If you must build on permafrost, you have three ways of dealing with it--keep it frozen, thaw it out, or let the building move.
Devise a plan to keep the ground frozen, create a thawing program, and design a structure that can move with ground subsidence.
Display the plans and structure.
The Alyeska Pipeline Service Company was concerned about permafrost underlying three-quarters of the 800-mile, trans-Alaska pipeline.
It drilled 12,000 holes to test for permafrost.
You can "drill" a test sample of your playground.
(Be sure to obtain permission.
) Drill a vertical hole to create a core, using tools like copper tubing, plastic tubing, or gardening tools for digging bulbs.
Call a local soil-testing firm for literature to share with your class.
Ice wedges form in the permafrost tunnel when water seeps into a crack in the frozen ground.
The water freezes and ice expands, pushing out in all directions.
The wedge partially melts during its formation, allowing more water to fill the void and expand the size of the wedge upon refreezing.
Simulate the ice wedging by packing a shoe box with dirt (preferably some fairly impermeable soil, such as clay).
Make a small crack and line it with plastic so it will hold water.
Place water in the lined crack.
Freeze the box.
Did the soil move?
Melt the ice, add more water to fill the plastic lining, and then refreeze the water.
The size of the space will increase, as it does in the case of an ice wedge.