Assertion : A large soap bubble expands while a small bubble shrinks, when they are connected to each other by a capillary tube.Reason : The excess pressure inside bubble (or drop) is inversely proportional to the radius.

Since the excess pressure due to surface tension is inversely proportional to its radius, it follows that smaller the bubble, greater is the excess pressure. Thus, when the larger and the smaller bubbles are put into communication, air starts passing from the smaller into the large bubble because excess pressure inside the former is greater than inside the latter. As a result, the smaller bubble shrinks and the larger one swells.