Up north in Ohio, New York, etc., many oil & gas wells don't need drilling mud; the pressure deep down won't go that high, so they use pressurized air to blow the cuttings out while they drill. Sometimes a little water trickles in, but not enough to where they can't handle it: they add a little detergent to the compressed air and it picks up any water in the hole, turns it to foam, and it blows out of the wellbore easier.

Once in New York there was snow on the ground, and my little mobile lab-trailer was near the holding tank where the blown out suds were released. I was walking back to the trailer with a sample of rock cuttings to analyze, when I sensed something - looming - over my shoulder. It was a mass of white foam bubbles from the tank which had broken off in an irregularly shaped mass about 10 feet long and 4 feet thick! About scared the hell out of me; it was about to GET me! I think for an instant I saw a 10 foot snowball about to crush me. Or something.

I figured the heat of the earth had heated the foam, and on the cold day the hot foam was just barely above the ambient air in buoyancy. Not to mention that foam is a good insulator so it held the heat for a while. A big slab of foam had just broken from the top of the tank and floated free.

Now that colder temps are more likely, perhaps you could simply try some hot air bubbles. I'd start with a tub of water as hot as I could get it, detergent, whatever glycerin is right. Maybe use a pre-heat tube coil to ensure the air used is also nice and warm prior to making the bubbles. Also, H2O vapor is lighter than air in itself. It doesn't saturate the air enough to make much difference really, however. Mostly it's hot air that will lift the hot foam suds on a cold day.

Then again, you're in Cal, it seems, so it may never get cold. And I don't know if a 180 degree F. soap bubble won't pop.

I'll help you visualize what happened. A "tank" can also mean a man-made pond. They call them that in Texas, a place I spent too much time. I also have lingering regrets at working in an industry that polluted (and still does though things are a bit better as time goes by).



The "tank" was a manmade pond with banks scraped up by bulldozers. So the hot foam was shooting out of a pipe at one side and on the far side, away from where the pipe spewed it, pretty much bobbing around on warm water at ground level. It was from there that the huge "chunk" broke off straight up and drifted towards me (while my back was turned!)