Am I crazy for believing that hot water does NOT freeze faster than cold water?

[CTyankee]

Back in the day, people would tell me to put hot water in my ice cube trays (which nobody has anymore). I told them it was against the laws of physics for hot water to freeze faster than cold and would get a big argument.

It's snowing outside and below freezing. So DUers, tellme, if I put out two pots of water, one hot and one cold, which one would be ice first?

[AllegroRondo]

1. no, you're correct

cold water freezes faster.

[redqueen]

2. Are you postive about that?

I coulda sworn I'd seen it done one one of those science shows for kids, and the hot froze faster. They even explained why... but I forgot what they said.

[AllegroRondo]

9. think about it this way

lets say the hot water does get colder faster. At some point, its going to be the same temperature that the cold water started at. But the cold water will already have gotten colder.

[CreekDog]

23. in the freezer, hot water will evaporate more quickly than cold water

the phase change from liquid to gas should result in a greater net energy loss for the surface of the hot water (evaporating more quickly than the cold). whether or not that really means that the hot water will cool and thus freeze faster than the cold water --i don't know, but i would guess that's the logic.

could also be related to how the water freezes. if a layer of ice freezes on top first, that might insultate the rest of the water to some extent.

where's bill nye, this is his territory.

[ThomCat]

3. I would think you're right.

A consistent rate of heat loss would require that the warmer water takes longer to freeze. :shrug:

[redqueen]

5. That's the trick... it's not consistent.

The heat evaporates from the hot more quickly, I think.

I could've sowrn that this was true.

[billyskank]

30. .

[gmoney]

4. I thought it was hot water freezes clearer

if you want those sexay, crystal clear cubes... but I dunno

[ThomCat]

8. That would be more probable.

Water that was hot might have released more oxygen, so it might form fewer bubbles and form clearer ice.

I'd want to see tests to see if that's true, but it sounds reasonable on the face of it.

[redqueen]

6. Not crazy... it's the Mpemba Effect, and it's only in certain circumstances.

I *knew* I learned this. :P

[CTyankee]

13. And I thought they were thinking about Jello! n/t

[Heidi]

7. It'scounter-intuitive, but it happens.

Mpemba effect. :hi:

[billyskank]

27. .

[Pierre.Suave]

10. From Teh Google...

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

[Fox Mulder]

11. Hot water does freeze faster than cold water.

Explanation here.

[IronLionZion]

15. who knew? That's fascinating. Thanks for sharing. nt

[Pierre.Suave]

26. Did you just copy my link

and repackage it?

[Fox Mulder]

32. No.

It was the first link when I checked in google.

Just a coincidence.

[IronLionZion]

12. There's one surefire way to find out, and you can do it today

I still use the ice cube trays too. So if you have two, just try one of each and see. Let us know how it works out.

Discovery channel tried some different ways of cooling beer. Salted ice water cooled it fastest I think. But they also tried ice water, and plain ice without water, and I don't remember what else.

[madinmaryland]

17. Just sticking beers in the freezer for a few minutes works for me!

:beer:

[IronLionZion]

18. until they explode!

don't do that. You don't want to forget about them.

[madinmaryland]

20. Don't leave them in overnight!!

:rofl:

[Solon]

24. I did that once, by accident, and when it burst, it froze in mid burst...

it was like a frozen fountain, it was so cool looking, cleaning it up was a pain in the ass though.

[CreekDog]

35. ice cube trays??????!!!!

that's so old school. dayum mang.

there are two things i don't like: Rush and ice cube trays.

:wtf:

[Drum]

14. Interesting...and here's another conundrum that I've always noticed and wondered about:

Whenever I brew coffee with cinnamon in it (that is, adding it into the brew basket) I always find that the coffee cools much faster in my cup than w/o cinnamon. Honestly! What could account for this? I've noticed it enough times---with no other circumstances being different---that it sticks in my mind and makes me wonder....

I'm glad that the Lounge is also involved in the laws of thermodynamics...bookmarking!

:)

[Solon]

16. I don't know the exact chemistry involved...

but I think there are chemical reactions that increase the cooling factor of some liquids and solids, similar to how some chemical reactions increase the amount of heat generated in a substance, like the setting of Concrete after water is added.

[Drum]

19. thanks for pondering and replying, Solon!

:hi:

[PVnRT]

21. If you have ultrapure water

The hot water will freeze slower - there are fewer dissolved chemical species in it around which ice crystals can form, some of it will evaporate and lower the necessary heat removal load, and so on.

However, for the water 99% of use encounter in our daily lives, it's not going to make much of a difference.

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

[CreekDog]

22. hot water doesn't freeze at all

even cold water only freezes if it's below the freezing point.:think:

[billyskank]

29. .

[billyskank]

25. It takes longer.

The temperature of cooling water (or any other substance) when plotted against time follows a curve, exactly the same shape as a half-life. If the water starts hotter then it starts further up the curve away from the freezing point (which, at normal atmospheric pressure, is always zero C).

The bucket of cold water would certainly become ice first.

[Pierre.Suave]

28. me thinks you need to read up on this...

cause it does indeed happen.

[billyskank]

31. Whoever answered me above, I have you on ignore.

There is no point answering my posts.

[Pierre.Suave]

33. HAHAHAHAHAHAH

now THATS funny...

That reminds me of the guy on Mythbusters that "jokingly" says, I reject your reality and assume my own. Who needs science...

Why would you have ME on ignore?

[CreekDog]

34. Wait, you just responded to #25, which was your msg. that you were ignoring it

are you ignoring yourself?

how much do you have to donate to access that feature?

do you enjoy that feature?

am i a troublemaker? :thumbsup: