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For a conventional soap bubble which burst very easily, mostly due to water evaporates or run into things that corrupt the surface tension.

Would it be feasible to make a machine that keeps humidity and floating air such that the bubble is always floating and last forever ?

If not what is the bottleneck ?

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It might be possible, if the humidity were high enough. But there is a better way.

In addition to containing soap-like compounds, the bubble liquid used for making mega-bubbles contains a humectant, which is a chemical that tends strongly to absorb water out of its surroundings and hold onto it. Chief among nontoxic humectants is glycerin and other glycols. Putting a little glycerin into the bubble liquid inhibits water loss from the bubble walls and makes the bubbles last much longer than they otherwise would.

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  • $\begingroup$ thanks for the introduction of humectant! As a physical question, I guess a followup is that, is water evaporates the only factor that makes the bubble break? and also whether it's feasible to make a system that produces a stable airflow that makes the bubble floating in a certain region. I am trying to compare the floating bubble with a flaming torch since both are forms of a stable system. $\endgroup$ – yupbank Aug 6 '20 at 12:08
  • $\begingroup$ since the bubble wall consists of fluid, eventually gravity will thicken the wall at its bottom and thin it out at the top, which inevitably causes breakage. humectants slow this down by pulling water out of the air but you can't stop gravity! $\endgroup$ – niels nielsen Aug 6 '20 at 16:08
  • $\begingroup$ Can’t I put it in a machine that is constantly rotating to offset the gravity? $\endgroup$ – yupbank Aug 6 '20 at 16:09
  • $\begingroup$ i wouldn't want to be the guy who had to design that machine... $\endgroup$ – niels nielsen Aug 6 '20 at 16:11
  • $\begingroup$ I mean, a constantly rotating machine would just be a spaceship ? $\endgroup$ – yupbank Aug 6 '20 at 16:13

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