We all know that a dropped or shaken can of soda carries the risk of causing a fizzy rash. People use different techniques to prevent these bubbly explosions, including tapping the top of the can. This advice has been bandied about for years, but does it really work? The answer lies in the physics of what happens inside the can. Bubble formation To make a carbonated drink, carbon dioxide is injected into a liquid, such as soda, beer, or champagne, at high pressure and a cold temperature. Latest videos from Live Science”[Bubbles] They form as a result of what is called supersaturation of carbon dioxide,” Roberto Zenit, an engineering professor at Brown University who studies fluid mechanics, told Live Science. Supersaturation is an unstable state in which a liquid or gas can contain more dissolved materials than normal conditions allow. Thanks to its instability, there are some actions, such as shaking a can, that can encourage more bubble production. Subscribe to our newsletter (Image credit: Marilyn Perkins / Future) Sign up for our weekly Life’s Little Mystery Newsletter to get the latest mysteries before they appear online.”Mechanical action (striking or shaking) generates violent pressure waves within the liquid; These waves bounce off the walls, creating low-pressure zones where small bubbles form,” Javier Rodríguez Rodríguez, associate professor of fluid mechanics at the Carlos III University of Madrid, told Live Science in an email. “If given enough time (minutes to tens of minutes, depending on the drink and container), these bubbles dissolve again and the can ‘forgets’ that it has been disturbed.” However, if the soda can is open while the bubbles are suspended in the liquid, the sudden pressure drop when opening the can encourages more In some rare cases, such as spraying champagne after a NASCAR victory, creating a geyser of foam is exactly the goal, which drivers achieve by vigorously shaking the bottles beforehand. Does tapping really work? Unlike NASCAR drivers, most people are looking to save their drink, so they can try tapping the top of the can. According to Zenit, carbon dioxide bubbles can expand from small ones. imperfections called nucleation. “The reason you tap is basically to remove any potential bubbles or dust particles inside the soda can,” Zenit said. By removing them, you can reduce the rate of bubble formation, he added. Tapping a soda can can also work for carbonated drinks in glass and plastic bottles. (Image credit: Pornchai Jaito/EyeEm via Getty Images) in the air pocket above the soda before opening it. With fewer nucleation sites left in the liquid, there would be fewer places for bubbles to grow quickly once the can was opened and the pressure dropped. But that explanation comes with an important caveat: While tapping gently might dislodge a handful of bubbles, tapping too hard or tapping repeatedly could create more bubbles, Rodriguez Rodriguez said. Tapping a beer bottle can cause the foam to bubble. Whether tapping really helps, and some experiments suggest that, in general, it probably doesn’t. In a 2019 preprint study, researchers tested 1,031 beer cans by dividing them into four groups: shaken and tapped, shaken and unpopped, unshaken and tapped, and unshaken and unpopped. The researchers found no statistically significant differences in the amount of beer lost between capped and unpopped cans, regardless of whether they had been shaken. conclusion that tapping “does not prevent beer loss” and that the practice is not supported by their observations. That does not necessarily resolve the soft drink issue, but it does imply that tapping is not an effective method. “Beer and soft drinks differ in composition and foaming behavior, but the study provides relevant experimental evidence that tapping. “It’s not a proven solution,” Kit Yam, a food scientist at Rutgers University, told LiveScience in an email. How can you stop a soda can from bubbling? If hitting isn’t the answer, time probably is. Letting a shaken can sit upright for several minutes gives the bubbles time to dissolve or rise to the air pocket at the top of the can. Keeping the drink cold can also help, because carbon dioxide dissolves more easily at lower temperatures. “Place the can that you accidentally dropped or hit in the refrigerator for half an hour and in the meantime open another one!” said Rodríguez Rodríguez. If you don’t have another can or don’t want to wait, Rodríguez Rodríguez suggested another option: open the can slowly. “This way the gas can escape, but I only leave a small slit for the foam to come out,” he explained. “Then, when you hear that the gas is no longer escaping, you can safely open the can completely.” You can use the same process to reduce the amount of foam that spills out when pouring a carbonated drink into a glass. “If you pour it slowly,” Zenit said, “then it reduces this agitation.”
