Effectively heat transfer
increases at -54 degrees F. I presume they
avoided actual freezing in this experiment and this is a condition never to be
seen in nature anyway.
Recall though deep ice used to
test life forming models develops strange fractures with apparent liquid in the
interstices. I have never though that
water would give up giving anytime soon.
It is meant to drive us crazy.
In the meantime, what I term as
biological water does a neat job of slightly changing the physical characteristics
of water along a predictable path and will produce fine needle like crystals within
one degree of predicted freezing point and is observed in ponds. I suggest young students make a point of
collecting such ice for experimental purposes in science projects.
Weird world of water gets a little weirder
by Staff Writers
Strange, stranger, strangest! To the weird nature of one of the
simplest chemical compounds - the stuff so familiar that even non-scientists
know its chemical formula - add another odd twist. Scientists are reporting
that good old H2O, when chilled below the freezing point, can shift into a new
type of liquid. The report appears in ACS' Journal of Physical Chemistry B.
Pradeep Kumar and
H. Eugene Stanley explain that water is one weird substance, exhibiting more
than 80 unusual properties, by one count, including some that scientists still
struggle to understand. For example, water can exist in all three states of matter
(solid, liquid,gas) at the same time.
And the forces at its surface
enable insects to walk on water and water to rise up from the roots into the
leaves of trees and other plants.
In another strange turn, scientists have proposed that water can go
from being one type of liquid into another in a so-called
"liquid-liquid" phase transition, but it is impossible to test
this with today's laboratory equipment
because these things happen so fast.
That's why Kumar and Stanley used computer simulations to check it out.
They found that when they chilled liquid water in their simulation, its
propensity to conduct heat decreases, as expected for an ordinary liquid.
But, when they lowered the temperature to about 54 degrees below
zero Fahrenheit, the liquid water started to conduct heat even better in the
simulation.
Their studies suggest
that below this temperature, liquid water undergoes sharp but continuous
structural changes whereas the local structure of liquid becomes extremely
ordered - very much like ice.
These structural changes in liquid water lead to increase of heat
conduction at lower temperatures.
The researchers say that this surprising result supports the idea
that water has a liquid-liquid phase transition.
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