Hot water freezing faster than cold water

In summary, the phenomenon of hot water freezing faster than cold water, known as the Mpemba effect, has been observed and studied for centuries. While the exact cause of this counterintuitive phenomenon is still debated, it is believed that factors such as evaporation, dissolved gases, and the unique properties of water molecules may play a role. This effect has practical applications in areas such as ice cream making and emergency water freezing, but it also challenges our understanding of thermodynamics and the behavior of matter.
  • #1
Yashbhatt
348
13
This question has puzzled me for a long time and there have been many kinds of answer for it. The most sensible explanation I have heard is this one. http://physics.stackexchange.com/a/33026/40382

But then I found another explanation at http://shows.howstuffworks.com/brainstuff/hot-water-freeze-faster-video.htm and http://www.iflscience.com/chemistry/hot-water-freezes-faster-cold-and-now-we-know-why

Here's the original paper : http://arxiv.org/abs/1310.6514

Can anyone shed some light on what is the correct explanation of the Mpemba effect?
 
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  • #2
The best "explanation", to me, is that it is mostly a myth; a product of poorly controlled experiments. It only happens under certain, generally highly contrived situations.

We have a few threads on this: you should do a search for them.
 
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  • #4
You make it sound like this always happens. Not the case.
 
  • #5
I have read something like that it happens when water is heated to 35 degree Celsius.
 
  • #6
Vanadium 50 said:
You make it sound like this always happens. Not the case.
Agreed, experimental repeatability has been elusive. This suggests we have not yet identified all the relevant variables.
 
  • #7
I know the origin of the idea that hot water freezes faster than cold water. It was a misprint in a list of hints in a syndicated household hints column in newspapers.

The original tip was "For faster ice, use cold water. For clearer ice, use hot water."

When it was put on the wire service, someone accidentally left part of the text out: "For faster ice, use hot water."

I actually didn't read that column. I read the correction notice a few days later and thought it was funny. But don't ask me when it happened. That was decades ago.
 

What is the Mpemba effect?

The Mpemba effect is the phenomenon where hot water freezes faster than cold water under certain conditions.

Why does hot water freeze faster than cold water?

The exact reason for the Mpemba effect is still debated among scientists. Some theories suggest that hot water loses heat faster, resulting in a faster decrease in temperature and therefore a shorter freezing time. Other theories propose that certain dissolved gases in hot water can affect the freezing process. More research is needed to fully understand the mechanism behind this phenomenon.

Does the Mpemba effect always occur?

No, the Mpemba effect does not always occur and it is not predictable. Many factors, such as the initial temperature, volume, and composition of the water, can influence the freezing process. The Mpemba effect has been observed in specific conditions, but it does not happen consistently or universally.

Can hot water freeze faster than cold water in all situations?

No, hot water does not always freeze faster than cold water. The Mpemba effect has been observed in certain conditions, such as when the hot and cold water have the same composition and are placed in the same environment. However, in other scenarios, cold water may freeze faster due to a variety of factors.

Are there any practical applications for the Mpemba effect?

The Mpemba effect is a fascinating phenomenon that has sparked scientific curiosity and research. While there are no direct practical applications for this effect, understanding the underlying mechanisms can have implications in various fields, such as materials science and engineering. Additionally, understanding the Mpemba effect can lead to a better understanding of the complex behavior of water and its phase changes.

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