A homemade volcano can be made using just a few household items. Use modeling clay to create the form of your volcano. Make a hole in the top and open the inside up about 3 – 4 inches deep from the top. Pour 3 tablespoons of baking soda in the hole. Then pour about 1/2 cup of vinegar in the hole. Make sure you keep your face away from the hole, or use protective eye wear.