Mpemba Effect - Why Hot Water Freezes Faster Than Cold Water
People have interested in the events occurs around their surroundings. Like these questions “How the world was shaped. Why do not we fall from the world? Why does the sun rise from the east” wondered by many people and made effort to solve. One of the questions people have noticed but not solved is that hot water first discovered by Aristotle is frozen faster than cold water.
It's a big question to figure out why there is water on the Earth's surface. But there is another big enigma. Here is the enigma “hot water freezes faster than cold water” this phenomenon is called Mpemba Effect. Normally, the liquids become densier when they get cold. But water is different from other liquids. The water reaches its maximum density at 4 degrees and its intensity starts to decrease again before and after this point. Lesser density is the reason that ice swims on surface of the water. This unexplained condition is actually one of the basic causes of life on earth. Because of this feature, the living creatures in the water find an environment that allows them to live without freezing. If a more dense ice mass was possible than water, in such an environment the freezing will start from the bottom of the sea, and creatures in the water will not find a vital area. Besides this mysterious state of water, there is also a unique state called Mpemba effect. Why this enigma called Mpemba effect is that Mpemba is the first one who discovered that hot ingredients prepared for ice cream become solid faster than cold ingredients prepared for ice cream. The effect of the Mpemba has not been answered until now.
There are lots of reasons that cause Mpemba Effect. Only one factor or combination of different factors causes the Mpemba. One of the factors that cause the effect of the Mpemba is the mass of the liquid. Another effect is the convective current due to the temperature distribution in the water at the cap. Cold and hot water may appear to be the same in the naked eye but may contain different amounts of dissolved gas. Hot water contains less dissolved gas than cold water. However, when liquids with the same amount of dissolved gas are used, Mpemba effect can be observed.
Although there are many hypotheses on this subject, there is not yet a proven answer. The most scientific answer to be brought to this issue is that may be the structure of hydrogen bonds recognized by chemists recently. Hydrogen bonds bring water molecules closer together. These covalent bonds store energy. The reason why hot water freezes faster than cold water may be covalent bonds.
When the working mechanism of hydrogen bonds is resolved, this enigma can be solved.
References
- http://math.ucr.edu/home/baez/physics/General/hot_water.html
- https://en.wikipedia.org/wiki/Mpemba_effect
- http://www1.lsbu.ac.uk/water/mpemba_effect.html
Hey @kedi good thought here... From what I know is that hot water molecules since being hot have atoms that are excited and moving around quickly. Due to this movement there is collision and loss of energy is observed . Again like you said there isn't a proven theory behind all this. Maybe in the near future this mystery will be solved .
Very informative post👍