Guess what, it works. Now if I could only get students to have fun playing in the mud. Why are they happy to make a mess unless you hand them messy stuff.
Anyways, we mixed the plaster of paris with acrylic paint, there really isn't an exact amount we just made it look like thick pancake batter. Then we put it on a canvas and used palette knives to move the mixture around to create either shapes or textures. Afterwards we watered down acrylic paints and applied layers of color with brushes and sponges to get the desired affects. This step took some time and some had difficulty with it, but if it was horrible coloring all they had to do was paint over it and start over.