# When beverage can stay-on tabs are lifted do they depressurise the can by lifting the rivet?

I understand that the inside of a carbonated aluminium beverage can is pressurised. When the tab is pulled up,a rivet is lifted. Does this cause the can to depressurise? So then the can can be pierced with less force.

Thanks.

• I haven't done the math but I believe the change in the volume of the can due to the rivet being manipulated would be infinitesimal when it comes to changing the pressure of the can. – Dopeybob435 Oct 5 '16 at 18:27
• @Dopeybob435 you're probably right, but it's not the can's $\Delta$ volume but rather the $\Delta$ volume of gas above the fluid which matters. – Carl Witthoft Oct 6 '16 at 13:09
• Wouldn't the pressure of the gas in the can and the fluid in the can be the same? As the volume in the top of the can changes, the pressure throughout will change accordingly. – Dopeybob435 Oct 12 '16 at 13:14

## 1 Answer

Yes. You are correct. The can is first depressurized as the rivet is lifted allowing the lever action of the tab to pop open the scored can opening

Watch this short video showing this is detail: https://youtu.be/ekv0kprA3AY

• My interpretation is different from yours. The presenter says quite clearly that in the first phase, the internal pressure aids in the lever action, not that the lever causes depressurization. – Carl Witthoft Oct 6 '16 at 13:08