Boiling water

[mizfiesta]

A friend of mine said to me recently that it was possible for boiling water to freeze to ice in mid air (say when being poured from a mug eg) before it reached the ground, in certain, very cold places, in the world. Is this true?

[THECORBYLOON]

Watch this

[treborwood]

im not sure about the video?
i know through experience that in industrial freezers which go to about -20 it would'nt do that.
it would have to be a whole lot colder to freeze in a matter of seconds.

[boink]

wasn't there something about this in a news report during the last cold spell in Russia? i know thats very vague, but it might help someone remember more!

[Hamish]

It is all about the rate of heat transfer. In the vid the water is thown into the air and therefore there is a huge increase in surface area to vol ratio. This means that the heat can be lost very quickly. If you wanted to do this in a freezer you would have to ensure that the freezer could cool itself faster than the water could heat it. In cold weather however there is a huge thermal mass to be heated (ie several cubic miles of air), therefore the air remains cold and the water freezes.

[stevie_c2it]

On a recent trip to Toronto a water main burst on the CN Tower, the police had to cordon off the area below as the hot water was landing in the street as bullets of ice. It was -35.

[Gnisy]

How do you get it hot enough to boil in the first place?

[tommy666]

to Gnisy:

Me make fire. Fire goooood. *begins ritual, cavemanlike dance around the fire*

to get it hot enough to boil, you heat it to 100 degrees celcius or above ;)

[mizfiesta]

ha, yea and watch for the bubbles!

[mizfiesta]

well kinda is Eddie, only in this scenario then surely we could almost believe that urine, at body temp, would have at least the likelihood of freezing before it hit the ground. Still not so convinced about boiling water though ; )

[Hamish]

You can work it out. I havent the time. You need to use the heat capacity of water to cal the themal enerygy in a droplet, cal its surface area and rate of heat loss based on outside temp. Then calc time to hit floor. is the former shorter than the latter? if so then it will freeze before hitting the floor.

[Gnisy]

to tommy18 ( look, i can add ):

me ask how water boil because air so cold that water be ice, how can there be hot fire to boil?

me have better english cos me took Cave-English 102