home to many giants of 20th-century science including John von Neumann, Wolfgang Pauli, Kurt Gödel and, most famously, Albert Einstein. By the time Feynman arrived, it had become ground zero for quantum mechanics.

But the reason Princeton had assumed this role was also to dictate the next stage in Feynman's career - the rise of the Nazis had driven out Germany's Jewish scientific community, and many of them became involved in the Manhattan Project in a race to beat Hitler to "the bomb".

As a brilliant young physicist, Feynman was encouraged to lend his skills to the project, so he moved to Los Alamos in New Mexico to work under J Robert Oppenheimer, "the destroyer of worlds", and alongside Niels Bohr, the Danish father of quantum mechanics. Around this time, however, his first wife, Arline Greenbaum, was suffering from tuberculosis and, after her death and the detonation of atomic bombs at Hiroshima and Nagasaki, Feynman slipped into a depression prompted by grief and, according to himself, an awareness of the level of destruction he had helped unleash.

He felt a man-made apocalypse was inevitable and with that realisation came a sort of suffocating nihilism - all life, as he saw it, was futile, all human endeavour a waste of time and effort.

In subsequent years, Feynman became openly contrite about his contribution to the Manhattan Project and, with his characteristic honesty, he ruefully compared the scenes of celebration at Los Alamos with those of devastation at Hiroshima. His great regret, he later admitted, was of not questioning the wisdom of pursuing the bomb after the defeat of the Nazis.

In the years following the war, Feynman worked at Cornell University, during which time he rebuilt the theory of quantum electrodynamics - the work that subsequently won him the Nobel Prize for physics in 1965.

Even on the Nobel Prize, he was typically iconoclastic: "I've already got the prize," he said, in an interview with the BBC in 1981. "The prize is the pleasure of finding the thing out, the kick in the discovery, the observation that other people use it . . . those are the real things. The honours are unreal to me." Such epaulettes, as he called them, held little value for him.

That hints at the casual unorthodoxy that made him so popular - he spent most of his career at the California Institute of Technology, where he thrived in his role as an educator. His 1964 textbook, The Feynman Lectures on Physics,became an unlikely crossover success and established Feynman's reputation as the greatest science teacher of his era. Among his other books, Surely You're Joking, Mr Feynman!,his 1985 anecdote-filled memoir, is the most successful, and gives an insight into his amusing, curious, generous personality. Among the traits it reveals is his fondness for topless bars - notoriously, he used to work out of one near his offices.

But Feynman's talent wasn't confined to physics - he is probably one of the most famous bongo players of the 20th century, an unlikely honour that is as much a reflection of Feynman's widespread interests as it is of the rarity of well-known bongo players.

In 1988, less than two years after playing a key part in the Rogers Commission investigating the Challenger Space Shuttle disaster, he died of cancer at the age of 69.