What the title says. Pop means soda btw.
In: 1560
It’s not a myth, and it actually works best when you tap the sides! When a soda is shaken, lots of tiny air bubbles are formed by the tiny bit of air in the top of the can. These bubbles serve as nucleation sites for the CO2 to come out of solution from being dissolved in the soda. These nucleation points make the CO2 come out of solution far, far faster than it would otherwise be able to do! When you tap the sides of the can, you dislodge the air bubbles and the float to the top and pop, so they can’t help the CO2 come out.
Nucleation sites are important for many chemical and physical reactions, including raindrops forming, water boiling, and crystal formation. All require a nucleation site in order to happen!
Edit: So, I did some digging after posting my comment, and [this video](https://youtu.be/r6tLeYJQS58) seems to indicate that tapping itself has no effect, but the time delay from the tapping is what does the trick.
The explanation which makes the most sense to me is this: cans have bubbles clinging to the side, tapping the can encourages them to the top. The closed can is under pressure. Since liquid is fairly incompressible, the effects of that pressure makes the bubbles small. When you open the can, the pressure drops, so the bubbles expand. If they are at the sides, they push the contents out of the way, where it goes out the only place it can go, the opening. If the gas under pressure is instead at the top of the can, it has no liquid to push ahead of itself, so just gas come out.
It’s 80% myth based on 20% plausible but irrelevant science, as all good myths usually are.
The premise is that small bubbles clinging to the side serve as nucleation points – nucleation being a process by which dissolved gas is able to emerge from solution and return to a gas, a process hindered by smooth surfaces like the inside of a can.
The issue is that nucleation only has limited bearing on the rapid expansion of gas bubbles that occurs when a can is shaken, moreover, the premise relies on the notion that the bubbles dislodge when tapped, using transparent bottles you can see that only a minority of such bubbles are affected by a couple of taps. Moreover, cans already have plenty of nucleation sites, especially when talking about carbonated alcoholic drinks or sugary drinks.
Am I allowed to ask follow up questions? I’ve always tapped my beer cans too. It made sense to me since they are also carbonated. But recently a friend made fun on me and said that is only a thing for soda. So does it work for beer cans too?
It depends on if there are bubbles clinging to the inside of the can(those bubbles can be caused by an increase in temperature). If so, tapping can dislodge them so they don’t act as nucleation sites.
If you’re talking about doing it between shaking a can and opening it, that’s more of a myth, what matters then is just waiting for the suspended bubbles to rise to the surface before opening it. Just waiting for a minute before opening it will be more effective.
Myth! There’s actually a [good mythical morning episode](https://youtu.be/944cu1HNWn8) where they test this out.
Like, they aren’t an incredibly reliable scientific source lol. BUT! They did a bunch of experiments and the only thing that actually made soda fizz less was waiting 30 seconds. And the myth that tapping helps is likely because while you are tapping you’re waiting to open the soda so it calms down regardless .
My assumption is that the gas always wants to be on top. And for reasons explained in other posts it’ll get stuck to the sides when shaken up. So if you just give it a minute for the gas to reorient itself it’ll go from the sides to the top again.
My wife always taps the top of her Coke cans before opening.
I never tap the top of my beer cans before opening.
I don’t think tapping on the top of the can does a damn thing. Neither of us have had cans explode on us unless they were violently dropped just before opening.
it’s a myth. What really happens is, as you tap the can, you’re basically giving the fizz time to settle down. You get identical results if you just wait and do nothing special with your can. You can prove this with a simple experiment with two cans more or less identically shaken. Tap one, and don’t tap the other, they’ll both behave the same when they’re opened.
Basically when you shake the soda it increase the surface area, and the amount of bubbles that leave the pressurized soda is dependent on how much surface area there is.
So, tapping it helps get the trapped bits of gas under the surface back to the top, reducing the surface area exposed to air.
The same thing that makes shaken soda explode is also the same thing that causes mentos to really fizz. Loads of surface area
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