why hot water freezes more faster than cold water?
Answers
In fact, scientists were struggling to prove the perfect exist in the 1st place as the 1st episode of Derek Muller 's new science channel, sciencium explains. The phenomenon of hot water freezing faster then the cold water is known as the Mpemba effect named after Erasto Mpemba, a Tanzanian student who, in 1963 made ice cream as a part of a school project.
The students were meant to boil a mixture of cream and sugar then let it cool down a storm then put it in the freezer.
Worried about getting a spot in the freezer Mpemba instead put his mixture in while it was still scorching hot. But after 1.5 hrs it frozen.
Intrigued by this phenomenon, he went on to work with physics professor Denis Osborne and they together were a letter to replicate the findings and publish a paper in 1969 showing that warm water freezes faster .
During Aristotle in 4th cent BCE, he observed this too.
Some mechanisms are :
Frost Melting
Dissolved gases
Supercooling
Evaporation
Convection.
If we will have an equal amount of hot and cold tap water and when we will place them in a freezer then the cold water will freeze faster.
This is first observed by a scientist named as Mpemba. On his name this effect is named as the Mpemba's effect. This is his observation defined below.
Mpemba's effect says that the warm water freezes more quickly than the cold water.
He has given his explanation as there is a better thermal contact between the refrigerator and the hot container than the thermal contact between the refrigerator and the cold container.
There are many more explanation given by the other scientist also but the above one is the most common.
The more explanation are as follows:-
1) In warm water the hydrogen bonding is beaker.
2) Evaporation take place in hot water and reduces it's mass so as it can cool faster.