Firewalking is the act of walking barefoot over a bed of hot embers or stones. It has been practiced by many people and cultures in many parts of the world, with the earliest known reference dating from Iron Age India . It is often used as a rite of passage, as a test of strength and courage, and in religion as a test of faith. Modern physics has explained the phenomenon, concluding that the foot does not touch the hot surface long enough to burn and that embers are poor conductors of heat. History Walking on fire has existed for several thousand years, with records dating back to 1200 BCE. Cultures across the globe use firewalking for rites of healing, initiation, and faith. Firewalking is also practiced by: The Sawau clan on the island of Beqa, to the south of Viti Levu in the Fijian Islands. The phenomenon was examined in 1902 when it was already a tourist attraction, with a "Probable Explanation of the Mystery" arrived at. San Pedro Manrique, a village of Soria, Central Spain Eastern Orthodox Christians in parts of Greece (see Anastenaria) and Bulgaria (see nestinarstvo), during some popular religious feasts. Tribes throughout Polynesia, documented in scientific journals (with pictures and chants) between 1893 and 1953. Persistence and functions Social theorists have long argued that the performance of intensely arousing collective events such as firewalking persists because it serves some basic socialising function, such as social cohesion, team building, and so on. Émile Durkheim attributed this effect to the theorized notion of collective effervescence, whereby collective arousal results in a feeling of togetherness and assimilation. A scientific study conducted during a fire-walking ritual at the village of San Pedro Manrique, Spain, showed synchronized heart rate rhythms between performers of the firewalk and non-performing spectators. Notably, levels of synchronicity also depended on social proximity. This research suggests that there is a physiological foundation for collective religious rituals, through the alignment of emotional states, which strengthens group dynamics and forges a common identity amongst participants. Explanation Per the second law of thermodynamics, 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. What that temperature is, and how quickly it is reached, depends on the thermodynamic properties of the two bodies. The important properties are