Thursday, 20 March 2008

The Claim: Cold Water Boils More Quickly Than Hot Water.

The New York Times: Really? The claim is repeated so often that many people accept it as fact. But according to scientists, the notion that a body of cold water will reach boiling temperature more quickly than an identical body of hot water under the same parameters is simply false.

This kitchen myth may have started as a way to encourage people to cook with cold water, not hot, which can contain more impurities. It may also have its origins in the fact that cold water generally gains heat more rapidly than water that is already hot, though it will not boil faster.

But under the right circumstances, the reverse phenomenon can occur, and hot water can freeze more quickly than cool water.

Part of the reason appears to be that hotter water loses mass to evaporation, and because it has less mass, less energy is needed to freeze it. That phenomenon was described as far back as 350 B.C. by Aristotle. The phenomenon is now known as the Mpemba effect, named after Erasto B. Mpemba, a student who noticed it in 1963 while using boiled milk to make ice cream and reintroduced the concept to the scientific literature.

A study published in the American Journal of Physics in 2006 described a number of reasons for the phenomenon.


Cold water does not boil faster than hot water, but hot water can freeze more quickly than cool water.

Click here to learn about the Seven great medical myths posted earlier on Syra Star.


JT said...

Cool .. Heres a recipe when u r short of ice at a party .. Boil Water & pour it into an ice cube tray and leave it for 2 mins in freezer .. ur 2 min Ice Cubes are ready .. serve as required

DISCLAIMER: Time taken to Boil water is subjective and depends on enviromental factors. Thus it is subtracted from Recipe total time

bilal farooq said...

LOL @ the disclaimer above

i had this intuition that hot water would freez quickly and i was right :)

never did i believe/hear that cold water boils faster than relatively hot water...

mOi said...

Interesting ... but a fact is tea made by boiling cold water is far tasty than the one made by warm water ...!

^^ I'm referring to the water boiling part before throwing tea leaves in it :)