To make a homemade volcano, use multicolor modeling clay to form your volcano, and then insert a hole deep in the middle. Put baking soda in the hole, and then using an old pencil, stick the pencil down inside the baking soda to form another hole inside the baking soda. Take vinegar and put inside the hole with the baking soda. Make sure you wear goggles to protect your eyes. Also, red food coloring can be used in the vinegar to create a red eruption.