Hot Ice Sculptures

Handwarmers often contain a supersaturated solution of sodium ethanoate (CH3COONa). (Supersaturated means that the water in which the sodium ethanoate is dissolved is 'carrying' more sodium ethanoate than it should and at the slightest provocation, the ethanoate will precipitate out. This occurs because hot water will dissolve far more sodium ethanoate than cold water, but having done so, the ethanoate will stay dissolved as the water cools down.)

A seed crystal, or even a speck of dust, will provoke the precipitation of the ethanoate. In this experiment, a clear saturated solution of sodium ethanoate is poured onto a plate at which point it will solidify, creating an ethanoate tower, stalagmite or ice sculpture.

You can also touch a clear solution of sodium ethanoate and cause it to solidify in front of your eyes....

To read more click here to download Dr Hal's fact sheet on Hot Ice Sculptures (900kb pdf file)