First, you need to make the model. You can make it out of clay, paper mache'; or salt dough. I like the salt dough better. The recipe is:

The fun part is mixing this up with your hands. Better than gushy mud pies! If you think you need more water, add a little at a time. Make sure all the ingredients are mixed together good.

You can add food coloring or you can paint it with poster paint once it dries.

Get a box from the supermarket and cut it down to only 3" high. Line the box with aluminum foil and place it on an old cookie sheet. Be sure to cover your work area. If you use newspaper, then you can just throw it and the mess away when you are done.

Shape the salt dough around a small plastic soda bottle to make a mountain. The soda bottle acts as the chimney of the volcano. If you want to put small trees and bushes on the mountain, do it now before the salt dough dries.

Let the dough dry thoroughly. You can put it in the oven at 200-250 degrees, but check it often. When the dough is dry, you can paint it to look like a mountain.

Fill the bottle with warm water and red food coloring. Add 6 drops of liquid dishwashing detergent. With a funnel add 2 tablespoons of baking soda. The slowly add vinegar to the bottle. The liquid will foam and flow down the sides of the mountain.

When you mix vinegar and baking soda together, it creates carbon dioxide. Carbon dioxide is the same gas that causes the lava to bubble and is produced during a volcanic eruption.