An ice wedge box is made from strong wood so the dirt around the ice
wedges will not fall back together when the box is moved.
I took a long piece of wood and measured it to made 2 long pieces and 2
short pieces. I took a saw and cut
the wood and put it together and made a box with no front.
I got some Plexiglas and cut it in 1 long piece and glued it down. Then,
I took some slim wood and cut it to the right size and nailed it down.
I
put zip lock bags in the box and filled the box with dirt. I buried the bottom
half of the empty bags in the dirt and packed the dirt tightly. Next I filled
the top of the bags with water put it outside to wait over night. The next
morning, I brought it in and let it thaw. Each night I would take out and each
morning I would bring it in. Take
out, bring in every day for a long time and slowly it will get bigger and
bigger. It gets bigger because when
it freezes the water expands and pushes the soil apart so the ice wedges will
get bigger and bigger.
Permafrost
is permanently frozen ground. It is water or soil or even rock that has been
frozen at least for two years. We care about permafrost because if someone
builds a house on permafrost and the permafrost thaws, then the ground may
collapse as ice wedges melt.
In
permafrost,
there is massive ice and massive ice has 3 groups in it, ice wedges, ice lenses
and clear ice.
An
ice wedge’s name means the shape, wide at the top and slim at the bottom. Ice
wedges are formed when the top soil got colder than the deeper dirt and cracked
during the winter. Then, the next spring water got into the crack and froze,
pushing the crack out. (When liquid water freezes into ice, it expands.) Spring,
winter, spring, winter, on and on for thousands of years, the ice wedge grows
many feet wide, but it only grows fractions of an inch per year.
I
didn’t exactly do the cycle of an ice wedge. The real ice wedge does not thaw
when growing and does not need a bag and one cycle needs one year not 24 hours.
The ice wedge
forms when the soil contracts and a crack forms. The soil in my box didn’t
crack.
Grolier
Multimedia Encyclopedia. 1997. Permafrost.
McFadden,
T.T. and Bennett L.F. 1991.
Construction in Cold Regions. John Wiley & Sons, Inc.