How to Freeze Water While Boiling

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. 

what wuz going on in the first pickture and how do you do it?

Unbelievable.

Be careful with Acetone vapours and vac pumps, the slightest spark from static or a none sealed motor, could lead to an explosion.

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.

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.

Cool! Where do you get all these chemicals?!

Please use manual focus next time.