The Naked Scientists

The Naked Scientists Forum

Author Topic: How do you make ice in a bottle from banging water?  (Read 1307 times)

Offline annie123

  • Sr. Member
  • ****
  • Posts: 252
    • View Profile
i watched a programme called the Secret Life of ice in which a man took a bottle of water cooled by a bowl of ice  - didn't say for how long - and then banged it on a table and ice started to appear and eventually mostly filled the bottle. I tried this - several times - with varying degrees of coldness of the bottle and the ice didn't form. Does this only work on tv?? Or should I have had a smaller bottle - i would have tried this but didn't have one - only a litre bottle.


 

Offline Bored chemist

  • Neilep Level Member
  • ******
  • Posts: 8667
  • Thanked: 42 times
    • View Profile
Re: How do you make ice in a bottle from banging water?
« Reply #1 on: 20/10/2013 19:54:30 »
It's real.
You have to get the water below freezing point without it freezing.
This so called "supercooled" water isn't stable- it turns to ice when disturbed.

Since the water has to be cooled below freexing he can't have just cooled it in ice. It may have been a bowl of ice and salt.
 

Offline CliffordK

  • Neilep Level Member
  • ******
  • Posts: 6321
  • Thanked: 3 times
  • Site Moderator
    • View Profile
Re: How do you make ice in a bottle from banging water?
« Reply #2 on: 20/10/2013 21:19:24 »
I haven't done the experiment myself, but it apparently works.

The Latent heat of fusion of water is 79.5 calories per gram.

It takes about 1 calorie to heat or cool 1 gram of water by 1C.

Since it is unlikely you would ever reach super cooled water at -80C, the resulting ice you create from the bump is likely more of a slush than a solid ice.

Say, if you begin with the container supercooled to -5C, then immediately after the freezing transition, the temperature of the container should increase to 0C.
 

Offline annie123

  • Sr. Member
  • ****
  • Posts: 252
    • View Profile
Re: How do you make ice in a bottle from banging water?
« Reply #3 on: 22/10/2013 00:31:09 »
I tried it again with a smaller bottle and it worked, but as you say when the temp rose even a little it became water again. I poured it out into a glass and it was mostly water that came out with eventually a little slush of ice crystals.
 

The Naked Scientists Forum

Re: How do you make ice in a bottle from banging water?
« Reply #3 on: 22/10/2013 00:31:09 »

 

SMF 2.0.10 | SMF © 2015, Simple Machines
SMFAds for Free Forums