Humble Boy: There's a suicidal astrophysicist at the National. Best place for him

Over the past 10 years, the National Theatre has done its bit to break down the wall between art and science. Since CP Snow voiced the idea of "two cultures" in 1959, this division has become a cultural cliché. But plays such as Tom Stoppard's Arcadia and Michael Frayn's Copenhagen, both staged by the National, have appealed to bards and boffins alike.

Playwright Charlotte Jones, whose new comedy about a suicidal astrophysicist, Humble Boy, opens at the Cottesloe this week, says that the play began with an image of "a man pottering around a garden like a bumble bee" but she notes that "according to the laws of physics, the body shape of the bumble bee should make flight impossible."

While the young writer – who scored a hit last year with In Flame – admits that the story is probably apocryphal, hearing it was a "Eureka moment" when several ideas gel in one image. Similarly, her character, Felix Humble (played by Simon Russell Beale) searches for a "scientific Eureka moment", trying to work out "a unified field theory that will reconcile relativity and quantum mechanics".

At the same time, "Felix is also trying to bring his mother, who's having an affair, and his father, who's died, back together in his mind." In this metaphor-rich universe, his mother "is a black hole, warping him out of shape, and his father is just microscopic, fizzing away in the corner of his mind."

Jones uses a simple device to convey Humble's astrophysics. "He talks about string theory to a local woman in a charity shop so he has to use understandable language." What attracted Jones to string theory "was the theological language used to describe it: all about dwelling in possibility and questing after the unknowable, living in between doubt and fear."

Such metaphors suggest one reason why plays about science are so engaging – they're all about language. Michael Frayn says, "Heisenberg [who appears in Copenhagen] took the view that science is based on conversation, and so are most plays." Indeed, Steven Poliakoff's Blinded by the Sun (1996) was criticised by scientists because his boffins talked gobbledygook rather than real science.

Copenhagen was memorable also for its staging. "The set was part of the message. It was in the shape of a circular lecture theatre," says Frayn, "which was meant to suggest a demonstration, a moral forum, and – since the play is about understanding ourselves by looking at other people – the idea was to keep the audience in full view of one another."

Yet most playwrights are attracted to science for humanistic reasons. Tom Stoppard used the image of jam being stirred into rice pudding to demonstrate entropy and chaos theory in Arcadia (1993), proving, perhaps, that theatre is good at wordless stage pictures which make ideas tangible. At the end of Arcadia, two couples from different historical epochs dance across the stage, creating a sense of cosmic harmony. In the Far Side of the Moon, Robert Lepage used a mirror to give the illusion that his character is floating in space – finally free of his past.

Jack Bradley, the National's literary manager, says: "There is an enduring interest in science because theatre can simplify something, such as the uncertainty principle in Copenhagen, which we often think is beyond us." And, while books tend to be abstract, "a single visual image can make ideas corporeal."

Scientists, he says, "are modern heroes – they work at the edge of the unknown." And because it's on the frontiers of knowledge, "science offers an opportunity for moral debate. Theatre is best at being a public arena where people discuss issues."

Science is itself the stuff of theatre. "The more I read about it," says Jones, "the more conscious I am of its conflicts and drama." Frayn agrees: "Science is an extremely demanding activity and people in any demanding activity become very emotional, very worked up, fixated, competitive." In the end, the reason that science works well on stage is that playwrights use it to explore emotions – and we're all interested in those.

Humble Boy: Royal National Theatre, SE1 (020 7452 3000), from Thursday. Aleks Sierz's In-Yer-Face Theatre: British Drama Today is published by Faber, £9.99