Heat 2 cups water to boiling
Mix 1 cup cornstarch and 1 cup cold water. Stir in boiling water until thickened.
Add food coloring to make different colors.
Don't worry- it's non-toxic.
I like to give them primary colors so they can experiment with mixing colors.
Put an old t-shirt on them, a tablecloth on the table, and let 'em go at it.
And try it yourself, too! (paint therapy is good for the soul).
this came from here: