Have you ever wondered how bath fizzers work and why they do not start fizzing until they are placed in water? Bath bombs are a compact mixture of dry ingredients consisting of Sodium Bicarbonate and Citric Acid -along with oils that may add a pleasing scent to it- which will not react until exposed to an aqueous environment, in this case, your bath. While dissolving in your bath water(the reaction’s catalyst), the ingredients in the bomb are undergoing an acid base reaction that produces Carbon dioxide gas along with other products such as water, resulting in that pleasing fizzing, which gives the tingling sensation on the skin.