Festival of the Spoken Nerd, Bloomsbury Theatre, London

If there was a theme to Festival of the Spoken Nerd's mix of science and comedy tonight then it was pyrotechnics. From a tale of homemade napalm to a demonstration of a standing wave flame tube there were flashes and bangs aplenty, if no explosive end result.

Normally resident in the intimate surrounding of the New Red Lion Theatre, this Bloomsbury show was a big outing for swotty songstress Helen Arney, stand up and mathematician Matt Parker and comedian and “experiments guy” Steve Mould.

Though Arney and Parker have experienced popular science extravaganzas before, with the shows Uncaged Monkeys and Nine Lessons and Carols for Godless People, this didn't stop the first half feeling under-rehearsed. The fluency of proceedings wasn't helped by the incessant pausing for questions. Even Arney's sweet ditty about a disgruntled sun: (“You should have stopped at Copernicus/With me at the centre of your universe.”) was deemed ripe for post-performance inquisition.

The demands of the enquiring mind jarred with theatrical imperative, although Steve Mould's demonstration of the “missing fundamental” in sound, or “number ninja” Matt Parker's calculation of how much water there is in the world, begged curiosity. Their contributions in the second half were similarly intriguing, if, again, only mildy amusing.

The group dynamic around which all this wonder was wrapped was also slight. The question breaks allowed the trio to mesh a little but ultimately this was a collection of individual elements with no sign of them fusing as a compound.

The occasion demanded more guests, perhaps, and those that were invited provided good value. Wiry Australian Kent Valentine strutted like, and even sounded like, a young John Cleese as he recounted a teenage misdemeanor involving a wayward friend “petrol, Styrofoam and a healthy disregard for your own safety”. All of these factors resulted in making homemade napalm, an experiment that played havoc with “the default setting” of Valentine's family home, in other words: “not on fire”.

Chemist Professor Andrea Sella also played with fire, this time by experimenting with nitric oxide. Not all of his lectures may go with the whooping sound he makes with this chemical compound, but his students must find him entertaining. When Sella mentions the role of nitric oxide in making Viagra he warns his experiment will not have the same effect: “if it did I would have told you all to see me afterwards.”