# Why doesn't a soda-pop can "overfizz" after it falls inside the dispensing machine?
**URL:** https://boards.straightdope.com/t/why-doesnt-a-soda-pop-can-overfizz-after-it-falls-inside-the-dispensing-machine/829333
**Category:** Factual Questions
**Created:** [February 11, 2019, 12:40pm UTC](https://boards.straightdope.com/t/why-doesnt-a-soda-pop-can-overfizz-after-it-falls-inside-the-dispensing-machine/829333 "2019-02-11T12:40:05Z")
**Posts on this page:** 20
**Page:** 1
### Author:  [@zamboniracer](https://boards.straightdope.com/u/zamboniracer)
#### Post date: [February 11, 2019, 12:40pm UTC](https://boards.straightdope.com/t/why-doesnt-a-soda-pop-can-overfizz-after-it-falls-inside-the-dispensing-machine/829333/1 "2019-02-11T12:40:05Z")
We all know that if you shake a soda-pop can before opening it that it will explode with liquid and make a big mess. My question is, why doesn’t that happen when you open the can when it comes out of a dispensing machine. You put your money in, select the soda pop you want, push the button, hear the can tumble down to bottom inside the machine, reach into the machine and receive the can. You can open the can right away and it doesn’t explode. Why not?
Note: I am from northern Ohio. We call soda pop, “pop”. I don’t want to discuss that here. Call it pop, soda, coke, what-have-you.
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### Author:  [@Telemark](https://boards.straightdope.com/u/Telemark)
#### Post date: [February 11, 2019, 1:51pm UTC](https://boards.straightdope.com/t/why-doesnt-a-soda-pop-can-overfizz-after-it-falls-inside-the-dispensing-machine/829333/2 "2019-02-11T13:51:43Z")
While it may sound a bit violent, I suspect the can doesn’t really tumble and fall much at all. It probably just comes down a small chute.
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### Author:  [@Emergency911](https://boards.straightdope.com/u/Emergency911)
#### Post date: [February 11, 2019, 2:41pm UTC](https://boards.straightdope.com/t/why-doesnt-a-soda-pop-can-overfizz-after-it-falls-inside-the-dispensing-machine/829333/3 "2019-02-11T14:41:27Z")
It sounds worse than what happens. Most of the noise is from all the cans above shifting down after the soda is released to you. It drops a couple of inches to a chute. Slides down the chute to the spot where you pick it up.
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### Author:  [@TRC4941](https://boards.straightdope.com/u/TRC4941)
#### Post date: [February 11, 2019, 3:22pm UTC](https://boards.straightdope.com/t/why-doesnt-a-soda-pop-can-overfizz-after-it-falls-inside-the-dispensing-machine/829333/4 "2019-02-11T15:22:35Z")
I’ve never noticed it happening with pop in cans either. But…when I buy a diet Coke in a plastic bottle from a machine, I always twist open the top very slowly to let some of the air out because it will foam up. It doesn’t shoot all over, but it will foam over the neck of the bottle sometimes.
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### Author:  [@bardos](https://boards.straightdope.com/u/bardos)
#### Post date: [February 11, 2019, 5:05pm UTC](https://boards.straightdope.com/t/why-doesnt-a-soda-pop-can-overfizz-after-it-falls-inside-the-dispensing-machine/829333/5 "2019-02-11T17:05:41Z")
Still trying to get my arm out
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### Author:  [@Pixel\_Dent](https://boards.straightdope.com/u/Pixel_Dent)
#### Post date: [February 11, 2019, 5:39pm UTC](https://boards.straightdope.com/t/why-doesnt-a-soda-pop-can-overfizz-after-it-falls-inside-the-dispensing-machine/829333/6 "2019-02-11T17:39:42Z")
I suspect part of it is even after shaking a can of soda it returns to its at rest state very quickly. There’s a Penn & Teller trick in one of their books where they transfer the carbonation from one can to another. You furiously shake one can then put it down and say a brief magic spell over it to transfer the explosion to the other can. Open the shaken can and it doesn’t explode. Open the unshaken can which does explode.
