next message in archive
next message in thread
previous message in archive
previous message in thread
Index of Subjects
Index of Subjects
Hi Andy & All, Jan 14, 2008
Water is either liquid, solid, gas or adsorbed so this hardening of
the ground would be due either to drainage (not likely from you comments
about tracks having a lot of water), evaporation from the soil surface
or under greater soil moisture tension near the surface due to cooling.
An evaporation effect is consistent with the temperature being
warmer when you went out than the overnight low but I don't recall
appreciable wind so that seems doubtful.
I don't recall the magnitude of a second possible effect, but if the
soil was appreciably warmer, when it was mucky yesterday, than it was
this morning then the cooling would tend to 'firm up' the soil. Due to
changes in surface tension, I think, cold soil holds more water than
does warm soil, i.e. soil moisture tension increases as temperature
decreases making the soil appear more drained.
When I have time to dig out a soil physics book I will be able to
estimate magnitudes and at least confirm that I don't have it backwards.
Yt, Dave Webster, Kentville
Andy Moir/Chris Callaghan wrote:
> I have a question about the properties of water as it goes through the
> transition from liquid to solid.
>
> Yesterday, following the heavy rains and mild temperatures, our stable
> yard was quite a mucky mess. It was easy to sink well past one's
> ankles in mud. This morning when I went out, the ground was not
> frozen, but it was certainly much more solid to walk over.
>
> When I went out this morning, the temperature was +2.3C. The
> overnight low was +1.8C.
>
> There were still pools of water in the footprints (and hoofprints)
> made in yesterday's muck, so the ground certainly wasn't frozen, and
> there was certainly enough water around to make it every bit as mucky
> as the day before.
>
> So the question is, does water begin to "harden" before it actually
> becomes ice? I understand that the activity (of the molecules?) slows
> as the temperature drops, but when I stick my hand into cold water
> (say water just above freezing), it feels every bit as liquid as when
> I put my hand into lukewarm water. If there is a "hardening" process
> before forming ice, does it happen in a very narrow band of
> temperature just above the freezing point?
>
> I've tried to find an answer to this burning question on the internet.
> I found several sites that talked about super cooled water and the way
> the molecules line up in different ways in liquid water and ice, but
> nothing that explained why water that should still be liquid appears
> to be more solid, but not frozen, as the temperature drops to
> near freezing.
>
> Thanks,
>
> Andy Moir
>
> Freeport
>
>
>
>
>
next message in archive
next message in thread
previous message in archive
previous message in thread
Index of Subjects