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Firewalking

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Firewalking in Sri Lanka

Firewalking is the act of walking barefoot over a bed of hot embers or stones.

Firewalking has been practiced by many people and cultures in all parts of the world, with the earliest known reference dating back to Iron Age India – c. 1200 BC.[1] It is often used as a rite of passage, as a test of an individual's strength and courage, or in religion as a test of one's faith. Firewalking became popular in the twentieth century when author Tolly Burkan began giving public classes throughout the United States and Europe in an effort to demonstrate that the practice was not paranormal. [2]

Today, it is often used in corporate and team-building seminars and self-help workshops as a confidence-building exercise. Firewalking implies the belief that the feat requires the aid of a supernatural force, strong faith, or on an individual's ability to focus on "mind over matter".[3] Modern physics has largely debunked this however, showing that the amount of time the foot is in contact with the ground is not enough to induce a burn, combined with the fact that coal is not a very good conductor of heat.[1]

History

Walking on fire has existed for several thousand years, with records dating back to 1200 B.C.[4] Cultures across the globe, from Greece to China, used firewalking for rites of healing, initiation, and faith.[4]

Firewalking is practiced by:

Explanation

When two bodies of different temperatures meet, the hotter body will cool off, and the cooler body will heat up, until they are separated or until they meet at a temperature in between.[8] What that temperature is, and how quickly it is reached, depends on the thermodynamic properties of the two bodies. The important properties are temperature, density, specific heat capacity, and thermal conductivity.

The square root of the product of thermal conductivity, density, and specific heat capacity is called thermal effusivity, and tells how much heat energy the body absorbs or releases in a certain amount of time per unit area when its surface is at a certain temperature. Since the heat taken in by the cooler body must be the same as the heat given by the hotter one, the surface temperature must lie closer to the temperature of the body with the greater thermal effusivity. The bodies in question here are human feet (which mainly consist of water) and burning coals.

Due to these properties, David Willey, professor of physics, says he believes firewalking is explainable in terms of basic physics and is not supernatural or paranormal.[9] However, he adds, "The 120 foot walk done by Sara Raintree and Jim Jarvis, and reports of longer walks and people remaining stationary for extended periods on the coals are currently under investigation by the author." Willey notes that most fire-walks occur on coals that measure about 1,000 degrees Fahrenheit (550 degrees Celsius), but he once recorded someone walking on 1,800-degree (1,000 °C) coals.[4]

Additionally, Jearl Walker has postulated that walking over hot coals with wet feet may insulate the feet due to the Leidenfrost effect.[10]

Factors that prevent burning

Factors that act together to prevent the foot from burning
  • Water has a very high specific heat capacity (4.184 kJ/K kg), whereas coals have a very low one. Therefore the foot's temperature tends to change less than the coal's.
  • Water also has a high thermal conductivity, and on top of that, the rich blood flow in the foot will carry away the heat and spread it. On the other hand, coal has a poor thermal conductivity, so the hotter body consists only of the parts of the coal which are close to the foot.
  • When the coal cools down, its temperature sinks below the flash point, so it stops burning, and no new heat is generated.
  • Firewalkers do not spend very much time on the coals, and they keep moving.
  • Calluses on the feet may offer an additional level of protection, even if only from pain; however, most people do not have calluses that would make any significant difference.

Risks when doing firewalking improperly

There are risks when doing firewalking improperly
  • People have burned their feet when they remained in the fire for too long, enabling the thermal conductivity of the coals to catch up.
  • One is more likely to be burned when running through the coals since running pushes one's feet deeper into the embers, resulting in the top of the feet being burnt.
  • Foreign objects in the coals may result in burns. Metal is especially dangerous since it has a high thermal conductivity.
  • Coals which have not burned long enough can burn feet more quickly. Coals contain water, which increases their heat capacity as well as their thermal conductivity. The water must be evaporated already when the firewalk starts.
  • Wet feet can cause coals to cling to them, increasing the exposure time.

Notably in 2002, twenty managers of the KFC fast food chain in Australia received treatment for burns caused by firewalking.[11] However, this exercise in firewalking was practiced over timber, a more efficient heat conductor than charcoal. [12]

See also

References

  1. ^ a b Willey, David. "Firewalking Myth vs Physics". University of Pittsburgh. Retrieved June 29, 2010.
  2. ^ FYI; Web hits., Star-Tribune, April 28, 2001. "Meet Tolly Burkan, father of the global firewalking movement."
  3. ^ DeMello, Margo (2009). Feet and Footwear: A Cultural Encyclopedia. Macmillan. pp. 30–32. ISBN 9780313357145.
  4. ^ a b c Binns, Corey (2006-08-14). "World's Watch and Learn: Physics Professor Walks on Fire". Livescience.com. Retrieved 2007-04-13. (livescience.com)[unreliable source?]
  5. ^ Pigliasco, Guido Carlo, 2007. The Custodians of the Gift: Intangible Cultural Property and Commodification of the Fijian Firewalking Ceremony. Ph.D. Dissertation, University of Hawai‘i.
  6. ^ Pigliasco, Guido Carlo, 2010. "We Branded Ourselves Long Ago: Intangible Cultural Property and Commodification of Fijian Firewalking", Oceania 80 (2): 237–257.
  7. ^ Xygalatas, Dimitris, 2011. “Ethnography, Historiography, and the Making of History in the Tradition of the Anastenaria”, History and Anthropology 22 (1): 57-74
  8. ^ "Can you walk on hot coals in bare feet and not get burned?". The Straight Dope. 14 June 1991. Retrieved 2007-04-13.
  9. ^ Willey, David (2007). "Firewalking Myth vs Physics". University of Pittsburgh. Retrieved 2007-04-13.
  10. ^ Walker, Jearl, "Boiling and the Leidenfrost Effect" (PDF), Cleveland State University {{citation}}: Missing or empty |title= (help)
  11. ^ Kennedy, Les (2002-02-28). "KFC bosses aren't chicken, but they sure are tender". The Age. Retrieved 2007-04-13.
  12. ^ Mitchell, 1987.