Post dive exertion and Soft drinks

[spectrum]

While drinking a soft drink with my lunch I day dreamed my way into a question. Short of diverting the Chiropractor thread I will ask it here.

1. It is held that post dive exertion will promote the formation of bubbles.
2. Shaking a soft drink will cause the formation of bubbles.

Are the 2 related and in any even what gas law(s) are involved?

Henry deals with temperature and I suppose agitation in a small way contributes (heat?) energy. That idea sounds weak

Boyle will explain the release when opening the soft drinnk but does not seem to explain the escalation with shaking.

Pete

 

[spectrum]

Okay... I'm part way there:
http://www.sciam.com/askexpert_question.cfm?articleID=0005A05D-38D2-1C71-84A9809EC588EF21

Is reduction in surface tension from agitation the whole answer?

 

[TSandM]

It isn't so much a reduction in surface tension as nucleation. By shaking, you create small bubbles which are the nuclei for larger ones -- Gas diffuses into the small bubbles and enlarges them. The behavior of bubbles under pressure is mathematically predictable; ones below a certain size have so much surface tension that they will collapse. Ones above a certain size will grow. The more nuclei you have, the larger absolute number of bubbles will be at the critical radius, by normal distribution. It is thought that post-dive exercise also creates small bubbles which act as nuclei.

 

[Ben_ca]

Sounds like a job for the Mythbusters Jaime used to be a dive instrutor here in San Fran... I'm sure they would get a kick out of this one... why don't you send it in

 

[Dr Deco]

Hello Spectrum:

Bubble Formation

Bubble nuclei are formed when liquids are shaken. This is a process referred to as hydrodynamic cavitation. It means that energy from motion is put into a fluid and the tiny voids called “nuclei” are formed.

These voids cannot form easily on their own because of the great surface tension of water. The cohesion of the water molecules is great and prevents creation of these microcavities at body temperature. When water boils, heat energy is added, and you can actually see the cavities, which are filled with vapor (steam).

Shaking of liquids adds mechanical energy to the system and promotes the formation of numerous microbubbles. When dissolved carbon dioxide is present [as in carbonated beverages], then the microbubbles grow and are stabilized.

Tissue Bubbles

Tissue microbubbles are probably caused by a process called “viscous adhesion” (or Stephan adhesion). This occurs when two surfaces are rapidly separated and a void is momentarily created resulting in micronuclei. Exercise increases the possibiility of micronuclei formation.

Surface Tension

Surface tension only plays a role in the growth of the nuclei into microbubbles. Surface tension does not change as the bubbles grow but the inward pressure (Laplace pressure) from the surface tension decreases as the bubble radius increases.

Very tiny micronuclei have very large internal pressures. When they grow, the pressure decreases to a point where microbubbles will eventually expand. This, however, only occurs if the partial pressure of the dissolved CO2 (or nitrogen, in diving) is high enough.

Dr Deco :doctor: