Variations in bubble persistance

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SUMMARY

The discussion centers on the persistence of bubbles formed in a solution of ferrous chloride (Fe(II)Cl), water, and hydrochloric acid within a one-gallon airtight jug. Various bubble types—small, medium, large, and foam—were observed, with notable changes in color and persistence over time. Initially, the bubbles were yellow-green and lasted up to a minute, but as the experiment progressed, the persistence decreased, leading to larger bubbles that collapsed quickly. Eventually, a fine persistent foam formed, and the color shifted to a lightish darkish orange-brown indicative of Fe(III)Cl.

PREREQUISITES
  • Understanding of chemical reactions involving ferrous chloride (Fe(II)Cl)
  • Basic knowledge of fluid dynamics and bubble formation
  • Familiarity with color changes in chemical solutions
  • Experience with experimental setups in a laboratory environment
NEXT STEPS
  • Research the effects of pressure on bubble persistence in chemical solutions
  • Explore the chemistry of ferrous chloride and its transformations
  • Investigate fluid dynamics principles related to bubble formation and collapse
  • Learn about the properties and behaviors of foams in chemical reactions
USEFUL FOR

Chemists, materials scientists, and anyone interested in the dynamics of bubble formation and persistence in chemical solutions.

_Anthony_
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The apparatus consisted of a one gallon air tight clear plastic jug one quarter filled with ferrous chloride (uh, Fe(II)Cl ?), water and sufficient hydrochloric acid to complete the transformation. The remaining space was filled with oxygen at atmospheric pressure. When triggered a mechanism shook the jug for two seconds. The trigger could be set to repeat.

I recorded* four bubble types; small, medium, large and foam ignoring the subtle changes in shape, most notably wall thickness, during the course of the experiment. I also used various colored red laser pointers to evaluate changes in color, but I eye balled it.

Observation

At first the solution was a dirty green. The bubbles yellow green in color, foamy, and persistent. Lasting upwards to a minute. The foam disintegrates quickly leaving piles of small bubble and more and more mediums. The destruction of the assembly slows as it progresses.

After thirty seconds of shaking the bottle was substantially "sucked in"^. Oxygen was added to compensate. This was repeated slowing to every few minutes over the next half hour. All the while the persistence of the bubbles fell until no significant foam formed but rather mostly large bubbles collapsing quickly to short lived small and medium ones. The surface would clear within two seconds. The bubbles had turned bright yellow with little trace of green then just yellow then yellow with a trace of brown. It was noted that persistence was unchanged by the equalization of pressure. They lasted just as long and looked the same but there's a scribble "tiny bit greener?"

The absence of persistent bubbles persisted for half an hour then slowly the persistence grew. The color deepened and the yellowish brown adding a tinge of orange.

Over the next half hour a fine persistent foam formed on the surface encircling mostly medium and a few large bubbles floated in islands. The rest of the surface would suddenly collapse a bit like a single bubble bursting leaving those seemingly foam stabilize formations. The color became browner.

Over the next hour the persistence grew as did the size of the bubbles. A botryoidal surface formed and was slow to dissipate. Even after its collapse bubbles would continue clinging to the surface lasting well over a minute. The color became the unmistakable lightish darkish orange brown of (OK uh) Fe(III)Cl. Love that color. There's something enticing about it, like gold.

So there are many different fields represented there and asking leading questions tends to limit thinking. I guess I could just write, "explain all the observed phenomena" and hope for the best. I think that would take more than an hour. Maybe just explain a few. Obviously I have some idea of what's going on, I've researched, but I'm no expert in fluidity or how a thin wall breaking can alter chemistry and trigger a cascade. I'd like to not get called on a glaring mistake in understanding.

Anthony
*Bits of paper stuffed between the pages of a note book along with folded sheets of scribbles I added later to remind myself.

^Yeah yeah, poetic license. The pull of gravity makes no sense either.
 
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Clarification. I didn't mean to imply that the large bubbles became smaller bubbles. I miswrote. It seems a little like that but of course the other bubbles were already present.

And I just want my mentor to know, it took all my doing to not title the thread;
"Bubbles bubbles toils and troubles"
 

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