I have two ideas for you:
1. This is a great application for cave/rock art. You use wall board,
yep the stuff your walls are constructed from. Wallboard is not too
expensive, available at building supply stores, or watch where contruction is
going on. The wall board is very easy to cut into sections. Use a box
cutter, score one side, place the scored side down along the edge of a table
and push down. You will get an even break.
The wall board is plaster in the middle with paper covering front and
back. Lightly wet one side (doesn't matter which one) and start to rub the
paper off, using your fingertips and gently rub, wet, rub. It takes time but
it does work. 8th graders could easily do this. Remember to leave the paper
on the back side, you need it to hold the plaster together.
Now the students can create. They can carve into it using any non
breakable pointy item, plus they can break off edges to give it a old, rock
look. After the carving use watered down tempera in browns, blacks, greens
to give a wash of color over the 'rock carving'. They look quite realistic
and no one ever guesses what medium the students started with.
2. This is pure fun that even 8th graders would love. Have your room
prepared before they enter. Move all the chairs out of the way. Line up the
tables edges touching -or-cover over the tables with paper. You have created
a cave. Have the lights off when the students enter, and play a CD of
waterfalls, animal sounds. The students have to crawl on the cave floor,
tape paper unto the roof of the cave (the underside of the table top) and
create a cave painting. Note if you have more energy than me you can have the
paper already attached for them. You can also have a few flashlights for the
cave. They will love it.
Have FUN. Jean in Michigan