How to Freeze Water While Boiling

video How to Freeze Water While Boiling
This can actually happen. It seems unnatural, but the laws of physics don't lie. Liquids require heat to boil, and if the conditions are right one liquid can be boiled in order to freeze a second. Under a vacuum, the water in an acetone/water mixture can freeze while the acetone boils. Watch the video and see for yourself.

How to do this
Fill flask with 25mL of acetone and 10mL of water
place in a bell jar with a vacuum and turn on


16 comments
Feb 10, 2010. 7:14 PMemilfriedman says:
One ought to be able to do this with water alone and eliminate the fire hazards associated with acetone.  But if you don't have a vessel designed for high vacuum you could get a dangerous implosion, so consider this to be a thought experiment and do not try it unless you have experience working with high vacuums.

Imagine cooling some water to just above it's freezing point at ambient pressure.  Now imagine pulling a strong enough vacuum to boil the water.  Water has a very high heat of evaporation, so boiling will lower the temperature of the remaining water and ice ought to start forming as the liquid boils.  (Evaporation is a cooling process.  That's why we need to sweat.)*  Eventually you'll run out of liquid and the ice will start subliming, just like snow can in really dry cold weather. 

Notice I said "ought" and "imagine" and did not specify how strong a vacuum you need.  Basic thermodynamics says it ought to work if you can lower the pressure enough.  But I don't plan to try it and I recommend that only people who have experience with high vacuum work even consider trying it.  Implosions throw a lot of broken glass around and can kill or maim anyone nearby.

PS, I don't think you can pull a strong enough vacuum with an aspirator, no matter how strong the flow, because the water in the aspirator would boil before the water in your sample.  One would need a strong vacuum pump, vacuum grade equipment and the experience to use it safely.   Or one could get an astronaut to try it during a space walk.

* The fact that water expands upon freezing will help because that means that lowering the pressure will raise the freezing point. 
Apr 17, 2011. 7:34 AMdanakayama says:
This works with distilled water. The vacuum has to be on the order of one torr, and a liquid nitrogen cold trap is a good idea if you want to keep the vacuum oil clean.


Our video of the experiment is here on youtube.
http://www.youtube.com/watch?v=y4nPwztC-eU


Feb 9, 2010. 2:13 PMpyroninja21 says:
what wuz going on in the first pickture and how do you do it?
Sep 21, 2008. 5:21 AMjedidiah_victor says:
Unbelievable.
Sep 13, 2008. 5:19 AMBarefootRandom says:
Be careful with Acetone vapours and vac pumps, the slightest spark from static or a none sealed motor, could lead to an explosion.
Sep 6, 2008. 9:29 PMzomfibame says:
you can also get acetone in just about any hardware store... or the section in wal-mart that sells make-up. they have it in a plastic bottle along side fingernail polish. the metal quart costs about 6 bucks, the lil plastic bottle is only about 3.
May 23, 2008. 4:16 PMCat on my Lap says:
Heat is not required for water to boil. Boiling is merely the vapor pressure of the liquid equalizing the partial pressure. Hence, water can boil at far below it's standard boiling point of 100C if you reduce pressure. Look up the gas laws and the triple point chart for H2O.
Jun 12, 2008. 8:43 AMPKM says:
Perhaps a raise in temperature is not required to boil a liquid, but heat is still required. That's why letting off the pressure of compressed gases cools them down: the phase change from liquid to gas is endothermic and takes heat from the surroundings, causing (for example) the frost on the lighter refill can.
Feb 1, 2008. 3:12 PMGorillazMiko says:
Cool! Where do you get all these chemicals?!
May 17, 2008. 2:06 PMstuffman366 says:
ACE, westlake, wally world, hobby lobby
Feb 1, 2008. 3:25 PMbhunter736 says:
Acetone used to be found in finger nail polish remover. I think some types still contain it. It is great for cleaning certain types of mechanical parts when grease has dried into a solid state. I havent purchased any in a long time.
Feb 1, 2008. 3:15 PMvernors says:
ebay probable or is it eaby?
Feb 1, 2008. 7:06 PMguyfrom7up says:
go to wallmart, it's in the paint section. It's sold in those square metal containers. I think you can either get a galloon or a quart.
Feb 2, 2008. 8:21 AMtech-king says:
here, its only sold in liter jugs. and nail polish also contains alcohol, so be careful.
Feb 1, 2008. 12:15 PMxrobevansx says:
Please use manual focus next time.
Feb 1, 2008. 3:16 PMledzeppie says:
not all cameras have that...

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