Erin and Neva asked:
Does tapping a drink can to stop it exploding work? Or is it a myth?
It does certainly have an effect. Or it can have an effect. I havenít got it to work 100% but itís supposed to help. The idea is that if you have shaken up a can, the reason why it explodes is thereís lots of little bubbles of carbon dioxide in the liquid already. That gives the dissolved gas lots of nucleation sites - places to start bubbles, and they can get bigger very, very quickly. Because these bubbles start under the liquid, it all explodes and forms a foam. If you tap it, the idea is you dislodge the ones which are stuck around the bottom and along the sides to get fewer bubbles in there at the bottom, so it makes the foam much more slowly and it doesnít make a mess.
Erin asked the Naked Scientists: I hope that the Naked Scientists can burst this bubble...† I have heard that carbon dioxide bubbles cling to the sides of a soda can, and that the release of pressure is what causes soda to fizz up when you pop the top... the carbon dioxide rushing to the lower pressure air outside. So, does tapping the lid of a soda can before you open it dislodge the bubbles and prevent it from foaming over? Or is that simply a bunch of hot air? What do you think? ErinFromTexas, Fri, 2nd Oct 2009
This was recently discussed, take a look here: http://www.thenakedscientists.com/forum/index.php?topic=25481.0 Don_1, Fri, 2nd Oct 2009
Hmm - I'll see why this is a duplicated question... BRValsler, Fri, 2nd Oct 2009