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RSC offers 1000 for explanation of an unsolved legendary phenomenon
Royal Society of Chemistry ^ | 26 June 2012 | NA

Posted on 06/27/2012 12:41:32 AM PDT by 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.

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...


(Excerpt) Read more at rsc.org ...


TOPICS: Culture/Society; Extended News; News/Current Events; Technical
KEYWORDS: cooling; freezing; mpembaeffect; thempembaeffect
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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!
1 posted on 06/27/2012 12:41:44 AM PDT by neverdem
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To: neverdem
>" Why does hot water freeze faster than cold water?"

Because G_d made it that way.

2 posted on 06/27/2012 12:48:00 AM PDT by rawcatslyentist ("Behold, I am against you, O arrogant one," Jeremiah 50:31)
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To: neverdem
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

3 posted on 06/27/2012 12:52:02 AM PDT by bruinbirdman ("Those who control language control minds." -- Ayn Rand)
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To: neverdem
It really, really, doesn't.

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


4 posted on 06/27/2012 12:52:02 AM PDT by I see my hands (It's time to.. KICK OUT THE JAMS, MOTHER FREEPERS!)
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To: neverdem

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

Now where do I collect my prize?


5 posted on 06/27/2012 12:53:54 AM PDT by NTHockey (Rules of engagement #1: Take no prisoners)
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To: rawcatslyentist

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!


6 posted on 06/27/2012 12:57:08 AM PDT by 21twelve
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To: neverdem

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

I think the mythbusters busted that myth btw.


7 posted on 06/27/2012 1:01:53 AM PDT by Tzimisce (THIS SUCKS)
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To: El Gato; Ernest_at_the_Beach; Robert A. Cook, PE; lepton; LadyDoc; jb6; tiamat; PGalt; Dianna; ...
Immune system molecule weaves cobweb-like nanonets to snag Salmonella, other intestinal microbes

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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.

8 posted on 06/27/2012 1:03:00 AM PDT by neverdem (Xin loi minh oi)
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To: bruinbirdman
>" 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.

9 posted on 06/27/2012 1:05:18 AM PDT by rawcatslyentist ("Behold, I am against you, O arrogant one," Jeremiah 50:31)
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To: neverdem
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
10 posted on 06/27/2012 1:22:11 AM PDT by nicepaco
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To: bruinbirdman

Why does ice float?


11 posted on 06/27/2012 1:23:17 AM PDT by panaxanax (Voting 'Third Party' will ensure a Communist-Marxist-Socialist dominated Supreme Court!)
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To: neverdem
Why does hot water freeze faster than cold water?

Does it?

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


12 posted on 06/27/2012 1:39:24 AM PDT by GrandJediMasterYoda (Some day our schools will teach the difference between "lose" and "loose")
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To: neverdem
Y'know ... I was JUST thinkin' that and was gonn'a synopsize it with one word .... DRAMA
13 posted on 06/27/2012 1:51:25 AM PDT by knarf (I say things that are true ... I have no proof ... but they're true)
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To: neverdem; AdmSmith; AnonymousConservative; Berosus; bigheadfred; Bockscar; ColdOne; ...

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.


14 posted on 06/27/2012 3:03:23 AM PDT by SunkenCiv (https://secure.freerepublic.com/donate/)
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To: nicepaco
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.

15 posted on 06/27/2012 3:10:18 AM PDT by ClearCase_guy
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To: 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.

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.


16 posted on 06/27/2012 3:14:29 AM PDT by wideminded
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To: ClearCase_guy

FWIW:

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


17 posted on 06/27/2012 3:17:15 AM PDT by this_ol_patriot
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To: neverdem
"WHY DOES HOT WATER FREEZE FASTER."

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

18 posted on 06/27/2012 3:20:15 AM PDT by DeaconRed (My vote in Nov will be dictated by my extreme hatred for ZERO and what he is doing to our country.)
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To: wideminded

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


19 posted on 06/27/2012 3:22:48 AM PDT by Cboldt
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To: panaxanax

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.


