The Mpemba effect continues to captivate scientists with its complex interplay of physical mechanisms.
Facts for Prelims
Mpemba Effect: Hot Water’s Peculiar Freezing Quirk
Origin and Discovery:
- Named after Tanzanian student Erasto Mpemba who, in 1969, brought attention to this curious phenomenon that defies conventional expectations.
- The Mpemba effect defies intuition by asserting that hot water can freeze faster than cold water under similar conditions.
- While Aristotle, Francis Bacon, and René Descartes had noted this effect centuries earlier, it gained scientific attention more recently due to Mpemba’s observations.
- Numerous experiments have been conducted to understand the causes, but a consensus conclusion remains elusive.
- Microbubbles Hypothesis: One proposed cause is microbubbles left suspended in boiled water, promoting convection and facilitating faster heat transfer during cooling.
- Evaporation Impact: Warmer water’s higher evaporation rate contributes to enhanced convection and accelerated heat transfer due to lower density.
- Frost as an Insulator: Presence of frost in cold water may act as an insulator, slowing heat loss.
- Compounds in Water: Consideration of compounds like calcium carbonate precipitating and dissolving, influencing the freezing point.
-Source: The Hindu