The adjoining diagram shows three soap bubbles A, B and C prepared by blowing the capillary tube fitted with stop cocks, S1, S2 and S3. With stop cock S closed and stop cocks S1, S2 and S3 opened

Excess pressure in a soap bubble is inversely proportional to the radius of the bubble .Hence pressure in bubble A is maximum and pressure in bubble B is minimum . When S closed, and S1 , S2 , S3 opened. Both C and A will start collapsing with volume of B increasing.