The only trick at work here is that with current can designs it only takes about 15 seconds for a can to “settle down” and not explode after you shake it. (The second can explodes because you squeeze it as you open it).
And that’s with a can that’s been dramatically shaken. One that simply falls probably settles in seconds.
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### Author:  [@muldoonthief](https://boards.straightdope.com/u/muldoonthief)
#### Post date: [February 11, 2019, 5:54pm UTC](https://boards.straightdope.com/t/why-doesnt-a-soda-pop-can-overfizz-after-it-falls-inside-the-dispensing-machine/829333/7 "2019-02-11T17:54:21Z")
> [@bardos](#):
>
> Still trying to get my arm out
You have to [let go of the can](https://www.youtube.com/watch?v=w5o3PFtCLoo).
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### Author:  [@OldGuy](https://boards.straightdope.com/u/OldGuy)
#### Post date: [February 11, 2019, 5:59pm UTC](https://boards.straightdope.com/t/why-doesnt-a-soda-pop-can-overfizz-after-it-falls-inside-the-dispensing-machine/829333/8 "2019-02-11T17:59:01Z")
> [@Pixel\_Dent](#):
>
> The only trick at work here is that with current can designs it only takes about 15 seconds for a can to “settle down” and not explode after you shake it. (The second can explodes because you squeeze it as you open it).
I can see squeezing the can would shoot out liquid, but that looks quite different from a soda that’s foaming out.
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### Author:  [@Darren\_Garrison](https://boards.straightdope.com/u/Darren_Garrison)
#### Post date: [February 11, 2019, 6:24pm UTC](https://boards.straightdope.com/t/why-doesnt-a-soda-pop-can-overfizz-after-it-falls-inside-the-dispensing-machine/829333/9 "2019-02-11T18:24:16Z")
> [@zamboniracer](#):
>
> Note: I am from northern Ohio. We call soda pop, “pop”. I don’t want to discuss that here. Call it pop, soda, coke, what-have-you.
Where I come from [we call it “Coke Zero.”](http://boards.straightdope.com/sdmb/xkcd.com/210)
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### Author:  [@dtilque](https://boards.straightdope.com/u/dtilque)
#### Post date: [February 11, 2019, 6:41pm UTC](https://boards.straightdope.com/t/why-doesnt-a-soda-pop-can-overfizz-after-it-falls-inside-the-dispensing-machine/829333/10 "2019-02-11T18:41:30Z")
> [@Darren\_Garrison](#):
>
> Where I come from [we call it “Coke Zero.”](http://boards.straightdope.com/sdmb/xkcd.com/210)
Broken link, there. Try [this one](https://xkcd.com/2108/)
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### Author:  [@Enola\_Gay](https://boards.straightdope.com/u/Enola_Gay)
#### Post date: [February 11, 2019, 7:25pm UTC](https://boards.straightdope.com/t/why-doesnt-a-soda-pop-can-overfizz-after-it-falls-inside-the-dispensing-machine/829333/11 "2019-02-11T19:25:54Z")
I’ve sometimes opened them after they fell from the chute & while they didn’t explode, some liquid did bubble up and foam out of the top.
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### Author:  [@Dana\_Scully](https://boards.straightdope.com/u/Dana_Scully)
#### Post date: [February 11, 2019, 10:19pm UTC](https://boards.straightdope.com/t/why-doesnt-a-soda-pop-can-overfizz-after-it-falls-inside-the-dispensing-machine/829333/12 "2019-02-11T22:19:25Z")
> [@bardos](#):
>
> Still trying to get my arm out
😉
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### Author:  [@BigT](https://boards.straightdope.com/u/BigT)
#### Post date: [February 13, 2019, 1:36pm UTC](https://boards.straightdope.com/t/why-doesnt-a-soda-pop-can-overfizz-after-it-falls-inside-the-dispensing-machine/829333/13 "2019-02-13T13:36:12Z")
> [@Darren\_Garrison](#):
>
> Where I come from [we call it “Coke Zero.”](http://boards.straightdope.com/sdmb/xkcd.com/210)
Sorry, but XKCD hasn’t become a part of the Strait Dope Message Board. Maybe someday.
