SciTech

How Things Work: Fire art

Credit: Courtesy of [www.wikipedia.org](www.wikipedia.org) Credit: Courtesy of [www.wikipedia.org](www.wikipedia.org)

When watching performers walk over burning coals, put sticks of fire down their throats, or even pelt out a jet of fire from their mouths, it is hard not to squirm in sympathetic pain. But, unlike you, the performers usually finish their act with a smile on their face and show no semblance of the pain that they ought to have felt. How do these people manage to do their acts? Although all these acts are extremely dangerous, there are special techniques that the artists employ to minimize the danger. Playing around with simple scientific concepts helps these artists do what is almost unthinkable: play with fire.

The technique employed by the firewalkers is vested in the theories of conduction of heat and insulation. Fire-walkers actually never walked on flames, but rather walk on burning coals. An article in National Geographic News explains that heat is transferred to the feet of the walker by the process of heat conduction. When the coals have been burning for quite some time, they are reduced to mostly pure, lightweight carbon. Such carbon is an extremely poor conductor of heat and would take a long time to transfer heat.

The fire-walker never stands on the coals for a long period of time; the walker usually walks quickly over the coals and each foot remains touching the coals for hardly a second. Such a short period of time is not sufficient for a large amount of heat to transfer and the walker’s feet do not get burned.

The second aspect that makes this technique possible is the fact that the coals are covered with a layer of ash. Ash is basically an insulator and further hampers the transfer of heat to the feet of the artist.

The result is that the artists are able to walk across the coals quickly, without burning their feet.

According to this theory, artists should not be able to walk across hot metal as metal is a good conductor of heat and would cause the artists’ feet to burn. The National Geographic News article puts forth another theory to explain this art. As stated in the article, members of the Firewalking Institute of Research and Education in Twain Harte, Calif. were able to walk across a hot metal grill without burning themselves. The previously described theory of coal and ash has no way to explain this feat. Tolly Burkan, founder of the institute, believes that the ability has to do with the artist’s frame of mind. In the article, Burkan compared the ability to the way an egg boils in a paper cup kept on hot coals.

Although the hot coals should cause the paper to burn, it doesn’t. This is because the boiling water is at 100°C and the paper stays at this temperature, not burning. Similarly, if the artist’s feet have a good amount of blood supply, the blood flow prevents the flesh from burning.

Burkan believes that with a relaxed mindset, the artists can achieve this large amount of blood flow and not get burned.
Fire eating and fire breathing are much harder than walking on “fire.”
These feats usually do harm the artist and require the artist to develop some amount of pain tolerance. However, the basic techniques are based on physics and chemistry.

Artists who “breathe” fire basically shoot a jet of fuel from their mouths onto a source of flame in their hands. The fuel ignites on contact with the flame and the spectators get to see ball or jet of fire. However, fire breathing acts have gone terribly wrong when done by amateur artists, or even well-trained artists who have had poor judgment. This is because the exact force with which the artist sprays the fuel and the angle at which the spray is directed have to be precisely calculated. If the angle is too high, the fuel can fall back onto the performer’s face. If the angle is too low, the ignited fuel can fall to the ground, causing a fire at the performer’s feet. Another factor that artists have to keep in mind is the type of fuel they use. Many fuels are carcinogenic, so the artists have to try and find a safe fuel that causes them the least amount of harm.

Along with this, the artists have to keep in mind that the fuel should not create a fire so large that it is hard to control. Houseofpoi.com explains that knowing the flash point of the fuel being used is extremely important. Flash points are assigned to all flammable liquids and indicate the lowest temperature at which that liquid can ignite in air.
The lower the flash point, the more easily the liquid can burst into flames. Fire breathers, consequently, have to choose liquids that have a high flash point. Using low flash point liquids like gasoline or alcohol could cause dangerous explosions.

In spite of these precautions, a fire breather’s health is severely compromised and may get mouth and gum cancer, stomach ulcers, burns on the mouth and gums, and headaches. Even fire-walkers may get severely burned if they do not perform their acts carefully. There is a large amount of risk involved in all of these techniques, and if not done properly, they may lead to death.