Have you ever wondered by gas bubbles in a narrow vertical tube seem stuck inside, instead of rising upwards? The phenomenon was observed nearly a century ago, but scientists have been unable to come up with a reasonable explanation for the same — until now.
The results of the research, cited by Scitech Daily were first published in the Physical Review Fluids journal. According to the report, a bachelor's student from École Polytechnique Fédérale de Lausanne (EPFL) finally managed to solve the mystery.
Wassim Dhaouadi discovered that an extremely-thin film of liquid forms around the bubble, thus not allowing it rise freely, the report revealed, adding that Dhaouadi further discovered that the bubbles are actually in transition, but are moving extremely slow.
Wassim Dhaouadi, who is a Bachelor's student at the Engineering Mechanics Soft Interfaces laboratory (EMSI) within EPFL’s School of Engineering, was not only able to view the thin film of liquid, but surprisingly, was also able to measure the bubbles and describe the properties as well, something which has not been done ever before.
According to the report, his results pointed out that contrary to popular beliefs, the bubbles were not stuck, but were actually moving up in an extremely slow pace.
The research was carried out by Dhaouadi, along with EMSI lab head John Kolinskli who made use of an optical interference method to measure the film, which they found to be only a few dozen nanometres, the report revealed.
Dhaouadi's research further found that the bubble film changes shape when heat is applied to it and returns to its original shape when the heat is removed.
Scitech cited Kolinski saying, "This discovery disproves the most recent theories that the film would drain to zero thickness."
The measurements further pointed towards the slow movement of the bubbles. According to Kolinski, the slow movement of the bubbles is due to the thin film between the bulb and tube which creates a strong resistance to flow.