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Does tapping the can stop a drink fizzing over when you open it? © iStock

Does tapping the can stop a drink fizzing over when you open it?

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Ever been attacked with a spray of soft drink when you tried to open a can? Here we discuss the best way to stop this.

Asked by: Keith Duncan, Edinburgh


When you shake a can, some carbon dioxide comes out of solution and bubbles form on the inside. Opening it causes a sudden drop in pressure that makes the bubbles grow much larger. It also triggers new bubbles to form, as carbon dioxide comes out of the solution around existing bubbles – points known as nucleation sites. The bubbles rise suddenly to the surface, and the whole frothy mess explodes out of the top.

Tapping the sides of the can before you open it might help to dislodge the bubbles, so the gas is all at the top of the can and there are fewer nucleation sites. But it's only partially effective. Leaving the can to stand for a minute works better.


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luis villazon
Luis VillazonQ&A expert

Luis trained as a zoologist, but now works as a science and technology educator. In his spare time he builds 3D-printed robots, in the hope that he will be spared when the revolution inevitably comes.


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