Debunking the Myth: Does Hot Water Freeze Faster Than Cold Water?

It’s a question that has puzzled scientists and laymen alike for centuries: Does hot water freeze faster than cold water? This phenomenon, known as the Mpemba effect, has been the subject of numerous studies and debates. While it may seem counterintuitive, there are instances where hot water does indeed freeze faster than cold water. However, it’s not as simple as it sounds, and the reasons behind this phenomenon are complex and multifaceted. Let’s delve into this intriguing topic and debunk some myths.

The Mpemba Effect: An Overview

The Mpemba effect is named after Erasto Mpemba, a Tanzanian student who, in 1963, noticed that hot ice cream mix froze faster than a cold one. This observation led to a series of experiments and studies, which confirmed that under certain conditions, hot water can freeze faster than cold water. However, this phenomenon doesn’t always occur, and the conditions under which it happens are still a subject of ongoing research.

Why Does Hot Water Freeze Faster?

There are several theories that attempt to explain the Mpemba effect, but none of them can fully account for all the observed instances of this phenomenon. Here are some of the most popular explanations:

  • Evaporation: Hot water can lose mass faster through evaporation, which can help it cool and freeze faster.
  • Convection: Hot water may induce more efficient convection currents, leading to faster cooling.
  • Supercooling: Cold water can become supercooled, meaning it remains liquid below its freezing point, which can delay freezing.
  • Solutes: Dissolved gases and minerals can affect the freezing process. Hot water tends to have fewer solutes, which can make it freeze faster.

Does This Mean I Should Use Hot Water to Make Ice Cubes?

Not necessarily. While the Mpemba effect is fascinating, it doesn’t mean that using hot water is the most efficient way to make ice cubes. First, the conditions under which hot water freezes faster are quite specific and may not apply to your freezer or ice cube tray. Second, heating water uses energy, which could offset any time you might save. Finally, using hot water can lead to cloudy ice cubes due to the rapid freezing on the outside trapping gases in the middle.


So, does hot water freeze faster than cold water? Sometimes, yes, due to the Mpemba effect. But it’s not a hard and fast rule, and the reasons behind this phenomenon are complex and not fully understood. It’s a fascinating topic that continues to intrigue scientists and spark debates. But for practical purposes like making ice cubes, you’re probably better off sticking with cold water.