The Mpemba effect
The Mpemba effect is that hot water can, under certain circumstances, not only freeze but do so quicker than colder water. This phenomenon has been reported as working as far back as Ancient Greece, even though it would seem contradictory to the laws of thermodynamics. In 1969 a scientist named Erasto B. Mpemba did experiments that proved that the effect is real, however, scientists are left with more questions than answers. Many solutions have been suggested as reasons for this phenomenon, but none have been agreed upon by scientists and most contradictory explanations were obtained by very different experiments with different controls. Perhaps someday after more study scientists will understand this, but currently the results are inconclusive at best.