Why Does Hot Water Freeze Faster Than Cold?

Imagine you have two trays of water. One is warm and steaming. The other is cool and still. You put both in the freezer. Surprisingly, the warm one often turns into ice first! This strange trick is called the Mpemba effect.

Scientists have found a few good reasons for this. First, hot water has more energy to push out air bubbles and other gases that might slow down freezing. Second, the heat makes the water move around in loops called convection currents. These loops help the top layer cool down faster. Third, hot water evaporates, so you end up with less water to freeze.

It is not always true that hotter things stay hotter longer. Sometimes, being warm gives you a head start toward becoming cold.