20 posted on 06/27/2012 3:24:52 AM PDT by catfish1957 (My dream for hope and change is to see the punk POTUS in prison for treason)
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To: Cboldt

The specific gravity of water goes down until 39 or 40 F, 4 C. Then it goes slightly up until 32F or 0C where it stabilizes.


21 posted on 06/27/2012 3:28:06 AM PDT by catfish1957 (My dream for hope and change is to see the punk POTUS in prison for treason)
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To: catfish1957

Thank you.


22 posted on 06/27/2012 3:41:59 AM PDT by panaxanax (Voting 'Third Party' will ensure a Communist-Marxist-Socialist dominated Supreme Court!)
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To: panaxanax
"Why does ice float?"

Same reason a boat floats: the ice has a greater volume than liquid water, so it's less dense than the same volume of water. An object that is less dense than the water it displaces is forced upward, i.e., is bouyant. Young engineers at Old Dominion University are given first-hand experience in this effect in their annual Concrete Canoe contest.

23 posted on 06/27/2012 3:50:25 AM PDT by Chainmail
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To: this_ol_patriot

What that whole essay seems to be saying is that the hot water freezing faster is an illusion, caused by other factors which act upon the water.

Apparently, quite a few things need to be controlled in order to test the hypothesis that hot water freezes faster. The water must be degassed (to control for the change in freezing point caused by solutes). The water must be prevented from evaporating, which causes other complications—hot water can only be prevented from evaporating by putting it in a container that does not expand, and preventing it from expanding increases the pressure, and increasing the pressure increases the freezing point. So the cold water would have to be subjected to the same pressure. The water must be cooled slowly, so as to avoid the supercooling effect. And the water should be stirred to maintain an even temperature—but the stirring will lower the freezing point—although this may not be necessary if the cooling is sufficiently slow to prevent supercooling.

I remember doing crystallization studies back in undergrad chemistry classes. We had to put crystals into a tiny glass tube, and put the tube into a heater that took forever to heat. Then we sat there, looking through a magnifier at the crystal until it started to melt, and record the temperature. As I recall, the temperature change had to be very slow to get an accurate reading.

I also recall from those chemistry classes that a pure substance has to spend some time at a particular internal temperature before it undergoes a phase change. That is because the substance must gain or lose internal kinetic energy (depending on the direction of the phase change) before it can undergo the transition. Once the energy is gained or lost, the phase change occurs fairly rapidly.


24 posted on 06/27/2012 3:56:17 AM PDT by exDemMom (Now that I've finally accepted that I'm living a bad hair life, I'm more at peace with the world.)
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To: neverdem

Okay. 'series'. I was gonna say what you did neverdem, but in a simpler way.

Kinda like hot water molecules = car going 100 mph and hitting a concrete wall, vs a car going 10 mph and hitting the wall. The 'wall being Ice' in the case of water. And mph = molecular 'speed'.

25 posted on 06/27/2012 4:15:40 AM PDT by Condor51 (Never mess with an old man. He won't fight you he'll just kill you.)
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To: Condor51; neverdem
oops, should have added this: Enthalpy.

I haven't had to use that stuff since I learned it around 1975. Then forgot it as soon as I could thanks to those personal computer thingys and MS programs from that nasty and evil Bill Gates guy.

26 posted on 06/27/2012 4:31:51 AM PDT by Condor51 (Never mess with an old man. He won't fight you he'll just kill you.)
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To: this_ol_patriot
From that article you cite:

"But by the 20th century the phenomenon was only known as common folklore, until it was reintroduced to the scientific community in 1969 by Mpemba, a Tanzanian high school pupil. "

Something about this rings false to me. In 1965, a high school teacher of mine challenged me to do this same experiment at home, in private conversation with him. Later on that week or maybe a month later, he extended that same challenge to others in my class. So, somehow it was not "reintroduced to the scientific community" by someone who lived in Africa, but was apparently widely known in America.

