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When you freeze crushed ice it all sticks together. Is it possible to stop it sticking?
- Ani (age 12)
Linslade middle, England, Beds
You can reduce the sticking by keeping the
ice well below the freezing point at all times. The sticking mainly
comes from water that has melted on the surface of the crushed ice
pieces re-freezing, gluing the ice pieces together. If there never is
liquid water present, this process will not happen.
It is may
be impossible to keep all liquid water from forming because the process
of crushing the ice may melt some water (both due to pressure
and also the fact that crushing the ice adds energy which can melt some
of the ice. In addition, if the humidity of the air is high enough,
some water will condense on the ice pieces. This last one can be
minimized by doing the crushing quickly and in a low-humidity
The low-temperature approach to keeping the ice
from sticking is why it is hard to make a snowball that sticks together
when it is really really cold outside -- the best snowball-sticking
together temperature is right around freezing.
(published on 10/22/2007)
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