[FISH96]

i just finished a very spirted discussion concerning the topic, "hot water freezes faster then cold water."
i tried every thing i know from BTU content, latent heat, removal of heat,
etc., etc.,. could not convince these chaps they are off the tracks on this item. Their thoughts were molecular distance in the hot water.
Have any of you had this crazy-ness thrown at you. they are very steadfast in this belief. I am quite amazed at this thinking.

 

[Daniel Holzman]

I have been hearing this story for at least 25 years, along with a variety of other misplaced physics concepts. I have run into some very smart people who believe stories which to me seem absurd (earth is 12,000 years old, we never made it to the moon, the World Trade Center was not destroyed by airplanes etc.). I occasionally argue, but I have never dissuaded anyone from firmly held beliefs. The simplest way to refute the hot water story is to put two trays of water in the freezer, one hot and one cold, and see which one freezes faster. But even physical proof may not carry the day.

 

[ben's plumbing]

dan gets my vote.....do the simple test hot and cold water in freezer see who freezes 1 st.....at least you will know forget what others think....ben sr

 

[hvac benny]

You're both right. Hot water can freeze faster than cold water- its called the Mpemba effect. There's more to it than simple thermodynamics, and it's not really fully understood, but it is possible.

 

[danpik]

Several years ago I owned a building that had the hot and cold water lines feeding an upstairs appartment going thru a stairwell area. This area was not heated very well and thus the pipes froze once in a while. 9 times out of 10 it was the hot water pipe that was frozen and not the cold. These pipes ran up the wall about 2" apart. Same length, exposure, material etc. Tenant told me about the hot freezing before the cold "myth". did not know what to say so kind of shrugged it off. After giving it some thought I determined why the cold was never frozed as much as the hot. More cold water was being used at night than hot. toilets flushing etc. I have heard this "myth" other times and the only "credible" explanation is that if the water is heated enough it removes more of the oxygen out of it. I don't know.

Sounds like Jamie and Adam need to work on this one

 

[COLDIRON]

I'll go with Dan's test and bet on the cold freezing first. I am sure in the Lab environment anything is possible . Humidity, air pressure , vacuums, induction of chemicals , etc, etc.
In the Lab or a test environment I'm out.

 

[TheBobmanNH]

I've also heard the other way - that cold water boils faster than hot water.

 

[beenthere]

I've also heard the other way - that cold water boils faster than hot water.

Distilled water doesn't boil. Anyone can do the test at home to prove it.

 

[drtbk4ever]

I thought Jamie and Adam already did this one. I think they proved that hot does NOT freeze faster than cold. But I could be wrong. I'll google it later when I have more time.

All I know is they used hot water to flood the ice rink when I was a kid. Some said it was because hot water froze faster. But I argued the hot water in fact melted a bit of the underlying layer and froze to a more even surface. But that is a topic for another day.

 

[Missouri Bound]

danpik I believe has the most logical answer. I've seen it time and time again where a hot water pipe froze and the cold did not. Maybe the hot pipe will condensate first...then as a result freeze??

 

[Bondo]

i just finished a very spirted discussion concerning the topic, "hot water freezes faster then cold water."
i tried every thing i know from BTU content, latent heat, removal of heat,
etc., etc.,. could not convince these chaps they are off the tracks on this item. Their thoughts were molecular distance in the hot water.
Have any of you had this crazy-ness thrown at you. they are very steadfast in this belief. I am quite amazed at this thinking.

how did this tale start?

Ayuh,.... It started with Aristotle,.... a couple hundred years, BC....

I have been hearing this story for at least 25 years, along with a variety of other misplaced physics concepts.

I remember it from 6th grade science class, 1967...

 

[jagans]

"I got some, Ocean front property in Arizona, from my front porch you can see the sea, I got some, Ocean front property in Arizona and if you buy that ill throw the Golden gate in free"

George Strait

 

[Missouri Bound]

How about..............."the hot water pipes tend to build up with sediment over time, thus decreasing the volume of water in any given section. Less water, shorter time needed to freeze."

 

[beenthere]

One of the last things most people o before going to bed is brush their teeth. And most people use cold water to rinse. So the cold water line is kept warmer and doesn't freeze, while the hot water pipe hasn't had any new hot water ran through it for an hour longer then the cold water pipe.

 

[Starlight]

I've always heard that the hot water freezes first because there's less of it. Meaning that people put the same VOLUME of water outside to test, the hot freezes first because there is less WEIGHT of hot water than cold. If people would put the same WEIGHT of hot & cold out the cold would freeze first. The difference in weight of the same volume of hot & cold isn't that much - but it's enough to make a difference.

 

[TheBobmanNH]

Distilled water doesn't boil. Anyone can do the test at home to prove it.

What? Of course distilled water boils. Every liquid boils. It may not boil in the microwave, but it boils.

 

[Missouri Bound]

DISTILLED WATER UPDATE!!!

4 oz. distilled water
120 seconds @ 1000w microwave power
Boiling boiling boiling.......
:detective:
9:07 AM 1/16/2012

 

[northernlite]

Boiling water depletes it of oxygen, allowing it to freeze faster than an equal colder water sample. Ordinary hot water doesn't freeze faster than ordinary cold water, unless it's been boiled. At least, that's what I've read.

 

[hammerlane]

thread has been going on for 60 hours an noone has put two trays of water in the freezer yet to test?

 

[beenthere]

DISTILLED WATER UPDATE!!!

4 oz. distilled water
120 seconds @ 1000w microwave power
Boiling boiling boiling.......
:detective:
9:07 AM 1/16/2012

Distill your own water, and make sure the container your using is clean(dish washers tend to leave trace mineral deposits, and the no spot rinse chemical leaves a film) and free of any minerals or other foreign cleaners. Then try again, it won't boil.