An ice spike is an upward-facing icicle that forms as a body of water freezes. Ice spikes can form in natural environments or can be made artificially by freezing distilled water in plastic ice cube trays.
Water expands when it freezes. If there is already a thin sheet 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. 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.
Famous quotes containing the words ice and/or spike:
“He was high and mighty. But the kindest creature to his slaves—and the unfortunate results of his bad ways were not sold, had not to jump over ice blocks. They were kept in full view and provided for handsomely in his will. His wife and daughters in the might of their purity and innocence are supposed never to dream of what is as plain before their eyes as the sunlight, and they play their parts of unsuspecting angels to the letter.”
—Anonymous Antebellum Confederate Women. Previously quoted by Mary Boykin Chesnut in Mary Chesnut’s Civil War, edited by C. Vann Woodward (1981)
“From a hasty glance through the various tests I figure it out that I would be classified in Group B, indicating “Low Average Ability,” reserved usually for those just learning to speak the English Language and preparing for a career of holding a spike while another man hits it.”
—Robert Benchley (1889–1945)