iandol on mon 3 jul 00
Dear Diane Woloshyn=20
Thank you for those interesting observations.
I believe several things can happen when pugged or kneaded clay is =
frozen then thawed.
Point one. It sounds as though water has migrated to areas where there =
was least stress as the material cooled. Then as that free water froze =
it would have expanded. This would have separated the layers of clay =
from each other.
Point two. During freezing the complex structure which forms between =
clay particles and water may have been destroyed. I think this would be =
like dehydrating the clay. It would destroy its ability to adhere to the =
grog and the sand and could explain your experience.
Point three. I understand that during weathering, clay platelets shear =
along their weak cleavage plane which is parallel to their large flat =
face. So the more crystals you have the more plastic the clay becomes.
Now who is going to argue with that!
Sorry, Can=92t explain the air, but when water freezes, air comes out of =
solution and makes bubbles in ice.
Good to get that information.
Best regards.
Ivor Lewis. Redhill, South Australia
Bruce Gioia on mon 3 jul 00
Sorry, Can't explain the air, but when water freezes, air comes out of
solution and makes bubbles in ice.
Good to get that information
_________________
>From simple observation rather than higher education...
The larger volume/mass water assumes while freezing
reduces amospheric pressure allowing an isolated
decompression and thereby creating a gaseous "extraction"
(as you mention, water contains dissolved gases)
Sort of like having a sringe with half water half air
plug the hole and pull the plunger
and the gaseuos volume increases.
Also interested in hearing a more technical version.
Bruce
Shelley Corwin on mon 3 jul 00
we used to freeze beginning student work, to show the pattern of throwing,
and then could correct it. you've just explained why that works. s
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