By the way, no one who did the experiment found that hot water froze more quickly. The teacher laughingly explained that it success was more an effect of poor housekeeping -- that hot water melted ice/frost in the freezer, allowing the container more intimate contact with the freezer coils.

27 posted on 06/27/2012 5:02:49 AM PDT by AFPhys ((Praying for our troops, our citizens, that the Bible and Freedom become basis of the US law again))
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To: ClearCase_guy

Look at your line going to your icemaker in your frige——bet it is hooked up to your house hot water line. lol


28 posted on 06/27/2012 5:07:26 AM PDT by depenzz (There are two ways to conquer and enslave a nation. One is by sword. The other is by debt. John Adam)
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To: neverdem

My guess would be that it involves the amount of adsorbed gasses in cold water as opposed to hot water.

Heating the water over an extended period drives the adsorbed gasses out. So cold water will have more gasses adsorbed in it.

Adsorbing a gas in water lowers the freezing point. We’ve all seen this with a can of coke that’s very cold but still liquid, and when you pop-the-top and let some co2 out it immediately freezes.


29 posted on 06/27/2012 5:10:17 AM PDT by babygene (Figures don't lie, but liars can figure...)
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To: exDemMom
The water must be prevented from evaporating,

I once heard on a science radio show that evaporation (aka, less mass to freeze) is the key to the story.

30 posted on 06/27/2012 5:52:48 AM PDT by Calvin Locke
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To: babygene

Warm water makes for less cloudy ice cubes.


31 posted on 06/27/2012 6:06:51 AM PDT by CPOSharky (zero slogan: Expect less, pay more. (apologies to Target))
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To: CPOSharky

“Warm water makes for less cloudy ice cubes.”

I didn’t know that, but probably the same reason... less devolved gasses. You could test this by putting the cold water in an ultrasonic cleaner first. This will drive the gasses out.


32 posted on 06/27/2012 6:46:32 AM PDT by babygene (Figures don't lie, but liars can figure...)
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To: bruinbirdman
And while you'r at it, why does water increase in volume as it changes from liquid to solid state?

Because if that we not true, life on this planet would probably not have been possible. The fact that ice floats is incredibly important. I've always found it fascinating that water is one of only a couple of known substances that are less dense as solids than they are as liquids.

33 posted on 06/27/2012 7:05:06 AM PDT by zeugma (Those of us who work for a living are outnumbered by those who vote for a living.)
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To: babygene
My guess would be that it involves the amount of adsorbed gasses in cold water as opposed to hot water.

That's pretty much what I thought as well, mainly because of the clarity of the ice you get with hot water, as opposed to cold, although I think the speed of freezing also has something to do with how cloudy ice is.

Stand back folks! I'm going to attempt ... science!

34 posted on 06/27/2012 7:22:21 AM PDT by zeugma (Those of us who work for a living are outnumbered by those who vote for a living.)
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To: neverdem
I would say it's Mpemba's fault.

Whoever he was.

35 posted on 06/27/2012 8:28:43 AM PDT by Verginius Rufus
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To: neverdem

Hint: It’s related to the fact that water takes longer to boil if you stand there and watch it.


36 posted on 06/27/2012 8:57:52 AM PDT by USMCPOP (Father of LCpl. Karl Linn, KIA 1/26/2005 Al Haqlaniyah, Iraq)
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To: neverdem

RSBC offers £1000 for explanation of an unsolved legendary phenomenon
Royal Society of Body Chemistry ^ | 26 June 2012 | NA

Posted on Wednesday, June 27, 2012 3:41:32 AM by neverdoneit

Why does a hot woman warm up faster than a frigid woman?


37 posted on 06/27/2012 9:33:23 AM PDT by bunkerhill7 (what?? Who knew?)
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To: Cboldt
except that liquid water has a higher density

Note to self: When doing technical writing at 3 AM, expect to make glaring mistakes.

38 posted on 06/27/2012 12:07:53 PM PDT by wideminded
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To: bruinbirdman; wideminded

The layman’s version of wideminded’s answer: Because H20 in it’s solid form forms hexagonal crystals. Any lattice structure is always going have more surface area for the same mass as a non-latticed structure. What made you think this was unknown?


