Kieran Black (9), of Dunedin, Christchurch physicist Dr John Campbell (72) and student Alex Caulton (20) step quickly across glowing charcoal embers during a firewalking demonstration at the University of Otago last night.
Squeals of delight and a few flying embers resulted when scores of people followed Dr Campbell's firewalking example.
Dr Campbell, a retired research associate at the Canterbury University physics and astronomy department, showed that although physicists still cannot walk on water, they can do a pretty good job with fire.
Dr Campbell, who co-ordinates the ''Ask-A-Scientist'' newspaper column and is a biographer of Sir Ernest Rutherford, first gave a lecture at Otago University to about 200 people on the science of firewalking. He explained that firewalking could be undertaken safely because of the thermal properties of charcoal.
Although a thin surface area was burning about 900degC, the sub-surface temperature dropped to about 60degC.
Quick contact with skin did not cause burns, but careful safety organisation, including having water-filled trays available to stand in afterwards, was needed, he said.
