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Old 02-11-2019, 07:40 AM
zamboniracer zamboniracer is offline
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Why doesn't a soda-pop can "overfizz" after it falls inside the dispensing machine?

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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Old 02-11-2019, 08:51 AM
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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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Old 02-11-2019, 09:41 AM
Emergency911 Emergency911 is offline
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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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Old 02-11-2019, 10:22 AM
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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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Old 02-11-2019, 12:05 PM
bardos bardos is offline
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Still trying to get my arm out
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Old 02-11-2019, 12:39 PM
Pixel_Dent Pixel_Dent is offline
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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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Old 02-11-2019, 12:54 PM
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muldoonthief muldoonthief is offline
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Quote:
Originally Posted by bardos View Post
Still trying to get my arm out
You have to let go of the can.
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Old 02-11-2019, 12:59 PM
OldGuy OldGuy is offline
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Originally Posted by Pixel_Dent View Post
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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Old 02-11-2019, 01:24 PM
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Darren Garrison Darren Garrison is offline
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Quote:
Originally Posted by zamboniracer View Post

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."
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Old 02-11-2019, 01:41 PM
dtilque dtilque is online now
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Quote:
Originally Posted by Darren Garrison View Post
Where I come from we call it "Coke Zero."
Broken link, there. Try this one

Last edited by dtilque; 02-11-2019 at 01:42 PM.
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Old 02-11-2019, 02:25 PM
Enola Gay Enola Gay is offline
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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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Old 02-11-2019, 05:19 PM
Dana Scully Dana Scully is offline
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Quote:
Originally Posted by bardos View Post
Still trying to get my arm out

  #13  
Old 02-13-2019, 08:36 AM
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Quote:
Originally Posted by Darren Garrison View Post
Where I come from we call it "Coke Zero."
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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Old 02-13-2019, 09:00 AM
Colophon Colophon is online now
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Quote:
Originally Posted by Emergency911 View Post
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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Old 02-13-2019, 09:56 AM
aceplace57 aceplace57 is online now
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I've had soda bottles fizz up straight from the machine.

Cans don't seem to do it.
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Old 02-13-2019, 06:47 PM
uncle squeegee uncle squeegee is offline
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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.
  #17  
Old 02-13-2019, 07:56 PM
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Dr. Strangelove Dr. Strangelove is offline
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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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