This is a neat question that I have not come across before, so everything that follows is based only on my thinking this through for a short time (so I could be way off on this!) I agree that the pressure "should" increase when the bubble rises (and we saw that it really did) but I don't agree with your reasoning. I think that the real reason that the pressure at the bottom increases is because the volume of the bubble necessarily increases as it rises due to its pressure decreasing. If the container walls are approximated to be "magically rigid" then the water would have to occupy a smaller volume (and so its pressure goes up). If on the other hand, the water is treated as being magically incompressible, then the expansion of the bubble must cause additional flexing of the container walls (which results in a higher pressure everywhere in the container). Of course, neither the water nor the container is magically incompressible / rigid, so, I think it would be a bit of both and/or additional accommodation by the pressure sensor and flexible tubing used for it. If you replace the bubble with the perfectly rigid shell you propose at the end of the video, then I would not expect the pressure to change as the shell rises. I suggest that you repeat the experiment, but this time run a few trials in which you vary the amount of air in the “bubble”. By your reasoning, the initial size of the bubble should not affect the increase of pressure seen by your pressure sensor, but my reasoning, an initially smaller bubble should lead to a smaller pressure increase.
This is a neat question that I have not come across before, so everything that follows is based only on my thinking this through for a short time (so I could be way off on this!) I agree that the pressure "should" increase when the bubble rises (and we saw that it really did) but I don't agree with your reasoning. I think that the real reason that the pressure at the bottom increases is because the volume of the bubble necessarily increases as it rises due to its pressure decreasing. If the container walls are approximated to be "magically rigid" then the water would have to occupy a smaller volume (and so its pressure goes up). If on the other hand, the water is treated as being magically incompressible, then the expansion of the bubble must cause additional flexing of the container walls (which results in a higher pressure everywhere in the container). Of course, neither the water nor the container is magically incompressible / rigid, so, I think it would be a bit of both and/or additional accommodation by the pressure sensor and flexible tubing used for it. If you replace the bubble with the perfectly rigid shell you propose at the end of the video, then I would not expect the pressure to change as the shell rises.
I suggest that you repeat the experiment, but this time run a few trials in which you vary the amount of air in the “bubble”. By your reasoning, the initial size of the bubble should not affect the increase of pressure seen by your pressure sensor, but my reasoning, an initially smaller bubble should lead to a smaller pressure increase.
Thanks for the analysis! We're always looking for new ways to explore this phenomenon.
@@getaclass_physics That's great - I look forward to hearing about any updates on this.
Thanku this was intresting
I disagree, there will be no change in pressure at any point
And what do you think about the demonstrated experiment?