An old wives’ tale that still circulates in American homes is that, if you wish to freeze ice quickly in an ice tray, put hot tap water in it and then put it in the freezer. Of course, many homes have automatic ice dispensers in their refrigerators, so this tale is beginning to die out somewhat. Let’s dispel the myth now, however, and say that, no, hot water will not freeze faster than cold. However, what does work is boiling the water, then allowing it to cool down to a tepid temperature. Boiling the water removes air bubbles in the water, increasing thermal conductivity, and allowing the water to freeze more quickly. Of course, the time wasted boiling the water and then allowing it to cool would have been better spent by simply putting lukewarm water in the freezer in the first place! Not to mention that it would be more energy efficient not to boil the water.