Beer bottles and decompression

[Piscean]

Well, actually just beer, but I felt I had to mention at least one diving term. Dr. Deco, I know this is off topic, but you seem the most likely bloke to know the answer, I hope you don't mind me asking.

You know that trick in the bar where you slam your beer bottle on top of someone elses and theirs froths up and yours doesn't. Why is that? I was thinking it is probably the rapid acceleration of the bottom bottle down away from the beer which causes a very sudden and rapid drop in pressure at the bottom of the bottle thus leading to the growth of many nuclei which then all froth up. It doesn't happen to the top bottle because there the beer presses against the bottle so the pressure goes up.

Why I have always wondered, does it only work if the bottom bottle has not been drunk from yet? What happens when you take a swig that stops it from working any more?

Just curious...
Piscean.

P.S. Can this be related to diving in any way?

 

[MonkSeal]

Piscean once bubbled...
Can this be related to diving in any way?

It can be related with diving if your buddy do this to you after dive and your beer is bottom one.

 

[Dr Deco]

Dear Piscean:

Vibrations and Phase Changes

It is well known that shock waves can cause the formation of nuclei in liquids (in addition to explosions). That rapping on the side of a container of a liquid under stress will result in a phase change (e.g., bubble formation) was first described in 1838, more than 150 years ago. The French scientist Caignard-Latour observed that mechanical and acoustical vibrations could assist in gas bubble formation.

Bar Trick

I must admit that you have a good one here. Never having seen this done, I must therefore go on your description. Vibrations (shock waves) are no doubt the cause of the bubble production. Generally, micronuclei are present and the shock wave will simply enlarge the nucleus momentarily and allow the carbon dioxide to enter the bubble and stabilize it at a larger radius.

I do not know why the lower bottle will foam. It is possible that it is a reflection of an impulse and the upper bottle is protected because of the deceleration (and pressure pulse). It may also be that the liquid in the upper bottle is spared because one holds the bottle and not the neck thus adding a degree of damping. I would need to see this to make a better guess.

No doubt, the nature of the micronuclei is changed when the lower bottle is inverted. You say that someone cannot make it foam if it is a bottle from which someone has taken a drink. Assuming that “foam-breaking surfactants” are not introduced from one’s mouth, that would leave as an explanation an exposure of the bottom of the bottle to the air. The size-number distribution of nuclei is changed but I do not see exactly in what fashion this would affect the trick.

Conte coup Injury

When someone is given a blow to the head, there is a brain injury on the side of brain that has been hit as well as an injury to the opposite side – a “conte coup” lesion. This is the result of pressure pulses in an accelerating skull and brain. These pressures might be similar between the brain and the bottle. In fact, it has been proposed that the injury actually generates micronuclei and furthers the injury.

Naturally, for divers, nothing that generates nuclei is good. Walking, with its associated pressure impulses, might generate micronuclei in the legs.

Dr Deco :doctor:

Please note the next class in Decompression Physiology :grad:
http://wrigley.usc.edu/hyperbaric/advdeco.htm

 

[twatto]

Usually by the time you start smacking beer bottles on top of each other you're really pissed which makes the bubbles even more impressive... especially when the neck of the bottom bottle shatters... or it's not so impressive, and it's only realised when you get a shard or two of glass in your mouth..... tasty...

 

[Diver0001]

Dr Deco once bubbled...
Dear Piscean:

Vibrations and Phase Changes

It is well known that shock waves can cause the formation of nuclei in liquids (in addition to explosions). That rapping on the side of a container of a liquid under stress will result in a phase change (e.g., bubble formation) was first described in 1838, more than 150 years ago. The French scientist Caignard-Latour observed that mechanical and acoustical vibrations could assist in gas bubble formation.

Bar Trick

I must admit that you have a good one here. Never having seen this done, I must therefore go on your description. Vibrations (shock waves) are no doubt the cause of the bubble production. Generally, micronuclei are present and the shock wave will simply enlarge the nucleus momentarily and allow the carbon dioxide to enter the bubble and stabilize it at a larger radius.

I do not know why the lower bottle will foam. It is possible that it is a reflection of an impulse and the upper bottle is protected because of the deceleration (and pressure pulse). It may also be that the liquid in the upper bottle is spared because one holds the bottle and not the neck thus adding a degree of damping. I would need to see this to make a better guess.

No doubt, the nature of the micronuclei is changed when the lower bottle is inverted. You say that someone cannot make it foam if it is a bottle from which someone has taken a drink. Assuming that “foam-breaking surfactants” are not introduced from one’s mouth, that would leave as an explanation an exposure of the bottom of the bottle to the air. The size-number distribution of nuclei is changed but I do not see exactly in what fashion this would affect the trick.

Conte coup Injury

When someone is given a blow to the head, there is a brain injury on the side of brain that has been hit as well as an injury to the opposite side – a “conte coup” lesion. This is the result of pressure pulses in an accelerating skull and brain. These pressures might be similar between the brain and the bottle. In fact, it has been proposed that the injury actually generates micronuclei and furthers the injury.

Naturally, for divers, nothing that generates nuclei is good. Walking, with its associated pressure impulses, might generate micronuclei in the legs.

Dr Deco :doctor:

Please note the next class in Decompression Physiology :grad:
http://wrigley.usc.edu/hyperbaric/advdeco.htm

I've seen this done with the bottom bottle standing on the table and the top one (obviously) in the hand. I'd guess based on Dr. Deco's explanation that the hand holding the top bottle acts as a shock damper and therefore the top bottle doesn't get the full blast of vibration that the bottom one does.

R..