Oh, and yeah, I’d assume it has time to settle back down before you open it.
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### Author:  [@Colophon](https://boards.straightdope.com/u/Colophon)
#### Post date: [February 13, 2019, 2:00pm UTC](https://boards.straightdope.com/t/why-doesnt-a-soda-pop-can-overfizz-after-it-falls-inside-the-dispensing-machine/829333/14 "2019-02-13T14:00:38Z")
> [@Emergency911](#):
>
> It sounds worse than what happens. Most of the noise is from all the cans above shifting down after the soda is released to you. It drops a couple of inches to a chute. Slides down the chute to the spot where you pick it up.
Vending machines vary. The one in my office just pushes the cans off a kind of rack, via moving prongs, so they drop between one and two feet into the tray. The cans still don’t seem to fizz up when opened.
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### Author:  [@aceplace57](https://boards.straightdope.com/u/aceplace57)
#### Post date: [February 13, 2019, 2:56pm UTC](https://boards.straightdope.com/t/why-doesnt-a-soda-pop-can-overfizz-after-it-falls-inside-the-dispensing-machine/829333/15 "2019-02-13T14:56:22Z")
I’ve had soda bottles fizz up straight from the machine.
Cans don’t seem to do it.
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### Author:  [@uncle\_squeegee](https://boards.straightdope.com/u/uncle_squeegee)
#### Post date: [February 13, 2019, 11:47pm UTC](https://boards.straightdope.com/t/why-doesnt-a-soda-pop-can-overfizz-after-it-falls-inside-the-dispensing-machine/829333/16 "2019-02-13T23:47:45Z")
I agree with Big T. It doesn’t take that long for a shaken can of soda to settle down. By the time you reach down, grab it, and take it to your lunch table, the contents have settled.
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### Author:  [@Dr.Strangelove](https://boards.straightdope.com/u/Dr.Strangelove)
#### Post date: [February 14, 2019, 12:56am UTC](https://boards.straightdope.com/t/why-doesnt-a-soda-pop-can-overfizz-after-it-falls-inside-the-dispensing-machine/829333/17 "2019-02-14T00:56:29Z")
The can is also cold when it first comes out of the machine. CO2 dissolves better into cold water. Increasing the temperature, even just by a few degrees, is enough to bring some of the gas out of solution once the pressure is released. But a small thump when the can is at its coldest point isn’t going to do much.
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### Author:  [@zamboniracer](https://boards.straightdope.com/u/zamboniracer)
#### Post date: [February 23, 2019, 11:33pm UTC](https://boards.straightdope.com/t/why-doesnt-a-soda-pop-can-overfizz-after-it-falls-inside-the-dispensing-machine/829333/18 "2019-02-23T23:33:40Z")
> [@bardos](#):
>
> Still trying to get my arm out
I appreciate the effort. Science needs people like you. 😉
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### Author:  [@jasg](https://boards.straightdope.com/u/jasg)
#### Post date: [February 24, 2019, 2:15am UTC](https://boards.straightdope.com/t/why-doesnt-a-soda-pop-can-overfizz-after-it-falls-inside-the-dispensing-machine/829333/19 "2019-02-24T02:15:43Z")
> [@bardos](#):
>
> Still trying to get my arm out
That’s easy to deal with. I’m still pinned under the toppled coke machine…
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### Author:  [@albino\_manatee](https://boards.straightdope.com/u/albino_manatee)
#### Post date: [February 24, 2019, 11:41am UTC](https://boards.straightdope.com/t/why-doesnt-a-soda-pop-can-overfizz-after-it-falls-inside-the-dispensing-machine/829333/20 "2019-02-24T11:41:24Z")
happened often enough in the past for me … about 1 outta’ 7 would have the sustained energy to _‘fizz’_. i then learned to _‘snap’_ the can once or twice with the fingernail of my index-finger … and the bubbles which had attached themselves to the inside wall of the can would dissipate … and there’d be no _‘fizz’_. have never had one problem since.
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