Behavior of foam: floating vs. submerged

[Loren Booda]

Consider a cylindrical glass containing a column of foam. How do the characteristics (e.g. size, geometry, surface width, air pressure, etc.) of the bubbles near the top differ from those near the bottom?

 

[Andy Resnick]

Is the foam rigid or pliable? It is closed or open cell foam?

"Foams" are a class of materials, not a specific type of material.

http://www.amazon.com/dp/0198510977/?tag=pfamazon01-20

 

[Loren Booda]

Andy,

Thanks for the specification. I was thinking about a foam of soap bubbles. Thus, I believe them pliable and closed cell.

The book you refer to is a bit pricey and extensive for my own needs here on PF, but I appreciate your recommendation in general.

 

[Loren Booda]

I am under the impression that a column of soap bubbles compresses somewhat like the atmosphere does, exponential in character, but more visualizable.

The bubbles might form more complex geometry while progressing down the column -- more spherical near the top and more asymmetric near the bottom.

Also, bubble surface width on average would increase with increasing depth, to the extreme where there would be more soap volume than air volume.

Any contributions?

 

[Andy Resnick]

I'm not sure what kind of general statements can be made- the liquid will drain as well, so the whole system is quite dynamic.

http://www.physics.emory.edu/~weeks/lab/foam.html

Note the bubbles at bottom are much more spherical than the ones on top (due to drainage).

 

[Loren Booda]

Inspiring images and videos%

I wonder if a soap bubble has a limit for the number of neighboring bubbles.

What would be the effect of a sound wave passing through a medium of soap bubbles?

What is the minimum viscosity for a medium of soap bubbles?