How Do People Walk on Fire?

Fire walking is a spiritual ritual that has been practiced for thousands of years. This practice involves a person walking on a bed of red hot coal. While this practice may seem painful, many fire walkers get away with barely a blister. Is that even possible? Does spirituality defy the laws of Physics?

Well, for starters, hot coal is a poor conductor of heat.  While hot coal can reach temperatures of over 500 degrees Celsius (932 degrees Fahrenheit), it only conducts a measly 0.2 British Thermal Units (BTU). BTU refers to the amount of heat required to raise the temperature of one pound of water by one degree Fahrenheit. In addition, coal combustion produces ash, a terrible conductor of heat, which further diminishes the conductivity of coal.

When it comes to walking on the coal, fire walkers move quickly and calmly, taking special care to not disturb the ash layer. 

Some fire walkers wet their feet prior to walking on the coal. When water comes in contact with the significantly hotter coal, it evaporates to form a protective insulating vapor layer, a phenomenon known as Leidenfrost Effect.

Fire walking is a remarkable feat, no doubt. However, the boundaries are well within the laws of physics.

Reference:

http://www.physlink.com/education/askexperts/ae580.cfm

http://mentalfloss.com/article/52012/how-walk-across-hot-coals

https://en.wikipedia.org/wiki/Firewalking

http://www.pitt.edu/~dwilley/Fire/FireTxt/fire.html

http://www.abc.net.au/science/articles/2012/04/10/3472165.htm

https://www.skeptics.com.au/resources/articles/fire-walking-explained/

http://www.engineeringtoolbox.com/thermal-conductivity-d_429.html

https://en.wikipedia.org/wiki/Leidenfrost_effect