RSC offers £1000 for explanation of an unsolved legendary phenomenon

www.rsc.org...

26 June 2012

Why does hot water freeze faster than cold water?It seems a simple enough question - yet it has baffled the best brains for at least 2,300 years.

Aristotle agonized over it fruitlessly in the fourth century BC
Roger Bacon in the 13th century used it to advocate the scientific method in his book Opus Majus
Another Bacon, Francis, wrote in his 1620 Novum Organum, that "slightly tepid water freezes more easily than that which is utterly cold" but could not explain why
Descartes was defeated by it in the 17th century AD
Even perplexed 20th and 21st century scientists and intellectuals have swarmed over it without result
Now the Royal Society of Chemistry is offering £1000 to the person or team producing the best and most creative explanation of the phenomenon, known today as The Mpemba Effect.

Competition judges will be looking for an outside-the-box, inventive submission. In addition, the format of the submission should be creative and eye-catching.

Any medium or technology can be employed to make the case, including articles, illustrations or even film.

Submissions can be based on, and reference, existing research. The winning submission will be scientifically sound, and arresting in presentation and delivery.

My answer to this question is thermal flow. The larger the difference between two temperatures the faster the thermal flow between the two. The faster the flow between the two the more dominant of the two will gain. The ballance between two temperatures will take effect. Sample of this effect. Take a soda that is warm. Place it in a bucket of ice water. Take second soda can that is warm. Place it in a bucket of ice water. pick one of the cans and spin it. he spinning can will cool at faster rate due to the soda moving in the can from spinning. The can of soda that is still must cool the soda in the center of the can through the outer layers of soda slowing the cooling process.

Any thoughts?

reply to post by JBA2848


Temperature-changing equivalent of inertia. Larger delta equals faster rate of change, inertia carries this higher rate of change through to freezing. Looking forward to the check in my mailbox.

Aristotle agonized over it fruitlessly in the fourth century BC

Of all the things to agonize over...

He picked this?

Sheesh

reply to post by whyamIhere


People had more free time then, and/or time to think when going through repetitive tasks.

Water vapour would be my guess.

The warmer water molecules begin to evaporate, whilst separate from the body of water they freeze and sink. This happens repeatedly until the water cools by which time the molecules have reached freezing temperature quicker. This in combination with all the mentioned properties of warmer water.

That's in layman's terms.

Wouldn't thermal imaging answer this question?
Just noticed the reply below mine, S* for you.

Ugghhh...

Why not take a thermal imaging device and couple it to a magnetic resonating imager, (to get a 3-D image) and prove your thermal flow theory. Or at the least, see if flow occurs through the process by itself, without "spinning" anything.
In theory, the outer portions of the mass of hot liquid would cool first, condense and flow down due to gravity. Upon reaching the bottom of the vessel or container the inflow of chilled liquid would be forced up through the center of the mass as a column, cooling the rest from the inside out, as well.

My theory is more like this:
Energy, which heat is a form of, has a resistance. Just like electricity or objects in motion. It requires much more force to overcome this resistance the bigger or faster, you go.
We know the complete absence of heat, is absolute zero, but the hotter you get, the more energy is required to maintain that temperature, right?

Therefore, heat's natural resistance is the main force in accelerating it's dissapation over any external means.

Just a thought...

It has to be the thermal flow of heat rising and cold falling creating a thermal flow. The bigger the difference the faster the flow. Meaning the balance of temperature will be faster with a faster flow. The spinning of a can in the bucket of ice simply creates a artifical flow that is faster then normal processes speeding the freezing time. Showing that it is the speed of the thermal flow that speeds the feezing time. Spinning a can of soda in a bucket of ice will make it ice cold within a minute. A can just sitting in a bucket of ice will take several minutes to even cool.

Temperature is an aspect of vibration. A hotter object has particles vibrating more quickly and the energy wants to expell itself. For example an ice cube placed in a big bucket of room temperature water will take several minutes to melt but a red hot piece of metal dropped into the same bucket will cool to water temperature in a minute or less. This is what I think. And I want to add there is a counter point to this question. Why does food thaw quicker with cold water than hot?

reply to post by lysacid


The hot piece of metal speeds the thermal flow. The hot piece of metal breaks the water h20 bond. Sending the heat up out in a bubble. Speeding the cooling time. A ice cube is a solid which will hold its core temperature due to the lack of thermal flow inside of it that you would have if it were liquid. That slows the thermal flow and slows the melting. The ice cube would have a thermal flow but only in the liquid or air out side it not inside the ice cube.

possibly

the energy of the hot water molecules drops faster in relation to the molecules of the colder water??

the hot water's molecules lose more energy in shorter period of time compared to the cold water?

just a guess