Water - The Source of Life and Mystery: The Mpemba Effect
The Reason For It All
Water is the elixir of life. It is necessary for plants and animals to grow and function.
Without water, there would be no life on Earth. Animals would never come into existence, humans would never be able to build breathtaking sky scrapers or the internet which allows you to access this article right now.
If there is a reason that everything is here, from a scientific point of view at the least, it is because of water.
Since this liquid is so integral scientists have discovered many key properties and general behaviors of water.
Even someone who doesn’t consider themselves a scientists knows a lot of fundamental facts about water just because of how much humans interact with water in our day-to-day lives.
We know that water freezes when it becomes cold enough, specifically 32°F or 0°C. Therefore, it would logically make sense that a cooler liquid would freeze faster since the temperature of a cool liquid is closer to 32°F or 0°C than a warm liquid.
Makes sense, right?
What if I told you that you’re wrong?
The Mpemba Effect
Aristotle was the first person to discover the Mpemba Effect, noting that he saw hot water freeze faster than cool water in the 4th century BCE. However, for sake of story and simplicity, let’s look at the story of the man whom this phenomenon is named after. The year was 1963, Erasto Mpemba sat at a table in his cooking class where the teacher instructed them to create ice cream. Mpemba, a thirteen year old boy at the time, decided to skip the step of letting the boiled sugar and milk mixture cool and simply put this hot concoction in the fridge.
Contrary to intuition, Mpemba’s mixture froze much faster than his classmates. This became known as the Mpemba Effect, which stated that a hot liquid can freeze
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While physicists debate the true cause of the Mpemba Effect, there are several theories:
- Hot liquids has more energy than cool liquids because the energy from the heat source transfers to the liquid, causing molecules to move faster and thus have convection currents that are more powerful. Such currents aid the transfer of heat, thus allowing the substance to cool faster.
- Hot water evaporates faster, decreasing mass and heat of the liquid, which allows it to cool faster.
- Frost prevents heat from being lost, and when cooler liquids reach freezing point, they develop frost that encases the water, increasing heat retention, thus increasing the time required to freeze.
- Cold water can hold more carbon dioxide (CO2) than warm water. Carbon dioxide is a greenhouse gas, which is infamous for storing heat. Thus, do to increased CO2 in colder waters, they are more likely to retain more heat and freeze slower.
An Ongoing Mystery
To this day, over 60 years after its discovery, the Mpemba Effect remains one of many scientific mysteries. Some scientists believe there is a singular cause for this effect while others argue a combination of causes leads to the Mpemba Effects. Still more scientist are dubious of whether the effect is even real, and due to lack of consistent evidence, even in controlled environments, its hard to say for sure.
All we know for sure, is that curiosity and continual experimentation in this field is the only way that society can learn more about the key aspects of our planets and solve the countless paradoxes of science.
References
Salinas, K. (2015, January 18). Unsolved Mysteries: The Mpemba Effect — Yale Scientific Magazine. https://www.yalescientific.org/2015/01/unsolved-mysteries-the-mpemba-effect/
Geniebook. (n.d.). Why hot water freezes faster than cold water | Geniebook.com. https://geniebook.com/tuition/primary-5/science/why-hot-water-freezes-faster-cold-water-mpemba-effect#:~:text=How%20it%20all%20began,explanation%20for%20this%20strange%20phenomenon.
Bier, M. (2023, June 20). The rise and fall of the MPeMba effect. Skeptical Inquirer. https://skepticalinquirer.org/2023/06/the-rise-and-fall-of-the-mpemba-effect/
Stoye, E. (2024, June 10). The Mpemba effect: fact or fiction? Chemistry World. https://www.chemistryworld.com/news/the-mpemba-effect-fact-or-fiction/3008257.article
Why do most gases dissolve easier at colder temperatures? (n.d.). Physics Stack Exchange. https://physics.stackexchange.com/questions/311409/why-do-most-gases-dissolve-easier-at-colder-temperatures
Edwards, L. (2010, March 26). Mpemba effect: Why hot water can freeze faster than cold. Phys.ORG. https://phys.org/news/2010-03-mpemba-effect-hot-faster-cold.html
