Scientists answer 500-year-old Da Vinci Paradox about air bubbles movement

Two Spanish and one British researchers have successfully explained the 500-year-old paradox about the zigzag ascending of air bubbles in water, known as the ‘Leonardo Da Vinci Paradox’. This mechanism, studied and published in the PNAS journal, contributes to the understanding of particles movement that cannot be classified as either solid nor gas.

The two researchers from the Spanish University of Seville and a professor from the British University of Bristol have developed a numerical discretization technique to accurately characterize the air-water interface of the bubble. This allowed them to simulate its movement and study its stability.

According to their findings, the bubbles deviate from the straight trajectory in the water if their spherical radius exceeds 0.926 millimeters. The scientists have proposed a mechanism for the instability of the bubble trajectory in which a periodic inclination of the bubble changes its curvature, leading to a wobble in the trajectory. This instability was found to repeat in a cycle.

The results of this new study expand the knowledge about the peculiar behavior of bubbles and other objects that are hard to classify due to their intermediate between a gas and a solid. In addition to answering the mystery posed by Leonardo Da Vinci, this study proves to be useful to investigate the small imperfections in the field.