The disc has one case for city growth and water supply. The scenerio has
   the city addint housin and building a desalination plant to provide more
   water.
   ...
   Can folks think of another  setting where this could be used? Its a bit too
   advanced for grade school.
Nils,  at the lower levels, it might be good to do sim-city 2000 based analysis
and simulations.  Kids love it, its interactive and allows them to test
various scenarios to see what blows up and what works.  Give it a thought,
the interactive simulation technologies applied to social/infrastructure
growth issues at the local level would be good to encourage at the younger
ages (and even the older ones....)
johnt