Why do people tap on soda cans before opening them?
People tap on soda cans to avoid a soda explosion from a can that has been shaken up. Tapping may, in fact, decrease the likelihood of such an explosion, but a positive outcome is not guaranteed. Carbonated beverages contain dissolved carbon-dioxide gas. The way to get gas to dissolve in liquid is to pressurize the mixture, meaning that the pressure inside a soda can is greater than the pressure outside the can. This is why you see little bubbles spray out when you open a soda can — breaking the seal depressurizes the mixture, causing the gas to come out of solution, starting with the gas closest to the top (that’s where the pressure decrease starts). Because gas is lighter than liquid, as soon as it comes out of solution, it rises to escape the can. When it escapes, it carries with it a small amount of liquid from the very top of the can because that liquid is blocking its path. When you shake a soda can, some of the gas comes out of solution. There are a bunch of carbon dioxide bubb
