Marshmallows demonstrate Boyle's Law as just a bit of gas

Explosions, smoke and steam made for a lively presentation at Waterford Institute of Technology during two demonstration lectures entitled, "Magic Molecules". The two, part of Science Week Ireland, attracted more than 500 10- to 15-year-old pupils from nearby schools, according to Mr Eoin Gill, a lecturer in engineering at Waterford IT.

Two scientists from the Open University of London, Dr Rob Janes and Dr Adrian Dobbs, staged the presentations yesterday. They were organised by Mr Gill, also of the Institution of Engineers of Ireland and Dr Sheila Donegan of the Royal Society of Chemistry.

"It was electric, the atmosphere was terrific," Mr Gill said. "They were illustrating chemical and physical properties in exciting ways."

While the science was very real, the methods used to demonstrate it were most innovative. The demonstrations used marshmallows to explain Boyle's Law, named after the famous Irish scientist, Robert Boyle, who came from Waterford. The law relates to gas pressures. Dr Janes and Dr Dobbs placed marshmallows in a vacuum chamber and withdrew air causing the marshmallows to balloon out.

They showed how Charles's Law worked by placing an air-filled balloon in liquid nitrogen, shrinking down the balloon as the air condensed. The still sealed balloon immediately reinflated when removed from the liquid nitrogen, showing that the gas had warmed up and expanded.

"There were a lot of explosions, smoke and steam," Mr Gill said. The presenters also frightened a teacher by igniting his ethanol-and-water-soaked tenner. There were plenty of flames, Mr Gill said, but the banknote survived the treatment without damage.

The Royal Society of Chemistry and the Institution wanted to encourage students to take up the sciences, Mr Gill said. "From the Institution of Engineers' point of view we are also interested in kids picking the sciences in schools and in third level. What we are trying to do is to expand the overall pool."

Science had become a significant news issue to the public because of problems such as BSE, incineration and modified foods, he said. "It is important that people have some understanding of science. Science is too important to be left to the scientists."