# Bubble Detachment Dynamics

How does a gas bubble detach from a wall (say, for example, bubbles which form when water in a vessel is heated) it was sticking to?

I have an idea...

It is that when we increase the internal pressure by introducing heat into the system... the ends of the thin film (the layer formed by surface molecules) which connect to the wall, approach closer so as to try to resist the increase in the surface area due to a tendency for expansion. What actually happens in the process, it reduces the radius of curvature of the bubble in the attempt so as to increase the need for more excess pressure( $$\delta p = 2T/r$$) thereby trying to approach equilibrium in this way. Now as we go on heating up the system, the ends approach closer and closer until they join. Now if we heat it more, it cannot reduce the radius even more by approaching more close, so what happens is, it detaches... because of an obvious force imbalance...

I am not absolutely sure about the process, but it seems reasonable to me that the bubble should absolutely try to prevent expansion, thus increase in surface area (as it is not energetically favourable) and so it will try other methods to achieve equilibrium...But maybe the process is not that simple but rather complicated beyond high school level physics...😅

A help from your side will be highly appreciated...😊

Edit: You can actually see that the volume can still remain unaltered in an attempt to reduce the radius of curvature... so this does not alter the pressure...

• Are you considering a frame with or without contributions from buoyancy? If the former, what is the alignment of the wall + bubble (horizontal or vertical)? Finally, you may first consider "why" the bubble detaches (what are the net the forces on the bubble at any given set of conditions). After this, you can deduce "how" the bubble detaches (an acceleration vector arises when the forces are not balanced). – Jeffrey J Weimer Aug 1 '20 at 15:41
• O yes, here I am considering the bubbles at the bottom of the container... And perhaps I think I have not included buoyancy into my calculations... But, I think it will not create any hindrance, rather play an important role in the detachment...Due to a net buoyant force on the trapped gas, it will tend to stretch the bubble therefore increasing the tendency for the ends of the film to move closer... am I wrong? Perhaps you can explain it better...😊 – user266637 Aug 2 '20 at 3:55