Let me try to explain it in a way you might understand...
Tapping on the top of a carbonated beverage can (or bottle) before opening it may help prevent the drink from exploding out of the can upon opening (although it might not be sufficient!). Sparkling or carbonated beverages contain carbon dioxide gas that is dissolved in the liquid by pressurizing the contents of the can. When the can is opened, the mixture depressurizes and the carbon dioxide comes out of solution, escaping as carbon dioxide gas. If there is liquid between the gas bubble and the outside of the can, then some of the liquid may be pushed out of the can with the bubble. The pressure gradient when the can is opened is greatest near the opening and the carbon dioxide at the top of the can escapes first.
If the can has been shaken, then the pressure differential inside the can during shaking will force some of the carbon dioxide out of solution to form bubbles. Some bubbles float to the top and some stick to the sides and bottom of the can. Given sufficient time, equilibrium will be achieved and the carbon dioxide will dissolve back into the beverage. If the can is opened immediately after shaking, it is likely that the beverage will spray all over the place, since some liquid from all parts of the can will be pushed ahead of escaping gas and out the can (hey, bubbles float to the top and these bubbles are under pressure too!). When the can is tapped before opening, bubbles adhering to the sides and bottom of the can may be jarred free. Assuming the can is upright, the bubbles, being lighter than the liquid, will float to the top of the can. Then when the can is opened, the bubbles are already near the opening, so they don't push through the beverage on their way out.
( Monty Boyce, My cheese game is strong, Fri 26 Nov 2010, 16:44, 2 replies, latest was 15 years ago)

Theoretically, there is nothing wrong with this explanation
other than the fact that in reality it is utter bollocks.
(Bazongaloid, Fri 26 Nov 2010, 16:45, Reply)

how was that explaining it in a way that I might understand? Needs moar Kitty words.
also you totally copied and pasted that.
( Kitty v1.0 desperately naive, Fri 26 Nov 2010, 16:52, Reply)

shake can leave bad gas on sides of can.
open can gas go boom. Spray kitty with sticky liquid.

Tap can make bad gas float to top of can.

Open can gas go boom but no sticky liquid cover kitty.

Kitty sad and go wank off commuters for 3.50 a go
(Bazongaloid, Fri 26 Nov 2010, 16:56, Reply)

thanks for that end bit

( Kitty v1.0 desperately naive, Fri 26 Nov 2010, 16:57, Reply)

Here you go:
Don't tap = bubbles on sides and bottom = pushes liquid out of can
Tap = bubbles come off sides and bottom = doesn't push liquid out of can
(PenguinOfDeath is Scottish, and most likely angry, Fri 26 Nov 2010, 16:57, Reply)

I still think you could all have shoehorned the words 'nommy drink' in there

( Kitty v1.0 desperately naive, Fri 26 Nov 2010, 16:58, Reply)

And as I said, that's brilliant except it doesn't actually happen like that

(Bazongaloid, Fri 26 Nov 2010, 16:58, Reply)

Well yes, I know
But she wanted a simplification of the crap that was said by Monty, so I gave her it. She's going to continue getting covered in nommy drinks anyway, 'cause I can't be bothered explaining it.
(PenguinOfDeath is Scottish, and most likely angry, Fri 26 Nov 2010, 17:00, Reply)

I don't usually drink fizzy drinks anyway
because the bubbles hurt my thwoat.
( Kitty v1.0 desperately naive, Fri 26 Nov 2010, 17:02, Reply)

of course I did you Deacon.

( Monty Boyce, My cheese game is strong, Fri 26 Nov 2010, 17:02, Reply)

you said 'let me explain it'
when really you should have said "let me rip off someone who has taken the time to explain it"
( Kitty v1.0 desperately naive, Fri 26 Nov 2010, 17:03, Reply)

That was the joke, you blithering halfwit.


I thought of you the other day, during a conversation about sleepwalking. I have been unable to shake the term 'nomnambulist' ever since. This is neither a lie nor a joke, unfortunately.
( Monty Boyce, My cheese game is strong, Fri 26 Nov 2010, 17:04, Reply)

Surely that's someone who sleepwalks and eats yummy things at teh same time?

(Bazongaloid, Fri 26 Nov 2010, 17:12, Reply)

I'm so glad I'm not one of those sleepwalkers who goes in the fridge in the early hours
sleeping is about the only time my stomach gets to have a break
( Kitty v1.0 desperately naive, Fri 26 Nov 2010, 17:25, Reply)

hahaha
I is in ur hed, takin over ur thorts
( Kitty v1.0 desperately naive, Fri 26 Nov 2010, 17:21, Reply)