Earlier this month, 120 sceptics gathered in Southampton to prove that anyone can walk over red-hot coals and come away with their feet intact. The "firewalk" was organised by Wessex Skeptics, one of a network of sceptics' groups around the country.

Few people initially thought they would be able to walk on fire, but more than 100 of the sceptics, including university students, staff and friends, crossed the coals at temperatures of up to 593 °C (1,100°F) - nearly hot enough to melt aluminium. None had had any "spiritual training" but all were able to walk home comfortably.

Firewalking is such a spectacular defiance of common sense that throughout history it has been used as evidence of spiritual superiority. There are references to it in the Bible, and it has been reported in such different places as South Africa, Japan and Bali.

In 1984 tens of thousands of Californians paid hundreds of dollars each for "fear seminars", at which firewalks were promoted as the cure for everything from drug addiction to insomnia.

In fact, firewalking has little to do with mind over matter and everything to do with the laws of physics concerning heat capacity and conductivity. To set up this month's event, the Wessex Skeptics raked the embers of a bonfire of storm-damaged oak and beech into a bed about 1 metre wide by 3.5 metres long.

Firewalkers were warned to walk briskly and avoid letting their toes sink into the embers. Wet blankets and buckets of water were positioned at the end of the walk, so they could cool their feet down quickly afterwards.

Physicist Robin Allen, a research fellow at Southampton University and president of the Wessex Skeptics, gave a prior talk on the physics involved.

A substance may be hot but will transfer that heat slowly. To take a commonplace example, think of a cake baking in a tin in an oven at 200 °C. The air in the oven, the tin and, after a while, the cake, are at the same high temperature. If you put your hand in the oven, the air will feel hot but won't burn you in the time it takes to remove the cake. Similarly, you won't I get burned touching the cake. But you will get burned if you touch the cake tin or the metal oven racks.

Metal holds large amounts of heat energy and transfers it quickly, whereas air and cake have low heat capacity and poor thermal conductivity. For firewalking, wood and its ash behave like the cake. In some parts of the world, porous rocks are used instead of embers — they are also poor conductors of heat. And, because feet have a high heat capacity, the embers actually cool down when walkers step on them. The trick is not to spend too long on the embers — the effects are cumulative.

It takes an average four or five steps to cross a 3.5 metre bed of coals. At the recommended brisk pace, each foot is in contact with the embers for no more than a second or a second and a half, not long enough to cause burns.

At the Wessex Skeptics firewalk, a few blisters did appear, but they were caused by embers sticking to walkers' feet. Experienced firewalkers recommend drying the feet carefully first to avoid this. "The only mind over matter," says Mr Allen, "is finding the courage to take the first step." But don't try it at home. Fire is still fire — and still dangerous.

Wendy Grossman


OM PERSONAL MULTIMEDIA ENGLISH: Desde 1999 en Internet  © Orlando Moure - Todos los Derechos Reservados
Buenos Aires, República Argentina
 | Home Page: | Correo:
Queda absolutamente prohibida la reproducción o descarga de contenidos de este portal  Términos Legales