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January 25, 2005 2:22 PM   Subscribe

Which will freeze faster, a liter of water at 60° F or a liter of water at 80° F? Meet the Mpemba effect.
posted by BlueMetal (43 comments total) 1 user marked this as a favorite

 
More links? What circumstances?
posted by thedevildancedlightly at 2:26 PM on January 25, 2005


Oh no you di'int!
posted by trharlan at 2:26 PM on January 25, 2005


Fool!
posted by _sirmissalot_ at 2:29 PM on January 25, 2005


Wow. A link with the same number of sentences as your post. Possibly an historic low for an FPP?
posted by rockabilly_pete at 2:31 PM on January 25, 2005


BlueMetal, although this may be a neat effect, it's generally not acceptable to link to a single wikipedia entry without any other interesting links. We all know about wikipedia and could harvest it for interesting bits of information until the end of time. In the future, something like this wikipedia information can be used to supplement another link, but not as the sole link.
posted by The God Complex at 2:33 PM on January 25, 2005


From the Physics FAQ
posted by Zurishaddai at 2:34 PM on January 25, 2005


Maybe we can just pretend BlueMetal posted that link?
posted by Zurishaddai at 2:35 PM on January 25, 2005


nice to meet you Mpemba effect, I'm Joel.
posted by joelf at 2:36 PM on January 25, 2005


damn, you guys are tough.
posted by terrier319 at 2:37 PM on January 25, 2005


Zurishaddai's link is awesome.
posted by erebora at 2:39 PM on January 25, 2005


Cecil links are always good, too.
posted by mudpuppie at 2:41 PM on January 25, 2005


damn, you guys are tough.

I think that's "damn you guys are cold"

get it? cold?

ha!
posted by eyeballkid at 2:43 PM on January 25, 2005


By the way, this is why a Zamboni deposits heated water onto the ice surface.
posted by AlexReynolds at 2:44 PM on January 25, 2005


I find the Mpemba effect very disturbing. Thank you for bringing it to my attention.
posted by Pretty_Generic at 2:46 PM on January 25, 2005


The technician later reported that the hot water froze first, and said "But we'll keep on repeating the experiment until we get the right result."

Metafilter: We'll keep on posting until we get the right result.

Don't mention the war.
posted by weapons-grade pandemonium at 2:50 PM on January 25, 2005


A little searching found some nice instructions for making Thermodynamical toys, an especially cool-looking film can cannon, an unanswered question about an ice cube tray and some Unwise Microwave Experiments.
posted by BT at 2:50 PM on January 25, 2005


this is why a Zamboni deposits heated water onto the ice surface

Doesn't that also help to smooth out cuts and ridges in the ice by melting the very top layer of crystals? Maybe that's just me.
posted by thedevildancedlightly at 2:53 PM on January 25, 2005



Doesn't that also help to smooth out cuts and ridges in the ice by melting the very top layer of crystals? Maybe that's just me.


I'm pretty sure I'd remember if you were out there fixing cuts and ridges in the ice.

*rimshot*
posted by The God Complex at 3:00 PM on January 25, 2005


Heh heh, you said "Zamboni".
posted by Specklet at 3:02 PM on January 25, 2005


Is this anything like "a watched pot never boils?"
posted by ScotchLynx at 3:13 PM on January 25, 2005


No mention in the HowStuffWorks article on ice resurfacing that mentions hot water freezing faster being the reason they use it, instead of cold, in Zambonis and their ilk. It's about what you'd expect: cleaning up chips, and also forming a tougher layer of ice than cold water would.
posted by wolftrouble at 3:13 PM on January 25, 2005


From Zurishaddai's link:

The earliest known reference to this phenomenon is by Aristotle ... in support of a mistaken idea which he called antiperistasis. Antiperistasis is defined as "the supposed increase in the intensity of a quality as a result of being surrounded by its contrary quality, for instance, the sudden heating of a warm body when surrounded by cold"

That's a great new word. I'll try to use it today.
posted by painquale at 3:15 PM on January 25, 2005


the supposed increase in the intensity of a quality as a result of being surrounded by its contrary quality,

Just like a vaccine.
posted by _sirmissalot_ at 3:24 PM on January 25, 2005


Just like a vaccine.

Wait, how's that like a vaccine?

posted by Specklet at 3:38 PM on January 25, 2005


Is this anything like "a watched pot never boils?"

