How much pressure in a bottle of Coke?

[scoobydrew]

OK here is one that I have been wandering about but for no particular reason.

You may have heard the analogy of the bottle of coke used as a mataphore to describe the effect of pressure decreasing rapidly causing excess bubbles to form in order to describe the effect of ascending too quickly and causing DCI/DCS

Basically take the lid off slowly (ascend slowly) and the bubbles have a chance to dissipate as opposed to fizzing over (you dont get bent).

So with that as the case, at what minimum depth could you open a bottle of coke (upside down I guess) and the bubbles remain pressurized?

 

[Doc Harry]

Yikes! We'll have to ask Mr. Wizard to answer that one!

 

[DevonDiver]

This website lists some different results and studies: Pressure in a Can of Soda

Obviously, the pressure is dependant on temperature and CO2 content, but the results seem to be between the 30-50psi range.

Each type of soda drink contains a different amount of carbon dioxide, and thus has varying amounts of pressure. On average, the 12 ounce soda cans sold in the US tend to have a pressure of roughly 120 kPa when canned at 4 °C, and 250 kPa when stored at 20 °C.

Specifically, a refrigerated can of 7UP® contains 210 kPa of pressure. On the other hand, Pepsi-Cola® contains 276 kPa at approximately 16 °C. Lastly, a can of Coca-Cola Classic® at 34 °C has an internal pressure of approximately 380 kPa. These numbers came from employees of the soft drink companies themselves.

(1 atm = 101.3 kPa = 14.7 psi)

So.... somewhere around 2-3atm of depth depending on the drink and temperature. Open a coke at 30-40m and it shouldn't be fizzy.

 

[myscubastory.com]

Good question actually! I bet there's some maths behind that one! Try taking a tomato down to 20 meters on your next dive! It will turn into a tiny purple ball like a grape NO JOKE - then turns back into a tomato

 

[Charlie99]

Take the Coke ice diving. Then the pressure will be very low.

The solubility of CO2 in water doubles when going from 20C down to 0C.
0.17g CO2 per 100g H2O at 20C up to 0.3g/100g at 0C, 1atm.

A little over 30 years ago I did some work on detection of glass chips inside glass soda bottles (typically caused by breakage in the filling line). We would cool down the soda to a bit less than 0C, uncap it, drop in known contaminants, and then reseal. We lost very little, if any of the CO2.

 

[knotical]

...Try taking a tomato down to 20 meters on your next dive! It will turn into a tiny purple ball like a grape NO JOKE - then turns back into a tomato

You are joking of course. It will change color as water differentially absorbs various colors in the spectrum, but it will not compress, and most certainly not to anywhere near "tiny".

 

[Ed Palma]

Good question actually! I bet there's some maths behind that one! Try taking a tomato down to 20 meters on your next dive! It will turn into a tiny purple ball like a grape NO JOKE - then turns back into a tomato

Ok, for the sake of science, I'll be throwing a tomato in my pressure pot later and taking video. Although I don't see how it'll compress considering it is composed mostly of water as well...

 

[CuracaoJ]

OK, that's the cake. I'm putting a tomato in my BC pocket for next weekend. Having just learned the Capri Sun trick, I figure it's time to come up with something new.

 

[UnderSeaBumbleBee]

Ok, for the sake of science, I'll be throwing a tomato in my pressure pot later and taking video. Although I don't see how it'll compress considering it is composed mostly of water as well...

Take an orange with thick skin too. They are fun to play with under water. The are neutral and you can spin and hover them.

 

[Guba]

Actually, I HAVE done the soft drink thing, but I used Sprite. However, I was nowhere close to "30-40 m". For a video I wanted to show my physical science classes, I took the unopened Sprite to 45 feet and opened it...no bubbles. Of course, we also shot opening a Sprite on land for comparison...lots of spewing. Water temp was 70 degrees F.