Scientists have, for first time, successfully used supercomputer-powered simulations to demonstrate the Mpemba effect, counterintuitive phenomenon where hot water freezes faster than cold water under certain conditions.
The breakthrough study was conducted by researchers from the Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR), an autonomous institute under the Department of Science and Technology, and has been published in the international journal Communications Physics.
Key Highlights
- First-ever computational (simulation-based) proof of the Mpemba effect during ice formation.
- Demonstrates that the Mpemba effect is not unique to water and can also appear in other fluid-to-solid phase transitions.
- Resolves long-standing experimental and theoretical controversy surrounding the effect in water.
- Provides new insights into out-of-equilibrium physics—systems undergoing rapid temperature changes.
- Opens avenues for improved thermal control strategies in:
- Next-generation electronics
- Advanced cooling systems
- Materials science and industrial processes
Why This Research Is Important
- Water simulations are computationally demanding due to complex hydrogen bonding.
- Until now, no complete simulation study existed to explain the Mpemba effect conclusively.
- Experimental results on water had become controversial and inconsistent.
- This study bridges the gap between theory, simulation, and experiment.
Science Behind It
- When water cools, it does not freeze immediately.
- It can become trapped in short-lived intermediate molecular arrangements before true ice nucleation begins.
- These intermediate states delay freezing.
- Hot water, under certain conditions:
- Avoids these delays
- Reaches ice nucleation faster
- Thus, hot water may take a “shorter pathway” to freezing than colder water.
This behavior is a hallmark of non-equilibrium (out-of-equilibrium) physics.
What is the Mpemba Effect?
Definition
- The Mpemba effect refers to the phenomenon where hot water freezes faster than cold water under specific conditions.
Origin
- Named after Erasto Mpemba, who reported it scientifically in 1969.
- Earlier noted by:
- Aristotle
- Francis Bacon
- René Descartes
Mechanisms Behind the Mpemba Effect
There is no single universal explanation. Multiple factors may contribute:
- Evaporation – Hot water loses mass, leaving less water to freeze
- Dissolved gases – Heating expels gases, altering freezing behavior
- Convection currents – Hot water enhances internal heat transfer
- Supercooling differences – Hot water may freeze at a higher temperature
- Environmental effects – Hot containers modify cooling conditions
Different mechanisms dominate under different experimental setups.
Broader Applications
- Deepens understanding of phase transitions and non-equilibrium thermodynamics
- Helps improve:
- Climate and cryosphere models (ice formation)
- Industrial freezing and food processing
- Materials design and thermal engineering
- Demonstrates the critical role of supercomputing in solving classical physics paradoxes