Hot Water - Frozen Faster than Cold

Sounds counterintuitive, right? This is known as the Mpemba effect, named after a Tanzanian student, Erasto Mpemba, who found out this peculiar behavior by chance while making ice cream.

The phenomenon is that, under certain conditions, warmer water freezes more quickly than colder water.

Although the effect seems contradictory to the laws of physics, it has been observed in numerous experiments and yet an agreement on why this happens isn't reached by the scientific community.

Possible explanations include evaporation (hot water can evaporate more, hence reduced volume can cool and freeze faster), convection (hot water may set up convection currents that cool it more rapidly), and the constitution of water molecules themselves.

The Mpemba effect is a prime example of how even simple, everyday phenomena can stump the best of scientists..