What external pressure is required to burst a soap bubble with a radius of 4 cm?

I'm looking to learn more about bubbles and I would really appreciate some help with this. So, I'm doing this practice problem. :)

I understand that you might require the surface tension variable. I'm still super new to this stuff.

Edit: Original title referred to atmospheric pressure, but I've since learned that this is a constant value that represents pressure at sea level.

  • $\begingroup$ Please note that we don't answer homework or worked example type questions. Please read How do I ask homework questions on Physics Stack Exchange? and Are check-my-work questions on-topic? for "check my work" problems. $\endgroup$
    – Yashas
    Apr 11, 2017 at 15:59
  • $\begingroup$ @Yashas, correct. This isn't a homework problem, it's a practice problem that I created (poorly). I wasn't sure what tag to put :*( The appropriate tags have been added. $\endgroup$ Apr 11, 2017 at 16:01
  • $\begingroup$ Changes in ambient air pressure will change the radius. Popping requires a blemish of some sort in the soap film. $\endgroup$
    – Whit3rd
    Apr 11, 2017 at 23:54

1 Answer 1


I don't think the atmospheric pressure is the cause of bubbles popping. If you can blow a bubble in a given place then I don't think the atmosphere is the reason the bubble pops. http://www.bubbles.org/html/questions/pop.htm is a good place to go for more information on what variables cause a bubble to burst. I hope I helped!

  • $\begingroup$ Thanks for the answer! I'm glad I now know that the evaporation of water in dry air can lead to a bubble popping. The reason for this is that the water tension diminishes as the water evaporates, correct? Is it also possible that outside atmospheric pressure can pop a bubble? $\endgroup$ Apr 11, 2017 at 16:39
  • $\begingroup$ I believe they meant "what external pressure is required to burst the bubble". Atmospheric pressure is generally a single standard value, the question doesn't really make sense asking "what atmospheric pressure" would cause something to fail. $\endgroup$
    – JMac
    Apr 11, 2017 at 16:39
  • $\begingroup$ @JMac, so a bubble that forms in an atmosphere with a pressure of 20 lb/in^2 wouldn't pop, as it would require more water tension? What about if a bubble was formed in an atmosphere with our pressure (~14.7 lb/in^2), then was magically teleported to another atmosphere with 1.5x the pressure? $\endgroup$ Apr 11, 2017 at 16:42
  • $\begingroup$ @JasonProcka "Atmospheric pressure" generally refers to the standard atmospheric pressure at sea level of ~101 kPa. It's usually used as a constant value. A less ambiguous way to word it would be to talk about the internal and external pressures in the bubble. $\endgroup$
    – JMac
    Apr 11, 2017 at 16:45
  • $\begingroup$ @JMac, oh okay, I see! So what would that pressure be? $\endgroup$ Apr 11, 2017 at 16:48

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