Paris student finds solution to age-old physical problem of "stuck bubble"

A graduate of the École Polytechnique de Lausanne and now a student at the Ecole Polytechnique in Paris, Vassim Dhauadi proposed a method that helped find a solution to a problem that dates back almost a century. We are talking about the phenomenon of a "stuck bubble", when, contrary to the known physical principles, an air bubble in a very thin tube does not move from its place. The student proved that there is movement in this case - it's just incredibly slow.

The problem of the stuck bubble therefore got its name, which is (more precisely, it was) one of the unsolved problems. Usually, bubbles in the liquid form at the walls of the container, where the water comes into contact with another medium. Depending on the conditions of formation - for example, heating during boiling - the gas bubble receives a certain amount of energy. Further, two situations are possible - if the amount of energy is greater than the surface tension force, which "attracts" the bubble to the vessel wall, then it floats up. And if it is less, it remains where it was formed.

In a very thin tube, several millimeters in diameter, even if you transfer enough energy to the bubble, it still does not move. It is easy to see that it blocks the tube, as it were, but the space for the liquid still remains. Dhauadi wanted to accurately measure this distance, and at the same time the thickness of the film surrounding the bubble, for which he suggested that the head of the laboratory use a laser.

While irradiating the bubble and measuring the parameters of the reflected light, the researchers noticed dynamic errors. They increased the measurement accuracy and saw that the position of the film and the bubble itself were changing - it was moving. Only very, very slowly, because I have to overcome the force of attraction of the film, which literally clings to the walls of the tube around the entire bubble, and not on one side, as in a wide container. Because of this, the difference in the opposing forces is so negligible that it is almost impossible to notice it - but the accuracy of modern laser instruments made it possible to do this.