Question

If you have an equal amount of hot and cold tap water and place them in a freezer, which will freeze faster?

Answer 1

Everyone would expect the cold water to freeze fast. But its not so.The warm water will freeze fast.

Answer 2

$\underline \bold{Answer:-}$

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.