ice re-freezes quicker if hotter water used to melt it?

verdigris

I have read on the faq section of the google physics group that sometimes ice re-freezes faster after hotter water is added to it.How can this happen -
surely something hotter takes longer to cool down?

Gokul43201

http://physicsforums.com/showthread.php?t=101337

verdigris

This paper on the arxiv (http://arxiv.org/abs/physics/0512262) about the so-called Mpemba effect strikes me as inconclusive.The section that says hot water pipes burst more often than cold water pipes doesn't mention that the material hot pipes are made from could be weakened by heating and cooling and be more likely to burst on freezing because of this.The mention of dissolved carbon dioxide affecting the enthalpy of freezing is important because crystals need impurities to help them grow and ice crystals are probably no different.I suspect that in many instances of the Mpemba effect energetic hot water has removed chemicals from container walls and that these are impurities that help ice-crystals form.