No, that's the Quantum Zeno Effect.
posted by talos at 3:42 PM on January 25, 2005


Antiperistasis is defined as "the supposed increase in the intensity of a quality as a result of being surrounded by its contrary quality.
The bad news: Antiperistasis only exists for those who don't believe in it.
posted by weapons-grade pandemonium at 4:04 PM on January 25, 2005


Wait, how's that like a vaccine?

You know, it was obvious to me at the time I wrote it, but now that you have interrogated my proposition, I have no idea in the world.
posted by _sirmissalot_ at 4:08 PM on January 25, 2005


That's a quantum vaccine.
posted by weapons-grade pandemonium at 4:10 PM on January 25, 2005



DEAR SIR/MADAM,
MY NAME IS JOHN MPEMBA, THE ELDER SON OF THE LATE DR ERASTO MPEMBA, FORMER CHIEF OF THE TANZANIAN ICE SKATING AGENCY. BEFORE HIS DEATH, MY FATHER REVEALED TO ME THE LOCATION OF 1,000,000 (ONE MILLION) ZAMBONIS, WHICH WERE REJECTED BY THE PURCHASING DEPARTMENT FOR USING WATER OF THE WRONG TEMPERATURE.

IF YOU ARE ABLE TO ASSIST ME IN FINDING A BUYER IN YOUR COUNTRY FOR A 10% FEE, PLEASE INDICATE YOUR ACCEPTANCE OF THIS OFFER BY POSTING A DISCREET MESSAGE AT WWW.METAFILTER.COM.
SINCERELY, JOHN MPEMBA

posted by Deepspace at 4:14 PM on January 25, 2005


Maybe we can just pretend BlueMetal posted that link?

Let's! It's awesome.
posted by redfoxtail at 4:22 PM on January 25, 2005


(I suspect, also, that BlueMetal meant to link to this Wikipedia entry, which is linked in that one-line bit he actually pointed to, and is much more thorough.)
posted by redfoxtail at 4:25 PM on January 25, 2005


Is antiperistasis like vomiting? Wait... that's stalsis.

Err.
posted by fet at 4:46 PM on January 25, 2005


Good one, Deepspace. I'm still laughing.
posted by weapons-grade pandemonium at 5:44 PM on January 25, 2005


1) Visit www.googly.com.

2) Type in "mpemba effect."

3) Hit "I'm feeling lucky."

4) Land here.

5) Observe that, while this isn't the best site in the world, it contains 10x the information in the original post and a nifty mini-quiz to make sure you were paying attention.

[/pile-on]
posted by googly at 5:45 PM on January 25, 2005


er....thats, um www.google.com


how embarrassing....
posted by googly at 5:57 PM on January 25, 2005


...wait, so it's true?




ha.
posted by nearo at 6:12 PM on January 25, 2005


This thread was saved by the discussion. Please hammer, don't hurt 'em!
posted by zpousman at 6:36 PM on January 25, 2005


Indeed, zpousman. This is my favorite thread today. Thanks everyone for the very interesting links, thanks especially for not derailing a sparse FPP.
posted by odinsdream at 6:56 PM on January 25, 2005


No, that's the Quantum Zeno Effect.

For the sake of preserving Equal Opportunity Quantum Weirdness, let's not forget the Anti-Zeno Effect.

But damn, talos, it's like you were in my head. Still, Deepspace wins.
posted by fatllama at 8:01 PM on January 25, 2005


the supposed increase in the intensity of a quality as a result of being surrounded by its contrary quality,

Just like a vaccine.


I imagine because a vaccine, which contains antigens, strengthens the immune system by causing it to produce lots of antibodies, the opposite of antigens.

I've always been partial to the Casimir Effect.
posted by euphorb at 8:27 PM on January 25, 2005


Actualy, I think my mom mentioned this to me as a little kid, and I'd always just accepted it as true.

If you want to see a really freaky effect of thermodynamics on water, check out what happens to water heated in a microwave compared to water heated normaly. The microwave heated water cools faster, given the same heat-sink.
posted by delmoi at 9:19 PM on January 25, 2005


Deepspace, that is one of the funniest things I have ever read.

One MIIIIIIIIIILLLLION Zambonis bwahhahahhahahahahh
posted by effugas at 9:21 PM on January 25, 2005


thank god there's an army of nitpickers to point out all the bad FPPs. Cause this shit really matters.
posted by nanojath at 7:42 PM on February 24, 2005


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