Star Turn: Beaumont and Williams

David Mosford meets the duo who put the fun back into photobiology.

The names Beaumont and Williams may not have the resonance of Cannon & Ball, but these two biochemists are bringing showbiz razzmatazz to the world of photobiology. For the past six years, Paul Beaumont and John Williams have toured British lecture theatres and indulged in literal pyrotechnics, setting fire to various substances in the cause of introducing sixth-formers to the delights of Things That Glow In The Dark and perhaps a science degree.

"From Sellotape to fireflies" is an entertaining canter through the twin subjects of luminescence and colour by Beaumont, head of natural and applied sciences at Edge Hill College of Higher Education, and Williams, who is professor in applied biochemistry at Chester College. First Beaumont and Williams plunge their audience into darkness and set fire to a series of dishes. Blue, green and red flames rise, fireworks splutter and fume and the couple insist cheerily that no one should worry:

"We've turned off the smoke detectors."

Having demonstrated that different chemicals burn with different-coloured flames, the pair explain that they are not just going to show how light can be produced by putting in heat. "Putting light in also gets light out," says Beaumont, flourishing a fluorescent tube. Fluorescence is a big part of the Beaumont and Williams experience. They display calcite and fluorspar that glow eerily blue and orange after being exposed to ultraviolet light, and biological washing powders that cause clothes to give off blue light in discos.

"When you use Lemon Flash on kitchen work surfaces, it gives off fluorescence," says Beaumont. "This is nothing to do with cleanliness. It's because of additives in the cleaner that stick to surfaces and emit light when exposed to the sun."

He says Sellotape will also glow after a few minutes if the room is dark enough and if you first introduce energy by tearing off a strip. Williams has brought along slides of fireflies that show how these insects switch their tail lights on and off at will in order to attract a mate. He also has pictures of the deep-sea angler fish, which uses a luminous rod to lure its prey. "Sex and food are the reasons why most things happen in nature," he explains. Williams produces a corked flask of bacteria that begins to glow when air is reintroduced. "They'd run out of oxygen. But see what happens when I take the cork off."

The lecture does not seek to explain the mechanism by which living creatures can create light, but it is rich in examples that surprise the audience. Beaumont mixes a series of chemicals with luminol to show how the solutions glow with different colours in the dark. Each fades after a few minutes but, as he points out, the yellowish-green solution appears to stay brighter longer because our eyes are better adapted to picking up that part of the colour spectrum.

Lest the audience think luminescence is for fun, Williams cites grisly examples of how it can be used for forensic purposes.

To the strains of the 1812 Overture , the pair co-opt 15 volunteers, each with a flask in front of them representing a different strength of iodic acid. When Williams gives the cue, sulphuric acid is added to the flasks, with the result that they turn blue in sequence - and in time to the music. The Generation Game would have enjoyed that one.