- Ice spike
An ice spike is an upward-facing
icicle that forms as a body ofwater freezes. Ice spikes can form in natural environments or can be made artificially by freezingdistilled water in plasticice cube tray s.Water expands when it freezes. If there already is a thin sheet of surface ice over the body of water, further freezing can force water out and upwards through a crack or weak point in the sheet. This can produce a tube-like structure where water emerges at the tip, progressively lengthening the tube. [citation|last = Dorsey|first = H E|year = 1921|title = Peculiar Ice Formations|journal = Physics Review|volume = 18|issue = 162] Tube formation stops when the tip freezes and seals.
Ice spikes rarely form when freezing "normal" non-distilled water because impurities in the water act as an
ice nucleus so the water freezes before an ice spike can form.The formation of ice spikes is related to the shape of the water body, the concentration of dissolved impurities, air temperature and air circulation above the water. [citation|last1 = Libbrecht|first1 = K G|last2 = Lui|first2 = K|year = 2003|url = http://www.its.caltech.edu/~atomic/snowcrystals/icespikes/icespikes.pdf|title = An Investigation of Laboratory-Grown Ice Spikes]
References
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