Bubbles in Space

[sqljunkey]

If I compressed this ball of water, would the bubbles inside continue to merge until they become one big bubble?

 

[sqljunkey]

I guess I found the Ostwald Ripening concept, and it seems to indicate that if you increase the pressure of the total system the process would speed up. I guess the last thing is to figure out if microgravity has any effect.

 

[Baluncore]

If I compressed this ball of water, would the bubbles inside continue to merge until they become one big bubble?

Yes.

You cannot compress the ball of water unless it contains bubbles of a gas, it is then the bubbles you are compressing, not the water.

Microgravity is not a vacuum. Assume the external atmospheric confining pressure in the lab was 1 atm, then imagine doing the experiment at 2 atm, or 10 atm. The bubbles would simply contain higher density CO₂. The mass of gas produced would be the same, but the total volume generated would be proportionally less.

At higher atmospheric confining pressure, the bubbles would be smaller, so the distance between the bubbles would be greater. They are not going to merge as quickly as they would at a lower confining pressures.

It is counterintuitive, but like a balloon, the pressure inside the ball of water, due to surface tension, will fall as the ball becomes larger. As more gas is evolved within the bubble, the bubble becomes larger, so the internal pressure becomes less. The same is true of the internal bubbles, smaller bubbles contain higher pressure gas due to surface tension.

When two smaller bubbles merge, the gas pressure is reduced, so the total volume is increased, and the ball of water becomes larger with less external pressure due to surface tension, but the same external confining pressure due to the atmosphere.