I tried to send this off-list - but the message got kicked back to me......
How about claymation - you wouldn't necessarily have to animate the figures
and take pictures (but you could -- might be fun to take some digital
photos).
I would go out an buy some plasticine clay - the oil base clay- that
doesn't dry out. Buy all sorts of different colors. My art teach students
LOVED doing claymation (8th graders) -- and the expense of less that $20.00
was well worth having a classroom of happy kids.
Let me know if you are interested - I can help find some sites for you.
The great "How-To" page is no longer online - but I am sure there are sites
out there
You could also have kids do some glaze testing. Have them experiment what
happens when glazes are put one on top of another - you get some fabulous
results! Give them a bunch of combinations (some that you know will work -
some you are unsure of). Just make a bunch of glaze test tiles -- maybe 1
1/2" by 3" (texture some part of the tile too). I bend my test tiles so I
can stand them uon the kiln shelf (an "L" bend).