To make a baking soda volcano, gather baking soda, vinegar, materials to create dough and a plastic bottle. Additional supplies include dish detergent and food coloring. Begin by creating the volcano using dough and the plastic bottle, and then add the materials that cause the eruption.
Make the dough for the volcano's cone by mixing 3 cups of flour, 1 cup of salt, 1 cup of water and 2 tablespoons of cooking oil. Stir the mixture by hand or with a spoon until it is smooth and free from lumps and bubbles. Add food coloring to give the dough an earth tone. Stand the plastic bottle in the center of a baking pan, and mold the dough around the bottle into a volcano shape, leaving the opening of the bottle unclogged.
Fill the bottle nearly full with warm water and a few drops of red, yellow and purple food coloring. Next, add six drops of dish detergent to the bottle to trap bubbles and achieve better lava flow. Follow this by adding 2 tablespoons of baking soda to the mixture. When it is time to demonstrate the eruption, add the vinegar, which reacts with the baking soda and causes the lava to flow over the sides of the cone. Pour a small amount slowly into the bottle, and watch the bright lava flow as the carbon dioxide builds and pushes the bubbles over the rim of the bottle.