Some notes on the materials needed.First, just about any bottle will work, but keep in mind that the bootle size will determine the volcano height. Second, haveing sides around the volcano helps keep the "lava" contained. However, if having sides is not desired, then subsitute a flat peice of cardboardThey also dry wuickly with little need to vent paint fumes. Green, blue, yellow, red, white, and black or brown should provide plenty of variety. You can cut out the bottom of a small Styrofoam glass to use for mixing colors and to dispense the paint.