Naked Science Forum

On the Lighter Side => That CAN'T be true! => Topic started by: ErinFromTexas on 08/09/2009 21:57:01

Title: Tapping the Soda Can...
Post by: ErinFromTexas on 08/09/2009 21:57:01

I hope that the Naked Scientists can burst this bubble...  [:I]
 
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?

Thanks!!!!

Title: Tapping the Soda Can...
Post by: Don_1 on 09/09/2009 08:27:18

How strange! I actually saw someone do this just the other day. He dropped his can of fizzy pop, stood it upright, gently tapped the ring-pull a few times with his finger nail and opened it. It actually worked! I stood back, expecting to be smothered in Dr Pepper, or whatever it was, but there was no gush of sticky liquid, just the usual PHSSST that would expect.

Title: Tapping the Soda Can...
Post by: AllenG on 09/09/2009 14:37:29

I've heard of that ritual most of my life.
I don't know any of the science behind it.

Title: Tapping the Soda Can...
Post by: BenV on 09/09/2009 15:38:11

Erin's got the theory right at least - care to test it?

The problem is that the bubbles expand underneath some drink, so if you can knock them all to the surface (by tapping the top) you should find that only gas escapes.

The problem is that cans are opaque, so you can never know how bubble-free the sides are until it's too late...

Title: Tapping the Soda Can...
Post by: Nizzle on 10/09/2009 16:16:46

I've been doing this my whole life already :)

And the experiment works with a PET bottle of coke, which is transparent...