Hi! Have you ever heard of putting baking soda in vinegar? Well if you do you will probably know that what happens is the alkali (baking soda) neutralises the acid (vinegar) and produces carbon dioxide CO2. If you add red food dye and put it in a papier machie volcano it will look like a effusive eruption (usually found on shield volcanos and the settings are low viscosity and low gas)! But I wonder what would happen if you used a stronger acid and a stronger alkali then perhaps that might result in a Hawaiian Fire Fountain or even a Vulcanian eruption!