Get the Popular Science daily newsletter💡 Breakthroughs, discoveries, and DIY tips sent six days a week. Picture this: You’re at a picnic on a hot day and grab a cold Coke out of the cooler. It’s wet, you drop it, but think “eh, it’s fine.” You pop the can open and SPLASH—there’s soda all over white shirt. Upon cracking the tab open, the CO2 gas bubbles push the liquid out with a surge. By strategically tapping the can in four key places, you can move those gas bubbles back where they belong.