Q: Does tapping the top of a soda can stop it from foaming?

chow.com — A: Those who think so follow this logic: When you shake a soda can, little molecules of carbon dioxide bump into each other and form bubbles. These bubbles hang around on the sides and bottom of the can until you pop the top, at which time they shoot out, eager to escape to the lower air pressure outside the can Nov 11, 2007 View in Crawl 4