RSC offers £1000 for explanation of an unsolved legendary phenomenon

Royal Society of Chemistry ^ | 26 June 2012 | NA

[neverdem]

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 18th 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.

The public has four weeks to crack the case before a group of the world's brightest young science brains take on the challenge in London as one aspect of a special science communications meeting entitled Hermes 2012.

Fittingly, that group's bid for glory will be made in the first week of the Olympics. The sharpest international postgraduate science students will travel to England from around the globe to participate in the Hermes 2012 event.

The Royal Society of Chemistry is sponsoring this visit to the UK of the hand-picked young scientists, who will gather at Cumberland Lodge in Windsor Great Park...

[neverdem]

IMHO, higher temperatures mean greater molecular, ionic or microscopic particulate velocity in a solution or suspension, in which those little suckers are moving, which causes a faster rate of crystal formation. It maximizes wasted heat energy, i.e. entropy, for which the Second Law of Thermodynamics goes wild!

[rawcatslyentist]

>" Why does hot water freeze faster than cold water?"

Because G_d made it that way.

[bruinbirdman]

And while you'r at it, why does water increase in volume as it changes from liquid to solid state?

In fact, only The Lord knows. Ask Bacon or Aristotle or even anyone living.

yitbos

[I see my hands]

It really, really, doesn't.

This 'contest' is an effort to render objectivity as evil.

[NTHockey]

Close; but one of my courses in Chemical Engineering explained it so many years ago.

Now where do I collect my prize?

[21twelve]

Every once in a while I would answer my geology or physics exam questions with that if I had no clue. Never worked though - although it is the truth!

[Tzimisce]

How did anyone prior to refrigeration know that boiling water freezes faster than cold water?

I think the mythbusters busted that myth btw.

[neverdem]

Immune system molecule weaves cobweb-like nanonets to snag Salmonella, other intestinal microbes

New method generates cardiac muscle patches from stem cells

A Gene for Fish Odor

Mysterious Asian ‘corpse flower’ parasite actually steals huge chunks of its host’s DNA – but what does it do with it?

FReepmail me if you want on or off my health and science ping list.

[rawcatslyentist]

>" And while you'r at it, why does water increase in volume as it changes from liquid to solid state?"

One things for certain, if it didn't we'd all drown.

The two most volatile elements, put em together and they kill fire. Without chlorine life as we know it wouldn't exist either. Oh but it's all randumb chance, and accidental.

[nicepaco]

It doesn't.
Won a bet on this in 1980
with a friend who always filled
the ice cube trays with hot water.
I understand that you can make the
hot water win in a vacuum at the speed
of light in the presence of 2 blind cats
and some green crystals but if you want a
cocktail in a hurry fill the trays with cold
water

[panaxanax]

Why does ice float?

[GrandJediMasterYoda]

Why does hot water freeze faster than cold water?

Does it?

I did not know that. I honestly did not know that.

[knarf]

Y'know ... I was JUST thinkin' that and was gonn'a synopsize it with one word .... DRAMA

[SunkenCiv]

The Mpemba Effect, good one... cold water is more dense, so there’s more of it from which to remove heat? Oh wait, that doesn’t work, water is one of the few (or the only?) material which increases in volume as it approaches the freezing point (hence, ice floats), and as the temperature continues to fall in the ice, *then* starts to shrink.

Thanks neverdem.

[ClearCase_guy]

I've spent my whole life under the impression that was a well-known myth of science. An old wive's tale. Silly, unscientific people fill their ice cube trays with hot water under the mistaken assumption that it will freeze faster that way. But people who understand science know that the hot water needs to become cold water before it becomes frozen water, so starting with cold water will give you a head start and will get you to frozen water faster.

For 40 years I've been told that the "hot water freezes faster" thing is a myth.

I feel that this "contest" is meant to be a joke.

[wideminded]

And while you'r at it, why does water increase in volume as it changes from liquid to solid state? In fact, only The Lord knows.

Here's a summary of the Wikipedia explanation:

The oxygen atom in each water molecule attracts electrons more strongly than the hydrogen atoms, so the hydrogens have a slight positive charge. This allows water to form "hydrogen bonds" in which the positive hydrogens are attracted to the negative oxygen atoms of other molecules.

Each hydrogen can form a hydrogen bond with another water molecule and each oxygen can bond with two hydrogen atoms, so altogether one water molecule can have up to 4 hydrogen bonds with other water molecules. In an ice crystal there is a lattice of water atoms held together with these "hydrogen bonds".

The hydrogen bonds have a certain length that holds the water molecules in position at a certain distance apart from each other. As the ice is heated and melts, fewer hydrogen bonds can form, the lattice structure breaks, and the water molecules are allowed to come slightly closer together. This causes liquid water to have a lower density.

[this_ol_patriot]

FWIW:

http://math.ucr.edu/home/baez/physics/General/hot_water.html

[DeaconRed]

"WHY DOES HOT WATER FREEZE FASTER."

Because of the down hill slide effect.
Now send me my money. . . . .

[Cboldt]

That was what i was taught too, except that liquid water has a higher density, not lower, compared with ice.

[catfish1957]

If I remember correctly, water is at it’s densest at about 39 or 40 degrees Farenheit. The surrounding water around the ice is about or near that temperature. Lowest specific gravity always floats, while highest sinks.