39 posted on 06/27/2012 12:31:01 PM PDT by Melas (u)
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To: Tzimisce

Sometimes, some places, it gets cold enough to freeze water even without refrigeration. Besides, you can make ice in cool temperatures that are way above freezing. The Romans did it in antiquity.


40 posted on 06/27/2012 12:34:24 PM PDT by Melas (u)
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To: neverdem

Isn’t this a test by the Royal Society, to see who is dumber?

The general public or their students ?

A new ‘evaluation’ method, perhaps?

Or is the Royal Society training their students to accept ‘academic’ knowledge (the belief that hot water freezes faster) without question?


41 posted on 06/27/2012 1:08:58 PM PDT by UCANSEE2 (Lame and ill-informed post)
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To: neverdem

If you put two identical ice trays, filled with exactly the same amount of water, at the exact same temperature, in the freezer, which one will freeze first ?


42 posted on 06/27/2012 1:11:40 PM PDT by UCANSEE2 (Lame and ill-informed post)
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To: neverdem

If you look at the water molecule it is ‘lopesided’. When heated, a body of water tends to layer thus tends to align the lopesidedness, allowing a faster crystalization when the temperature drops.


43 posted on 06/27/2012 1:16:07 PM PDT by MHGinTN (Being deceived can be cured.)
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To: babygene

I like your answer best.


44 posted on 06/27/2012 1:23:03 PM PDT by MHGinTN (Being deceived can be cured.)
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To: neverdem

Hot water freezes faster than cold water for the same reason that global warming e-mails keep getting changed by outside forces when subject to observation by discriminating minds.


45 posted on 06/27/2012 3:15:17 PM PDT by LachlanMinnesota
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To: Calvin Locke
I once heard on a science radio show that evaporation (aka, less mass to freeze) is the key to the story.

That's part of it. Evaporation itself causes cooling, which is another part.

I remember trying to test the old wive's tale as a kid, by putting a tray of cold water and one of hot water in the freezer at the same time. I don't know which froze first, but the hot water tray only had half sized icecubes.

46 posted on 06/27/2012 3:45:51 PM PDT by exDemMom (Now that I've finally accepted that I'm living a bad hair life, I'm more at peace with the world.)
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To: Chainmail

Maybe I’m stupid, but I still don’t get it. Please help me our here if you would. Thank you.

Let’s say I make a canoe out of solid ice and a canoe out of solid concrete, then drill a 6” hole in the bottom of each.

Which one will meet with the bottom of the lake sooner?

The ice canoe will still float. The concrete one will sink faster than....well, a concrete boat with a 6” hole in the hull. I am aware of boats using concrete hulls.

Remember those little ice cubes that had hole in the middle? They floated.

I’m not trying to be sarcastic or mean, just realistic, IMHO. Please correct me if I’m wrong.


47 posted on 06/27/2012 4:39:39 PM PDT by panaxanax (Voting 'Third Party' will ensure a Communist-Marxist-Socialist dominated Supreme Court!)
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To: wideminded
"Here's a summary of the Wikipedia explanation:"

Phooey. It is not the case with other molecules.

yitbos

48 posted on 06/27/2012 5:02:37 PM PDT by bruinbirdman ("Those who control language control minds." -- Ayn Rand)
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To: this_ol_patriot

After reading all that, I’m now more convinced that it DOES have something to do with the lopsidedness of the water molecule and the easier crytalization of a more uniform molecular array. What other molecule has the unique property of water that it is expands to reduce density when frozen?


49 posted on 06/27/2012 6:17:14 PM PDT by MHGinTN (Being deceived can be cured.)
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To: this_ol_patriot

After reading all that, I’m now more convinced that it DOES have something to do with the lopsidedness of the water molecule and the easier crytalization of a more uniform molecular array. What other molecule has the unique property of water that it expands to reduce density when frozen?


50 posted on 06/27/2012 6:17:28 PM PDT by MHGinTN (Being deceived can be cured.)
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